diff options
53 files changed, 2071 insertions, 120 deletions
diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst index 91b2fa456618..51982dee6c2a 100644 --- a/Documentation/x86/index.rst +++ b/Documentation/x86/index.rst @@ -26,6 +26,7 @@ x86-specific Documentation intel_txt amd-memory-encryption amd_hsmp + tdx pti mds microcode diff --git a/Documentation/x86/tdx.rst b/Documentation/x86/tdx.rst new file mode 100644 index 000000000000..b8fa4329e1a5 --- /dev/null +++ b/Documentation/x86/tdx.rst @@ -0,0 +1,218 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +Intel Trust Domain Extensions (TDX) +===================================== + +Intel's Trust Domain Extensions (TDX) protect confidential guest VMs from +the host and physical attacks by isolating the guest register state and by +encrypting the guest memory. In TDX, a special module running in a special +mode sits between the host and the guest and manages the guest/host +separation. + +Since the host cannot directly access guest registers or memory, much +normal functionality of a hypervisor must be moved into the guest. This is +implemented using a Virtualization Exception (#VE) that is handled by the +guest kernel. A #VE is handled entirely inside the guest kernel, but some +require the hypervisor to be consulted. + +TDX includes new hypercall-like mechanisms for communicating from the +guest to the hypervisor or the TDX module. + +New TDX Exceptions +================== + +TDX guests behave differently from bare-metal and traditional VMX guests. +In TDX guests, otherwise normal instructions or memory accesses can cause +#VE or #GP exceptions. + +Instructions marked with an '*' conditionally cause exceptions. The +details for these instructions are discussed below. + +Instruction-based #VE +--------------------- + +- Port I/O (INS, OUTS, IN, OUT) +- HLT +- MONITOR, MWAIT +- WBINVD, INVD +- VMCALL +- RDMSR*,WRMSR* +- CPUID* + +Instruction-based #GP +--------------------- + +- All VMX instructions: INVEPT, INVVPID, VMCLEAR, VMFUNC, VMLAUNCH, + VMPTRLD, VMPTRST, VMREAD, VMRESUME, VMWRITE, VMXOFF, VMXON +- ENCLS, ENCLU +- GETSEC +- RSM +- ENQCMD +- RDMSR*,WRMSR* + +RDMSR/WRMSR Behavior +-------------------- + +MSR access behavior falls into three categories: + +- #GP generated +- #VE generated +- "Just works" + +In general, the #GP MSRs should not be used in guests. Their use likely +indicates a bug in the guest. The guest may try to handle the #GP with a +hypercall but it is unlikely to succeed. + +The #VE MSRs are typically able to be handled by the hypervisor. Guests +can make a hypercall to the hypervisor to handle the #VE. + +The "just works" MSRs do not need any special guest handling. They might +be implemented by directly passing through the MSR to the hardware or by +trapping and handling in the TDX module. Other than possibly being slow, +these MSRs appear to function just as they would on bare metal. + +CPUID Behavior +-------------- + +For some CPUID leaves and sub-leaves, the virtualized bit fields of CPUID +return values (in guest EAX/EBX/ECX/EDX) are configurable by the +hypervisor. For such cases, the Intel TDX module architecture defines two +virtualization types: + +- Bit fields for which the hypervisor controls the value seen by the guest + TD. + +- Bit fields for which the hypervisor configures the value such that the + guest TD either sees their native value or a value of 0. For these bit + fields, the hypervisor can mask off the native values, but it can not + turn *on* values. + +A #VE is generated for CPUID leaves and sub-leaves that the TDX module does +not know how to handle. The guest kernel may ask the hypervisor for the +value with a hypercall. + +#VE on Memory Accesses +====================== + +There are essentially two classes of TDX memory: private and shared. +Private memory receives full TDX protections. Its content is protected +against access from the hypervisor. Shared memory is expected to be +shared between guest and hypervisor and does not receive full TDX +protections. + +A TD guest is in control of whether its memory accesses are treated as +private or shared. It selects the behavior with a bit in its page table +entries. This helps ensure that a guest does not place sensitive +information in shared memory, exposing it to the untrusted hypervisor. + +#VE on Shared Memory +-------------------- + +Access to shared mappings can cause a #VE. The hypervisor ultimately +controls whether a shared memory access causes a #VE, so the guest must be +careful to only reference shared pages it can safely handle a #VE. For +instance, the guest should be careful not to access shared memory in the +#VE handler before it reads the #VE info structure (TDG.VP.VEINFO.GET). + +Shared mapping content is entirely controlled by the hypervisor. The guest +should only use shared mappings for communicating with the hypervisor. +Shared mappings must never be used for sensitive memory content like kernel +stacks. A good rule of thumb is that hypervisor-shared memory should be +treated the same as memory mapped to userspace. Both the hypervisor and +userspace are completely untrusted. + +MMIO for virtual devices is implemented as shared memory. The guest must +be careful not to access device MMIO regions unless it is also prepared to +handle a #VE. + +#VE on Private Pages +-------------------- + +An access to private mappings can also cause a #VE. Since all kernel +memory is also private memory, the kernel might theoretically need to +handle a #VE on arbitrary kernel memory accesses. This is not feasible, so +TDX guests ensure that all guest memory has been "accepted" before memory +is used by the kernel. + +A modest amount of memory (typically 512M) is pre-accepted by the firmware +before the kernel runs to ensure that the kernel can start up without +being subjected to a #VE. + +The hypervisor is permitted to unilaterally move accepted pages to a +"blocked" state. However, if it does this, page access will not generate a +#VE. It will, instead, cause a "TD Exit" where the hypervisor is required +to handle the exception. + +Linux #VE handler +================= + +Just like page faults or #GP's, #VE exceptions can be either handled or be +fatal. Typically, an unhandled userspace #VE results in a SIGSEGV. +An unhandled kernel #VE results in an oops. + +Handling nested exceptions on x86 is typically nasty business. A #VE +could be interrupted by an NMI which triggers another #VE and hilarity +ensues. The TDX #VE architecture anticipated this scenario and includes a +feature to make it slightly less nasty. + +During #VE handling, the TDX module ensures that all interrupts (including +NMIs) are blocked. The block remains in place until the guest makes a +TDG.VP.VEINFO.GET TDCALL. This allows the guest to control when interrupts +or a new #VE can be delivered. + +However, the guest kernel must still be careful to avoid potential +#VE-triggering actions (discussed above) while this block is in place. +While the block is in place, any #VE is elevated to a double fault (#DF) +which is not recoverable. + +MMIO handling +============= + +In non-TDX VMs, MMIO is usually implemented by giving a guest access to a +mapping which will cause a VMEXIT on access, and then the hypervisor +emulates the access. That is not possible in TDX guests because VMEXIT +will expose the register state to the host. TDX guests don't trust the host +and can't have their state exposed to the host. + +In TDX, MMIO regions typically trigger a #VE exception in the guest. The +guest #VE handler then emulates the MMIO instruction inside the guest and +converts it into a controlled TDCALL to the host, rather than exposing +guest state to the host. + +MMIO addresses on x86 are just special physical addresses. They can +theoretically be accessed with any instruction that accesses memory. +However, the kernel instruction decoding method is limited. It is only +designed to decode instructions like those generated by io.h macros. + +MMIO access via other means (like structure overlays) may result in an +oops. + +Shared Memory Conversions +========================= + +All TDX guest memory starts out as private at boot. This memory can not +be accessed by the hypervisor. However, some kernel users like device +drivers might have a need to share data with the hypervisor. To do this, +memory must be converted between shared and private. This can be +accomplished using some existing memory encryption helpers: + + * set_memory_decrypted() converts a range of pages to shared. + * set_memory_encrypted() converts memory back to private. + +Device drivers are the primary user of shared memory, but there's no need +to touch every driver. DMA buffers and ioremap() do the conversions +automatically. + +TDX uses SWIOTLB for most DMA allocations. The SWIOTLB buffer is +converted to shared on boot. + +For coherent DMA allocation, the DMA buffer gets converted on the +allocation. Check force_dma_unencrypted() for details. + +References +========== + +TDX reference material is collected here: + +https://www.intel.com/content/www/us/en/developer/articles/technical/intel-trust-domain-extensions.html diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 4bed3abf444d..d90a33e96517 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -878,6 +878,21 @@ config ACRN_GUEST IOT with small footprint and real-time features. More details can be found in https://projectacrn.org/. +config INTEL_TDX_GUEST + bool "Intel TDX (Trust Domain Extensions) - Guest Support" + depends on X86_64 && CPU_SUP_INTEL + depends on X86_X2APIC + select ARCH_HAS_CC_PLATFORM + select X86_MEM_ENCRYPT + select X86_MCE + help + Support running as a guest under Intel TDX. Without this support, + the guest kernel can not boot or run under TDX. + TDX includes memory encryption and integrity capabilities + which protect the confidentiality and integrity of guest + memory contents and CPU state. TDX guests are protected from + some attacks from the VMM. + endif #HYPERVISOR_GUEST source "arch/x86/Kconfig.cpu" diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h index 34c9dbb6a47d..b42b91606ca8 100644 --- a/arch/x86/boot/boot.h +++ b/arch/x86/boot/boot.h @@ -26,6 +26,7 @@ #include "bitops.h" #include "ctype.h" #include "cpuflags.h" +#include "io.h" /* Useful macros */ #define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x))) @@ -35,44 +36,10 @@ extern struct boot_params boot_params; #define cpu_relax() asm volatile("rep; nop") -/* Basic port I/O */ -static inline void outb(u8 v, u16 port) -{ - asm volatile("outb %0,%1" : : "a" (v), "dN" (port)); -} -static inline u8 inb(u16 port) -{ - u8 v; - asm volatile("inb %1,%0" : "=a" (v) : "dN" (port)); - return v; -} - -static