x86/sme: Replace occurrences of sme_active() with cc_platform_has()

Replace uses of sme_active() with the more generic cc_platform_has()
using CC_ATTR_HOST_MEM_ENCRYPT. If future support is added for other
memory encryption technologies, the use of CC_ATTR_HOST_MEM_ENCRYPT
can be updated, as required.

This also replaces two usages of sev_active() that are really geared
towards detecting if SME is active.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-6-bp@alien8.de

3 files changed, 15 insertions, 13 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index ccff76cedd8f..a7250fa3d45f 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -14,7 +14,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/mmiotrace.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
 #include <linux/efi.h>
 #include <linux/pgtable.h>
 
@@ -703,7 +703,7 @@ bool arch_memremap_can_ram_remap(resource_size_t phys_addr, unsigned long size,
 	if (flags & MEMREMAP_DEC)
 		return false;
 
-	if (sme_active()) {
+	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
 		if (memremap_is_setup_data(phys_addr, size) ||
 		    memremap_is_efi_data(phys_addr, size))
 			return false;
@@ -729,7 +729,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,
 
 	encrypted_prot = true;
 
-	if (sme_active()) {
+	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
 		if (early_memremap_is_setup_data(phys_addr, size) ||
 		    memremap_is_efi_data(phys_addr, size))
 			encrypted_prot = false;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index e29b1418d00c..2163485a74e1 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -144,7 +144,7 @@ void __init sme_unmap_bootdata(char *real_mode_data)
 	struct boot_params *boot_data;
 	unsigned long cmdline_paddr;
 
-	if (!sme_active())
+	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
 		return;
 
 	/* Get the command line address before unmapping the real_mode_data */
@@ -164,7 +164,7 @@ void __init sme_map_bootdata(char *real_mode_data)
 	struct boot_params *boot_data;
 	unsigned long cmdline_paddr;
 
-	if (!sme_active())
+	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
 		return;
 
 	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
@@ -377,11 +377,6 @@ bool sev_active(void)
 {
 	return sev_status & MSR_AMD64_SEV_ENABLED;
 }
-
-bool sme_active(void)
-{
-	return sme_me_mask && !sev_active();
-}
 EXPORT_SYMBOL_GPL(sev_active);
 
 /* Needs to be called from non-instrumentable code */
@@ -404,7 +399,7 @@ bool force_dma_unencrypted(struct device *dev)
 	 * device does not support DMA to addresses that include the
 	 * encryption mask.
 	 */
-	if (sme_active()) {
+	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
 		u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask));
 		u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask,
 						dev->bus_dma_limit);
@@ -445,7 +440,7 @@ static void print_mem_encrypt_feature_info(void)
 	pr_info("AMD Memory Encryption Features active:");
 
 	/* Secure Memory Encryption */
-	if (sme_active()) {
+	if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) {
 		/*
 		 * SME is mutually exclusive with any of the SEV
 		 * features below.
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 470b20208430..f8c612902038 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -30,6 +30,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
 
 #include <asm/setup.h>
 #include <asm/sections.h>
@@ -287,7 +288,13 @@ void __init sme_encrypt_kernel(struct boot_params *bp)
 	unsigned long pgtable_area_len;
 	unsigned long decrypted_base;
 
-	if (!sme_active())
+	/*
+	 * This is early code, use an open coded check for SME instead of
+	 * using cc_platform_has(). This eliminates worries about removing
+	 * instrumentation or checking boot_cpu_data in the cc_platform_has()
+	 * function.
+	 */
+	if (!sme_get_me_mask() || sev_status & MSR_AMD64_SEV_ENABLED)
 		return;
 
 	/*