Merge tag 'for-linus-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML updates from Richard Weinberger:

 - Support for optimized routines based on the host CPU

 - Support for PCI via virtio

 - Various fixes

* tag 'for-linus-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: remove unneeded semicolon in um_arch.c
  um: Remove the repeated declaration
  um: fix error return code in winch_tramp()
  um: fix error return code in slip_open()
  um: Fix stack pointer alignment
  um: implement flush_cache_vmap/flush_cache_vunmap
  um: add a UML specific futex implementation
  um: enable the use of optimized xor routines in UML
  um: Add support for host CPU flags and alignment
  um: allow not setting extra rpaths in the linux binary
  um: virtio/pci: enable suspend/resume
  um: add PCI over virtio emulation driver
  um: irqs: allow invoking time-travel handler multiple times
  um: time-travel/signals: fix ndelay() in interrupt
  um: expose time-travel mode to userspace side
  um: export signals_enabled directly
  um: remove unused smp_sigio_handler() declaration
  lib: add iomem emulation (logic_iomem)
  um: allow disabling NO_IOMEM

41 files changed, 1667 insertions, 105 deletions

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 57cfd9a1c082..0561b73cfd9a 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -15,7 +15,7 @@ config UML
 	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DEBUG_BUGVERBOSE
-	select NO_DMA
+	select NO_DMA if !UML_DMA_EMULATION
 	select GENERIC_IRQ_SHOW
 	select GENERIC_CPU_DEVICES
 	select HAVE_GCC_PLUGINS
@@ -26,7 +26,22 @@ config MMU
 	bool
 	default y
 
+config UML_DMA_EMULATION
+	bool
+
 config NO_IOMEM
+	bool "disable IOMEM" if EXPERT
+	depends on !INDIRECT_IOMEM
+	default y
+
+config UML_IOMEM_EMULATION
+	bool
+	select INDIRECT_IOMEM
+	select GENERIC_PCI_IOMAP
+	select GENERIC_IOMAP
+	select NO_GENERIC_PCI_IOPORT_MAP
+
+config NO_IOPORT_MAP
 	def_bool y
 
 config ISA
@@ -61,6 +76,9 @@ config NR_CPUS
 	range 1 1
 	default 1
 
+config ARCH_HAS_CACHE_LINE_SIZE
+	def_bool y
+
 source "arch/$(HEADER_ARCH)/um/Kconfig"
 
 config MAY_HAVE_RUNTIME_DEPS
@@ -91,6 +109,19 @@ config LD_SCRIPT_DYN
 	depends on !LD_SCRIPT_STATIC
 	select MODULE_REL_CRCS if MODVERSIONS
 
+config LD_SCRIPT_DYN_RPATH
+	bool "set rpath in the binary" if EXPERT
+	default y
+	depends on LD_SCRIPT_DYN
+	help
+	  Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
+	  explicitly.
+
+	  You may need to turn this off if compiling for nix systems
+	  that have their libraries in random /nix directories and
+	  might otherwise unexpected use libraries from /lib or /lib64
+	  instead of the desired ones.
+
 config HOSTFS
 	tristate "Host filesystem"
 	help
diff --git a/arch/um/Makefile b/arch/um/Makefile
index 1cea46ff9bb7..12a7acef0357 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -118,7 +118,8 @@ archprepare:
 	$(Q)$(MAKE) $(build)=$(HOST_DIR)/um include/generated/user_constants.h
 
 LINK-$(CONFIG_LD_SCRIPT_STATIC) += -static
-LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib $(call cc-option, -no-pie)
+LINK-$(CONFIG_LD_SCRIPT_DYN) += $(call cc-option, -no-pie)
+LINK-$(CONFIG_LD_SCRIPT_DYN_RPATH) += -Wl,-rpath,/lib
 
 CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) \
 	-fno-stack-protector $(call cc-option, -fno-stack-protector-all)
diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
index 03ba34b61115..f145842c40b9 100644
--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -357,3 +357,23 @@ config UML_RTC
 	  rtcwake, especially in time-travel mode. This driver enables that
 	  by providing a fake RTC clock that causes a wakeup at the right
 	  time.
+
+config UML_PCI_OVER_VIRTIO
+	bool "Enable PCI over VIRTIO device simulation"
+	# in theory, just VIRTIO is enough, but that causes recursion
+	depends on VIRTIO_UML
+	select FORCE_PCI
+	select UML_IOMEM_EMULATION
+	select UML_DMA_EMULATION
+	select PCI_MSI
+	select PCI_MSI_IRQ_DOMAIN
+	select PCI_LOCKLESS_CONFIG
+
+config UML_PCI_OVER_VIRTIO_DEVICE_ID
+	int "set the virtio device ID for PCI emulation"
+	default -1
+	depends on UML_PCI_OVER_VIRTIO
+	help
+	  There's no official device ID assigned (yet), set the one you
+	  wish to use for experimentation here. The default of -1 is
+	  not valid and will cause the driver to fail at probe.
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index dcc64a02f81f..803666e85414 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o
 obj-$(CONFIG_UML_RANDOM) += random.o
 obj-$(CONFIG_VIRTIO_UML) += virtio_uml.o
 obj-$(CONFIG_UML_RTC) += rtc.o
+obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virt-pci.o
 
 # pcap_user.o must be added explicitly.
 USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o pcap_user.o vde_user.o vector_user.o
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index d8845d4aac6a..6040817c036f 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -256,7 +256,8 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
 		goto out_close;
 	}
 
-	if (os_set_fd_block(*fd_out, 0)) {
+	err = os_set_fd_block(*fd_out, 0);
+	if (err) {
 		printk(UM_KERN_ERR "winch_tramp: failed to set thread_fd "
 		       "non-blocking.\n");
 		goto out_close;
diff --git a/arch/um/drivers/slip_user.c b/arch/um/drivers/slip_user.c
index 482a19c5105c..7334019c9e60 100644
--- a/arch/um/drivers/slip_user.c
+++ b/arch/um/drivers/slip_user.c
@@ -145,7 +145,8 @@ static int slip_open(void *data)
 	}
 	sfd = err;
 
-	if (set_up_tty(sfd))
+	err = set_up_tty(sfd);
+	if (err)
 		goto out_close2;
 