inline void outw(u16 v, u16 port) -{ - asm volatile("outw %0,%1" : : "a" (v), "dN" (port)); -} -static inline u16 inw(u16 port) -{ - u16 v; - asm volatile("inw %1,%0" : "=a" (v) : "dN" (port)); - return v; -} - -static inline void outl(u32 v, u16 port) -{ - asm volatile("outl %0,%1" : : "a" (v), "dN" (port)); -} -static inline u32 inl(u16 port) -{ - u32 v; - asm volatile("inl %1,%0" : "=a" (v) : "dN" (port)); - return v; -} - static inline void io_delay(void) { const u16 DELAY_PORT = 0x80; - asm volatile("outb %%al,%0" : : "dN" (DELAY_PORT)); + outb(0, DELAY_PORT); } /* These functions are used to reference data in other segments. */ diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index e69c3d2e0628..19e1905dcbf6 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -101,6 +101,7 @@ ifdef CONFIG_X86_64 endif vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o +vmlinux-objs-$(CONFIG_INTEL_TDX_GUEST) += $(obj)/tdx.o $(obj)/tdcall.o vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 4cd661165d4a..d33f060900d2 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -289,7 +289,7 @@ SYM_FUNC_START(startup_32) pushl %eax /* Enter paged protected Mode, activating Long Mode */ - movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */ + movl $CR0_STATE, %eax movl %eax, %cr0 /* Jump from 32bit compatibility mode into 64bit mode. */ @@ -649,12 +649,28 @@ SYM_CODE_START(trampoline_32bit_src) movl $MSR_EFER, %ecx rdmsr btsl $_EFER_LME, %eax + /* Avoid writing EFER if no change was made (for TDX guest) */ + jc 1f wrmsr - popl %edx +1: popl %edx popl %ecx +#ifdef CONFIG_X86_MCE + /* + * Preserve CR4.MCE if the kernel will enable #MC support. + * Clearing MCE may fault in some environments (that also force #MC + * support). Any machine check that occurs before #MC support is fully + * configured will crash the system regardless of the CR4.MCE value set + * here. + */ + movl %cr4, %eax + andl $X86_CR4_MCE, %eax +#else + movl $0, %eax +#endif + /* Enable PAE and LA57 (if required) paging modes */ - movl $X86_CR4_PAE, %eax + orl $X86_CR4_PAE, %eax testl %edx, %edx jz 1f orl $X86_CR4_LA57, %eax @@ -668,8 +684,9 @@ SYM_CODE_START(trampoline_32bit_src) pushl $__KERNEL_CS pushl %eax - /* Enable paging again */ - movl $(X86_CR0_PG | X86_CR0_PE), %eax + /* Enable paging again. */ + movl %cr0, %eax + btsl $X86_CR0_PG_BIT, %eax movl %eax, %cr0 lret diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index ca6820f99b40..cf690d8712f4 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -48,6 +48,8 @@ void *memmove(void *dest, const void *src, size_t n); */ struct boot_params *boot_params; +struct port_io_ops pio_ops; + memptr free_mem_ptr; memptr free_mem_end_ptr; @@ -374,6 +376,16 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, lines = boot_params->screen_info.orig_video_lines; cols = boot_params->screen_info.orig_video_cols; + init_default_io_ops(); + + /* + * Detect TDX guest environment. + * + * It has to be done before console_init() in order to use + * paravirtualized port I/O operations if needed. + */ + early_tdx_detect(); + console_init(); /* diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 4ca2857ea041..4910bf230d7b 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -22,17 +22,19 @@ #include <linux/linkage.h> #include <linux/screen_info.h> #include <linux/elf.h> -#include <linux/io.h> #include <asm/page.h> #include <asm/boot.h> #include <asm/bootparam.h> #include <asm/desc_defs.h> +#include "tdx.h" + #define BOOT_CTYPE_H #include <linux/acpi.h> #define BOOT_BOOT_H #include "../ctype.h" +#include "../io.h" #include "efi.h" diff --git a/arch/x86/boot/compressed/pgtable.h b/arch/x86/boot/compressed/pgtable.h index 6ff7e81b5628..cc9b2529a086 100644 --- a/arch/x86/boot/compressed/pgtable.h +++ b/arch/x86/boot/compressed/pgtable.h @@ -6,7 +6,7 @@ #define TRAMPOLINE_32BIT_PGTABLE_OFFSET 0 #define TRAMPOLINE_32BIT_CODE_OFFSET PAGE_SIZE -#define TRAMPOLINE_32BIT_CODE_SIZE 0x70 +#define TRAMPOLINE_32BIT_CODE_SIZE 0x80 #define TRAMPOLINE_32BIT_STACK_END TRAMPOLINE_32BIT_SIZE diff --git a/arch/x86/boot/compressed/tdcall.S b/arch/x86/boot/compressed/tdcall.S new file mode 100644 index 000000000000..46d0495e0d3a --- /dev/null +++ b/arch/x86/boot/compressed/tdcall.S @@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include "../../coco/tdx/tdcall.S" diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c new file mode 100644 index 000000000000..918a7606f53c --- /dev/null +++ b/arch/x86/boot/compressed/tdx.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "../cpuflags.h" +#include "../string.h" +#include "../io.h" +#include "error.h" + +#include <vdso/limits.h> +#include <uapi/asm/vmx.h> + +#include <asm/shared/tdx.h> + +/* Called from __tdx_hypercall() for unrecoverable failure */ +void __tdx_hypercall_failed(void) +{ + error("TDVMCALL failed. TDX module bug?"); +} + +static inline unsigned int tdx_io_in(int size, u16 port) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = EXIT_REASON_IO_INSTRUCTION, + .r12 = size, + .r13 = 0, + .r14 = port, + }; + + if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT)) + return UINT_MAX; + + return args.r11; +} + +static inline void tdx_io_out(int size, u16 port, u32 value) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = EXIT_REASON_IO_INSTRUCTION, + .r12 = size, + .r13 = 1, + .r14 = port, + .r15 = value, + }; + + __tdx_hypercall(&args, 0); +} + +static inline u8 tdx_inb(u16 port) +{ + return tdx_io_in(1, port); +} + +static inline void tdx_outb(u8 value, u16 port) +{ + tdx_io_out(1, port, value); +} + +static inline void tdx_outw(u16 value, u16 port) +{ + tdx_io_out(2, port, value); +} + +void early_tdx_detect(void) +{ + u32 eax, sig[3]; + + cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]); + + if (memcmp(TDX_IDENT, sig, sizeof(sig))) + return; + + /* Use hypercalls instead of I/O instructions */ + pio_ops.f_inb = tdx_inb; + pio_ops.f_outb = tdx_outb; + pio_ops.f_outw = tdx_outw; +} diff --git a/arch/x86/boot/compressed/tdx.h b/arch/x86/boot/compressed/tdx.h new file mode 100644 index 000000000000..9055482cd35c --- /dev/null +++ b/arch/x86/boot/compressed/tdx.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef BOOT_COMPRESSED_TDX_H +#define BOOT_COMPRESSED_TDX_H + +#include <linux/types.h> + +#ifdef CONFIG_INTEL_TDX_GUEST +void early_tdx_detect(void); +#else +static inline void early_tdx_detect(void) { }; +#endif + +#endif /* BOOT_COMPRESSED_TDX_H */ diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c index a0b75f73dc63..a83d67ec627d 100644 --- a/arch/x86/boot/cpuflags.c +++ b/arch/x86/boot/cpuflags.c @@ -71,8 +71,7 @@ int has_eflag(unsigned long mask) # define EBX_REG "=b" #endif -static inline void cpuid_count(u32 id, u32 count, - u32 *a, u32 *b, u32 *c, u32 *d) +void cpuid_count(u32 id, u32 count, u32 *a, u32 *b, u32 *c, u32 *d) { asm volatile(".ifnc %%ebx,%3 ; movl %%ebx,%3 ; .endif \n\t" "cpuid \n\t" diff --git a/arch/x86/boot/cpuflags.h b/arch/x86/boot/cpuflags.h index 2e20814d3ce3..475b8fde90f7 100644 --- a/arch/x86/boot/cpuflags.h +++ b/arch/x86/boot/cpuflags.h @@ -17,5 +17,6 @@ extern u32 cpu_vendor[3]; int has_eflag(unsigned long mask); void get_cpuflags(void); +void cpuid_count(u32 id, u32 count, u32 *a, u32 *b, u32 *c, u32 *d); #endif diff --git a/arch/x86/boot/io.h b/arch/x86/boot/io.h new file mode 100644 index 000000000000..110880907f87 --- /dev/null +++ b/arch/x86/boot/io.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef BOOT_IO_H +#define BOOT_IO_H + +#include <asm/shared/io.h> + +#undef inb +#undef inw +#undef inl +#undef outb +#undef outw +#undef outl + +struct port_io_ops { + u8 (*f_inb)(u16 port); + void (*f_outb)(u8 v, u16 port); + void (*f_outw)(u16 v, u16 port); +}; + +extern struct port_io_ops pio_ops; + +/* + * Use the normal I/O instructions by default. + * TDX guests override these to use hypercalls. + */ +static inline void init_default_io_ops(void) +{ + pio_ops.f_inb = __inb; + pio_ops.f_outb = __outb; + pio_ops.f_outw = __outw; +} + +/* + * Redirect port I/O operations via pio_ops callbacks. + * TDX guests override these callbacks with TDX-specific helpers. + */ +#define inb pio_ops.f_inb +#define outb pio_ops.f_outb +#define outw pio_ops.f_outw + +#endif diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c index e3add857c2c9..1202d4f8a390 100644 --- a/arch/x86/boot/main.c +++ b/arch/x86/boot/main.c @@ -17,6 +17,8 @@ struct boot_params boot_params __attribute__((aligned(16))); +struct port_io_ops pio_ops; + char *HEAP = _end; char *heap_end = _end; /* Default end of heap = no heap */ @@ -133,6 +135,8 @@ static void init_heap(void) void main(void) { + init_default_io_ops(); + /* First, copy the boot header into the "zeropage" */ copy_boot_params(); diff --git a/arch/x86/coco/Makefile b/arch/x86/coco/Makefile index c1ead00017a7..c816acf78b6a 100644 --- a/arch/x86/coco/Makefile +++ b/arch/x86/coco/Makefile @@ -4,3 +4,5 @@ KASAN_SANITIZE_core.o := n CFLAGS_core.o += -fno-stack-protector obj-y += core.o + +obj-$(CONFIG_INTEL_TDX_GUEST) += tdx/ diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c index dafd4881ce29..49b44f881484 100644 --- a/arch/x86/coco/core.c +++ b/arch/x86/coco/core.c @@ -18,7 +18,15 @@ static u64 cc_mask __ro_after_init; static bool intel_cc_platform_has(enum cc_attr attr) { - return false; + switch (attr) { + case CC_ATTR_GUEST_UNROLL_STRING_IO: + case CC_ATTR_HOTPLUG_DISABLED: + case CC_ATTR_GUEST_MEM_ENCRYPT: + case CC_ATTR_MEM_ENCRYPT: + return true; + default: + return false; + } } /* @@ -90,9 +98,18 @@ EXPORT_SYMBOL_GPL(cc_platform_has); u64 cc_mkenc(u64 val) { + /* + * Both AMD and Intel use a bit in the page table to indicate + * encryption status of the page. + * + * - for AMD, bit *set* means the page is encrypted + * - for Intel *clear* means encrypted. + */ switch (vendor) { case CC_VENDOR_AMD: return val | cc_mask; + case CC_VENDOR_INTEL: + return val & ~cc_mask; default: return val; } @@ -100,9 +117,12 @@ u64 cc_mkenc(u64 val) u64 cc_mkdec(u64 val) { + /* See comment in cc_mkenc() */ switch (vendor) { case CC_VENDOR_AMD: return val & ~cc_mask; + case CC_VENDOR_INTEL: + return val | cc_mask; default: return val; } diff --git a/arch/x86/coco/tdx/Makefile b/arch/x86/coco/tdx/Makefile new file mode 100644 index 000000000000..46c55998557d --- /dev/null +++ b/arch/x86/coco/tdx/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-y += tdx.o tdcall.o diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S new file mode 100644 index 000000000000..f9eb1134f22d --- /dev/null +++ b/arch/x86/coco/tdx/tdcall.S @@ -0,0 +1,205 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <asm/asm-offsets.h> +#include <asm/asm.h> +#include <asm/frame.h> +#include <asm/unwind_hints.h> + +#include <linux/linkage.h> +#include <linux/bits.h> +#include <linux/errno.h> + +#include "../../virt/vmx/tdx/tdxcall.S" + +/* + * Bitmasks of exposed registers (with VMM). + */ +#define TDX_R10 BIT(10) +#define TDX_R11 BIT(11) +#define TDX_R12 BIT(12) +#define TDX_R13 BIT(13) +#define TDX_R14 BIT(14) +#define TDX_R15 BIT(15) + +/* + * These registers are clobbered to hold arguments for each + * TDVMCALL. They are safe to expose to the VMM. + * Each bit in this mask represents a register ID. Bit field + * details can be found in TDX GHCI specification, section + * titled "TDCALL [TDG.VP.VMCALL] leaf". + */ +#define TDVMCALL_EXPOSE_REGS_MASK ( TDX_R10 | TDX_R11 | \ + TDX_R12 | TDX_R13 | \ + TDX_R14 | TDX_R15 ) + +/* + * __tdx_module_call() - Used by TDX guests to request services from + * the TDX module (does not include VMM services) using TDCALL instruction. + * + * Transforms function call register arguments into the TDCALL register ABI. + * After TDCALL operation, TDX module output is saved in @out (if it is + * provided by the user). + * + *------------------------------------------------------------------------- + * TDCALL ABI: + *------------------------------------------------------------------------- + * Input Registers: + * + * RAX - TDCALL Leaf number. + * RCX,RDX,R8-R9 - TDCALL Leaf specific input registers. + * + * Output Registers: + * + * RAX - TDCALL instruction error code. + * RCX,RDX,R8-R11 - TDCALL Leaf specific output registers. + * + *------------------------------------------------------------------------- + * + * __tdx_module_call() function ABI: + * + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @rcx (RSI) - Input parameter 1, moved to RCX + * @rdx (RDX) - Input parameter 2, moved to RDX + * @r8 (RCX) - Input parameter 3, moved to R8 + * @r9 (R8) - Input parameter 4, moved to R9 + * + * @out (R9) - struct tdx_module_output pointer + * stored temporarily in R12 (not + * shared with the TDX module). It + * can be NULL. + * + * Return status of TDCALL via RAX. + */ +SYM_FUNC_START(__tdx_module_call) + FRAME_BEGIN + TDX_MODULE_CALL host=0 + FRAME_END + RET +SYM_FUNC_END(__tdx_module_call) + +/* + * __tdx_hypercall() - Make hypercalls to a TDX VMM using TDVMCALL leaf + * of TDCALL instruction + * + * Transforms values in function call argument struct tdx_hypercall_args @args + * into the TDCALL register ABI. After TDCALL operation, VMM output is saved + * back in @args. + * + *------------------------------------------------------------------------- + * TD VMCALL ABI: + *------------------------------------------------------------------------- + * + * Input Registers: + * + * RAX - TDCALL instruction leaf number (0 - TDG.VP.VMCALL) + * RCX - BITMAP which controls which part of TD Guest GPR + * is passed as-is to the VMM and back. + * R10 - Set 0 to indicate TDCALL follows standard TDX ABI + * specification. Non zero value indicates vendor + * specific ABI. + * R11 - VMCALL sub function number + * RBX, RBP, RDI, RSI - Used to pass VMCALL sub function specific arguments. + * R8-R9, R12-R15 - Same as above. + * + * Output Registers: + * + * RAX - TDCALL instruction status (Not related to hypercall + * output). + * R10 - Hypercall output error code. + * R11-R15 - Hypercall sub function specific output values. + * + *------------------------------------------------------------------------- + * + * __tdx_hypercall() function ABI: + * + * @args (RDI) - struct tdx_hypercall_args for input and output + * @flags (RSI) - TDX_HCALL_* flags + * + * On successful completion, return the hypercall error code. + */ +SYM_FUNC_START(__tdx_hypercall) + FRAME_BEGIN + + /* Save callee-saved GPRs as mandated by the x86_64 ABI */ + push %r15 + push %r14 + push %r13 + push %r12 + + /* Mangle function call ABI into TDCALL ABI: */ + /* Set TDCALL leaf ID (TDVMCALL (0)) in RAX */ + xor %eax, %eax + + /* Copy hypercall registers from arg struct: */ + movq TDX_HYPERCALL_r10(%rdi), %r10 + movq TDX_HYPERCALL_r11(%rdi), %r11 + movq TDX_HYPERCALL_r12(%rdi), %r12 + movq TDX_HYPERCALL_r13(%rdi), %r13 + movq TDX_HYPERCALL_r14(%rdi), %r14 + movq TDX_HYPERCALL_r15(%rdi), %r15 + + movl $TDVMCALL_EXPOSE_REGS_MASK, %ecx + + /* + * For the idle loop STI needs to be called directly before the TDCALL + * that enters idle (EXIT_REASON_HLT case). STI instruction enables + * interrupts only one instruction later. If there is a window between + * STI and the instruction that emulates the HALT state, there is a + * chance for interrupts to happen in this window, which can delay the + * HLT operation indefinitely. Since this is the not the desired + * result, conditionally call STI before TDCALL. + */ + testq $TDX_HCALL_ISSUE_STI, %rsi + jz .Lskip_sti + sti +.Lskip_sti: + tdcall + + /* + * RAX==0 indicates a failure of the TDVMCALL mechanism itself and that + * something has gone horribly wrong with the TDX module. + * + * The return status of the hypercall operation is in a separate + * register (in R10). Hypercall errors are a part of normal operation + * and are handled by callers. + */ + testq %rax, %rax + jne .Lpanic + + /* TDVMCALL leaf return code is in R10 */ + movq %r10, %rax + + /* Copy hypercall result registers to arg struct if needed */ + testq $TDX_HCALL_HAS_OUTPUT, %rsi + jz .Lout + + movq %r10, TDX_HYPERCALL_r10(%rdi) + movq %r11, TDX_HYPERCALL_r11(%rdi) + movq %r12, TDX_HYPERCALL_r12(%rdi) + movq %r13, TDX_HYPERCALL_r13(%rdi) + movq %r14, TDX_HYPERCALL_r14(%rdi) + movq %r15, TDX_HYPERCALL_r15(%rdi) +.Lout: + /* + * Zero out registers exposed to the VMM to avoid speculative execution + * with VMM-controlled values. This needs to include all registers + * present in TDVMCALL_EXPOSE_REGS_MASK (except R12-R15). R12-R15 + * context will be restored. + */ + xor %r10d, %r10d + xor %r11d, %r11d + + /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ + pop %r12 + pop %r13 + pop %r14 + pop %r15 + + FRAME_END + + RET +.Lpanic: + call __tdx_hypercall_failed + /* __tdx_hypercall_failed never returns */ + REACHABLE + jmp .Lpanic +SYM_FUNC_END(__tdx_hypercall) diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c new file mode 100644 index 000000000000..03deb4d6920d --- /dev/null +++ b/arch/x86/coco/tdx/tdx.c @@ -0,0 +1,692 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2021-2022 Intel Corporation */ + +#undef pr_fmt +#define pr_fmt(fmt) "tdx: " fmt + +#include <linux/cpufeature.h> +#include <asm/coco.h> +#include <asm/tdx.h> +#include <asm/vmx.h> +#include <asm/insn.h> +#include <asm/insn-eval.h> +#include <asm/pgtable.h> + +/* TDX module Call Leaf IDs */ +#define TDX_GET_INFO 1 +#define TDX_GET_VEINFO 3 +#define TDX_ACCEPT_PAGE 6 + +/* TDX hypercall Leaf IDs */ +#define TDVMCALL_MAP_GPA 0x10001 + +/* MMIO direction */ +#define EPT_READ 0 +#define EPT_WRITE 1 + +/* Port I/O direction */ +#define PORT_READ 0 +#define PORT_WRITE 1 + +/* See Exit Qualification for I/O Instructions in VMX documentation */ +#define VE_IS_IO_IN(e) ((e) & BIT(3)) +#define VE_GET_IO_SIZE(e) (((e) & GENMASK(2, 0)) + 1) +#define VE_GET_PORT_NUM(e) ((e) >> 16) +#define VE_IS_IO_STRING(e) ((e) & BIT(4)) + +/* + * Wrapper for standard use of __tdx_hypercall with no output aside from + * return code. + */ +static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = fn, + .r12 = r12, + .r13 = r13, + .r14 = r14, + .r15 = r15, + }; + + return __tdx_hypercall(&args, 0); +} + +/* Called from __tdx_hypercall() for unrecoverable failure */ +void __tdx_hypercall_failed(void) +{ + panic("TDVMCALL failed. TDX module bug?"); +} + +/* + * The TDG.VP.VMCALL-Instruction-execution sub-functions are defined + * independently from but are currently matched 1:1 with VMX EXIT_REASONs. + * Reusing the KVM EXIT_REASON macros makes it easier to connect the host and + * guest sides of these calls. + */ +static u64 hcall_func(u64 exit_reason) +{ + return exit_reason; +} + +#ifdef CONFIG_KVM_GUEST +long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2, + unsigned long p3, unsigned long p4) +{ + struct tdx_hypercall_args args = { + .r10 = nr, + .r11 = p1, + .r12 = p2, + .r13 = p3, + .r14 = p4, + }; + + return __tdx_hypercall(&args, 0); +} +EXPORT_SYMBOL_GPL(tdx_kvm_hypercall); +#endif + +/* + * Used for TDX guests to make calls directly to the TD module. This + * should only be used for calls that have no legitimate reason to fail + * or where the kernel can not survive the call failing. + */ +static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, + struct tdx_module_output *out) +{ + if (__tdx_module_call(fn, rcx, rdx, r8, r9, out)) + panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); +} + +static u64 get_cc_mask(void) +{ + struct tdx_module_output out; + unsigned int gpa_width; + + /* + * TDINFO TDX module call is used to get the TD execution environment + * information like GPA width, number of available vcpus, debug mode + * information, etc. More details about the ABI can be found in TDX + * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL + * [TDG.VP.INFO]. + * + * The GPA width that comes out of this call is critical. TDX guests + * can not meaningfully run without it. + */ + tdx_module_call(TDX_GET_INFO, 0, 0, 0, 0, &out); + + gpa_width = out.rcx & GENMASK(5, 0); + + /* + * The highest bit of a guest physical address is the "sharing" bit. + * Set it for shared pages and clear it for private pages. + */ + return BIT_ULL(gpa_width - 1); +} + +static u64 __cpuidle __halt(const bool irq_disabled, const bool do_sti) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = hcall_func(EXIT_REASON_HLT), + .r12 = irq_disabled, + }; + + /* + * Emulate HLT operation via hypercall. More info about ABI + * can be found in TDX Guest-Host-Communication Interface + * (GHCI), section 3.8 TDG.VP.VMCALL<Instruction.HLT>. + * + * The VMM uses the "IRQ disabled" param to understand IRQ + * enabled status (RFLAGS.IF) of the TD guest and to determine + * whether or not it should schedule the halted vCPU if an + * IRQ becomes pending. E.g. if IRQs are disabled, the VMM + * can keep the vCPU in virtual HLT, even if an IRQ is + * pending, without hanging/breaking the guest. + */ + return __tdx_hypercall(&args, do_sti ? TDX_HCALL_ISSUE_STI : 0); +} + +static bool handle_halt(void) +{ + /* + * Since non safe halt is mainly used in CPU offlining + * and the guest will always stay in the halt state, don't + * call the STI instruction (set do_sti as false). + */ + const bool irq_disabled = irqs_disabled(); + const bool do_sti = false; + + if (__halt(irq_disabled, do_sti)) + return false; + + return true; +} + +void __cpuidle tdx_safe_halt(void) +{ + /* + * For do_sti=true case, __tdx_hypercall() function enables + * interrupts using the STI instruction before the TDCALL. So + * set irq_disabled as false. + */ + const bool irq_disabled = false; + const bool do_sti = true; + + /* + * Use WARN_ONCE() to report the failure. + */ + if (__halt(irq_disabled, do_sti)) + WARN_ONCE(1, "HLT instruction emulation failed\n"); +} + +static bool read_msr(struct pt_regs *regs) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = hcall_func(EXIT_REASON_MSR_READ), + .r12 = regs->cx, + }; + + /* + * Emulate the MSR read via hypercall. More info about ABI + * can be found in TDX Guest-Host-Communication Interface + * (GHCI), section titled "TDG.VP.VMCALL<Instruction.RDMSR>". + */ + if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT)) + return false; + + regs->ax = lower_32_bits(args.r11); + regs->dx = upper_32_bits(args.r11); + return true; +} + +static bool write_msr(struct pt_regs *regs) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = hcall_func(EXIT_REASON_MSR_WRITE), + .r12 = regs->cx, + .r13 = (u64)regs->dx << 32 | regs->ax, + }; + + /* + * Emulate the MSR write via hypercall. More info about ABI + * can be found in TDX Guest-Host-Communication Interface + * (GHCI) section titled "TDG.VP.VMCALL<Instruction.WRMSR>". + */ + return !