Merge tag 'uml-for-linux-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Johannes Berg:

 - proper nofault accesses and read-only rodata

 - hostfs fix for host inode number reuse

 - fixes for host errno handling

 - various cleanups/small fixes

* tag 'uml-for-linux-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: Rewrite the sigio workaround based on epoll and tgkill
  um: Prohibit the VM_CLONE flag in run_helper_thread()
  um: Switch to the pthread-based helper in sigio workaround
  um: ubd: Switch to the pthread-based helper
  um: Add pthread-based helper support
  um: x86: clean up elf specific definitions
  um: Store full CSGSFS and SS register from mcontext
  um: virt-pci: Refactor virtio_pcidev into its own module
  um: work around sched_yield not yielding in time-travel mode
  um/locking: Remove semicolon from "lock" prefix
  um: Update min_low_pfn to match changes in uml_reserved
  um: use str_yes_no() to remove hardcoded "yes" and "no"
  um: hostfs: avoid issues on inode number reuse by host
  um: Allocate vdso page pointer statically
  um: remove copy_from_kernel_nofault_allowed
  um: mark rodata read-only and implement _nofault accesses
  um: Pass the correct Rust target and options with gcc

44 files changed, 1121 insertions, 1111 deletions

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 18051b1cfce0..79509c7f39de 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -12,6 +12,7 @@ config UML
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_STRNCPY_FROM_USER
 	select ARCH_HAS_STRNLEN_USER
+	select ARCH_HAS_STRICT_KERNEL_RWX
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_KASAN if X86_64
 	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
index ede40a160c5e..9cb196070614 100644
--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -345,16 +345,20 @@ config UML_RTC
 	  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
+config UML_PCI
+	bool
 	select FORCE_PCI
 	select UML_IOMEM_EMULATION
 	select UML_DMA_EMULATION
 	select PCI_MSI
 	select PCI_LOCKLESS_CONFIG
 
+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 UML_PCI
+
 config UML_PCI_OVER_VIRTIO_DEVICE_ID
 	int "set the virtio device ID for PCI emulation"
 	default -1
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index 57882e6bc215..0a5820343ad3 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -60,7 +60,8 @@ 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-$(CONFIG_UML_PCI_OVER_VIRTIO) += virt-pci.o
+obj-$(CONFIG_UML_PCI) += virt-pci.o
+obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virtio_pcidev.o
 
 # pcap_user.o must be added explicitly.
 USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o vde_user.o vector_user.o
diff --git a/arch/um/drivers/random.c b/arch/um/drivers/random.c
index da985e0dc69a..ca08c91f47a3 100644
--- a/arch/um/drivers/random.c
+++ b/arch/um/drivers/random.c
@@ -79,7 +79,7 @@ static int __init rng_init (void)
 	if (err < 0)
 		goto err_out_cleanup_hw;
 
-	sigio_broken(random_fd);
+	sigio_broken();
 	hwrng.name = RNG_MODULE_NAME;
 	hwrng.read = rng_dev_read;
 
diff --git a/arch/um/drivers/rtc_user.c b/arch/um/drivers/rtc_user.c
index 7c3cec4c68cf..51e79f3148cd 100644
--- a/arch/um/drivers/rtc_user.c
+++ b/arch/um/drivers/rtc_user.c
@@ -39,7 +39,7 @@ int uml_rtc_start(bool timetravel)
 		}
 
 		/* apparently timerfd won't send SIGIO, use workaround */
-		sigio_broken(uml_rtc_irq_fds[0]);
+		sigio_broken();
 		err = add_sigio_fd(uml_rtc_irq_fds[0]);
 		if (err < 0) {
 			close(uml_rtc_irq_fds[0]);
diff --git a/arch/um/drivers/ubd.h b/arch/um/drivers/ubd.h
index f016fe15499f..2985c14661f4 100644
--- a/arch/um/drivers/ubd.h
+++ b/arch/um/drivers/ubd.h
@@ -7,8 +7,10 @@
 #ifndef __UM_UBD_USER_H
 #define __UM_UBD_USER_H
 