 	pri->slave = sfd;
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 8e0b43cf089f..cbd4f00fe77e 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1242,8 +1242,7 @@ static int __init ubd_driver_init(void){
 		 * enough. So use anyway the io thread. */
 	}
 	stack = alloc_stack(0, 0);
-	io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
-				 &thread_fd);
+	io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd);
 	if(io_pid < 0){
 		printk(KERN_ERR
 		       "ubd : Failed to start I/O thread (errno = %d) - "
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
new file mode 100644
index 000000000000..0b802834f40a
--- /dev/null
+++ b/arch/um/drivers/virt-pci.c
@@ -0,0 +1,895 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Intel Corporation
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/logic_iomem.h>
+#include <linux/irqdomain.h>
+#include <linux/virtio_pcidev.h>
+#include <linux/virtio-uml.h>
+#include <linux/delay.h>
+#include <linux/msi.h>
+#include <asm/unaligned.h>
+#include <irq_kern.h>
+
+#define MAX_DEVICES 8
+#define MAX_MSI_VECTORS 32
+#define CFG_SPACE_SIZE 4096
+
+/* for MSI-X we have a 32-bit payload */
+#define MAX_IRQ_MSG_SIZE (sizeof(struct virtio_pcidev_msg) + sizeof(u32))
+#define NUM_IRQ_MSGS	10
+
+#define HANDLE_NO_FREE(ptr) ((void *)((unsigned long)(ptr) | 1))
+#define HANDLE_IS_NO_FREE(ptr) ((unsigned long)(ptr) & 1)
+
+struct um_pci_device {
+	struct virtio_device *vdev;
+
+	/* for now just standard BARs */
+	u8 resptr[PCI_STD_NUM_BARS];
+
+	struct virtqueue *cmd_vq, *irq_vq;
+
+#define UM_PCI_STAT_WAITING	0
+	unsigned long status;
+
+	int irq;
+};
+
+struct um_pci_device_reg {
+	struct um_pci_device *dev;
+	void __iomem *iomem;
+};
+
+static struct pci_host_bridge *bridge;
+static DEFINE_MUTEX(um_pci_mtx);
+static struct um_pci_device_reg um_pci_devices[MAX_DEVICES];
+static struct fwnode_handle *um_pci_fwnode;
+static struct irq_domain *um_pci_inner_domain;
+static struct irq_domain *um_pci_msi_domain;
+static unsigned long um_pci_msi_used[BITS_TO_LONGS(MAX_MSI_VECTORS)];
+
+#define UM_VIRT_PCI_MAXDELAY 40000
+
+static int um_pci_send_cmd(struct um_pci_device *dev,
+			   struct virtio_pcidev_msg *cmd,
+			   unsigned int cmd_size,
+			   const void *extra, unsigned int extra_size,
+			   void *out, unsigned int out_size)
+{
+	struct scatterlist out_sg, extra_sg, in_sg;
+	struct scatterlist *sgs_list[] = {
+		[0] = &out_sg,
+		[1] = extra ? &extra_sg : &in_sg,
+		[2] = extra ? &in_sg : NULL,
+	};
+	int delay_count = 0;
+	int ret, len;
+	bool posted;
+
+	if (WARN_ON(cmd_size < sizeof(*cmd)))
+		return -EINVAL;
+
+	switch (cmd->op) {
+	case VIRTIO_PCIDEV_OP_CFG_WRITE:
+	case VIRTIO_PCIDEV_OP_MMIO_WRITE:
+	case VIRTIO_PCIDEV_OP_MMIO_MEMSET:
+		/* in PCI, writes are posted, so don't wait */
+		posted = !out;
+		WARN_ON(!posted);
+		break;
+	default:
+		posted = false;
+		break;
+	}
+
+	if (posted) {
+		u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC);
+
+		if (ncmd) {
+			memcpy(ncmd, cmd, cmd_size);
+			if (extra)
+				memcpy(ncmd + cmd_size, extra, extra_size);
+			cmd = (void *)ncmd;
+			cmd_size += extra_size;
+			extra = NULL;
+			extra_size = 0;
+		} else {
+			/* try without allocating memory */
+			posted = false;
+		}
+	}
+
+	sg_init_one(&out_sg, cmd, cmd_size);
+	if (extra)
+		sg_init_one(&extra_sg, extra, extra_size);
+	if (out)
+		sg_init_one(&in_sg, out, out_size);
+
+	/* add to internal virtio queue */
+	ret = virtqueue_add_sgs(dev->cmd_vq, sgs_list,
+				extra ? 2 : 1,
+				out ? 1 : 0,
+				posted ? cmd : HANDLE_NO_FREE(cmd),
+				GFP_ATOMIC);
+	if (ret)
+		return ret;
+
+	if (posted) {
+		virtqueue_kick(dev->cmd_vq);
+		return 0;
+	}
+
+	/* kick and poll for getting a response on the queue */
+	set_bit(UM_PCI_STAT_WAITING, &dev->status);
+	virtqueue_kick(dev->cmd_vq);
+
+	while (1) {
+		void *completed = virtqueue_get_buf(dev->cmd_vq, &len);
+
+		if (completed == HANDLE_NO_FREE(cmd))
+			break;
+
+		if (completed && !HANDLE_IS_NO_FREE(completed))
+			kfree(completed);
+
+		if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) ||
+			      ++delay_count > UM_VIRT_PCI_MAXDELAY,
+			      "um virt-pci delay: %d", delay_count)) {
+			ret = -EIO;
+			break;
+		}
+		udelay(1);
+	}
+	clear_bit(UM_PCI_STAT_WAITING, &dev->status);
+
+	return ret;
+}
+
+static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
+					  int size)
+{
+	struct um_pci_device_reg *reg = priv;
+	struct um_pci_device *dev = reg->dev;
+	struct virtio_pcidev_msg hdr = {
+		.op = VIRTIO_PCIDEV_OP_CFG_READ,
+		.size = size,
+		.addr = offset,
+	};
+	/* maximum size - we may only use parts of it */
+	u8 data[8];
+
+	if (!dev)
+		return ~0ULL;
+
+	memset(data, 0xff, sizeof(data));
+
+	switch (size) {
+	case 1:
+	case 2:
+	case 4:
+#ifdef CONFIG_64BIT
+	case 8:
+#endif
+		break;
+	default:
+		WARN(1, "invalid config space read size %d\n", size);
+		return ~0ULL;
+	}
+
+	if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0,
+			    data, sizeof(data)))
+		return ~0ULL;
+
+	switch (size) {
+	case 1:
+		return data[0];
+	case 2:
+		return le16_to_cpup((void *)data);
+	case 4:
+		return le32_to_cpup((void *)data);
+#ifdef CONFIG_64BIT
+	case 8:
+		return le64_to_cpup((void *)data);
+#endif
+	default:
+		return ~0ULL;
+	}
+}
+
+static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size,
+				  unsigned long val)
+{
+	struct um_pci_device_reg *reg = priv;
+	struct um_pci_device *dev = reg->dev;
+	struct {
+		struct virtio_pcidev_msg hdr;
+		/* maximum size - we may only use parts of it */
+		u8 data[8];
+	} msg = {
+		.hdr = {
+			.op = VIRTIO_PCIDEV_OP_CFG_WRITE,
+			.size = size,
+			.addr = offset,
+		},
+	};
+
+	if (!dev)
+		return;
+
+	switch (size) {
+	case 1:
+		msg.data[0] = (u8)val;
+		break;
+	case 2:
+		put_unaligned_le16(val, (void *)msg.data);
+		break;
+	case 4:
+		put_unaligned_le32(val, (void *)msg.data);
+		break;
+#ifdef CONFIG_64BIT
+	case 8:
+		put_unaligned_le64(val, (void *)msg.data);
+		break;
+#endif
+	default:
+		WARN(1, "invalid config space write size %d\n", size);
+		return;
+	}
+
+	WARN_ON(um_pci_send_cmd(dev, &msg.hdr, sizeof(msg), NULL, 0, NULL, 0));
+}
+
+static const struct logic_iomem_ops um_pci_device_cfgspace_ops = {
+	.read = um_pci_cfgspace_read,
+	.write = um_pci_cfgspace_write,
+};
+
+static void um_pci_bar_copy_from(void *priv, void *buffer,
+				 unsigned int offset, int size)
+{
+	u8 *resptr = priv;
+	struct um_pci_device *dev = container_of(resptr - *resptr,
+						 struct um_pci_device,
+						 resptr[0]);
+	struct virtio_pcidev_msg hdr = {
+		.op = VIRTIO_PCIDEV_OP_MMIO_READ,
+		.bar = *resptr,
+		.size = size,
+		.addr = offset,
+	};
+
+	memset(buffer, 0xff, size);
+
+	um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, buffer, size);
+}
+
+static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
+				     int size)
+{
+	/* maximum size - we may only use parts of it */
+	u8 data[8];
+
+	switch (size) {
+	case 1:
+	case 2:
+	case 4:
+#ifdef CONFIG_64BIT
+	case 8:
+#endif
+		break;
+	default:
+		WARN(1, "invalid config space read size %d\n", size);
+		return ~0ULL;
+	}
+
+	um_pci_bar_copy_from(priv, data, offset, size);
+
+	switch (size) {
+	case 1:
+		return data[0];
+	case 2:
+		return le16_to_cpup((void *)data);
+	case 4:
+		return le32_to_cpup((void *)data);
+#ifdef CONFIG_64BIT
+	case 8:
+		return le64_to_cpup((void *)data);
+#endif
+	default:
+		return ~0ULL;
+	}
+}
+
+static void um_pci_bar_copy_to(void *priv, unsigned int offset,
+			       const void *buffer, int size)
+{
+	u8 *resptr = priv;
+	struct um_pci_device *dev = container_of(resptr - *resptr,
+						 struct um_pci_device,
+						 resptr[0]);
+	struct virtio_pcidev_msg hdr = {
+		.op = VIRTIO_PCIDEV_OP_MMIO_WRITE,
+		.bar = *resptr,
+		.size = size,
+		.addr = offset,
+	};
+
+	um_pci_send_cmd(dev, &hdr, sizeof(hdr), buffer, size, NULL, 0);
+}
+
+static void um_pci_bar_write(void *priv, unsigned int offset, int size,
+			     unsigned long val)
+{
+	/* maximum size - we may only use parts of it */
+	u8 data[8];
+
+	switch (size) {
+	case 1:
+		data[0] = (u8)val;
+		break;
+	case 2:
+		put_unaligned_le16(val, (void *)data);
+		break;
+	case 4:
+		put_unaligned_le32(val, (void *)data);
+		break;
+#ifdef CONFIG_64BIT
+	case 8:
+		put_unaligned_le64(val, (void *)data);
+		break;
+#endif
+	default:
+		WARN(1, "invalid config space write size %d\n", size);
+		return;
+	}
+
+	um_pci_bar_copy_to(priv, offset, data, size);
+}
+
+static void um_pci_bar_set(void *priv, unsigned int offset, u8 value, int size)
+{
+	u8 *resptr = priv;
+	struct um_pci_device *dev = container_of(resptr - *resptr,
+						 struct um_pci_device,
+						 resptr[0]);
+	struct {
+		struct virtio_pcidev_msg hdr;
+		u8 data;
+	} msg = {
+		.hdr = {
+			.op = VIRTIO_PCIDEV_OP_CFG_WRITE,
+			.bar = *resptr,
+			.size = size,
+			.addr = offset,
+		},
+		.data = value,
+	};
+
+	um_pci_send_cmd(dev, &msg.hdr, sizeof(msg), NULL, 0, NULL, 0);
+}
+
+static const struct logic_iomem_ops um_pci_device_bar_ops = {
+	.read = um_pci_bar_read,
+	.write = um_pci_bar_write,
+	.set = um_pci_bar_set,
+	.copy_from = um_pci_bar_copy_from,
+	.copy_to = um_pci_bar_copy_to,
+};
+
+static void __iomem *um_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
+				    int where)
+{
+	struct um_pci_device_reg *dev;
+	unsigned int busn = bus->number;
+
+	if (busn > 0)
+		return NULL;
+
+	/* not allowing functions for now ... */
+	if (devfn % 8)
+		return NULL;
+
+	if (devfn / 8 >= ARRAY_SIZE(um_pci_devices))
+		return NULL;
+
+	dev = &um_pci_devices[devfn / 8];
+	if (!dev)
+		return NULL;
+
+	return (void __iomem *)((unsigned long)dev->iomem + where);
+}
+
+static struct pci_ops um_pci_ops = {
+	.map_bus = um_pci_map_bus,
+	.read = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+static void um_pci_rescan(void)
+{
+	pci_lock_rescan_remove();
+	pci_rescan_bus(bridge->bus);
+	pci_unlock_rescan_remove();
+}
+
+static void um_pci_irq_vq_addbuf(struct virtqueue *vq, void *buf, bool kick)
+{
+	struct scatterlist sg[1];
+
+	sg_init_one(sg, buf, MAX_IRQ_MSG_SIZE);
+	if (virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC))
+		kfree(buf);
+	else if (kick)
+		virtqueue_kick(vq);
+}
+
+static void um_pci_handle_irq_message(struct virtqueue *vq,
+				      struct virtio_pcidev_msg *msg)
+{
+	struct virtio_device *vdev = vq->vdev;
+	struct um_pci_device *dev = vdev->priv;
+
+	/* we should properly chain interrupts, but on ARCH=um we don't care */
+
+	switch (msg->op) {
+	case VIRTIO_PCIDEV_OP_INT:
+		generic_handle_irq(dev->irq);
+		break;
+	case VIRTIO_PCIDEV_OP_MSI:
+		/* our MSI message is just the interrupt number */
+		if (msg->size == sizeof(u32))
+			generic_handle_irq(le32_to_cpup((void *)msg->data));