__tdx_hypercall(&args, 0); +} + +static bool handle_cpuid(struct pt_regs *regs) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = hcall_func(EXIT_REASON_CPUID), + .r12 = regs->ax, + .r13 = regs->cx, + }; + + /* + * Only allow VMM to control range reserved for hypervisor + * communication. + * + * Return all-zeros for any CPUID outside the range. It matches CPU + * behaviour for non-supported leaf. + */ + if (regs->ax < 0x40000000 || regs->ax > 0x4FFFFFFF) { + regs->ax = regs->bx = regs->cx = regs->dx = 0; + return true; + } + + /* + * Emulate the CPUID instruction via a hypercall. More info about + * ABI can be found in TDX Guest-Host-Communication Interface + * (GHCI), section titled "VP.VMCALL<Instruction.CPUID>". + */ + if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT)) + return false; + + /* + * As per TDX GHCI CPUID ABI, r12-r15 registers contain contents of + * EAX, EBX, ECX, EDX registers after the CPUID instruction execution. + * So copy the register contents back to pt_regs. + */ + regs->ax = args.r12; + regs->bx = args.r13; + regs->cx = args.r14; + regs->dx = args.r15; + + return true; +} + +static bool mmio_read(int size, unsigned long addr, unsigned long *val) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = hcall_func(EXIT_REASON_EPT_VIOLATION), + .r12 = size, + .r13 = EPT_READ, + .r14 = addr, + .r15 = *val, + }; + + if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT)) + return false; + *val = args.r11; + return true; +} + +static bool mmio_write(int size, unsigned long addr, unsigned long val) +{ + return !_tdx_hypercall(hcall_func(EXIT_REASON_EPT_VIOLATION), size, + EPT_WRITE, addr, val); +} + +static bool handle_mmio(struct pt_regs *regs, struct ve_info *ve) +{ + char buffer[MAX_INSN_SIZE]; + unsigned long *reg, val; + struct insn insn = {}; + enum mmio_type mmio; + int size, extend_size; + u8 extend_val = 0; + + /* Only in-kernel MMIO is supported */ + if (WARN_ON_ONCE(user_mode(regs))) + return false; + + if (copy_from_kernel_nofault(buffer, (void *)regs->ip, MAX_INSN_SIZE)) + return false; + + if (insn_decode(&insn, buffer, MAX_INSN_SIZE, INSN_MODE_64)) + return false; + + mmio = insn_decode_mmio(&insn, &size); + if (WARN_ON_ONCE(mmio == MMIO_DECODE_FAILED)) + return false; + + if (mmio != MMIO_WRITE_IMM && mmio != MMIO_MOVS) { + reg = insn_get_modrm_reg_ptr(&insn, regs); + if (!reg) + return false; + } + + ve->instr_len = insn.length; + + /* Handle writes first */ + switch (mmio) { + case MMIO_WRITE: + memcpy(&val, reg, size); + return mmio_write(size, ve->gpa, val); + case MMIO_WRITE_IMM: + val = insn.immediate.value; + return mmio_write(size, ve->gpa, val); + case MMIO_READ: + case MMIO_READ_ZERO_EXTEND: + case MMIO_READ_SIGN_EXTEND: + /* Reads are handled below */ + break; + case MMIO_MOVS: + case MMIO_DECODE_FAILED: + /* + * MMIO was accessed with an instruction that could not be + * decoded or handled properly. It was likely not using io.h + * helpers or accessed MMIO accidentally. + */ + return false; + default: + WARN_ONCE(1, "Unknown insn_decode_mmio() decode value?"); + return false; + } + + /* Handle reads */ + if (!mmio_read(size, ve->gpa, &val)) + return false; + + switch (mmio) { + case MMIO_READ: + /* Zero-extend for 32-bit operation */ + extend_size = size == 4 ? sizeof(*reg) : 0; + break; + case MMIO_READ_ZERO_EXTEND: + /* Zero extend based on operand size */ + extend_size = insn.opnd_bytes; + break; + case MMIO_READ_SIGN_EXTEND: + /* Sign extend based on operand size */ + extend_size = insn.opnd_bytes; + if (size == 1 && val & BIT(7)) + extend_val = 0xFF; + else if (size > 1 && val & BIT(15)) + extend_val = 0xFF; + break; + default: + /* All other cases has to be covered with the first switch() */ + WARN_ON_ONCE(1); + return false; + } + + if (extend_size) + memset(reg, extend_val, extend_size); + memcpy(reg, &val, size); + return true; +} + +static bool handle_in(struct pt_regs *regs, int size, int port) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = hcall_func(EXIT_REASON_IO_INSTRUCTION), + .r12 = size, + .r13 = PORT_READ, + .r14 = port, + }; + u64 mask = GENMASK(BITS_PER_BYTE * size, 0); + bool success; + + /* + * Emulate the I/O read via hypercall. More info about ABI can be found + * in TDX Guest-Host-Communication Interface (GHCI) section titled + * "TDG.VP.VMCALL<Instruction.IO>". + */ + success = !__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT); + + /* Update part of the register affected by the emulated instruction */ + regs->ax &= ~mask; + if (success) + regs->ax |= args.r11 & mask; + + return success; +} + +static bool handle_out(struct pt_regs *regs, int size, int port) +{ + u64 mask = GENMASK(BITS_PER_BYTE * size, 0); + + /* + * Emulate the I/O write via hypercall. More info about ABI can be found + * in TDX Guest-Host-Communication Interface (GHCI) section titled + * "TDG.VP.VMCALL<Instruction.IO>". + */ + return !_tdx_hypercall(hcall_func(EXIT_REASON_IO_INSTRUCTION), size, + PORT_WRITE, port, regs->ax & mask); +} + +/* + * Emulate I/O using hypercall. + * + * Assumes the IO instruction was using ax, which is enforced + * by the standard io.h macros. + * + * Return True on success or False on failure. + */ +static bool handle_io(struct pt_regs *regs, u32 exit_qual) +{ + int size, port; + bool in; + + if (VE_IS_IO_STRING(exit_qual)) + return false; + + in = VE_IS_IO_IN(exit_qual); + size = VE_GET_IO_SIZE(exit_qual); + port = VE_GET_PORT_NUM(exit_qual); + + + if (in) + return handle_in(regs, size, port); + else + return handle_out(regs, size, port); +} + +/* + * Early #VE exception handler. Only handles a subset of port I/O. + * Intended only for earlyprintk. If failed, return false. + */ +__init bool tdx_early_handle_ve(struct pt_regs *regs) +{ + struct ve_info ve; + + tdx_get_ve_info(&ve); + + if (ve.exit_reason != EXIT_REASON_IO_INSTRUCTION) + return false; + + return handle_io(regs, ve.exit_qual); +} + +void tdx_get_ve_info(struct ve_info *ve) +{ + struct tdx_module_output out; + + /* + * Called during #VE handling to retrieve the #VE info from the + * TDX module. + * + * This has to be called early in #VE handling. A "nested" #VE which + * occurs before this will raise a #DF and is not recoverable. + * + * The call retrieves the #VE info from the TDX module, which also + * clears the "#VE valid" flag. This must be done before anything else + * because any #VE that occurs while the valid flag is set will lead to + * #DF. + * + * Note, the TDX module treats virtual NMIs as inhibited if the #VE + * valid flag is set. It means that NMI=>#VE will not result in a #DF. + */ + tdx_module_call(TDX_GET_VEINFO, 0, 0, 0, 0, &out); + + /* Transfer the output parameters */ + ve->exit_reason = out.rcx; + ve->exit_qual = out.rdx; + ve->gla = out.r8; + ve->gpa = out.r9; + ve->instr_len = lower_32_bits(out.r10); + ve->instr_info = upper_32_bits(out.r10); +} + +/* Handle the user initiated #VE */ +static bool virt_exception_user(struct pt_regs *regs, struct ve_info *ve) +{ + switch (ve->exit_reason) { + case EXIT_REASON_CPUID: + return handle_cpuid(regs); + default: + pr_warn("Unexpected #VE: %lld\n", ve->exit_reason); + return false; + } +} + +/* Handle the kernel #VE */ +static bool virt_exception_kernel(struct pt_regs *regs, struct ve_info *ve) +{ + switch (ve->exit_reason) { + case EXIT_REASON_HLT: + return handle_halt(); + case EXIT_REASON_MSR_READ: + return read_msr(regs); + case EXIT_REASON_MSR_WRITE: + return write_msr(regs); + case EXIT_REASON_CPUID: + return handle_cpuid(regs); + case EXIT_REASON_EPT_VIOLATION: + return handle_mmio(regs, ve); + case EXIT_REASON_IO_INSTRUCTION: + return handle_io(regs, ve->exit_qual); + default: + pr_warn("Unexpected #VE: %lld\n", ve->exit_reason); + return false; + } +} + +bool tdx_handle_virt_exception(struct pt_regs *regs, struct ve_info *ve) +{ + bool ret; + + if (user_mode(regs)) + ret = virt_exception_user(regs, ve); + else + ret = virt_exception_kernel(regs, ve); + + /* After successful #VE handling, move the IP */ + if (ret) + regs->ip += ve->instr_len; + + return ret; +} + +static bool tdx_tlb_flush_required(bool private) +{ + /* + * TDX guest is responsible for flushing TLB on private->shared + * transition. VMM is responsible for flushing on shared->private. + * + * The VMM _can't_ flush private addresses as it can't generate PAs + * with the guest's HKID. Shared memory isn't subject to integrity + * checking, i.e. the VMM doesn't need to flush for its own protection. + * + * There's no need to flush when converting from shared to private, + * as flushing is the VMM's responsibility in this case, e.g. it must + * flush to avoid integrity failures in the face of a buggy or + * malicious guest. + */ + return !private; +} + +static bool tdx_cache_flush_required(void) +{ + /* + * AMD SME/SEV can avoid cache flushing if HW enforces cache coherence. + * TDX doesn't have such capability. + * + * Flush cache unconditionally. + */ + return true; +} + +static bool try_accept_one(phys_addr_t *start, unsigned long len, + enum pg_level pg_level) +{ + unsigned long accept_size = page_level_size(pg_level); + u64 tdcall_rcx; + u8 page_size; + + if (!IS_ALIGNED(*start, accept_size)) + return false; + + if (len < accept_size) + return false; + + /* + * Pass the page physical address to the TDX module to accept the + * pending, private page. + * + * Bits 2:0 of RCX encode page size: 0 - 4K, 1 - 2M, 2 - 1G. + */ + switch (pg_level) { + case PG_LEVEL_4K: + page_size = 0; + break; + case PG_LEVEL_2M: + page_size = 1; + break; + case PG_LEVEL_1G: + page_size = 2; + break; + default: + return false; + } + + tdcall_rcx = *start | page_size; + if (__tdx_module_call(TDX_ACCEPT_PAGE, tdcall_rcx, 