-extern int start_io_thread(unsigned long sp, int *fds_out);
-extern int io_thread(void *arg);
+#include <os.h>
+
+int start_io_thread(struct os_helper_thread **td_out, int *fd_out);
+void *io_thread(void *arg);
 extern int kernel_fd;
 
 extern int ubd_read_poll(int timeout);
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 0b1e61f72fb3..4de6613e7468 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -474,12 +474,12 @@ static irqreturn_t ubd_intr(int irq, void *dev)
 }
 
 /* Only changed by ubd_init, which is an initcall. */
-static int io_pid = -1;
+static struct os_helper_thread *io_td;
 
 static void kill_io_thread(void)
 {
-	if(io_pid != -1)
-		os_kill_process(io_pid, 1);
+	if (io_td)
+		os_kill_helper_thread(io_td);
 }
 
 __uml_exitcall(kill_io_thread);
@@ -1104,8 +1104,8 @@ static int __init ubd_init(void)
 
 late_initcall(ubd_init);
 
-static int __init ubd_driver_init(void){
-	unsigned long stack;
+static int __init ubd_driver_init(void)
+{
 	int err;
 
 	/* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
@@ -1114,13 +1114,11 @@ static int __init ubd_driver_init(void){
 		/* Letting ubd=sync be like using ubd#s= instead of ubd#= is
 		 * enough. So use anyway the io thread. */
 	}
-	stack = alloc_stack(0, 0);
-	io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd);
-	if(io_pid < 0){
+	err = start_io_thread(&io_td, &thread_fd);
+	if (err < 0) {
 		printk(KERN_ERR
 		       "ubd : Failed to start I/O thread (errno = %d) - "
-		       "falling back to synchronous I/O\n", -io_pid);
-		io_pid = -1;
+		       "falling back to synchronous I/O\n", -err);
 		return 0;
 	}
 	err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
@@ -1496,12 +1494,11 @@ int kernel_fd = -1;
 /* Only changed by the io thread. XXX: currently unused. */
 static int io_count;
 
-int io_thread(void *arg)
+void *io_thread(void *arg)
 {
 	int n, count, written, res;
 
-	os_set_pdeathsig();
-	os_fix_helper_signals();
+	os_fix_helper_thread_signals();
 
 	while(1){
 		n = bulk_req_safe_read(
@@ -1543,5 +1540,5 @@ int io_thread(void *arg)
 		} while (written < n);
 	}
 
-	return 0;
+	return NULL;
 }
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index b4f8b8e60564..c5e6545f6fcf 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -25,9 +25,9 @@
 
 static struct pollfd kernel_pollfd;
 
-int start_io_thread(unsigned long sp, int *fd_out)
+int start_io_thread(struct os_helper_thread **td_out, int *fd_out)
 {
-	int pid, fds[2], err;
+	int fds[2], err;
 
 	err = os_pipe(fds, 1, 1);
 	if(err < 0){
@@ -47,14 +47,14 @@ int start_io_thread(unsigned long sp, int *fd_out)
 		goto out_close;
 	}
 
-	pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM, NULL);
-	if(pid < 0){
-		err = -errno;
-		printk("start_io_thread - clone failed : errno = %d\n", errno);
+	err = os_run_helper_thread(td_out, io_thread, NULL);
+	if (err < 0) {
+		printk("%s - failed to run helper thread, err = %d\n",
+		       __func__, -err);
 		goto out_close;
 	}
 
-	return(pid);
+	return 0;
 
  out_close:
 	os_close_file(fds[0]);
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
index dd5580f975cc..b83b5a765d4e 100644
--- a/arch/um/drivers/virt-pci.c
+++ b/arch/um/drivers/virt-pci.c
@@ -5,52 +5,19 @@
  */
 #include <linux/module.h>
 #include <linux/pci.h>
-#include <linux/virtio.h>
-#include <linux/virtio_config.h>
 #include <linux/logic_iomem.h>
 #include <linux/of_platform.h>
 #include <linux/irqdomain.h>
-#include <linux/virtio_pcidev.h>
-#include <linux/virtio-uml.h>
-#include <linux/delay.h>
 #include <linux/msi.h>
 #include <linux/unaligned.h>
 #include <irq_kern.h>
 