+		else
+			generic_handle_irq(le16_to_cpup((void *)msg->data));
+		break;
+	case VIRTIO_PCIDEV_OP_PME:
+		/* nothing to do - we already woke up due to the message */
+		break;
+	default:
+		dev_err(&vdev->dev, "unexpected virt-pci message %d\n", msg->op);
+		break;
+	}
+}
+
+static void um_pci_cmd_vq_cb(struct virtqueue *vq)
+{
+	struct virtio_device *vdev = vq->vdev;
+	struct um_pci_device *dev = vdev->priv;
+	void *cmd;
+	int len;
+
+	if (test_bit(UM_PCI_STAT_WAITING, &dev->status))
+		return;
+
+	while ((cmd = virtqueue_get_buf(vq, &len))) {
+		if (WARN_ON(HANDLE_IS_NO_FREE(cmd)))
+			continue;
+		kfree(cmd);
+	}
+}
+
+static void um_pci_irq_vq_cb(struct virtqueue *vq)
+{
+	struct virtio_pcidev_msg *msg;
+	int len;
+
+	while ((msg = virtqueue_get_buf(vq, &len))) {
+		if (len >= sizeof(*msg))
+			um_pci_handle_irq_message(vq, msg);
+
+		/* recycle the message buffer */
+		um_pci_irq_vq_addbuf(vq, msg, true);
+	}
+}
+
+static int um_pci_init_vqs(struct um_pci_device *dev)
+{
+	struct virtqueue *vqs[2];
+	static const char *const names[2] = { "cmd", "irq" };
+	vq_callback_t *cbs[2] = { um_pci_cmd_vq_cb, um_pci_irq_vq_cb };
+	int err, i;
+
+	err = virtio_find_vqs(dev->vdev, 2, vqs, cbs, names, NULL);
+	if (err)
+		return err;
+
+	dev->cmd_vq = vqs[0];
+	dev->irq_vq = vqs[1];
+
+	for (i = 0; i < NUM_IRQ_MSGS; i++) {
+		void *msg = kzalloc(MAX_IRQ_MSG_SIZE, GFP_KERNEL);
+
+		if (msg)
+			um_pci_irq_vq_addbuf(dev->irq_vq, msg, false);
+	}
+
+	virtqueue_kick(dev->irq_vq);
+
+	return 0;
+}
+
+static int um_pci_virtio_probe(struct virtio_device *vdev)
+{
+	struct um_pci_device *dev;
+	int i, free = -1;
+	int err = -ENOSPC;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->vdev = vdev;
+	vdev->priv = dev;
+
+	mutex_lock(&um_pci_mtx);
+	for (i = 0; i < MAX_DEVICES; i++) {
+		if (um_pci_devices[i].dev)
+			continue;
+		free = i;
+		break;
+	}
+
+	if (free < 0)
+		goto error;
+
+	err = um_pci_init_vqs(dev);
+	if (err)
+		goto error;
+
+	dev->irq = irq_alloc_desc(numa_node_id());
+	if (dev->irq < 0) {
+		err = dev->irq;
+		goto error;
+	}
+	um_pci_devices[free].dev = dev;
+	vdev->priv = dev;
+
+	mutex_unlock(&um_pci_mtx);
+
+	device_set_wakeup_enable(&vdev->dev, true);
+
+	/*
+	 * In order to do suspend-resume properly, don't allow VQs
+	 * to be suspended.
+	 */
+	virtio_uml_set_no_vq_suspend(vdev, true);
+
+	um_pci_rescan();
+	return 0;
+error:
+	mutex_unlock(&um_pci_mtx);
+	kfree(dev);
+	return err;
+}
+
+static void um_pci_virtio_remove(struct virtio_device *vdev)
+{
+	struct um_pci_device *dev = vdev->priv;
+	int i;
+
+        /* Stop all virtqueues */
+        vdev->config->reset(vdev);
+        vdev->config->del_vqs(vdev);
+
+	device_set_wakeup_enable(&vdev->dev, false);
+
+	mutex_lock(&um_pci_mtx);
+	for (i = 0; i < MAX_DEVICES; i++) {
+		if (um_pci_devices[i].dev != dev)
+			continue;
+		um_pci_devices[i].dev = NULL;
+		irq_free_desc(dev->irq);
+	}
+	mutex_unlock(&um_pci_mtx);
+
+	um_pci_rescan();
+
+	kfree(dev);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+static struct virtio_driver um_pci_virtio_driver = {
+	.driver.name = "virtio-pci",
+	.driver.owner = THIS_MODULE,
+	.id_table = id_table,
+	.probe = um_pci_virtio_probe,
+	.remove = um_pci_virtio_remove,
+};
+
+static struct resource virt_cfgspace_resource = {
+	.name = "PCI config space",
+	.start = 0xf0000000 - MAX_DEVICES * CFG_SPACE_SIZE,
+	.end = 0xf0000000 - 1,
+	.flags = IORESOURCE_MEM,
+};
+
+static long um_pci_map_cfgspace(unsigned long offset, size_t size,
+				const struct logic_iomem_ops **ops,
+				void **priv)
+{
+	if (WARN_ON(size > CFG_SPACE_SIZE || offset % CFG_SPACE_SIZE))
+		return -EINVAL;
+
+	if (offset / CFG_SPACE_SIZE < MAX_DEVICES) {
+		*ops = &um_pci_device_cfgspace_ops;
+		*priv = &um_pci_devices[offset / CFG_SPACE_SIZE];
+		return 0;
+	}
+
+	WARN(1, "cannot map offset 0x%lx/0x%zx\n", offset, size);
+	return -ENOENT;
+}
+
+static const struct logic_iomem_region_ops um_pci_cfgspace_ops = {
+	.map = um_pci_map_cfgspace,
+};
+
+static struct resource virt_iomem_resource = {
+	.name = "PCI iomem",
+	.start = 0xf0000000,
+	.end = 0xffffffff,
+	.flags = IORESOURCE_MEM,
+};
+
+struct um_pci_map_iomem_data {
+	unsigned long offset;
+	size_t size;
+	const struct logic_iomem_ops **ops;
+	void **priv;
+	long ret;
+};
+
+static int um_pci_map_iomem_walk(struct pci_dev *pdev, void *_data)
+{
+	struct um_pci_map_iomem_data *data = _data;
+	struct um_pci_device_reg *reg = &um_pci_devices[pdev->devfn / 8];
+	struct um_pci_device *dev;
+	int i;
+
+	if (!reg->dev)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(dev->resptr); i++) {
+		struct resource *r = &pdev->resource[i];
+
+		if ((r->flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM)
+			continue;
+
+		/*
+		 * must be the whole or part of the resource,
+		 * not allowed to only overlap
+		 */
+		if (data->offset < r->start || data->offset > r->end)
+			continue;
+		if (data->offset + data->size - 1 > r->end)
+			continue;
+
+		dev = reg->dev;
+		*data->ops = &um_pci_device_bar_ops;
+		dev->resptr[i] = i;
+		*data->priv = &dev->resptr[i];
+		data->ret = data->offset - r->start;
+
+		/* no need to continue */
+		return 1;
+	}
+
+	return 0;
+}
+
+static long um_pci_map_iomem(unsigned long offset, size_t size,
+			     const struct logic_iomem_ops **ops,
+			     void **priv)
+{
+	struct um_pci_map_iomem_data data = {
+		/* we want the full address here */
+		.offset = offset + virt_iomem_resource.start,
+		.size = size,
+		.ops = ops,
+		.priv = priv,
+		.ret = -ENOENT,
+	};
+
+	pci_walk_bus(bridge->bus, um_pci_map_iomem_walk, &data);
+	return data.ret;
+}
+
+static const struct logic_iomem_region_ops um_pci_iomem_ops = {
+	.map = um_pci_map_iomem,
+};
+
+static void um_pci_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	/*
+	 * This is a very low address and not actually valid 'physical' memory
+	 * in UML, so we can simply map MSI(-X) vectors to there, it cannot be
+	 * legitimately written to by the device in any other way.
+	 * We use the (virtual) IRQ number here as the message to simplify the
+	 * code that receives the message, where for now we simply trust the
+	 * device to send the correct message.
+	 */
+	msg->address_hi = 0;
+	msg->address_lo = 0xa0000;
+	msg->data = data->irq;
+}
+
+static struct irq_chip um_pci_msi_bottom_irq_chip = {
+	.name = "UM virtio MSI",
+	.irq_compose_msi_msg = um_pci_compose_msi_msg,
+};
+
+static int um_pci_inner_domain_alloc(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs,
+				     void *args)
+{
+	unsigned long bit;
+
+	WARN_ON(nr_irqs != 1);
+
+	mutex_lock(&um_pci_mtx);
+	bit = find_first_zero_bit(um_pci_msi_used, MAX_MSI_VECTORS);
+	if (bit >= MAX_MSI_VECTORS) {
+		mutex_unlock(&um_pci_mtx);
+		return -ENOSPC;
+	}
+
+	set_bit(bit, um_pci_msi_used);
+	mutex_unlock(&um_pci_mtx);
+
+	irq_domain_set_info(domain, virq, bit, &um_pci_msi_bottom_irq_chip,
+			    domain->host_data, handle_simple_irq,
+			    NULL, NULL);
+
+	return 0;
+}
+
+static void um_pci_inner_domain_free(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+
+	mutex_lock(&um_pci_mtx);
+
+	if (!test_bit(d->hwirq, um_pci_msi_used))
+		pr_err("trying to free unused MSI#%lu\n", d->hwirq);
+	else
+		__clear_bit(d->hwirq, um_pci_msi_used);
+
+	mutex_unlock(&um_pci_mtx);
+}
+
+static const struct irq_domain_ops um_pci_inner_domain_ops = {
+	.alloc = um_pci_inner_domain_alloc,
+	.free = um_pci_inner_domain_free,
+};
+
+static struct irq_chip um_pci_msi_irq_chip = {
+	.name = "UM virtio PCIe MSI",
+	.irq_mask = pci_msi_mask_irq,
+	.irq_unmask = pci_msi_unmask_irq,
+};
+
+static struct msi_domain_info um_pci_msi_domain_info = {
+	.flags	= MSI_FLAG_USE_DEF_DOM_OPS |
+		  MSI_FLAG_USE_DEF_CHIP_OPS |
+		  MSI_FLAG_PCI_MSIX,
+	.chip	= &um_pci_msi_irq_chip,
+};
+
+static struct resource busn_resource = {
+	.name	= "PCI busn",
+	.start	= 0,
+	.end	= 0,
+	.flags	= IORESOURCE_BUS,
+};
+
+static int um_pci_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
+{
+	struct um_pci_device_reg *reg = &um_pci_devices[pdev->devfn / 8];
+
+	if (WARN_ON(!reg->dev))
+		return -EINVAL;
+
+	/* Yes, we map all pins to the same IRQ ... doesn't matter for now. */
+	return reg->dev->irq;
+}
+
+void *pci_root_bus_fwnode(struct pci_bus *bus)
+{
+	return um_pci_fwnode;
+}
+
+int um_pci_init(void)
+{
+	int err, i;
+
+	WARN_ON(logic_iomem_add_region(&virt_cfgspace_resource,
+				       &um_pci_cfgspace_ops));
+	WARN_ON(logic_iomem_add_region(&virt_iomem_resource,
+				       &um_pci_iomem_ops));
+
+	if (WARN(CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID < 0,
+		 "No virtio device ID configured for PCI - no PCI support\n"))
+		return 0;
+
+	bridge = pci_alloc_host_bridge(0);
+	if (!bridge)
+		return -ENOMEM;
+
+	um_pci_fwnode = irq_domain_alloc_named_fwnode("um-pci");
+	if (!um_pci_fwnode) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	um_pci_inner_domain = __irq_domain_add(um_pci_fwnode, MAX_MSI_VECTORS,
+					       MAX_MSI_VECTORS, 0,
+					       &um_pci_inner_domain_ops, NULL);
+	if (!um_pci_inner_domain) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	um_pci_msi_domain = pci_msi_create_irq_domain(um_pci_fwnode,
+						      &um_pci_msi_domain_info,
+						      um_pci_inner_domain);
+	if (!um_pci_msi_domain) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	pci_add_resource(&bridge->windows, &virt_iomem_resource);
+	pci_add_resource(&bridge->windows, &busn_resource);
+	bridge->ops = &um_pci_ops;
+	bridge->map_irq = um_pci_map_irq;
+
+	for (i = 0; i < MAX_DEVICES; i++) {
+		resource_size_t start;
+
+		start = virt_cfgspace_resource.start + i * CFG_SPACE_SIZE;
+		um_pci_devices[i].iomem = ioremap(start, CFG_SPACE_SIZE);
+		if (WARN(!um_pci_devices[i].iomem, "failed to map %d\n", i)) {
+			err = -ENOMEM;
+			goto free;
+		}
+	}
+
+	err = pci_host_probe(bridge);
+	if (err)
+		goto free;
+
+	err = register_virtio_driver(&um_pci_virtio_driver);
+	if (err)
+		goto free;
+	return 0;
+free:
+	if (um_pci_inner_domain)
+		irq_domain_remove(um_pci_inner_domain);
+	if (um_pci_fwnode)
+		irq_domain_free_fwnode(um_pci_fwnode);
+	pci_free_resource_list(&bridge->windows);
+	pci_free_host_bridge(bridge);
+	return err;
+}
+module_init(um_pci_init);
+
+void um_pci_exit(void)
+{
+	unregister_virtio_driver(&um_pci_virtio_driver);
+	irq_domain_remove(um_pci_msi_domain);
+	irq_domain_remove(um_pci_inner_domain);
+	pci_free_resource_list(&bridge->windows);
+	pci_free_host_bridge(bridge);
+}
+module_exit(um_pci_exit);
diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index 91ddf74ca888..4412d6febade 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -56,6 +56,7 @@ struct virtio_uml_device {
 	u8 status;
 	u8 registered:1;
 	u8 suspended:1;
+	u8 no_vq_suspend:1;
 
