vfio: selftests: Add a helper library for VFIO selftests

Add a basic helper library to be used by VFIO selftests.

The basic unit of the library is struct vfio_pci_device, which
represents a single PCI device that is bound to the vfio-pci driver. The
library currently only supports a single device per group and container,
and VFIO IOMMU types.

The code in this library was heavily based on prior work done by
Raghavendra Rao Ananta <rananta@google.com>, and the VFIO_ASSERT*()
macros were written by Vipin Sharma <vipinsh@google.com>.

Separate that Makefile rules for building the library into a separate
script so that the library can be built by and linked into KVM selftests
in a subsequent commit.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20250822212518.4156428-3-dmatlack@google.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
David Matlack
2025-08-22 21:24:49 +00:00
committed by Alex Williamson
parent 292e9ee22b
commit 19faf6fd96
4 changed files with 534 additions and 0 deletions

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@@ -1,2 +1,16 @@
CFLAGS = $(KHDR_INCLUDES)
include ../lib.mk
include lib/libvfio.mk
CFLAGS += -I$(top_srcdir)/tools/include
CFLAGS += -MD
CFLAGS += $(EXTRA_CFLAGS)
$(TEST_GEN_PROGS): %: %.o $(LIBVFIO_O)
$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $< $(LIBVFIO_O) $(LDLIBS) -o $@
TEST_GEN_PROGS_O = $(patsubst %, %.o, $(TEST_GEN_PROGS))
TEST_DEP_FILES = $(patsubst %.o, %.d, $(TEST_GEN_PROGS_O) $(LIBVFIO_O))
-include $(TEST_DEP_FILES)
EXTRA_CLEAN += $(TEST_GEN_PROGS_O) $(TEST_DEP_FILES)

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@@ -0,0 +1,140 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef SELFTESTS_VFIO_LIB_INCLUDE_VFIO_UTIL_H
#define SELFTESTS_VFIO_LIB_INCLUDE_VFIO_UTIL_H
#include <string.h>
#include <linux/vfio.h>
#include <linux/list.h>
#include <linux/pci_regs.h>
#include "../../../kselftest.h"
#define VFIO_LOG_AND_EXIT(...) do { \
fprintf(stderr, " " __VA_ARGS__); \
fprintf(stderr, "\n"); \
exit(KSFT_FAIL); \
} while (0)
#define VFIO_ASSERT_OP(_lhs, _rhs, _op, ...) do { \
typeof(_lhs) __lhs = (_lhs); \
typeof(_rhs) __rhs = (_rhs); \
\
if (__lhs _op __rhs) \
break; \
\
fprintf(stderr, "%s:%u: Assertion Failure\n\n", __FILE__, __LINE__); \
fprintf(stderr, " Expression: " #_lhs " " #_op " " #_rhs "\n"); \
fprintf(stderr, " Observed: %#lx %s %#lx\n", \
(u64)__lhs, #_op, (u64)__rhs); \
fprintf(stderr, " [errno: %d - %s]\n", errno, strerror(errno)); \
VFIO_LOG_AND_EXIT(__VA_ARGS__); \
} while (0)
#define VFIO_ASSERT_EQ(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, ==, ##__VA_ARGS__)
#define VFIO_ASSERT_NE(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, !=, ##__VA_ARGS__)
#define VFIO_ASSERT_LT(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, <, ##__VA_ARGS__)
#define VFIO_ASSERT_LE(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, <=, ##__VA_ARGS__)
#define VFIO_ASSERT_GT(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, >, ##__VA_ARGS__)
#define VFIO_ASSERT_GE(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, >=, ##__VA_ARGS__)
#define VFIO_ASSERT_TRUE(_a, ...) VFIO_ASSERT_NE(false, (_a), ##__VA_ARGS__)
#define VFIO_ASSERT_FALSE(_a, ...) VFIO_ASSERT_EQ(false, (_a), ##__VA_ARGS__)
#define VFIO_ASSERT_NULL(_a, ...) VFIO_ASSERT_EQ(NULL, _a, ##__VA_ARGS__)
#define VFIO_ASSERT_NOT_NULL(_a, ...) VFIO_ASSERT_NE(NULL, _a, ##__VA_ARGS__)
#define VFIO_FAIL(_fmt, ...) do { \
fprintf(stderr, "%s:%u: FAIL\n\n", __FILE__, __LINE__); \
VFIO_LOG_AND_EXIT(_fmt, ##__VA_ARGS__); \
} while (0)
struct vfio_pci_bar {
struct vfio_region_info info;
void *vaddr;
};
struct vfio_pci_device {
int fd;
int group_fd;
int container_fd;
struct vfio_device_info info;
struct vfio_region_info config_space;
struct vfio_pci_bar bars[PCI_STD_NUM_BARS];
struct vfio_irq_info msi_info;
struct vfio_irq_info msix_info;
/* eventfds for MSI and MSI-x interrupts */
int msi_eventfds[PCI_MSIX_FLAGS_QSIZE + 1];
};
/*
* Return the BDF string of the device that the test should use.