+#include "virt-pci.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
-
-struct um_pci_message_buffer {
-	struct virtio_pcidev_msg hdr;
-	u8 data[8];
-};
-
-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_WRITE_BUFS	20
-	struct um_pci_message_buffer bufs[UM_PCI_WRITE_BUFS + 1];
-	void *extra_ptrs[UM_PCI_WRITE_BUFS + 1];
-	DECLARE_BITMAP(used_bufs, UM_PCI_WRITE_BUFS);
-
-#define UM_PCI_STAT_WAITING	0
-	unsigned long status;
-
-	int irq;
-
-	bool platform;
-};
-
 struct um_pci_device_reg {
 	struct um_pci_device *dev;
 	void __iomem *iomem;
@@ -65,179 +32,15 @@ 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)];
 
-static unsigned int um_pci_max_delay_us = 40000;
-module_param_named(max_delay_us, um_pci_max_delay_us, uint, 0644);
-
-static int um_pci_get_buf(struct um_pci_device *dev, bool *posted)
-{
-	int i;
-
-	for (i = 0; i < UM_PCI_WRITE_BUFS; i++) {
-		if (!test_and_set_bit(i, dev->used_bufs))
-			return i;
-	}
-
-	*posted = false;
-	return UM_PCI_WRITE_BUFS;
-}
-
-static void um_pci_free_buf(struct um_pci_device *dev, void *buf)
-{
-	int i;
-
-	if (buf == &dev->bufs[UM_PCI_WRITE_BUFS]) {
-		kfree(dev->extra_ptrs[UM_PCI_WRITE_BUFS]);
-		dev->extra_ptrs[UM_PCI_WRITE_BUFS] = NULL;
-		return;
-	}
-
-	for (i = 0; i < UM_PCI_WRITE_BUFS; i++) {
-		if (buf == &dev->bufs[i]) {
-			kfree(dev->extra_ptrs[i]);
-			dev->extra_ptrs[i] = NULL;
-			WARN_ON(!test_and_clear_bit(i, dev->used_bufs));
-			return;
-		}
-	}
-
-	WARN_ON(1);
-}
-
-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,
-	};
-	struct um_pci_message_buffer *buf;
-	int delay_count = 0;
-	bool bounce_out;
-	int ret, len;
-	int buf_idx;
-	bool posted;
-
-	if (WARN_ON(cmd_size < sizeof(*cmd) || cmd_size > sizeof(*buf)))
-		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;
-	}
-
-	bounce_out = !posted && cmd_size <= sizeof(*cmd) &&
-		     out && out_size <= sizeof(buf->data);
-
-	buf_idx = um_pci_get_buf(dev, &posted);
-	buf = &dev->bufs[buf_idx];
-	memcpy(buf, cmd, cmd_size);
-
-	if (posted && extra && extra_size > sizeof(buf) - cmd_size) {
-		dev->extra_ptrs[buf_idx] = kmemdup(extra, extra_size,
-						   GFP_ATOMIC);
-
-		if (!dev->extra_ptrs[buf_idx]) {
-			um_pci_free_buf(dev, buf);
-			return -ENOMEM;
-		}
-		extra = dev->extra_ptrs[buf_idx];
-	} else if (extra && extra_size <= sizeof(buf) - cmd_size) {
-		memcpy((u8 *)buf + cmd_size, extra, extra_size);
-		cmd_size += extra_size;
-		extra_size = 0;
-		extra = NULL;
-		cmd = (void *)buf;
-	} else {
-		cmd = (void *)buf;
-	}
-
-	sg_init_one(&out_sg, cmd, cmd_size);
-	if (extra)
-		sg_init_one(&extra_sg, extra, extra_size);
-	/* allow stack for small buffers */
-	if (bounce_out)
-		sg_init_one(&in_sg, buf->data, out_size);
-	else 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,
-				cmd, GFP_ATOMIC);
-	if (ret) {
-		um_pci_free_buf(dev, buf);
-		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);
-	ret = 0;
-
-	while (1) {
-		void *completed = virtqueue_get_buf(dev->cmd_vq, &len);
-
-		if (completed == buf)
-			break;
-
-		if (completed)
-			um_pci_free_buf(dev, completed);
-
-		if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) ||
-			      ++delay_count > um_pci_max_delay_us,
-			      "um virt-pci delay: %d", delay_count)) {
-			ret = -EIO;
-			break;
-		}
-		udelay(1);
-	}
-	clear_bit(UM_PCI_STAT_WAITING, &dev->status);
-
-	if (bounce_out)
-		memcpy(out, buf->data, out_size);
-
-	um_pci_free_buf(dev, buf);
-
-	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,
-	};
-	/* max 8, we might not use it all */
-	u8 data[8];
 
 	if (!dev)
 		return ULONG_MAX;
 