 	u8 config_changed_irq:1;
 	uint64_t vq_irq_vq_map;
@@ -1098,6 +1099,19 @@ static void virtio_uml_release_dev(struct device *d)
 	kfree(vu_dev);
 }
 
+void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev,
+				  bool no_vq_suspend)
+{
+	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
+
+	if (WARN_ON(vdev->config != &virtio_uml_config_ops))
+		return;
+
+	vu_dev->no_vq_suspend = no_vq_suspend;
+	dev_info(&vdev->dev, "%sabled VQ suspend\n",
+		 no_vq_suspend ? "dis" : "en");
+}
+
 /* Platform device */
 
 static int virtio_uml_probe(struct platform_device *pdev)
@@ -1302,13 +1316,16 @@ MODULE_DEVICE_TABLE(of, virtio_uml_match);
 static int virtio_uml_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
-	struct virtqueue *vq;
 
-	virtio_device_for_each_vq((&vu_dev->vdev), vq) {
-		struct virtio_uml_vq_info *info = vq->priv;
+	if (!vu_dev->no_vq_suspend) {
+		struct virtqueue *vq;
 
-		info->suspended = true;
-		vhost_user_set_vring_enable(vu_dev, vq->index, false);
+		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
+			struct virtio_uml_vq_info *info = vq->priv;
+
+			info->suspended = true;
+			vhost_user_set_vring_enable(vu_dev, vq->index, false);
+		}
 	}
 
 	if (!device_may_wakeup(&vu_dev->vdev.dev)) {
@@ -1322,13 +1339,16 @@ static int virtio_uml_suspend(struct platform_device *pdev, pm_message_t state)
 static int virtio_uml_resume(struct platform_device *pdev)
 {
 	struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
-	struct virtqueue *vq;
 
-	virtio_device_for_each_vq((&vu_dev->vdev), vq) {
-		struct virtio_uml_vq_info *info = vq->priv;
+	if (!vu_dev->no_vq_suspend) {
+		struct virtqueue *vq;
+
+		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
+			struct virtio_uml_vq_info *info = vq->priv;
 
-		info->suspended = false;
-		vhost_user_set_vring_enable(vu_dev, vq->index, true);
+			info->suspended = false;
+			vhost_user_set_vring_enable(vu_dev, vq->index, true);
+		}
 	}
 
 	vu_dev->suspended = false;
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index d7492e5a1bbb..e5a7b552bb38 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -7,8 +7,8 @@ generic-y += device.h
 generic-y += emergency-restart.h
 generic-y += exec.h
 generic-y += extable.h
+generic-y += fb.h
 generic-y += ftrace.h
-generic-y += futex.h
 generic-y += hw_irq.h
 generic-y += irq_regs.h
 generic-y += irq_work.h
@@ -17,7 +17,6 @@ generic-y += mcs_spinlock.h
 generic-y += mmiowb.h
 generic-y += module.lds.h
 generic-y += param.h
-generic-y += pci.h
 generic-y += percpu.h
 generic-y += preempt.h
 generic-y += softirq_stack.h
@@ -27,3 +26,4 @@ generic-y += trace_clock.h
 generic-y += word-at-a-time.h
 generic-y += kprobes.h
 generic-y += mm_hooks.h
+generic-y += vga.h
diff --git a/arch/um/include/asm/cacheflush.h b/arch/um/include/asm/cacheflush.h
new file mode 100644
index 000000000000..4c9858cd36ec
--- /dev/null
+++ b/arch/um/include/asm/cacheflush.h
@@ -0,0 +1,9 @@
+#ifndef __UM_ASM_CACHEFLUSH_H
+#define __UM_ASM_CACHEFLUSH_H
+
+#include <asm/tlbflush.h>
+#define flush_cache_vmap flush_tlb_kernel_range
+#define flush_cache_vunmap flush_tlb_kernel_range
+
+#include <asm-generic/cacheflush.h>
+#endif /* __UM_ASM_CACHEFLUSH_H */
diff --git a/arch/um/include/asm/cpufeature.h b/arch/um/include/asm/cpufeature.h
new file mode 100644
index 000000000000..19cd7ed6ec3c
--- /dev/null
+++ b/arch/um/include/asm/cpufeature.h
@@ -0,0 +1,157 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_UM_CPUFEATURE_H
+#define _ASM_UM_CPUFEATURE_H
+
+#include <asm/processor.h>
+
+#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
+
+#include <asm/asm.h>
+#include <linux/bitops.h>
+
+extern const char * const x86_cap_flags[NCAPINTS*32];
+extern const char * const x86_power_flags[32];
+#define X86_CAP_FMT "%s"
+#define x86_cap_flag(flag) x86_cap_flags[flag]
+
+/*
+ * In order to save room, we index into this array by doing
+ * X86_BUG_<name> - NCAPINTS*32.
+ */
+extern const char * const x86_bug_flags[NBUGINTS*32];
+
+#define test_cpu_cap(c, bit)						\
+	 test_bit(bit, (unsigned long *)((c)->x86_capability))
+
+/*
+ * There are 32 bits/features in each mask word.  The high bits
+ * (selected with (bit>>5) give us the word number and the low 5
+ * bits give us the bit/feature number inside the word.
+ * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
+ * see if it is set in the mask word.
+ */
+#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)	\
+	(((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
+
+#define cpu_has(c, bit)							\
+	 test_cpu_cap(c, bit)
+
+#define this_cpu_has(bit)						\
+	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
+	 x86_this_cpu_test_bit(bit,					\
+		(unsigned long __percpu *)&cpu_info.x86_capability))
+
+/*
+ * This macro is for detection of features which need kernel
+ * infrastructure to be used.  It may *not* directly test the CPU
+ * itself.  Use the cpu_has() family if you want true runtime
+ * testing of CPU features, like in hypervisor code where you are
+ * supporting a possible guest feature where host support for it
+ * is not relevant.
+ */
+#define cpu_feature_enabled(bit)	\
+	(__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
+
+#define boot_cpu_has(bit)	cpu_has(&boot_cpu_data, bit)
+
+#define set_cpu_cap(c, bit)	set_bit(bit, (unsigned long *)((c)->x86_capability))
+
+extern void setup_clear_cpu_cap(unsigned int bit);
+
+#define setup_force_cpu_cap(bit) do { \
+	set_cpu_cap(&boot_cpu_data, bit);	\
+	set_bit(bit, (unsigned long *)cpu_caps_set);	\
+} while (0)
+
+#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
+
+#if defined(__clang__) && !defined(CONFIG_CC_HAS_ASM_GOTO)
+
+/*
+ * Workaround for the sake of BPF compilation which utilizes kernel
+ * headers, but clang does not support ASM GOTO and fails the build.
+ */
+#ifndef __BPF_TRACING__
+#warning "Compiler lacks ASM_GOTO support. Add -D __BPF_TRACING__ to your compiler arguments"
+#endif
+
+#define static_cpu_has(bit)            boot_cpu_has(bit)
+
+#else
+
+/*
+ * Static testing of CPU features. Used the same as boot_cpu_has(). It
+ * statically patches the target code for additional performance. Use
+ * static_cpu_has() only in fast paths, where every cycle counts. Which
+ * means that the boot_cpu_has() variant is already fast enough for the
+ * majority of cases and you should stick to using it as it is generally
+ * only two instructions: a RIP-relative MOV and a TEST.
+ */
+static __always_inline bool _static_cpu_has(u16 bit)
+{
+	asm_volatile_goto("1: jmp 6f\n"
+		 "2:\n"
+		 ".skip -(((5f-4f) - (2b-1b)) > 0) * "
+			 "((5f-4f) - (2b-1b)),0x90\n"
+		 "3:\n"
+		 ".section .altinstructions,\"a\"\n"
+		 " .long 1b - .\n"		/* src offset */
+		 " .long 4f - .\n"		/* repl offset */
+		 " .word %P[always]\n"		/* always replace */
+		 " .byte 3b - 1b\n"		/* src len */
+		 " .byte 5f - 4f\n"		/* repl len */
+		 " .byte 3b - 2b\n"		/* pad len */
+		 ".previous\n"
+		 ".section .altinstr_replacement,\"ax\"\n"
+		 "4: jmp %l[t_no]\n"
+		 "5:\n"
+		 ".previous\n"
+		 ".section .altinstructions,\"a\"\n"
+		 " .long 1b - .\n"		/* src offset */
+		 " .long 0\n"			/* no replacement */
+		 " .word %P[feature]\n"		/* feature bit */
+		 " .byte 3b - 1b\n"		/* src len */
+		 " .byte 0\n"			/* repl len */
+		 " .byte 0\n"			/* pad len */
+		 ".previous\n"
+		 ".section .altinstr_aux,\"ax\"\n"
+		 "6:\n"
+		 " testb %[bitnum],%[cap_byte]\n"
+		 " jnz %l[t_yes]\n"
+		 " jmp %l[t_no]\n"
+		 ".previous\n"
+		 : : [feature]  "i" (bit),
+		     [always]   "i" (X86_FEATURE_ALWAYS),
+		     [bitnum]   "i" (1 << (bit & 7)),
+		     [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
+		 : : t_yes, t_no);
+t_yes:
+	return true;
+t_no:
+	return false;
+}
+
+#define static_cpu_has(bit)					\
+(								\
+	__builtin_constant_p(boot_cpu_has(bit)) ?		\
+		boot_cpu_has(bit) :				\
+		_static_cpu_has(bit)				\
+)
+#endif
+
+#define cpu_has_bug(c, bit)		cpu_has(c, (bit))
+#define set_cpu_bug(c, bit)		set_cpu_cap(c, (bit))
+
+#define static_cpu_has_bug(bit)		static_cpu_has((bit))
+#define boot_cpu_has_bug(bit)		cpu_has_bug(&boot_cpu_data, (bit))
+#define boot_cpu_set_bug(bit)		set_cpu_cap(&boot_cpu_data, (bit))
+
+#define MAX_CPU_FEATURES		(NCAPINTS * 32)
+#define cpu_have_feature		boot_cpu_has
+
+#define CPU_FEATURE_TYPEFMT		"x86,ven%04Xfam%04Xmod%04X"
+#define CPU_FEATURE_TYPEVAL		boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
+					boot_cpu_data.x86_model
+
+#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
+#endif /* _ASM_UM_CPUFEATURE_H */
diff --git a/arch/um/include/asm/fpu/api.h b/arch/um/include/asm/fpu/api.h
new file mode 100644
index 000000000000..71bfd9ef3938
--- /dev/null
+++ b/arch/um/include/asm/fpu/api.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ASM_UM_FPU_API_H
+#define _ASM_UM_FPU_API_H
+
+/* Copyright (c) 2020 Cambridge Greys Ltd
+ * Copyright (c) 2020 Red Hat Inc.
+ * A set of "dummy" defines to allow the direct inclusion
+ * of x86 optimized copy, xor, etc routines into the
+ * UML code tree. */
+
+#define kernel_fpu_begin() (void)0
+#define kernel_fpu_end() (void)0
+
+static inline bool irq_fpu_usable(void)
+{
+	return true;
+}
+
+
+#endif
diff --git a/arch/um/include/asm/futex.h b/arch/um/include/asm/futex.h
new file mode 100644
index 000000000000..780aa6bfc050
--- /dev/null
+++ b/arch/um/include/asm/futex.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_UM_FUTEX_H
+#define _ASM_UM_FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+
+
+int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr);
+int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval);
+
+#endif
diff --git a/arch/um/include/asm/io.h b/arch/um/include/asm/io.h
index 6ce18d343997..9ea42cc746d9 100644
--- a/arch/um/include/asm/io.h
+++ b/arch/um/include/asm/io.h
@@ -3,16 +3,23 @@
 #define _ASM_UM_IO_H
 #include <linux/types.h>
 