*
* If a BDF string is provided by the user on the command line (as the last
* element of argv[]), then this function will return that and decrement argc
* by 1.
*
* Otherwise this function will attempt to use the environment variable
* $VFIO_SELFTESTS_BDF.
*
* If BDF cannot be determined then the test will exit with KSFT_SKIP.
*/
const char *vfio_selftests_get_bdf(int *argc, char *argv[]);
struct vfio_pci_device *vfio_pci_device_init(const char *bdf, int iommu_type);
void vfio_pci_device_cleanup(struct vfio_pci_device *device);
void vfio_pci_dma_map(struct vfio_pci_device *device, u64 iova, u64 size,
void *vaddr);
void vfio_pci_dma_unmap(struct vfio_pci_device *device, u64 iova, u64 size);
void vfio_pci_config_access(struct vfio_pci_device *device, bool write,
size_t config, size_t size, void *data);
#define vfio_pci_config_read(_device, _offset, _type) ({ \
_type __data; \
vfio_pci_config_access((_device), false, _offset, sizeof(__data), &__data); \
__data; \
})
#define vfio_pci_config_readb(_d, _o) vfio_pci_config_read(_d, _o, u8)
#define vfio_pci_config_readw(_d, _o) vfio_pci_config_read(_d, _o, u16)
#define vfio_pci_config_readl(_d, _o) vfio_pci_config_read(_d, _o, u32)
#define vfio_pci_config_write(_device, _offset, _value, _type) do { \
_type __data = (_value); \
vfio_pci_config_access((_device), true, _offset, sizeof(_type), &__data); \
} while (0)
#define vfio_pci_config_writeb(_d, _o, _v) vfio_pci_config_write(_d, _o, _v, u8)
#define vfio_pci_config_writew(_d, _o, _v) vfio_pci_config_write(_d, _o, _v, u16)
#define vfio_pci_config_writel(_d, _o, _v) vfio_pci_config_write(_d, _o, _v, u32)
void vfio_pci_irq_enable(struct vfio_pci_device *device, u32 index,
u32 vector, int count);
void vfio_pci_irq_disable(struct vfio_pci_device *device, u32 index);
void vfio_pci_irq_trigger(struct vfio_pci_device *device, u32 index, u32 vector);
static inline void vfio_pci_msi_enable(struct vfio_pci_device *device,
u32 vector, int count)
{
vfio_pci_irq_enable(device, VFIO_PCI_MSI_IRQ_INDEX, vector, count);
}
static inline void vfio_pci_msi_disable(struct vfio_pci_device *device)
{
vfio_pci_irq_disable(device, VFIO_PCI_MSI_IRQ_INDEX);
}
static inline void vfio_pci_msix_enable(struct vfio_pci_device *device,
u32 vector, int count)
{
vfio_pci_irq_enable(device, VFIO_PCI_MSIX_IRQ_INDEX, vector, count);
}
static inline void vfio_pci_msix_disable(struct vfio_pci_device *device)
{
vfio_pci_irq_disable(device, VFIO_PCI_MSIX_IRQ_INDEX);
}
#endif /* SELFTESTS_VFIO_LIB_INCLUDE_VFIO_UTIL_H */

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@@ -0,0 +1,15 @@
VFIO_DIR := $(selfdir)/vfio
LIBVFIO_C := lib/vfio_pci_device.c
LIBVFIO_O := $(patsubst %.c, $(OUTPUT)/%.o, $(LIBVFIO_C))
LIBVFIO_O_DIRS := $(shell dirname $(LIBVFIO_O) | uniq)
$(shell mkdir -p $(LIBVFIO_O_DIRS))
CFLAGS += -I$(VFIO_DIR)/lib/include
$(LIBVFIO_O): $(OUTPUT)/%.o : $(VFIO_DIR)/%.c
$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
EXTRA_CLEAN += $(LIBVFIO_O)

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@@ -0,0 +1,365 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <fcntl.h>