-	memset(data, 0xff, sizeof(data));
-
 	switch (size) {
 	case 1:
 	case 2:
@@ -251,23 +54,7 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
 		return ULONG_MAX;
 	}
 
-	if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, size))
-		return ULONG_MAX;
-
-	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 ULONG_MAX;
-	}
+	return dev->ops->cfgspace_read(dev, offset, size);
 }
 
 static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size,
@@ -275,42 +62,24 @@ static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size,
 {
 	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
+		break;
 	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));
+	dev->ops->cfgspace_write(dev, offset, size, val);
 }
 
 static const struct logic_iomem_ops um_pci_device_cfgspace_ops = {
@@ -318,30 +87,14 @@ static const struct logic_iomem_ops um_pci_device_cfgspace_ops = {
 	.write = um_pci_cfgspace_write,
 };
 
-static void um_pci_bar_copy_from(void *priv, void *buffer,
-				 unsigned int offset, int size)
+static unsigned long um_pci_bar_read(void *priv, 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)
-{
-	/* 8 is maximum size - we may only use parts of it */
-	u8 data[8];
+	u8 bar = *resptr;
 
 	switch (size) {
 	case 1:
@@ -352,72 +105,60 @@ static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
 #endif
 		break;
 	default:
-		WARN(1, "invalid config space read size %d\n", size);
+		WARN(1, "invalid bar read size %d\n", size);
 		return ULONG_MAX;
 	}
 
-	um_pci_bar_copy_from(priv, data, offset, size);
+	return dev->ops->bar_read(dev, bar, offset, size);
+}
+
+static void um_pci_bar_write(void *priv, unsigned int offset, int size,
+			     unsigned long val)
+{
+	u8 *resptr = priv;
+	struct um_pci_device *dev = container_of(resptr - *resptr,
+						 struct um_pci_device,
+						 resptr[0]);
+	u8 bar = *resptr;
 
 	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
+		break;
 	default:
-		return ULONG_MAX;
+		WARN(1, "invalid bar write size %d\n", size);
+		return;
 	}
+
+	dev->ops->bar_write(dev, bar, offset, size, val);
 }
 
-static void um_pci_bar_copy_to(void *priv, unsigned int offset,
-			       const void *buffer, int size)
+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_WRITE,
-		.bar = *resptr,
-		.size = size,
-		.addr = offset,
-	};
+	u8 bar = *resptr;
 
-	um_pci_send_cmd(dev, &hdr, sizeof(hdr), buffer, size, NULL, 0);
+	dev->ops->bar_copy_from(dev, bar, buffer, offset, size);
 }
 
-static void um_pci_bar_write(void *priv, unsigned int offset, int size,
-			     unsigned long val)
+static void um_pci_bar_copy_to(void *priv, unsigned int offset,
+			       const void *buffer, int size)
 {
-	/* 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;
-	}
+	u8 *resptr = priv;
+	struct um_pci_device *dev = container_of(resptr - *resptr,
+						 struct um_pci_device,
+						 resptr[0]);
+	u8 bar = *resptr;
 
-	um_pci_bar_copy_to(priv, offset, data, size);
+	dev->ops->bar_copy_to(dev, bar, offset, buffer, size);
 }
 
 static void um_pci_bar_set(void *priv, unsigned int offset, u8 value, int size)
@@ -426,20 +167,9 @@ static void um_pci_bar_set(void *priv, unsigned int offset, u8 value, int size)
 	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,
-	};
+	u8 bar = *resptr;
 
-	um_pci_send_cmd(dev, &msg.hdr, sizeof(msg), NULL, 0, NULL, 0);
+	dev->ops->bar_set(dev, bar, offset, value, size);
 }
 
 static const struct logic_iomem_ops um_pci_device_bar_ops = {
@@ -486,76 +216,6 @@ static void um_pci_rescan(void)
 	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;
-
-	if (!dev->irq)
-		return;
-
-	/* 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)))
-		um_pci_free_buf(dev, cmd);
-}
-
-static void um_pci_irq_vq_cb(struct virtqu