+/* get emulated iomem (if desired) */
+#include <asm-generic/logic_io.h>
+
+#ifndef ioremap
 #define ioremap ioremap
 static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
 {
 	return NULL;
 }
+#endif /* ioremap */
 
+#ifndef iounmap
 #define iounmap iounmap
 static inline void iounmap(void __iomem *addr)
 {
 }
+#endif /* iounmap */
 
 #include <asm-generic/io.h>
 
diff --git a/arch/um/include/asm/irq.h b/arch/um/include/asm/irq.h
index 3f5d3e8228fc..e187c789369d 100644
--- a/arch/um/include/asm/irq.h
+++ b/arch/um/include/asm/irq.h
@@ -31,7 +31,13 @@
 
 #endif
 
-#define NR_IRQS			64
+#define UM_LAST_SIGNAL_IRQ	64
+/* If we have (simulated) PCI MSI, allow 64 more interrupt numbers for it */
+#ifdef CONFIG_PCI_MSI
+#define NR_IRQS			(UM_LAST_SIGNAL_IRQ + 64)
+#else
+#define NR_IRQS			UM_LAST_SIGNAL_IRQ
+#endif /* CONFIG_PCI_MSI */
 
 #include <asm-generic/irq.h>
 #endif
diff --git a/arch/um/include/asm/irqflags.h b/arch/um/include/asm/irqflags.h
index 0642ad9035d1..dab5744e9253 100644
--- a/arch/um/include/asm/irqflags.h
+++ b/arch/um/include/asm/irqflags.h
@@ -2,15 +2,15 @@
 #ifndef __UM_IRQFLAGS_H
 #define __UM_IRQFLAGS_H
 
-extern int get_signals(void);
-extern int set_signals(int enable);
-extern void block_signals(void);
-extern void unblock_signals(void);
+extern int signals_enabled;
+int set_signals(int enable);
+void block_signals(void);
+void unblock_signals(void);
 
 #define arch_local_save_flags arch_local_save_flags
 static inline unsigned long arch_local_save_flags(void)
 {
-	return get_signals();
+	return signals_enabled;
 }
 
 #define arch_local_irq_restore arch_local_irq_restore
diff --git a/arch/um/include/asm/msi.h b/arch/um/include/asm/msi.h
new file mode 100644
index 000000000000..c8c6c381f394
--- /dev/null
+++ b/arch/um/include/asm/msi.h
@@ -0,0 +1 @@
+#include <asm-generic/msi.h>
diff --git a/arch/um/include/asm/pci.h b/arch/um/include/asm/pci.h
new file mode 100644
index 000000000000..da13fd5519ef
--- /dev/null
+++ b/arch/um/include/asm/pci.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_UM_PCI_H
+#define __ASM_UM_PCI_H
+#include <linux/types.h>
+#include <asm/io.h>
+
+#define PCIBIOS_MIN_IO		0
+#define PCIBIOS_MIN_MEM		0
+
+#define pcibios_assign_all_busses() 1
+
+extern int isa_dma_bridge_buggy;
+
+#ifdef CONFIG_PCI
+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+{
+	/* no legacy IRQs */
+	return -ENODEV;
+}
+#endif
+
+#ifdef CONFIG_PCI_DOMAINS
+static inline int pci_proc_domain(struct pci_bus *bus)
+{
+	/* always show the domain in /proc */
+	return 1;
+}
+#endif  /* CONFIG_PCI */
+
+#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
+/*
+ * This is a bit of an annoying hack, and it assumes we only have
+ * the virt-pci (if anything). Which is true, but still.
+ */
+void *pci_root_bus_fwnode(struct pci_bus *bus);
+#define pci_root_bus_fwnode	pci_root_bus_fwnode
+#endif
+
+#endif  /* __ASM_UM_PCI_H */
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index afd9b267cf81..b5cf0ed116d9 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -16,6 +16,8 @@ struct task_struct;
 
 #include <linux/prefetch.h>
 
+#include <asm/cpufeatures.h>
+
 struct mm_struct;
 
 struct thread_struct {
@@ -90,12 +92,18 @@ extern void start_thread(struct pt_regs *regs, unsigned long entry,
 struct cpuinfo_um {
 	unsigned long loops_per_jiffy;
 	int ipi_pipe[2];
+	int cache_alignment;
+	union {
+		__u32		x86_capability[NCAPINTS + NBUGINTS];
+		unsigned long	x86_capability_alignment;
+	};
 };
 
 extern struct cpuinfo_um boot_cpu_data;
 
 #define cpu_data (&boot_cpu_data)
 #define current_cpu_data boot_cpu_data
+#define cache_line_size()	(boot_cpu_data.cache_alignment)
 
 #define KSTK_REG(tsk, reg) get_thread_reg(reg, &tsk->thread.switch_buf)
 extern unsigned long get_wchan(struct task_struct *p);
diff --git a/arch/um/include/asm/tlb.h b/arch/um/include/asm/tlb.h
index ff9c62828962..0422467bda5b 100644
--- a/arch/um/include/asm/tlb.h
+++ b/arch/um/include/asm/tlb.h
@@ -5,7 +5,7 @@
 #include <linux/mm.h>
 
 #include <asm/tlbflush.h>
-#include <asm-generic/cacheflush.h>
+#include <asm/cacheflush.h>
 #include <asm-generic/tlb.h>
 
 #endif
diff --git a/arch/um/include/asm/xor.h b/arch/um/include/asm/xor.h
index 36b33d62a35d..f512704a9ec7 100644
--- a/arch/um/include/asm/xor.h
+++ b/arch/um/include/asm/xor.h
@@ -1,7 +1,22 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#include <asm-generic/xor.h>
+#ifndef _ASM_UM_XOR_H
+#define _ASM_UM_XOR_H
+
+#ifdef CONFIG_64BIT
+#undef CONFIG_X86_32
+#else
+#define CONFIG_X86_32 1
+#endif
+
+#include <asm/cpufeature.h>
+#include <../../x86/include/asm/xor.h>
 #include <linux/time-internal.h>
 