#include <libgen.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/eventfd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/limits.h>
#include <linux/mman.h>
#include <linux/types.h>
#include <linux/vfio.h>
#include "../../../kselftest.h"
#include <vfio_util.h>
#define VFIO_DEV_PATH "/dev/vfio/vfio"
#define PCI_SYSFS_PATH "/sys/bus/pci/devices"
#define ioctl_assert(_fd, _op, _arg) do { \
void *__arg = (_arg); \
int __ret = ioctl((_fd), (_op), (__arg)); \
VFIO_ASSERT_EQ(__ret, 0, "ioctl(%s, %s, %s) returned %d\n", #_fd, #_op, #_arg, __ret); \
} while (0)
static void vfio_pci_irq_set(struct vfio_pci_device *device,
u32 index, u32 vector, u32 count, int *fds)
{
u8 buf[sizeof(struct vfio_irq_set) + sizeof(int) * count] = {};
struct vfio_irq_set *irq = (void *)&buf;
int *irq_fds = (void *)&irq->data;
irq->argsz = sizeof(buf);
irq->flags = VFIO_IRQ_SET_ACTION_TRIGGER;
irq->index = index;
irq->start = vector;
irq->count = count;
if (count) {
irq->flags |= VFIO_IRQ_SET_DATA_EVENTFD;
memcpy(irq_fds, fds, sizeof(int) * count);
} else {
irq->flags |= VFIO_IRQ_SET_DATA_NONE;
}
ioctl_assert(device->fd, VFIO_DEVICE_SET_IRQS, irq);
}
void vfio_pci_irq_trigger(struct vfio_pci_device *device, u32 index, u32 vector)
{
struct vfio_irq_set irq = {
.argsz = sizeof(irq),
.flags = VFIO_IRQ_SET_ACTION_TRIGGER | VFIO_IRQ_SET_DATA_NONE,
.index = index,
.start = vector,
.count = 1,
};
ioctl_assert(device->fd, VFIO_DEVICE_SET_IRQS, &irq);
}
static void check_supported_irq_index(u32 index)
{
/* VFIO selftests only supports MSI and MSI-x for now. */
VFIO_ASSERT_TRUE(index == VFIO_PCI_MSI_IRQ_INDEX ||
index == VFIO_PCI_MSIX_IRQ_INDEX,
"Unsupported IRQ index: %u\n", index);
}
void vfio_pci_irq_enable(struct vfio_pci_device *device, u32 index, u32 vector,
int count)
{
int i;
check_supported_irq_index(index);
for (i = vector; i < vector + count; i++) {
VFIO_ASSERT_LT(device->msi_eventfds[i], 0);
device->msi_eventfds[i] = eventfd(0, 0);
VFIO_ASSERT_GE(device->msi_eventfds[i], 0);
}
vfio_pci_irq_set(device, index, vector, count, device->msi_eventfds + vector);
}
void vfio_pci_irq_disable(struct vfio_pci_device *device, u32 index)
{
int i;
check_supported_irq_index(index);
for (i = 0; i < ARRAY_SIZE(device->msi_eventfds); i++) {
if (device->msi_eventfds[i] < 0)
continue;
VFIO_ASSERT_EQ(close(device->msi_eventfds[i]), 0);
device->msi_eventfds[i] = -1;
}
vfio_pci_irq_set(device, index, 0, 0, NULL);
}
static void vfio_pci_irq_get(struct vfio_pci_device *device, u32 index,
struct vfio_irq_info *irq_info)
{
irq_info->argsz = sizeof(*irq_info);
irq_info->index = index;
ioctl_assert(device->fd, VFIO_DEVICE_GET_IRQ_INFO, irq_info);
}
void vfio_pci_dma_map(struct vfio_pci_device *device, u64 iova, u64 size, void *vaddr)
{
struct vfio_iommu_type1_dma_map map = {
.argsz = sizeof(map),
.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
.vaddr = (u64)vaddr,
.iova = iova,
.size = size,
};
ioctl_assert(device->container_fd, VFIO_IOMMU_MAP_DMA, &map);
}
void vfio_pci_dma_unmap(struct vfio_pci_device *device, u64 iova, u64 size)
{
struct vfio_iommu_type1_dma_unmap unmap = {
.argsz = sizeof(unmap),
.iova = iova,
.size = size,
};
ioctl_assert(device->container_fd, VFIO_IOMMU_UNMAP_DMA, &unmap);