0, 0, 0, NULL)) + return false; + + *start += accept_size; + return true; +} + +/* + * Inform the VMM of the guest's intent for this physical page: shared with + * the VMM or private to the guest. The VMM is expected to change its mapping + * of the page in response. + */ +static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) +{ + phys_addr_t start = __pa(vaddr); + phys_addr_t end = __pa(vaddr + numpages * PAGE_SIZE); + + if (!enc) { + /* Set the shared (decrypted) bits: */ + start |= cc_mkdec(0); + end |= cc_mkdec(0); + } + + /* + * Notify the VMM about page mapping conversion. More info about ABI + * can be found in TDX Guest-Host-Communication Interface (GHCI), + * section "TDG.VP.VMCALL<MapGPA>" + */ + if (_tdx_hypercall(TDVMCALL_MAP_GPA, start, end - start, 0, 0)) + return false; + + /* private->shared conversion requires only MapGPA call */ + if (!enc) + return true; + + /* + * For shared->private conversion, accept the page using + * TDX_ACCEPT_PAGE TDX module call. + */ + while (start < end) { + unsigned long len = end - start; + + /* + * Try larger accepts first. It gives chance to VMM to keep + * 1G/2M SEPT entries where possible and speeds up process by + * cutting number of hypercalls (if successful). + */ + + if (try_accept_one(&start, len, PG_LEVEL_1G)) + continue; + + if (try_accept_one(&start, len, PG_LEVEL_2M)) + continue; + + if (!try_accept_one(&start, len, PG_LEVEL_4K)) + return false; + } + + return true; +} + +void __init tdx_early_init(void) +{ + u64 cc_mask; + u32 eax, sig[3]; + + cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]); + + if (memcmp(TDX_IDENT, sig, sizeof(sig))) + return; + + setup_force_cpu_cap(X86_FEATURE_TDX_GUEST); + + cc_set_vendor(CC_VENDOR_INTEL); + cc_mask = get_cc_mask(); + cc_set_mask(cc_mask); + + /* + * All bits above GPA width are reserved and kernel treats shared bit + * as flag, not as part of physical address. + * + * Adjust physical mask to only cover valid GPA bits. + */ + physical_mask &= cc_mask - 1; + + x86_platform.guest.enc_cache_flush_required = tdx_cache_flush_required; + x86_platform.guest.enc_tlb_flush_required = tdx_tlb_flush_required; + x86_platform.guest.enc_status_change_finish = tdx_enc_status_changed; + + pr_info("Guest detected\n"); +} diff --git a/arch/x86/include/asm/acenv.h b/arch/x86/include/asm/acenv.h index 9aff97f0de7f..d937c55e717e 100644 --- a/arch/x86/include/asm/acenv.h +++ b/arch/x86/include/asm/acenv.h @@ -13,7 +13,19 @@ /* Asm macros */ -#define ACPI_FLUSH_CPU_CACHE() wbinvd() +/* + * ACPI_FLUSH_CPU_CACHE() flushes caches on entering sleep states. + * It is required to prevent data loss. + * + * While running inside virtual machine, the kernel can bypass cache flushing. + * Changing sleep state in a virtual machine doesn't affect the host system + * sleep state and cannot lead to data loss. + */ +#define ACPI_FLUSH_CPU_CACHE() \ +do { \ + if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) \ + wbinvd(); \ +} while (0) int __acpi_acquire_global_lock(unsigned int *lock); int __acpi_release_global_lock(unsigned int *lock); diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 48067af94678..bd8ae0a7010a 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -328,6 +328,8 @@ struct apic { /* wakeup_secondary_cpu */ int (*wakeup_secondary_cpu)(int apicid, unsigned long start_eip); + /* wakeup secondary CPU using 64-bit wakeup point */ + int (*wakeup_secondary_cpu_64)(int apicid, unsigned long start_eip); void (*inquire_remote_apic)(int apicid); @@ -488,6 +490,11 @@ static inline unsigned int read_apic_id(void) return apic->get_apic_id(reg); } +#ifdef CONFIG_X86_64 +typedef int (*wakeup_cpu_handler)(int apicid, unsigned long start_eip); +extern void acpi_wake_cpu_handler_update(wakeup_cpu_handler handler); +#endif + extern int default_apic_id_valid(u32 apicid); extern int default_acpi_madt_oem_check(char *, char *); extern void default_setup_apic_routing(void); diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 73e643ae94b6..20df73b51025 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -238,6 +238,7 @@ #define X86_FEATURE_VMW_VMMCALL ( 8*32+19) /* "" VMware prefers VMMCALL hypercall instruction */ #define X86_FEATURE_PVUNLOCK ( 8*32+20) /* "" PV unlock function */ #define X86_FEATURE_VCPUPREEMPT ( 8*32+21) /* "" PV vcpu_is_preempted function */ +#define X86_FEATURE_TDX_GUEST ( 8*32+22) /* Intel Trust Domain Extensions Guest */ /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */ #define X86_FEATURE_FSGSBASE ( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/ diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index 1231d63f836d..b37de8268c9a 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -68,6 +68,12 @@ # define DISABLE_SGX (1 << (X86_FEATURE_SGX & 31)) #endif +#ifdef CONFIG_INTEL_TDX_GUEST +# define DISABLE_TDX_GUEST 0 +#else +# define DISABLE_TDX_GUEST (1 << (X86_FEATURE_TDX_GUEST & 31)) +#endif + /* * Make sure to add features to the correct mask */ @@ -79,7 +85,7 @@ #define DISABLED_MASK5 0 #define DISABLED_MASK6 0 #define DISABLED_MASK7 (DISABLE_PTI) -#define DISABLED_MASK8 0 +#define DISABLED_MASK8 (DISABLE_TDX_GUEST) #define DISABLED_MASK9 (DISABLE_SMAP|DISABLE_SGX) #define DISABLED_MASK10 0 #define DISABLED_MASK11 0 diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 7924f27f5c8b..72184b0b2219 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -632,6 +632,10 @@ DECLARE_IDTENTRY_XENCB(X86_TRAP_OTHER, exc_xen_hypervisor_callback); DECLARE_IDTENTRY_RAW(X86_TRAP_OTHER, exc_xen_unknown_trap); #endif +#ifdef CONFIG_INTEL_TDX_GUEST +DECLARE_IDTENTRY(X86_TRAP_VE, exc_virtualization_exception); +#endif + /* Device interrupts common/spurious */ DECLARE_IDTENTRY_IRQ(X86_TRAP_OTHER, common_interrupt); #ifdef CONFIG_X86_LOCAL_APIC diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index e9736af126b2..1870b99c3356 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -44,6 +44,7 @@ #include <asm/page.h> #include <asm/early_ioremap.h> #include <asm/pgtable_types.h> +#include <asm/shared/io.h> #define build_mmio_read(name, size, type, reg, barrier) \ static inline type name(const volatile void __iomem *addr) \ @@ -256,37 +257,23 @@ static inline void slow_down_io(void) #endif #define BUILDIO(bwl, bw, type) \ -static inline void out##bwl(unsigned type value, int port) \ -{ \ - asm volatile("out" #bwl " %" #bw "0, %w1" \ - : : "a"(value), "Nd"(port)); \ -} \ - \ -static inline unsigned type in##bwl(int port) \ -{ \ - unsigned type value; \ - asm volatile("in" #bwl " %w1, %" #bw "0" \ - : "=a"(value) : "Nd"(port)); \ - return value; \ -} \ - \ -static inline void out##bwl##_p(unsigned type value, int port) \ +static inline void out##bwl##_p(type value, u16 port) \ { \ out##bwl(value, port); \ slow_down_io(); \ } \ \ -static inline unsigned type in##bwl##_p(int port) \ +static inline type in##bwl##_p(u16 port) \ { \ - unsigned type value = in##bwl(port); \ + type value = in##bwl(port); \ slow_down_io(); \ return value; \ } \ \ -static inline void outs##bwl(int port, const void *addr, unsigned long count) \ +static inline void outs##bwl(u16 port, const void *addr, unsigned long count) \ { \ if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) { \ - unsigned type *value = (unsigned type *)addr; \ + type *value = (type *)addr; \ while (count) { \ out##bwl(*value, port); \ value++; \ @@ -299,10 +286,10 @@ static inline void outs##bwl(int port, const void *addr, unsigned long count) \ } \ } \ \ -static inline void ins##bwl(int port, void *addr, unsigned long count) \ +static inline void ins##bwl(u16 port, void *addr, unsigned long count) \ { \ if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) { \ - unsigned type *value = (unsigned type *)addr; \ + type *value = (type *)addr; \ while (count) { \ *value = in##bwl(port); \ value++; \ @@ -315,13 +302,11 @@ static inline void ins##bwl(int port, void *addr, unsigned long count) \ } \ } -BUILDIO(b, b, char) -BUILDIO(w, w, short) -BUILDIO(l, , int) +BUILDIO(b, b, u8) +BUILDIO(w, w, u16) +BUILDIO(l, , u32) +#undef BUILDIO -#define inb inb -#define inw inw -#define inl inl #define inb_p inb_p #define inw_p inw_p #define inl_p inl_p @@ -329,9 +314,6 @@ BUILDIO(l, , int) #define insw insw #define insl insl -#define outb outb -#define outw outw -#define outl outl #define outb_p outb_p #define outw_p outw_p #define outl_p outl_p diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index 56935ebb1dfe..57bc74e112f2 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -7,6 +7,8 @@ #include <linux/interrupt.h> #include <uapi/asm/kvm_para.h> +#include <asm/tdx.h> + #ifdef CONFIG_KVM_GUEST bool kvm_check_and_clear_guest_paused(void); #else @@ -32,6 +34,10 @@ static inline bool kvm_check_and_clear_guest_paused(void) static inline long kvm_hypercall0(unsigned int nr) { long ret; + + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) + return tdx_kvm_hypercall(nr, 0, 0, 0, 0); + asm volatile(KVM_HYPERCALL : "=a"(ret) : "a"(nr) @@ -42,6 +48,10 @@ static inline long kvm_hypercall0(unsigned int nr) static inline long kvm_hypercall1(unsigned int nr, unsigned long p1) { long ret; + + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) + return tdx_kvm_hypercall(nr, p1, 0, 0, 0); + asm volatile(KVM_HYPERCALL : "=a"(ret) : "a"(nr), "b"(p1) @@ -53,6 +63,10 @@ static inline long kvm_hypercall2(unsigned int nr, unsigned long p1, unsigned long p2) { long ret; + + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) + return tdx_kvm_hypercall(nr, p1, p2, 0, 0); + asm volatile(KVM_HYPERCALL : "=a"(ret) : "a"(nr), "b"(p1), "c"(p2) @@ -64,6 +78,10 @@ static inline long kvm_hypercall3(unsigned int nr, unsigned long p1, unsigned long p2, unsigned long p3) { long ret; + + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) + return tdx_kvm_hypercall(nr, p1, p2, p3, 0); + asm volatile(KVM_HYPERCALL : "=a"(ret) : "a"(nr), "b"(p1), "c"(p2), "d"(p3) @@ -76,6 +94,10 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1, unsigned long p4) { long ret; + + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) + return tdx_kvm_hypercall(nr, p1, p2, p3, p4); + asm volatile(KVM_HYPERCALL : "=a"(ret) : "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4) diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index e2c6f433ed10..88ceaf3648b3 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -49,9 +49,6 @@ void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, void __init mem_encrypt_free_decrypted_mem(void); -/* Architecture __weak replacement functions */ -void __init mem_encrypt_init(void); - void __init sev_es_init_vc_handling(void); #define __bss_decrypted __section(".bss..decrypted") @@ -89,6 +86,9 @@ static inline void mem_encrypt_free_decrypted_mem(void) { } #endif /* CONFIG_AMD_MEM_ENCRYPT */ +/* Architecture __weak replacement functions */ +void __init mem_encrypt_init(void); + /* * The __sme_pa() and __sme_pa_nodebug() macros are meant for use when * writing to or comparing values from the cr3 register. Having the diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h index 331474b150f1..fd6f6e5b755a 100644 --- a/arch/x86/include/asm/realmode.h +++ b/arch/x86/include/asm/realmode.h @@ -25,6 +25,7 @@ struct real_mode_header { u32 sev_es_trampoline_start; #endif #ifdef CONFIG_X86_64 + u32 trampoline_start64; u32 trampoline_pgd; #endif /* ACPI S3 wakeup */ diff --git a/arch/x86/include/asm/shared/io.h b/arch/x86/include/asm/shared/io.h new file mode 100644 index 000000000000..c0ef921c0586 --- /dev/null +++ b/arch/x86/include/asm/shared/io.h @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SHARED_IO_H +#define _ASM_X86_SHARED_IO_H + +#include <linux/types.h> + +#define BUILDIO(bwl, bw, type) \ +static inline void __out##bwl(type value, u16 port) \ +{ \ + asm volatile("out" #bwl " %" #bw "0, %w1" \ + : : "a"(value), "Nd"(port)); \ +} \ + \ +static inline type __in##bwl(u16 port) \ +{ \ + type value; \ + asm volatile("in" #bwl " %w1, %" #bw "0" \ + : "=a"(value) : "Nd"(port)); \ + return value; \ +} + +BUILDIO(b, b, u8) +BUILDIO(w, w, u16) +BUILDIO(l, , u32) +#undef BUILDIO + +#define inb __inb +#define inw __inw +#define inl __inl +#define outb __outb +#define outw __outw +#define outl __outl + +#endif diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h new file mode 100644 index 000000000000..e53f26228fbb --- /dev/null +++ b/arch/x86/include/asm/shared/tdx.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SHARED_TDX_H +#define _ASM_X86_SHARED_TDX_H + +#include <linux/bits.h> +#include <linux/types.h> + +#define TDX_HYPERCALL_STANDARD 0 + +#define TDX_HCALL_HAS_OUTPUT BIT(0) +#define TDX_HCALL_ISSUE_STI BIT(1) + +#define TDX_CPUID_LEAF_ID 0x21 +#define TDX_IDENT "IntelTDX " + +#ifndef __ASSEMBLY__ + +/* + * Used in __tdx_hypercall() to pass down and get back registers' values of + * the TDCALL instruction when requesting services from the VMM. + * + * This is a software only structure and not part of the TDX module/VMM ABI. + */ +struct tdx_hypercall_args { + u64 r10; + u64 r11; + u64 r12; + u64 r13; + u64 r14; + u64 r15; +}; + +/* Used to request services from the VMM */ +u64 __tdx_hypercall(struct tdx_hypercall_args *args, unsigned long flags); + +/* Called from __tdx_hypercall() for unrecoverable failure */ +void __tdx_hypercall_failed(void); + +#endif /* !__ASSEMBLY__ */ +#endif /* _ASM_X86_SHARED_TDX_H */ diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h new file mode 100644 index 000000000000..020c81a7c729 --- /dev/null +++ b/arch/x86/include/asm/tdx.h @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2021-2022 Intel Corporation */ +#ifndef _ASM_X86_TDX_H +#define _ASM_X86_TDX_H + +#include <linux/init.h> +#include <linux/bits.h> +#include <asm/ptrace.h> +#include <asm/shared/tdx.h> + +/* + * SW-defined error codes. + * + * Bits 47:40 == 0xFF indicate Reserved status code class that never used by + * TDX module. + */ +#define TDX_ERROR _BITUL(63) +#define TDX_SW_ERROR (TDX_ERROR | GENMASK_ULL(47, 40)) +#define TDX_SEAMCALL_VMFAILINVALID (TDX_SW_ERROR | _UL(0xFFFF0000)) + +#ifndef __ASSEMBLY__ + +/* + * Used to gather the output registers values of the TDCALL and SEAMCALL + * instructions when requesting services from the TDX module. + * + * This is a software only structure and not part of the TDX module/VMM ABI. + */ +struct tdx_module_output { + u64 rcx; + u64 rdx; + u64 r8; + u64 r9; + u64 r10; + u64 r11; +}; + +/* + * Used by the #VE exception handler to gather the #VE exception + * info from the TDX module. This is a software only structure + * and not part of the TDX module/VMM ABI. + */ +struct ve_info { + u64 exit_reason; + u64 exit_qual; + /* Guest Linear (virtual) Address */ + u64 gla; + /* Guest Physical Address */ + u64 gpa; + u32 instr_len; + u32 instr_info; +}; + +#ifdef CONFIG_INTEL_TDX_GUEST + +void __init tdx_early_init(void); + +/* Used to communicate with the TDX module */ +u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, + struct tdx_module_output *out); + +void tdx_get_ve_info(struct ve_info *ve); + +bool tdx_handle_virt_exception(struct pt_regs *regs, struct ve_info *ve); + +void tdx_safe_halt(void); + +bool tdx_early_handle_ve(struct pt_regs *regs); + +#else + +static inline void tdx_early_init(void) { }; +static inline void tdx_safe_halt(void) { }; + +static inline bool tdx_early_handle_ve(struct pt_regs *regs) { return false; } + +#endif /* CONFIG_INTEL_TDX_GUEST */ + +#if defined(CONFIG_KVM_GUEST) && defined(CONFIG_INTEL_TDX_GUEST) +long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2, + unsigned long p3, unsigned long p4); +#else +static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, + unsigned long p2, unsigned long p3, + unsigned long p4) +{ + return -ENODEV; +} +#endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */ +#endif /* !__ASSEMBLY__ */ +#endif /* _ASM_X86_TDX_H */ diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 0d01e7f5078c..6d2c50819501 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -65,6 +65,13 @@ static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; static bool acpi_support_online_capable; #endif +#ifdef CONFIG_X86_64 +/* Physical address of the Multiprocessor Wakeup Structure mailbox */ +static u64 acpi_mp_wake_mailbox_paddr; +/* Virtual address of the Multiprocessor Wakeup Structure mailbox */ +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; +#endif + #ifdef CONFIG_X86_IO_APIC /* * Locks related to IOAPIC hotplug @@ -336,7 +343,60 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e return 0; } -#endif /*CONFIG_X86_LOCAL_APIC */ +#ifdef CONFIG_X86_64 +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip) +{ + /* + * Remap mailbox memory only for the first call to acpi_wakeup_cpu(). + * + * Wakeup of secondary CPUs is fully serialized in the core code. + * No need to protect acpi_mp_wake_mailbox from concurrent accesses. + */ + if (!acpi_mp_wake_mailbox) { + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr, + sizeof(*acpi_mp_wake_mailbox), + MEMREMAP_WB); + } + + /* + * Mailbox memory is shared between the firmware and OS. Firmware will + * listen on mailbox command address, and once it receives the wakeup + * command, the CPU associated with the given apicid will be booted. + * + * The value of 'apic_id' and 'wakeup_vector' must be visible to the + * firmware before the wakeup command is visible. smp_store_release() + * ensures ordering and visibility. + */ + acpi_mp_wake_mailbox->apic_id = apicid; + acpi_mp_wake_mailbox->wakeup_vector = start_ip; + smp_store_release(&acpi_mp_wake_mailbox->command, + ACPI_MP_WAKE_COMMAND_WAKEUP); + + /* + * Wait for the CPU to wake up. + * + * The CPU being woken up is essentially in a spin loop waiting to be + * woken up. It should not take long for it wake up and acknowledge by + * zeroing out ->command. + * + * ACPI specification doesn't provide any guidance on how long kernel + * has to wait for a wake up acknowledgement. It also doesn't provide + * a way to cancel a wake up request if it takes too long. + * + * In TDX environment, the VMM has control over how long it takes to + * wake up secondary. It can postpone scheduling secondary vCPU + * indefinitely. Giving up on wake up request and reporting error opens + * possible attack vector for VMM: it can wake up a secondary CPU when + * kernel doesn't expect it. Wait until positive result of the wake up + * request. + */ + while (READ_ONCE(acpi_mp_wake_mailbox->command)) + cpu_relax(); + + return 0; +} +#endif /* CONFIG_X86_64 */ +#endif /* CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_IO_APIC #define MP_ISA_BUS 0 @@ -1083,6 +1143,29 @@ static int __init acpi_parse_madt_lapic_entries(void) } return 0; } + +#ifdef CONFIG_X86_64 +static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, + const unsigned long end) +{ + struct acpi_madt_multiproc_wakeup *mp_wake; + + if (!IS_ENABLED(CONFIG_SMP)) + return -ENODEV; + + mp_wake = (struct acpi_madt_multiproc_wakeup *)header; + if (BAD_MADT_ENTRY(mp_wake, end)) + return -EINVAL; + + acpi_table_print_madt_entry(&header->common); + + acpi_mp_wake_mailbox_paddr = mp_wake->base_address; + + acpi_wake_cpu_handler_update(acpi_wakeup_cpu); + + return 0; +} +#endif /* CONFIG_X86_64 */ #endif /* CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_IO_APIC @@ -1278,6 +1361,14 @@ static void __init acpi_process_madt(void) smp_found_config = 1; } + +#ifdef CONFIG_X86_64 + /* + * Parse MADT MP Wake entry. + */ + acpi_table_parse_madt(ACPI_MADT_TYPE_MULTIPROC_WAKEUP, + acpi_parse_mp_wake, 1); +#endif } if (error == -EINVAL) { /* diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b70344bf6600..3c8f2c797a98 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2551,6 +2551,16 @@ u32 x86_msi_msg_get_destid(struct msi_msg *msg, bool extid) } EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid); +#ifdef CONFIG_X86_64 +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) +{ + struct apic **drv; + + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) + (*drv)->wakeup_secondary_cpu_64 = handler; +} +#endif + /* * Override the generic EOI implementation with an optimized version. * Only called during early boot when only one CPU is active and with diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index c1bb384935b0..a868b76cd3d4 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -65,6 +65,7 @@ #include <asm/irq_remapping.h> #include <asm/hw_irq.h> #include <asm/apic.h> +#include <asm/pgtable.h> #define for_each_ioapic(idx) \ for ((idx) = 0; (idx) < nr_ioapics; (idx)++) @@ -2677,6 +2678,19 @@ static struct resource * __init ioapic_setup_resources(void) return res; } +static void io_apic_set_fixmap(enum fixed_addresses idx, phys_addr_t phys) +{ + pgprot_t flags = FIXMAP_PAGE_NOCACHE; + + /* + * Ensure fixmaps for IOAPIC MMIO respect memory encryption pgprot + * bits, just like normal ioremap(): + */ + flags = pgprot_decrypted(flags); + + __set_fixmap(idx, phys, flags); +} + void __init io_apic_init_mappings(void) { unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0; @@ -2709,7 +2723,7 @@ fake_ioapic_page: __func__, PAGE_SIZE, PAGE_SIZE); ioapic_phys = __pa(ioapic_phys); } - set_fixmap_nocache(idx, ioapic_phys); + io_apic_set_fixmap(idx, ioapic_phys); apic_printk(APIC_VERBOSE, "mapped IOAPIC to %08lx (%08lx)\n", __fix_to_virt(idx) + (ioapic_phys & ~PAGE_MASK), ioapic_phys); @@ -2838,7 +2852,7 @@ int mp_register_ioapic(int id, u32 address, u32 gsi_base, ioapics[idx].mp_config.flags = MPC_APIC_USABLE; ioapics[idx].mp_config.apicaddr = address; - set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address); + io_apic_set_fixmap(FIX_IO_APIC_BASE_0 + idx, address); if (bad_ioapic_register(idx)) { clear_fixmap(FIX_IO_APIC_BASE_0 + idx); return -ENODEV; diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 9fb0a2f8b62a..437308004ef2 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -18,6 +18,7 @@ #include <asm/bootparam.h> #include <asm/suspend.h> #include <asm/tlbflush.h> +#include <asm/tdx.h> #ifdef CONFIG_XEN #include <xen/interface/xen.h> @@ -66,6 +67,22 @@ static void __used common(void) #endif BLANK(); + OFFSET(TDX_MODULE_rcx, tdx_module_output, rcx); + OFFSET(TDX_MODULE_rdx, tdx_module_output, rdx); + OFFSET(TDX_MODULE_r8, tdx_module_output, r8); + OFFSET(TDX_MODULE_r9, tdx_module_output, r9); + OFFSET(TDX_MODULE_r10, tdx_module_output, r10); + OFFSET(TDX_MODULE_r11, tdx_module_output, r11); + + BLANK(); + OFFSET(TDX_HYPERCALL_r10, tdx_hypercall_args, r10); + OFFSET(TDX_HYPERCALL_r11, tdx_hypercall_args, r11); + OFFSET(TDX_HYPERCALL_r12, tdx_hypercall_args, r12); + OFFSET(TDX_HYPERCALL_r13, tdx_hypercall_args, r13); + OFFSET(TDX_HYPERCALL_r14, tdx_hypercall_args, r14); + OFFSET(TDX_HYPERCALL_r15, tdx_hypercall_args, r15); + + BLANK(); OFFSET(BP_scratch, boot_params, scratch); OFFSET(BP_secure_boot, boot_params, secure_boot); OFFSET(BP_loadflags, boot_params, hdr.loadflags); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index c185f4831498..bd4a34100ed0 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -40,6 +40,7 @@ #include <asm/extable.h> #include <asm/trapnr.h> #include <asm/sev.h> +#include <asm/tdx.h> /* * Manage page tables very early on. @@ -417,6 +418,9 @@ void __init do_early_exception(struct pt_regs *regs, int trapnr) trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs)) return; + if (trapnr == X86_TRAP_VE && tdx_early_handle_ve(regs)) + return; + early_fixup_exception(regs, trapnr); } @@ -515,6 +519,9 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) idt_setup_early_handler(); + /* Needed before cc_platform_has() can be used for TDX */ + tdx_early_init(); + copy_bootdata(__va(real_mode_data)); /* diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 7bac9a4bdf7c..92c4afa2b729 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -173,8 +173,22 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) addq $(init_top_pgt - __START_KERNEL_map), %rax 1: +#ifdef CONFIG_X86_MCE + /* + * Preserve CR4.MCE if the kernel will enable #MC support. + * Clearing MCE may fault in some environments (that also force #MC + * support). Any machine check that occurs before #MC support is fully + * configured will crash the system regardless of the CR4.MCE value set + * here. + */ + movq %cr4, %rcx + andl $X86_CR4_MCE, %ecx +#else + movl $0, %ecx +#endif + /* Enable PAE mode, PGE and LA57 */ - movl $(X86_CR4_PAE | X86_CR4_PGE), %ecx + orl $(X86_CR4_PAE | X86_CR4_PGE), %ecx #ifdef CONFIG_X86_5LEVEL testl $1, __pgtable_l5_enabled(%rip) jz 1f @@ -280,13 +294,23 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) /* Setup EFER (Extended Feature Enable Register) */ movl $MSR_EFER, %ecx rdmsr + /* + * Preserve current value of EFER for comparison and to skip + * EFER writes if no change was made (for TDX guest) + */ + movl %eax, %edx btsl $_EFER_SCE, %eax /* Enable System Call */ btl $20,%edi /* No Execute supported? */ jnc 1f btsl $_EFER_NX, %eax btsq $_PAGE_BIT_NX,early_pmd_flags(%rip) -1: wrmsr /* Make changes effective */ + /* Avoid writing EFER if no change was made (for TDX guest) */ +1: cmpl %edx, %eax + je 1f + xor %edx, %edx + wrmsr /* Make changes effective */ +1: /* Setup cr0 */ movl $CR0_STATE, %eax /* Make changes effective */ diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 608eb63bf044..a58c6bc1cd68 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -69,6 +69,9 @@ static const __initconst struct idt_data early_idts[] = { */ INTG(X86_TRAP_PF, asm_exc_page_fault), #endif +#ifdef CONFIG_INTEL_TDX_GUEST + INTG(X86_TRAP_VE, asm_exc_virtualization_exception), +#endif }; /* diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index b370767f5b19..dbaf12c43fe1 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -46,6 +46,7 @@ #include <asm/proto.h> #include <asm/frame.h> #include <asm/unwind.h> +#include <asm/tdx.h> #include "process.h" @@ -873,6 +874,9 @@ void select_idle_routine(const struct cpuinfo_x86 *c) } else if (prefer_mwait_c1_over_halt(c)) { pr_info("using mwait in idle threads\n"); x86_idle = mwait_idle; + } else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) { + pr_info("using TDX aware idle routine\n"); + x86_idle = tdx_safe_halt; } else x86_idle = default_idle; } diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 85d7b1c5eb70..66199f9574ef 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1083,6 +1083,11 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, unsigned long boot_error = 0; unsigned long timeout; +#ifdef CONFIG_X86_64 + /* If 64-bit wakeup method exists, use the 64-bit mode trampoline IP */ + if (apic->wakeup_secondary_cpu_64) + start_ip = real_mode_header->trampoline_start64; +#endif idle->thread.sp = (unsigned long)task_pt_regs(idle); early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu); initial_code = (unsigned long)start_secondary; @@ -1124,11 +1129,14 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, /* * Wake up a CPU in difference cases: - * - Use the method in the APIC driver if it's defined + * - Use a method from the APIC driver if one defined, with wakeup + * straight to 64-bit mode preferred over wakeup to RM. * Otherwise, * - Use an INIT boot APIC message for APs or NMI for BSP. */ - if (apic->wakeup_secondary_cpu) + if (apic->wakeup_secondary_cpu_64) + boot_error = apic->wakeup_secondary_cpu_64(apicid, start_ip); + else if (apic->wakeup_secondary_cpu) boot_error = apic->wakeup_secondary_cpu(apicid, start_ip); else boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid, diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 1563fb995005..a4e2efde5d1f 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -62,6 +62,7 @@ #include <asm/insn.h> #include <asm/insn-eval.h> #include <asm/vdso.h> +#include <asm/tdx.h> #ifdef CONFIG_X86_64 #include <asm/x86_init.h> @@ -686,13 +687,40 @@ static bool try_fixup_enqcmd_gp(void) #endif } +static bool gp_try_fixup_and_notify(struct pt_regs *regs, int trapnr, + unsigned long error_code, const char *str) +{ + if (fixup_exception(regs, trapnr, error_code, 0)) + return true; + + current->thread.error_code = error_code; + current->thread.trap_nr = trapnr; + + /* + * To be potentially processing a kprobe fault and to trust the result + * from kprobe_running(), we have to be non-preemptible. + */ + if (!preemptible() && kprobe_running() && + kprobe_fault_handler(regs, trapnr)) + return true; + + return notify_die(DIE_GPF, str, regs, error_code, trapnr, SIGSEGV) == NOTIFY_STOP; +} + +static void gp_user_force_sig_segv(struct pt_regs *regs, int trapnr, + unsigned long error_code, const char *str) +{ + current->thread.error_code = error_code; + current->thread.trap_nr = trapnr; + show_signal(current, SIGSEGV, "", str, regs, error_code); + force_sig(SIGSEGV); +} + DEFINE_IDTENTRY_ERRORCODE(exc_general_protection) { char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1] = GPFSTR; enum kernel_gp_hint hint = GP_NO_HINT; - struct task_struct *tsk; unsigned long gp_addr; - int ret; if (user_mode(regs) && try_fixup_enqcmd_gp()) return; @@ -711,40 +739,18 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection) return; } - tsk = current; - if (user_mode(regs)) { if (fixup_iopl_exception(regs)) goto exit; - tsk->thread.error_code = error_code; - tsk->thread.trap_nr = X86_TRAP_GP; - if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0)) goto exit; - show_signal(tsk, SIGSEGV, "", desc, regs, error_code); - force_sig(SIGSEGV); + gp_user_force_sig_segv(regs, X86_TRAP_GP, error_code, desc); goto exit; } - if (fixup_exception(regs, X86_TRAP_GP, error_code, 0)) - goto exit; - - tsk->thread.error_code = error_code; - tsk->thread.trap_nr = X86_TRAP_GP; - - /* - * To be potentially processing a kprobe fault and to trust the result - * from kprobe_running(), we have to be non-preemptible. - */ - if (!preemptible() && - kprobe_running() && - kprobe_fault_handler(regs, X86_TRAP_GP)) - goto exit; - - ret = notify_die(DIE_GPF, desc, regs, error_code, X86_TRAP_GP, SIGSEGV); - if (ret == NOTIFY_STOP) + if (gp_try_fixup_and_notify(regs, X86_TRAP_GP, error_code, desc)) goto exit; if (error_code) @@ -1343,6 +1349,91 @@ DEFINE_IDTENTRY(exc_device_not_available) } } +#ifdef CONFIG_INTEL_TDX_GUEST + +#define VE_FAULT_STR "VE fault" + +static void ve_raise_fault(struct pt_regs *regs, long error_code) +{ + if (user_mode(regs)) { + gp_user_force_sig_segv(regs, X86_TRAP_VE, error_code, VE_FAULT_STR); + return; + } + + if (gp_try_fixup_and_notify(regs, X86_TRAP_VE, error_code, VE_FAULT_STR)) + return; + + die_addr(VE_FAULT_STR, regs, error_code, 0); +} + +/* + * Virtualization Exceptions (#VE) are delivered to TDX guests due to + * specific guest actions which may happen in either user space or the + * kernel: + * + * * Specific instructions (WBINVD, for example) + * * Specific MSR accesses + * * Specific CPUID leaf accesses + * * Access to specific guest physical addresses + * + * In the settings that Linux will run in, virtualization exceptions are + * never generated on accesses to normal, TD-private memory that has been + * accepted (by BIOS or with tdx_enc_status_changed()). + * + * Syscall entry code has a critical window where the kernel stack is not + * yet set up. Any exception in this window leads to hard to debug issues + * and can be exploited for privilege escalation. Exceptions in the NMI + * entry code also cause issues. Returning from the exception handler with + * IRET will re-enable NMIs and nested NMI will corrupt the NMI stack. + * + * For these reasons, the kernel avoids #VEs during the syscall gap and + * the NMI entry code. Entry code paths do not access TD-shared memory, + * MMIO regions, use #VE triggering MSRs, instructions, or CPUID leaves + * that might generate #VE. VMM can remove memory from TD at any point, + * but access to unaccepted (or missing) private memory leads to VM + * termination, not to #VE. + * + * Similarly to page faults and breakpoints, #VEs are allowed in NMI + * handlers once the kernel is ready to deal with nested NMIs. + * + * During #VE delivery, all interrupts, including NMIs, are blocked until + * TDGETVEINFO is called. It prevents #VE nesting until the kernel reads + * the VE info. + * + * If a guest kernel action which would normally cause a #VE occurs in + * the interrupt-disabled region before TDGETVEINFO, a #DF (fault + * exception) is delivered to the guest which will result in an oops. + * + * The entry code has been audited carefully for following these expectations. + * Changes in the entry code have to be audited for correctness vs. this + * aspect. Similarly to #PF, #VE in these places will expose kernel to + * privilege escalation or may lead to random crashes. + */ +DEFINE_IDTENTRY(exc_virtualization_exception) +{ + struct ve_info ve; + + /* + * NMIs/Machine-checks/Interrupts will be in a disabled state + * till TDGETVEINFO TDCALL is executed. This ensures that VE + * info cannot be overwritten by a nested #VE. + */ + tdx_get_ve_info(&ve); + + cond_local_irq_enable(regs); + + /* + * If tdx_handle_virt_exception() could not process + * it successfully, treat it as #GP(0) and handle it. + */ + if (!tdx_handle_virt_exception(regs, &ve)) + ve_raise_fault(regs, 0); + + cond_local_irq_disable(regs); +} + +#endif + #ifdef CONFIG_X86_32 DEFINE_IDTENTRY_SW(iret_error) { diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c index 2b3eb8c948a3..a58f451a7dd3 100644 --- a/arch/x86/lib/kaslr.c +++ b/arch/x86/lib/kaslr.c @@ -11,7 +11,7 @@ #include <asm/msr.h> #include <asm/archrandom.h> #include <asm/e820/api.h> -#include <asm/io.h> +#include <asm/shared/io.h> /* * When built for the regular kernel, several functions need to be stubbed out diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 17a492c27306..1ad0228f8ceb 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -242,10 +242,15 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long size, * If the page being mapped is in memory and SEV is active then * make sure the memory encryption attribute is enabled in the * resulting mapping. + * In TDX guests, memory is marked private by default. If encryption + * is not requested (using encrypted), explicitly set decrypt + * attribute in all IOREMAPPED memory. */ prot = PAGE_KERNEL_IO; if ((io_desc.flags & IORES_MAP_ENCRYPTED) || encrypted) prot = pgprot_encrypted(prot); + else + prot = pgprot_decrypted(prot); switch (pcm) { case _PAGE_CACHE_MODE_UC: diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c index f85868c031c6..11350e2fd736 100644 --- a/arch/x86/mm/mem_encrypt.c +++ b/arch/x86/mm/mem_encrypt.c @@ -42,7 +42,14 @@ bool force_dma_unencrypted(struct device *dev) static void print_mem_encrypt_feature_info(void) { - pr_info("AMD Memory Encryption Features active:"); + pr_info("Memory Encryption Features active:"); + + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) { + pr_cont(" Intel TDX\n"); + return; + } + + pr_cont(" AMD"); /* Secure Memory Encryption */ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S index 8c1db5bf5d78..2eb62be6d256 100644 --- a/arch/x86/realmode/rm/header.S +++ b/arch/x86/realmode/rm/header.S @@ -24,6 +24,7 @@ SYM_DATA_START(real_mode_header) .long pa_sev_es_trampoline_start #endif #ifdef CONFIG_X86_64 + .long pa_trampoline_start64 .long pa_trampoline_pgd; #endif /* ACPI S3 wakeup */ diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S index cc8391f86cdb..e38d61d6562e 100644 --- a/arch/x86/realmode/rm/trampoline_64.S +++ b/arch/x86/realmode/rm/trampoline_64.S @@ -70,7 +70,7 @@ SYM_CODE_START(trampoline_start) movw $__KERNEL_DS, %dx # Data segment descriptor # Enable protected mode - movl $X86_CR0_PE, %eax # protected mode (PE) bit + movl $(CR0_STATE & ~X86_CR0_PG), %eax movl %eax, %cr0 # into protected mode # flush prefetch and jump to startup_32 @@ -143,13 +143,24 @@ SYM_CODE_START(startup_32) movl %eax, %cr3 # Set up EFER + movl $MSR_EFER, %ecx + rdmsr + /* + * Skip writing to EFER if the register already has desired + * value (to avoid #VE for the TDX guest). + */ + cmp pa_tr_efer, %eax + jne .Lwrite_efer + cmp pa_tr_efer + 4, %edx + je .Ldone_efer +.Lwrite_efer: movl pa_tr_efer, %eax movl pa_tr_efer + 4, %edx - movl $MSR_EFER, %ecx wrmsr - # Enable paging and in turn activate Long Mode - movl $(X86_CR0_PG | X86_CR0_WP | X86_CR0_PE), %eax +.Ldone_efer: + # Enable paging and in turn activate Long Mode. + movl $CR0_STATE, %eax movl %eax, %cr0 /* @@ -161,6 +172,19 @@ SYM_CODE_START(startup_32) ljmpl $__KERNEL_CS, $pa_startup_64 SYM_CODE_END(startup_32) +SYM_CODE_START(pa_trampoline_compat) + /* + * In compatibility mode. Prep ESP and DX for startup_32, then disable + * paging and complete the switch to legacy 32-bit mode. + */ + movl $rm_stack_end, %esp + movw $__KERNEL_DS, %dx + + movl $(CR0_STATE & ~X86_CR0_PG), %eax + movl %eax, %cr0 + ljmpl $__KERNEL32_CS, $pa_startup_32 +SYM_CODE_END(pa_trampoline_compat) + .section ".text64","ax" .code64 .balign 4 @@ -169,6 +193,20 @@ SYM_CODE_START(startup_64) jmpq *tr_start(%rip) SYM_CODE_END(startup_64) +SYM_CODE_START(trampoline_start64) + /* + * APs start here on a direct transfer from 64-bit BIOS with identity + * mapped page tables. Load the kernel's GDT in order to gear down to + * 32-bit mode (to handle 4-level vs. 5-level paging), and to (re)load + * segment registers. Load the zero IDT so any fault triggers a + * shutdown instead of jumping back into BIOS. + */ + lidt tr_idt(%rip) + lgdt tr_gdt64(%rip) + + ljmpl *tr_compat(%rip) +SYM_CODE_END(trampoline_start64) + .section ".rodata","a" # Duplicate the global descriptor table # so the kernel can live anywhere @@ -182,6 +220,17 @@ SYM_DATA_START(tr_gdt) .quad 0x00cf93000000ffff # __KERNEL_DS SYM_DATA_END_LABEL(tr_gdt, SYM_L_LOCAL, tr_gdt_end) +SYM_DATA_START(tr_gdt64) + .short tr_gdt_end - tr_gdt - 1 # gdt limit + .long pa_tr_gdt + .long 0 +SYM_DATA_END(tr_gdt64) + +SYM_DATA_START(tr_compat) + .long pa_trampoline_compat + .short __KERNEL32_CS +SYM_DATA_END(tr_compat) + .bss .balign PAGE_SIZE SYM_DATA(trampoline_pgd, .space PAGE_SIZE) diff --git a/arch/x86/realmode/rm/trampoline_common.S b/arch/x86/realmode/rm/trampoline_common.S index 5033e640f957..4331c32c47f8 100644 --- a/arch/x86/realmode/rm/trampoline_common.S +++ b/arch/x86/realmode/rm/trampoline_common.S @@ -1,4 +1,14 @@ /* SPDX-License-Identifier: GPL-2.0 */ .section ".rodata","a" .balign 16 -SYM_DATA_LOCAL(tr_idt, .fill 1, 6, 0) + +/* + * When a bootloader hands off to the kernel in 32-bit mode an + * IDT with a 2-byte limit and 4-byte base is needed. When a boot + * loader hands off to a kernel 64-bit mode the base address + * extends to 8-bytes. Reserve enough space for either scenario. + */ +SYM_DATA_START_LOCAL(tr_idt) + .short 0 + .quad 0 +SYM_DATA_END(tr_idt) diff --git a/arch/x86/realmode/rm/wakemain.c b/arch/x86/realmode/rm/wakemain.c index 1d6437e6d2ba..a6f4d8388ad8 100644 --- a/arch/x86/realmode/rm/wakemain.c +++ b/arch/x86/realmode/rm/wakemain.c @@ -62,8 +62,12 @@ static void send_morse(const char *pattern) } } +struct port_io_ops pio_ops; + void main(void) { + init_default_io_ops(); + /* Kill machine if structures are wrong */ if (wakeup_header.real_magic != 0x12345678) while (1) diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcall.S new file mode 100644 index 000000000000..49a54356ae99 --- /dev/null +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <asm/asm-offsets.h> +#include <asm/tdx.h> + +/* + * TDCALL and SEAMCALL are supported in Binutils >= 2.36. + */ +#define tdcall .byte 0x66,0x0f,0x01,0xcc +#define seamcall .byte 0x66,0x0f,0x01,0xcf + +/* + * TDX_MODULE_CALL - common helper macro for both + * TDCALL and SEAMCALL instructions. + * + * TDCALL - used by TDX guests to make requests to the + * TDX module and hypercalls to the VMM. + * SEAMCALL - used by TDX hosts to make requests to the + * TDX module. + */ +.macro TDX_MODULE_CALL host:req + /* + * R12 will be used as temporary storage for struct tdx_module_output + * pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL + * services supported by this function, it can be reused. + */ + + /* Callee saved, so preserve it */ + push %r12 + + /* + * Push output pointer to stack. + * After the operation, it will be fetched into R12 register. + */ + push %r9 + + /* Mangle function call ABI into TDCALL/SEAMCALL ABI: */ + /* Move Leaf ID to RAX */ + mov %rdi, %rax + /* Move input 4 to R9 */ + mov %r8, %r9 + /* Move input 3 to R8 */ + mov %rcx, %r8 + /* Move input 1 to RCX */ + mov %rsi, %rcx + /* Leave input param 2 in RDX */ + + .if \host + seamcall + /* + * SEAMCALL instruction is essentially a VMExit from VMX root + * mode to SEAM VMX root mode. VMfailInvalid (CF=1) indicates + * that the targeted SEAM firmware is not loaded or disabled, + * or P-SEAMLDR is busy with another SEAMCALL. %rax is not + * changed in this case. + * + * Set %rax to TDX_SEAMCALL_VMFAILINVALID for VMfailInvalid. + * This value will never be used as actual SEAMCALL error code as + * it is from the Reserved status code class. + */ + jnc .Lno_vmfailinvalid + mov $TDX_SEAMCALL_VMFAILINVALID, %rax +.Lno_vmfailinvalid: + + .else + tdcall + .endif + + /* + * Fetch output pointer from stack to R12 (It is used + * as temporary storage) + */ + pop %r12 + + /* + * Since this macro can be invoked with NULL as an output pointer, + * check if caller provided an output struct before storing output + * registers. + * + * Update output registers, even if the call failed (RAX != 0). + * Other registers may contain details of the failure. + */ + test %r12, %r12 + jz .Lno_output_struct + + /* Copy result registers to output struct: */ + movq %rcx, TDX_MODULE_rcx(%r12) + movq %rdx, TDX_MODULE_rdx(%r12) + movq %r8, TDX_MODULE_r8(%r12) + movq %r9, TDX_MODULE_r9(%r12) + movq %r10, TDX_MODULE_r10(%r12) + movq %r11, TDX_MODULE_r11(%r12) + +.Lno_output_struct: + /* Restore the state of R12 register */ + pop %r12 +.endm diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h index d08dd65b5c43..cb0d6cd1c12f 100644 --- a/include/linux/cc_platform.h +++ b/include/linux/cc_platform.h @@ -80,6 +80,16 @@ enum cc_attr { * using AMD SEV-SNP features. */ CC_ATTR_GUEST_SEV_SNP, + + /** + * @CC_ATTR_HOTPLUG_DISABLED: Hotplug is not supported or disabled. + * + * The platform/OS is running as a guest/virtual machine does not + * support CPU hotplug feature. + * + * Examples include TDX Guest. + */ + CC_ATTR_HOTPLUG_DISABLED, }; #ifdef CONFIG_ARCH_HAS_CC_PLATFORM diff --git a/kernel/cpu.c b/kernel/cpu.c index 02a77ac08399..bbad5e375d3b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -35,6 +35,7 @@ #include <linux/percpu-rwsem.h> #include <linux/cpuset.h> #include <linux/random.h> +#include <linux/cc_platform.h> #include <trace/events/power.h> #define CREATE_TRACE_POINTS @@ -1190,6 +1191,12 @@ out: static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) { + /* + * If the platform does not support hotplug, report it explicitly to + * differentiate it from a transient offlining failure. + */ + if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED)) + return -EOPNOTSUPP; if (cpu_hotplug_disabled) return -EBUSY; return _cpu_down(cpu, 0, target); |