+#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
+#undef XOR_SELECT_TEMPLATE
 /* pick an arbitrary one - measuring isn't possible with inf-cpu */
 #define XOR_SELECT_TEMPLATE(x)	\
 	(time_travel_mode == TT_MODE_INFCPU ? &xor_block_8regs : NULL)
+#endif
+
+#endif
diff --git a/arch/um/include/linux/time-internal.h b/arch/um/include/linux/time-internal.h
index 759956ab0108..b22226634ff6 100644
--- a/arch/um/include/linux/time-internal.h
+++ b/arch/um/include/linux/time-internal.h
@@ -8,17 +8,11 @@
 #define __TIMER_INTERNAL_H__
 #include <linux/list.h>
 #include <asm/bug.h>
+#include <shared/timetravel.h>
 
 #define TIMER_MULTIPLIER 256
 #define TIMER_MIN_DELTA  500
 
-enum time_travel_mode {
-	TT_MODE_OFF,
-	TT_MODE_BASIC,
-	TT_MODE_INFCPU,
-	TT_MODE_EXTERNAL,
-};
-
 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
 struct time_travel_event {
 	unsigned long long time;
@@ -27,8 +21,6 @@ struct time_travel_event {
 	bool pending, onstack;
 };
 
-extern enum time_travel_mode time_travel_mode;
-
 void time_travel_sleep(void);
 
 static inline void
@@ -62,8 +54,6 @@ bool time_travel_del_event(struct time_travel_event *e);
 struct time_travel_event {
 };
 
-#define time_travel_mode TT_MODE_OFF
-
 static inline void time_travel_sleep(void)
 {
 }
diff --git a/arch/um/include/linux/virtio-uml.h b/arch/um/include/linux/virtio-uml.h
new file mode 100644
index 000000000000..2f652fa90f04
--- /dev/null
+++ b/arch/um/include/linux/virtio-uml.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Intel Corporation
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+
+#ifndef __VIRTIO_UML_H__
+#define __VIRTIO_UML_H__
+
+void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev,
+				  bool no_vq_suspend);
+
+#endif /* __VIRTIO_UML_H__ */
diff --git a/arch/um/include/shared/irq_user.h b/arch/um/include/shared/irq_user.h
index 07239e801a5b..065829f443ae 100644
--- a/arch/um/include/shared/irq_user.h
+++ b/arch/um/include/shared/irq_user.h
@@ -17,6 +17,7 @@ enum um_irq_type {
 
 struct siginfo;
 extern void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
+void sigio_run_timetravel_handlers(void);
 extern void free_irq_by_fd(int fd);
 extern void deactivate_fd(int fd, int irqnum);
 extern int deactivate_all_fds(void);
diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index 2888ec812f6e..a2cfd42608a0 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h
@@ -33,7 +33,6 @@ extern int handle_page_fault(unsigned long address, unsigned long ip,
 			     int is_write, int is_user, int *code_out);
 
 extern unsigned int do_IRQ(int irq, struct uml_pt_regs *regs);
-extern int smp_sigio_handler(void);
 extern void initial_thread_cb(void (*proc)(void *), void *arg);
 extern int is_syscall(unsigned long addr);
 
diff --git a/arch/um/include/shared/longjmp.h b/arch/um/include/shared/longjmp.h
index 85a1cc290ecb..bdb2869b72b3 100644
--- a/arch/um/include/shared/longjmp.h
+++ b/arch/um/include/shared/longjmp.h
@@ -5,6 +5,7 @@
 #include <sysdep/archsetjmp.h>
 #include <os.h>
 
+extern int signals_enabled;
 extern int setjmp(jmp_buf);
 extern void longjmp(jmp_buf, int);
 
@@ -12,13 +13,12 @@ extern void longjmp(jmp_buf, int);
 	longjmp(*buf, val);	\
 } while(0)
 
-#define UML_SETJMP(buf) ({ \
-	int n;	   \
-	volatile int enable;	\
-	enable = get_signals(); \
-	n = setjmp(*buf); \
-	if(n != 0) \
-		set_signals_trace(enable); \
+#define UML_SETJMP(buf) ({				\
+	int n, enable;					\
+	enable = *(volatile int *)&signals_enabled;	\
+	n = setjmp(*buf);				\
+	if(n != 0)					\
+		set_signals_trace(enable);		\
 	n; })
 
 #endif
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 13d86f94cf0f..60b84edc8a68 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -187,6 +187,9 @@ int os_poll(unsigned int n, const int *fds);
 extern void os_early_checks(void);
 extern void os_check_bugs(void);
 extern void check_host_supports_tls(int *supports_tls, int *tls_min);
+extern void get_host_cpu_features(
+	void (*flags_helper_func)(char *line),
+	void (*cache_helper_func)(char *line));
 
 /* mem.c */
 extern int create_mem_file(unsigned long long len);
@@ -211,7 +214,6 @@ extern int os_protect_memory(void *addr, unsigned long len,
 extern int os_unmap_memory(void *addr, int len);
 extern int os_drop_memory(void *addr, int length);
 extern int can_drop_memory(void);
-extern void os_flush_stdout(void);
 extern int os_mincore(void *addr, unsigned long len);
 
 /* execvp.c */
@@ -237,12 +239,14 @@ extern void send_sigio_to_self(void);
 extern int change_sig(int signal, int on);
 extern void block_signals(void);
 extern void unblock_signals(void);
-extern int get_signals(void);
 extern int set_signals(int enable);
 extern int set_signals_trace(int enable);
 extern int os_is_signal_stack(void);
 extern void deliver_alarm(void);
 extern void register_pm_wake_signal(void);
+extern void block_signals_hard(void);
+extern void unblock_signals_hard(void);
+extern void mark_sigio_pending(void);
 
 /* util.c */
 extern void stack_protections(unsigned long address);
diff --git a/arch/um/include/shared/timetravel.h b/arch/um/include/shared/timetravel.h
new file mode 100644
index 000000000000..e5c3d69f1b69
--- /dev/null
+++ b/arch/um/include/shared/timetravel.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2021 Intel Corporation
+ */
+#ifndef _UM_TIME_TRAVEL_H_
+#define _UM_TIME_TRAVEL_H_
+
+enum time_travel_mode {
+	TT_MODE_OFF,
+	TT_MODE_BASIC,
+	TT_MODE_INFCPU,
+	TT_MODE_EXTERNAL,
+};
+
+#if defined(UML_CONFIG_UML_TIME_TRAVEL_SUPPORT) || \
+    defined(CONFIG_UML_TIME_TRAVEL_SUPPORT)
+extern enum time_travel_mode time_travel_mode;
+#else
+#define time_travel_mode TT_MODE_OFF
+#endif /* (UML_)CONFIG_UML_TIME_TRAVEL_SUPPORT */
+
+#endif /* _UM_TIME_TRAVEL_H_ */
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index e698e0c7dbdc..1d18e4e46989 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -17,18 +17,19 @@ extra-y := vmlinux.lds
 obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
 	physmem.o process.o ptrace.o reboot.o sigio.o \
 	signal.o syscall.o sysrq.o time.o tlb.o trap.o \
-	um_arch.o umid.o maccess.o kmsg_dump.o skas/
+	um_arch.o umid.o maccess.o kmsg_dump.o capflags.o skas/
 
 obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
 obj-$(CONFIG_GPROF)	+= gprof_syms.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
 
 USER_OBJS := config.o
 
 include arch/um/scripts/Makefile.rules
 
-targets := config.c config.tmp
+targets := config.c config.tmp capflags.c
 
 # Be careful with the below Sed code - sed is pitfall-rich!
 # We use sed to lower build requirements, for "embedded" builders for instance.
@@ -43,6 +44,15 @@ quiet_cmd_quote1 = QUOTE   $@
 $(obj)/config.c: $(src)/config.c.in $(obj)/config.tmp FORCE
 	$(call if_changed,quote2)
 
+quiet_cmd_mkcapflags = MKCAP   $@
+      cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/../../x86/kernel/cpu/mkcapflags.sh $@ $^
+
+cpufeature = $(src)/../../x86/include/asm/cpufeatures.h
+vmxfeature = $(src)/../../x86/include/asm/vmxfeatures.h
+
+$(obj)/capflags.c: $(cpufeature) $(vmxfeature) $(src)/../../x86/kernel/cpu/mkcapflags.sh FORCE
+	$(call if_changed,mkcapflags)
+
 quiet_cmd_quote2 = QUOTE   $@
       cmd_quote2 = sed -e '/CONFIG/{'          \
 		  -e 's/"CONFIG"//'            \
diff --git a/arch/um/kernel/ioport.c b/arch/um/kernel/ioport.c
new file mode 100644
index 000000000000..7220615b3beb
--- /dev/null
+++ b/arch/um/kernel/ioport.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Intel Corporation
+ * Author: Johannes Berg <johannes@sipsolutions.net>
+ */
+#include <asm/iomap.h>
+#include <asm-generic/pci_iomap.h>
+
+void __iomem *__pci_ioport_map(struct pci_dev *dev, unsigned long port,
+			       unsigned int nr)
+{
+	return NULL;
+}
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 82af5191e73d..a8873d9bc28b 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -56,7 +56,7 @@ struct irq_entry {
 
 static DEFINE_SPINLOCK(irq_lock);
 static LIST_HEAD(active_fds);
-static DECLARE_BITMAP(irqs_allocated, NR_IRQS);
+static DECLARE_BITMAP(irqs_allocated, UM_LAST_SIGNAL_IRQ);
 static bool irqs_suspended;
 
 static void irq_io_loop(struct irq_reg *irq, struct uml_pt_regs *regs)
@@ -101,10 +101,12 @@ static bool irq_do_timetravel_handler(struct irq_entry *entry,
 	if (!reg->timetravel_handler)
 		return false;
 
-	/* prevent nesting - we'll get it again later when we SIGIO ourselves */
-	if (reg->pending_on_resume)
-		return true;
-
+	/*
+	 * Handle all messages - we might get multiple even while
+	 * interrupts are already suspended, due to suspend order
+	 * etc. Note that time_travel_add_irq_event() will not add
+	 * an event twice, if it's pending already "first wins".
+	 */
 	reg->timetravel_handler(reg->irq, entry->fd, reg->id, &reg->event);
 
 	if (!reg->event.pending)
@@ -123,7 +125,8 @@ static bool irq_do_timetravel_handler(struct irq_entry *entry,
 #endif
 
 static void sigio_reg_handler(int idx, struct irq_entry *entry, enum um_irq_type t,
-			      struct uml_pt_regs *regs)
+			      struct uml_pt_regs *regs,
+			      bool timetravel_handlers_only)
 {
 	struct irq_reg *reg = &entry->reg[t];
 