}
static void vfio_pci_region_get(struct vfio_pci_device *device, int index,
struct vfio_region_info *info)
{
memset(info, 0, sizeof(*info));
info->argsz = sizeof(*info);
info->index = index;
ioctl_assert(device->fd, VFIO_DEVICE_GET_REGION_INFO, info);
}
static void vfio_pci_bar_map(struct vfio_pci_device *device, int index)
{
struct vfio_pci_bar *bar = &device->bars[index];
int prot = 0;
VFIO_ASSERT_LT(index, PCI_STD_NUM_BARS);
VFIO_ASSERT_NULL(bar->vaddr);
VFIO_ASSERT_TRUE(bar->info.flags & VFIO_REGION_INFO_FLAG_MMAP);
if (bar->info.flags & VFIO_REGION_INFO_FLAG_READ)
prot |= PROT_READ;
if (bar->info.flags & VFIO_REGION_INFO_FLAG_WRITE)
prot |= PROT_WRITE;
bar->vaddr = mmap(NULL, bar->info.size, prot, MAP_FILE | MAP_SHARED,
device->fd, bar->info.offset);
VFIO_ASSERT_NE(bar->vaddr, MAP_FAILED);
}
static void vfio_pci_bar_unmap(struct vfio_pci_device *device, int index)
{
struct vfio_pci_bar *bar = &device->bars[index];
VFIO_ASSERT_LT(index, PCI_STD_NUM_BARS);
VFIO_ASSERT_NOT_NULL(bar->vaddr);
VFIO_ASSERT_EQ(munmap(bar->vaddr, bar->info.size), 0);
bar->vaddr = NULL;
}
static void vfio_pci_bar_unmap_all(struct vfio_pci_device *device)
{
int i;
for (i = 0; i < PCI_STD_NUM_BARS; i++) {
if (device->bars[i].vaddr)
vfio_pci_bar_unmap(device, i);
}
}
void vfio_pci_config_access(struct vfio_pci_device *device, bool write,
size_t config, size_t size, void *data)
{
struct vfio_region_info *config_space = &device->config_space;
int ret;
if (write)
ret = pwrite(device->fd, data, size, config_space->offset + config);
else
ret = pread(device->fd, data, size, config_space->offset + config);
VFIO_ASSERT_EQ(ret, size, "Failed to %s PCI config space: 0x%lx\n",
write ? "write to" : "read from", config);
}
static unsigned int vfio_pci_get_group_from_dev(const char *bdf)
{
char dev_iommu_group_path[PATH_MAX] = {0};
char sysfs_path[PATH_MAX] = {0};
unsigned int group;
int ret;
snprintf(sysfs_path, PATH_MAX, "%s/%s/iommu_group", PCI_SYSFS_PATH, bdf);
ret = readlink(sysfs_path, dev_iommu_group_path, sizeof(dev_iommu_group_path));
VFIO_ASSERT_NE(ret, -1, "Failed to get the IOMMU group for device: %s\n", bdf);
ret = sscanf(basename(dev_iommu_group_path), "%u", &group);
VFIO_ASSERT_EQ(ret, 1, "Failed to get the IOMMU group for device: %s\n", bdf);
return group;
}
static void vfio_pci_container_setup(struct vfio_pci_device *device)
{
int version;
device->container_fd = open(VFIO_DEV_PATH, O_RDWR);
VFIO_ASSERT_GE(device->container_fd, 0, "open(%s) failed\n", VFIO_DEV_PATH);
version = ioctl(device->container_fd, VFIO_GET_API_VERSION);
VFIO_ASSERT_EQ(version, VFIO_API_VERSION);
}
static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf)
{
struct vfio_group_status group_status = {
.argsz = sizeof(group_status),
};
char group_path[32];
int group;
group = vfio_pci_get_group_from_dev(bdf);
snprintf(group_path, sizeof(group_path), "/dev/vfio/%d", group);
device->group_fd = open(group_path, O_RDWR);
VFIO_ASSERT_GE(device->group_fd, 0, "open(%s) failed\n", group_path);
ioctl_assert(device->group_fd, VFIO_GROUP_GET_STATUS, &group_status);
VFIO_ASSERT_TRUE(group_status.flags & VFIO_GROUP_FLAGS_VIABLE);