@@ -136,18 +139,29 @@ static void sigio_reg_handler(int idx, struct irq_entry *entry, enum um_irq_type
 	if (irq_do_timetravel_handler(entry, t))
 		return;
 
-	if (irqs_suspended)
+	/*
+	 * If we're called to only run time-travel handlers then don't
+	 * actually proceed but mark sigio as pending (if applicable).
+	 * For suspend/resume, timetravel_handlers_only may be true
+	 * despite time-travel not being configured and used.
+	 */
+	if (timetravel_handlers_only) {
+#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
+		mark_sigio_pending();
+#endif
 		return;
+	}
 
 	irq_io_loop(reg, regs);
 }
 
-void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
+static void _sigio_handler(struct uml_pt_regs *regs,
+			   bool timetravel_handlers_only)
 {
 	struct irq_entry *irq_entry;
 	int n, i;
 
-	if (irqs_suspended && !um_irq_timetravel_handler_used())
+	if (timetravel_handlers_only && !um_irq_timetravel_handler_used())
 		return;
 
 	while (1) {
@@ -172,14 +186,20 @@ void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 			irq_entry = os_epoll_get_data_pointer(i);
 
 			for (t = 0; t < NUM_IRQ_TYPES; t++)
-				sigio_reg_handler(i, irq_entry, t, regs);
+				sigio_reg_handler(i, irq_entry, t, regs,
+						  timetravel_handlers_only);
 		}
 	}
 
-	if (!irqs_suspended)
+	if (!timetravel_handlers_only)
 		free_irqs();
 }
 
+void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
+{
+	_sigio_handler(regs, irqs_suspended);
+}
+
 static struct irq_entry *get_irq_entry_by_fd(int fd)
 {
 	struct irq_entry *walk;
@@ -399,7 +419,8 @@ unsigned int do_IRQ(int irq, struct uml_pt_regs *regs)
 
 void um_free_irq(int irq, void *dev)
 {
-	if (WARN(irq < 0 || irq > NR_IRQS, "freeing invalid irq %d", irq))
+	if (WARN(irq < 0 || irq > UM_LAST_SIGNAL_IRQ,
+		 "freeing invalid irq %d", irq))
 		return;
 
 	free_irq_by_irq_and_dev(irq, dev);
@@ -467,6 +488,11 @@ int um_request_irq_tt(int irq, int fd, enum um_irq_type type,
 			       devname, dev_id, timetravel_handler);
 }
 EXPORT_SYMBOL(um_request_irq_tt);
+
+void sigio_run_timetravel_handlers(void)
+{
+	_sigio_handler(NULL, true);
+}
 #endif
 
 #ifdef CONFIG_PM_SLEEP
@@ -623,7 +649,7 @@ void __init init_IRQ(void)
 
 	irq_set_chip_and_handler(TIMER_IRQ, &alarm_irq_type, handle_edge_irq);
 
-	for (i = 1; i < NR_IRQS; i++)
+	for (i = 1; i < UM_LAST_SIGNAL_IRQ; i++)
 		irq_set_chip_and_handler(i, &normal_irq_type, handle_edge_irq);
 	/* Initialize EPOLL Loop */
 	os_setup_epoll();
diff --git a/arch/um/kernel/ksyms.c b/arch/um/kernel/ksyms.c
index 8ade54a86a7e..b1e5634398d0 100644
--- a/arch/um/kernel/ksyms.c
+++ b/arch/um/kernel/ksyms.c
@@ -7,7 +7,7 @@
 #include <os.h>
 
 EXPORT_SYMBOL(set_signals);
-EXPORT_SYMBOL(get_signals);
+EXPORT_SYMBOL(signals_enabled);
 
 EXPORT_SYMBOL(os_stat_fd);
 EXPORT_SYMBOL(os_stat_file);
diff --git a/arch/um/kernel/skas/clone.c b/arch/um/kernel/skas/clone.c
index 592cdb138441..5afac0fef24e 100644
--- a/arch/um/kernel/skas/clone.c
+++ b/arch/um/kernel/skas/clone.c
@@ -29,7 +29,7 @@ stub_clone_handler(void)
 	long err;
 
 	err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
-			    (unsigned long)data + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
+			    (unsigned long)data + UM_KERN_PAGE_SIZE / 2);
 	if (err) {
 		data->parent_err = err;
 		goto done;
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index 2dec915abe6f..6c76df96e858 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -11,6 +11,7 @@
 #include <asm/current.h>
 #include <asm/page.h>
 #include <kern_util.h>
+#include <asm/futex.h>
 #include <os.h>
 
 pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
@@ -248,3 +249,138 @@ long __strnlen_user(const void __user *str, long len)
 	return 0;
 }
 EXPORT_SYMBOL(__strnlen_user);
+
+/**
+ * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
+ *			  argument and comparison of the previous
+ *			  futex value with another constant.
+ *
+ * @encoded_op:	encoded operation to execute
+ * @uaddr:	pointer to user space address
+ *
+ * Return:
+ * 0 - On success
+ * -EFAULT - User access resulted in a page fault
+ * -EAGAIN - Atomic operation was unable to complete due to contention
+ * -ENOSYS - Operation not supported
+ */
+
+int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
+{
+	int oldval, ret;
+	struct page *page;
+	unsigned long addr = (unsigned long) uaddr;
+	pte_t *pte;
+
+	ret = -EFAULT;
+	if (!access_ok(uaddr, sizeof(*uaddr)))
+		return -EFAULT;
+	preempt_disable();
+	pte = maybe_map(addr, 1);
+	if (pte == NULL)
+		goto out_inuser;
+
+	page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+	pagefault_disable();
+	addr = (unsigned long) page_address(page) +
+			(((unsigned long) addr) & ~PAGE_MASK);
+#else
+	addr = (unsigned long) kmap_atomic(page) +
+		((unsigned long) addr & ~PAGE_MASK);
+#endif
+	uaddr = (u32 *) addr;
+	oldval = *uaddr;
+
+	ret = 0;
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		*uaddr = oparg;
+		break;
+	case FUTEX_OP_ADD:
+		*uaddr += oparg;
+		break;
+	case FUTEX_OP_OR:
+		*uaddr |= oparg;
+		break;
+	case FUTEX_OP_ANDN:
+		*uaddr &= ~oparg;
+		break;
+	case FUTEX_OP_XOR:
+		*uaddr ^= oparg;
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+#ifdef CONFIG_64BIT
+	pagefault_enable();
+#else
+	kunmap_atomic((void *)addr);
+#endif
+
+out_inuser:
+	preempt_enable();
+
+	if (ret == 0)
+		*oval = oldval;
+
+	return ret;
+}
+EXPORT_SYMBOL(arch_futex_atomic_op_inuser);
+
+/**
+ * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
+ *				uaddr with newval if the current value is
+ *				oldval.
+ * @uval:	pointer to store content of @uaddr
+ * @uaddr:	pointer to user space address
+ * @oldval:	old value
+ * @newval:	new value to store to @uaddr
+ *
+ * Return:
+ * 0 - On success
+ * -EFAULT - User access resulted in a page fault
+ * -EAGAIN - Atomic operation was unable to complete due to contention
+ * -ENOSYS - Function not implemented (only if !HAVE_FUTEX_CMPXCHG)
+ */
+
+int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval)
+{
+	struct page *page;
+	pte_t *pte;
+	int ret = -EFAULT;
+
+	if (!access_ok(uaddr, sizeof(*uaddr)))
+		return -EFAULT;
+
+	preempt_disable();
+	pte = maybe_map((unsigned long) uaddr, 1);
+	if (pte == NULL)
+		goto out_inatomic;
+
+	page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+	pagefault_disable();
+	uaddr = page_address(page) + (((unsigned long) uaddr) & ~PAGE_MASK);
+#else
+	uaddr = kmap_atomic(page) + ((unsigned long) uaddr & ~PAGE_MASK);
+#endif
+
+	*uval = *uaddr;
+
+	ret = cmpxchg(uaddr, oldval, newval);
+
+#ifdef CONFIG_64BIT
+	pagefault_enable();
+#else
+	kunmap_atomic(uaddr);
+#endif
+	ret = 0;
+
+out_inatomic:
+	preempt_enable();
+	return ret;
+}
+EXPORT_SYMBOL(futex_atomic_cmpxchg_inatomic);
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index e0cdb9694fb8..fddd1dec27e6 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -68,23 +68,15 @@ static void time_travel_handle_message(struct um_timetravel_msg *msg,
 	int ret;
 
 	/*
-	 * Poll outside the locked section (if we're not called to only read
-	 * the response) so we can get interrupts for e.g. virtio while we're
-	 * here, but then we need to lock to not get interrupted between the
-	 * read of the message and write of the ACK.
+	 * We can't unlock here, but interrupt signals with a timetravel_handler
+	 * (see um_request_irq_tt) get to the timetravel_handler anyway.
 	 */
 	if (mode != TTMH_READ) {
-		bool disabled = irqs_disabled();
+		BUG_ON(mode == TTMH_IDLE && !irqs_disabled());
 
-		BUG_ON(mode == TTMH_IDLE && !disabled);
-
-		if (disabled)
-			local_irq_enable();
 		while (os_poll(1, &time_travel_ext_fd) != 0) {
 			/* nothing */
 		}
-		if (disabled)
-			local_irq_disable();
 	}
 
 	ret = os_read_file(time_travel_ext_fd, msg, sizeof(*msg));
@@ -123,15 +115,15 @@ static u64 time_travel_ext_req(u32 op, u64 time)
 		.time = time,
 		.seq = mseq,
 	};
-	unsigned long flags;
 
 	/*
-	 * We need to save interrupts here and only restore when we
-	 * got the ACK - otherwise we can get interrupted and send
-	 * another request while we're still waiting for an ACK, but
-	 * the peer doesn't know we got interrupted and will send
-	 * the ACKs in the same order as the message, but we'd need
-	 * to see them in the opposite order ...
+	 * We need to block even the timetravel handlers of SIGIO here and
+	 * only restore their use when we got the ACK - otherwise we may
+	 * (will) get interrupted by that, try to queue the IRQ for future
+	 * processing and thus send another request while we're still waiting
+	 * for an ACK, but the peer doesn't know we got interrupted and will
+	 * send the ACKs in the same order as the message, but we'd need to
+	 * see them in the opposite order ...
 	 *
 	 * This wouldn't matter *too* much, but some ACKs carry the
 	 * current time (for UM_TIMETRAVEL_GET) and getting another
@@ -140,7 +132,7 @@ static u64 time_travel_ext_req(u32 op, u64 time)
 	 * The sequence number assignment that happens here lets us
 	 * debug such message handling issues more easily.
 	 */
-	local_irq_save(flags);
+	block_signals_hard();
 	os_write_file(time_travel_ext_fd, &msg, sizeof(msg));
 
 	while (msg.op != UM_TIMETRAVEL_ACK)
@@ -152,7 +144,7 @@ static u64 time_travel_ext_req(u32 op, u64 time)
 
 	if (op == UM_TIMETRAVEL_GET)
 		time_travel_set_time(msg.time);
-	local_irq_restore(flags);
+	unblock_signals_hard();
 
 	return msg.time;
 }
@@ -352,9 +344,6 @@ void deliver_time_travel_irqs(void)
 	while ((e = list_first_entry_or_null(&time_travel_irqs,
 					     struct time_travel_event,
 					     list))) {
-		WARN(e->time != time_travel_time,
-		     "time moved from %lld to %lld before IRQ delivery\n",
-		     time_travel_time, e->time);
 		list_del(&e->list);
 		e->pending = false;
 		e->fn(e);
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 9512253947d5..a149a5e9a16a 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -6,6 +6,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/mm.h>
+#include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/panic_notifier.h>
 #include <linux/seq_file.h>
@@ -17,6 +18,7 @@
 #include <linux/suspend.h>
 
 #include <asm/processor.h>
+#include <asm/cpufeature.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <as-layout.h>
@@ -51,9 +53,13 @@ static void __init add_arg(char *arg)
  */
 struct cpuinfo_um boot_cpu_data = {
 	.loops_per_jiffy	= 0,
-	.ipi_pipe		= { -1, -1 }
+	.ipi_pipe		= { -1, -1 },
+	.cache_alignment	= L1_CACHE_BYTES,
+	.x86_capability		= { 0 }
 };
 
+EXPORT_SYMBOL(boot_cpu_data);
+
 union thread_union cpu0_irqstack
 	__section(".data..init_irqstack") =
 		{ .thread_info = INIT_THREAD_INFO(init_task) };
@@ -63,17 +69,25 @@ static char host_info[(__NEW_UTS_LEN + 1) * 5];
 
 static int show_cpuinfo(struct seq_file *m, void *v)
 {
-	int index = 0;
+	int i = 0;
 
-	seq_printf(m, "processor\t: %d\n", index);
+	seq_printf(m, "processor\t: %d\n", i);
 	seq_printf(m, "vendor_id\t: User Mode Linux\n");
 	seq_printf(m, "model name\t: UML\n");
 	seq_printf(m, "mode\t\t: skas\n");
 	seq_printf(m, "host\t\t: %s\n", host_info);
-	seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
+	seq_printf(m, "fpu\t\t: %s\n", cpu_has(&boot_cpu_data, X86_FEATURE_FPU) ? "yes" : "no");
+	seq_printf(m, "flags\t\t:");
+	for (i = 0; i < 32*NCAPINTS; i++)
+		if (cpu_has(&boot_cpu_data, i) && (x86_cap_flags[i] != NULL))
+			seq_printf(m, " %s", x86_cap_flags[i]);
+	seq_printf(m, "\n");
+	seq_printf(m, "cache_alignment\t: %d\n", boot_cpu_data.cache_alignment);
+	seq_printf(m, "bogomips\t: %lu.%02lu\n",
 		   loops_per_jiffy/(500000/HZ),
 		   (loops_per_jiffy/(5000/HZ)) % 100);
 
+
 	return 0;
 }
 
@@ -262,6 +276,30 @@ EXPORT_SYMBOL(end_iomem);
 
 #define MIN_VMALLOC (32 * 1024 * 1024)
 
+static void parse_host_cpu_flags(char *line)
+{
+	int i;
+	for (i = 0; i < 32*NCAPINTS; i++) {
+		if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i]))
+			set_cpu_cap(&boot_cpu_data, i);
+	}
+}
+static void parse_cache_line(char *line)
+{
+	long res;
+	char *to_parse = strstr(line, ":");
+	if (to_parse) {
+		to_parse++;
+		while (*to_parse != 0 && isspace(*to_parse)) {
+			to_parse++;
+		}
+		if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res))
+			boot_cpu_data.cache_alignment = res;
+		else
+			boot_cpu_data.cache_alignment = L1_CACHE_BYTES;
+	}
+}
+
 int __init linux_main(int argc, char **argv)
 {
 	unsigned long avail, diff;
@@ -298,6 +336,8 @@ int __init linux_main(int argc, char **argv)
 	/* OS sanity checks that need to happen before the kernel runs */
 	os_early_checks();
 
+	get_host_cpu_features(parse_host_cpu_flags, parse_cache_line);
+
 	brk_start = (unsigned long) sbrk(0);
 
 	/*
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 9fa6e4187d4f..32e88baf18dd 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -64,7 +64,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
 		goto out_close;
 	}
 
-	sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
+	sp = stack + UM_KERN_PAGE_SIZE;
 	data.pre_exec = pre_exec;
 	data.pre_data = pre_data;
 	data.argv = argv;
@@ -120,7 +120,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
 	if (stack == 0)
 		return -ENOMEM;
 
-	sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
+	sp = stack + UM_KERN_PAGE_SIZE;
 	pid = clone(proc, (void *) sp, flags, arg);
 	if (pid < 0) {
 		err = -errno;
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 96f511d1aabe..6de99bb16113 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -18,6 +18,7 @@
 #include <sysdep/mcontext.h>
 #include <um_malloc.h>
 #include <sys/ucontext.h>
+#include <timetravel.h>
 
 void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
 	[SIGTRAP]	= relay_signal,
@@ -62,17 +63,30 @@ static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
 #define SIGALRM_BIT 1
 #define SIGALRM_MASK (1 << SIGALRM_BIT)
 
-static int signals_enabled;
+int signals_enabled;
+#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+static int signals_blocked;
+#else
+#define signals_blocked false
+#endif
 static unsigned int signals_pending;
 static unsigned int signals_active = 0;
 
 void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
 {
-	int enabled;
+	int enabled = signals_enabled;
 
-	enabled = signals_enabled;
-	if (!enabled && (sig == SIGIO)) {
-		signals_pending |= SIGIO_MASK;
+	if ((signals_blocked || !enabled) && (sig == SIGIO)) {
+		/*
+		 * In TT_MODE_EXTERNAL, need to still call time-travel
+		 * handlers unless signals are also blocked for the
+		 * external time message processing. This will mark
+		 * signals_pending by itself (only if necessary.)
+		 */
+		if (!signals_blocked && time_travel_mode == TT_MODE_EXTERNAL)
+			sigio_run_timetravel_handlers();
+		else
+			signals_pending |= SIGIO_MASK;
 		return;
 	}
 
@@ -129,7 +143,7 @@ void set_sigstack(void *sig_stack, int size)
 	stack_t stack = {
 		.ss_flags = 0,
 		.ss_sp = sig_stack,
-		.ss_size = size - sizeof(void *)
+		.ss_size = size
 	};
 
 	if (sigaltstack(&stack, NULL) != 0)
@@ -334,11 +348,6 @@ void unblock_signals(void)
 	}
 }
 
-int get_signals(void)
-{
-	return signals_enabled;
-}
-
 int set_signals(int enable)
 {
 	int ret;
@@ -368,6 +377,39 @@ int set_signals_trace(int enable)
 	return ret;
 }
 
+#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+void mark_sigio_pending(void)
+{
+	signals_pending |= SIGIO_MASK;
+}
+
+void block_signals_hard(void)
+{
+	if (signals_blocked)
+		return;
+	signals_blocked = 1;
+	barrier();
+}
+
+void unblock_signals_hard(void)
+{
+	if (!signals_blocked)
+		return;
+	/* Must be set to 0 before we check the pending bits etc. */
+	signals_blocked = 0;
+	barrier();
+
+	if (signals_pending && signals_enabled) {
+		/* this is a bit inefficient, but that's not really important */
+		block_signals();
+		unblock_signals();
+	} else if (signals_pending & SIGIO_MASK) {
+		/* we need to run time-travel handlers even if not enabled */
+		sigio_run_timetravel_handlers();
+	}
+}
+#endif
+
 int os_is_signal_stack(void)
 {
 	stack_t ss;
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index fba674fac8b7..87d3129e7362 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -327,7 +327,7 @@ int start_userspace(unsigned long stub_stack)
 	}
 
 	/* set stack pointer to the end of the stack page, so it can grow downwards */
-	sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
+	sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
 
 	flags = CLONE_FILES | SIGCHLD;
 
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index f79dc338279e..8a72c99994eb 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -321,6 +321,38 @@ static void __init check_coredump_limit(void)
 		os_info("%llu\n", (unsigned long long)lim.rlim_max);
 }
 
+void  __init get_host_cpu_features(
+		void (*flags_helper_func)(char *line),
+		void (*cache_helper_func)(char *line))
+{
+	FILE *cpuinfo;
+	char *line = NULL;
+	size_t len = 0;
+	int done_parsing = 0;
+
+	cpuinfo = fopen("/proc/cpuinfo", "r");
+	if (cpuinfo == NULL) {
+		os_info("Failed to get host CPU features\n");
+	} else {
+		while ((getline(&line, &len, cpuinfo)) != -1) {
+			if (strstr(line, "flags")) {
+				flags_helper_func(line);
+				done_parsing++;
+			}
+			if (strstr(line, "cache_alignment")) {
+				cache_helper_func(line);
+				done_parsing++;
+			}
+			free(line);
+			line = NULL;
+			if (done_parsing > 1)
+				break;
+		}
+		fclose(cpuinfo);
+	}
+}
+
+
 void __init os_early_checks(void)
 {
 	int pid;