ioctl_assert(device->group_fd, VFIO_GROUP_SET_CONTAINER, &device->container_fd);
}
static void vfio_pci_iommu_setup(struct vfio_pci_device *device, unsigned long iommu_type)
{
int ret;
ret = ioctl(device->container_fd, VFIO_CHECK_EXTENSION, iommu_type);
VFIO_ASSERT_GT(ret, 0, "VFIO IOMMU type %lu not supported\n", iommu_type);
ioctl_assert(device->container_fd, VFIO_SET_IOMMU, (void *)iommu_type);
}
static void vfio_pci_device_setup(struct vfio_pci_device *device, const char *bdf)
{
int i;
device->fd = ioctl(device->group_fd, VFIO_GROUP_GET_DEVICE_FD, bdf);
VFIO_ASSERT_GE(device->fd, 0);
device->info.argsz = sizeof(device->info);
ioctl_assert(device->fd, VFIO_DEVICE_GET_INFO, &device->info);
vfio_pci_region_get(device, VFIO_PCI_CONFIG_REGION_INDEX, &device->config_space);
/* Sanity check VFIO does not advertise mmap for config space */
VFIO_ASSERT_TRUE(!(device->config_space.flags & VFIO_REGION_INFO_FLAG_MMAP),
"PCI config space should not support mmap()\n");
for (i = 0; i < PCI_STD_NUM_BARS; i++) {
struct vfio_pci_bar *bar = device->bars + i;
vfio_pci_region_get(device, i, &bar->info);
if (bar->info.flags & VFIO_REGION_INFO_FLAG_MMAP)
vfio_pci_bar_map(device, i);
}
vfio_pci_irq_get(device, VFIO_PCI_MSI_IRQ_INDEX, &device->msi_info);
vfio_pci_irq_get(device, VFIO_PCI_MSIX_IRQ_INDEX, &device->msix_info);
for (i = 0; i < ARRAY_SIZE(device->msi_eventfds); i++)
device->msi_eventfds[i] = -1;
}
struct vfio_pci_device *vfio_pci_device_init(const char *bdf, int iommu_type)
{
struct vfio_pci_device *device;
device = calloc(1, sizeof(*device));
VFIO_ASSERT_NOT_NULL(device);
vfio_pci_container_setup(device);
vfio_pci_group_setup(device, bdf);
vfio_pci_iommu_setup(device, iommu_type);
vfio_pci_device_setup(device, bdf);
return device;
}
void vfio_pci_device_cleanup(struct vfio_pci_device *device)
{
int i;
vfio_pci_bar_unmap_all(device);
VFIO_ASSERT_EQ(close(device->fd), 0);
for (i = 0; i < ARRAY_SIZE(device->msi_eventfds); i++) {
if (device->msi_eventfds[i] < 0)
continue;
VFIO_ASSERT_EQ(close(device->msi_eventfds[i]), 0);
}
VFIO_ASSERT_EQ(close(device->group_fd), 0);
VFIO_ASSERT_EQ(close(device->container_fd), 0);
free(device);
}
static bool is_bdf(const char *str)
{
unsigned int s, b, d, f;
int length, count;
count = sscanf(str, "%4x:%2x:%2x.%2x%n", &s, &b, &d, &f, &length);
return count == 4 && length == strlen(str);
}
const char *vfio_selftests_get_bdf(int *argc, char *argv[])
{
char *bdf;
if (*argc > 1 && is_bdf(argv[*argc - 1]))
return argv[--(*argc)];
bdf = getenv("VFIO_SELFTESTS_BDF");
if (bdf) {
VFIO_ASSERT_TRUE(is_bdf(bdf), "Invalid BDF: %s\n", bdf);
return bdf;
}
fprintf(stderr, "Unable to determine which device to use, skipping test.\n");
fprintf(stderr, "\n");
fprintf(stderr, "To pass the device address via environment variable:\n");
fprintf(stderr, "\n");
fprintf(stderr, " export VFIO_SELFTESTS_BDF=segment:bus:device.function\n");
fprintf(stderr, " %s [options]\n", argv[0]);
fprintf(stderr, "\n");
fprintf(stderr, "To pass the device address via argv:\n");
fprintf(stderr, "\n");
fprintf(stderr, " %s [options] segment:bus:device.function\n", argv[0]);
fprintf(stderr, "\n");
exit(KSFT_SKIP);
}