From: Raghavendra Rao Ananta Date: Tue, 5 May 2026 21:28:33 +0000 (+0000) Subject: vfio: selftests: Introduce a sysfs lib X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5db77a035e1291e2c9b488073c28b441e5e44f3;p=thirdparty%2Fkernel%2Flinux.git vfio: selftests: Introduce a sysfs lib Introduce a sysfs library to handle the common reads/writes to the PCI sysfs files, for example, getting the total number of VFs supported by the device via /sys/bus/pci/devices/$BDF/sriov_totalvfs. The library will be used in the upcoming test patch to configure the VFs for a given PF device. Since readlink() is quite commonly used in the lib, introduce and use readlink_safe() to take care of potential buffer overrun errors and to safely terminate the buffer with '\0'. Opportunistically, move vfio_pci_get_group_from_dev() to this library as it falls under the same bucket. Rename it to sysfs_iommu_group_get() to align with other function names. Signed-off-by: Raghavendra Rao Ananta Reviewed-by: Vipin Sharma Reviewed-by: David Matlack Tested-by: David Matlack Link: https://lore.kernel.org/r/20260505212838.1698034-4-rananta@google.com Signed-off-by: Alex Williamson --- diff --git a/tools/testing/selftests/vfio/lib/include/libvfio.h b/tools/testing/selftests/vfio/lib/include/libvfio.h index 1b6da54cc2cb7..07862b470777b 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio.h @@ -5,6 +5,7 @@ #include #include #include +#include #include #include diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h b/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h new file mode 100644 index 0000000000000..c9ab1ea8f5a9c --- /dev/null +++ b/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_SYSFS_H +#define SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_SYSFS_H + +int sysfs_sriov_totalvfs_get(const char *bdf); +int sysfs_sriov_numvfs_get(const char *bdf); +void sysfs_sriov_numvfs_set(const char *bdf, int numvfs); +char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i); +int sysfs_iommu_group_get(const char *bdf); +char *sysfs_driver_get(const char *bdf); + +#endif /* SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_SYSFS_H */ diff --git a/tools/testing/selftests/vfio/lib/libvfio.mk b/tools/testing/selftests/vfio/lib/libvfio.mk index 9f47bceed16f4..b7857319c3f1f 100644 --- a/tools/testing/selftests/vfio/lib/libvfio.mk +++ b/tools/testing/selftests/vfio/lib/libvfio.mk @@ -6,6 +6,7 @@ LIBVFIO_SRCDIR := $(selfdir)/vfio/lib LIBVFIO_C := iommu.c LIBVFIO_C += iova_allocator.c LIBVFIO_C += libvfio.c +LIBVFIO_C += sysfs.c LIBVFIO_C += vfio_pci_device.c LIBVFIO_C += vfio_pci_driver.c diff --git a/tools/testing/selftests/vfio/lib/sysfs.c b/tools/testing/selftests/vfio/lib/sysfs.c new file mode 100644 index 0000000000000..11415448b2e29 --- /dev/null +++ b/tools/testing/selftests/vfio/lib/sysfs.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include + +#include + +#define readlink_safe(_path, _buf) ({ \ + int __ret; \ + \ + _Static_assert(!__builtin_types_compatible_p( \ + __typeof__(_buf), char *), \ + "readlink_safe: _buf must be an array, not a pointer"); \ + \ + __ret = readlink(_path, _buf, sizeof(_buf) - 1); \ + if (__ret != -1) \ + _buf[__ret] = 0; \ + __ret; \ +}) + +static void readlink_base(const char *path, const char *data_fmt, void *out_data) +{ + char rl_path[PATH_MAX]; + int ret; + + ret = readlink_safe(path, rl_path); + VFIO_ASSERT_NE(ret, -1); + + ret = sscanf(basename(rl_path), data_fmt, out_data); + VFIO_ASSERT_EQ(ret, 1); +} + +static int sysfs_val_get_int(const char *component, const char *name, + const char *file) +{ + char path[PATH_MAX]; + char buf[32]; + int ret; + int fd; + + snprintf_assert(path, PATH_MAX, "/sys/bus/pci/%s/%s/%s", component, name, file); + fd = open(path, O_RDONLY); + if (fd < 0) + return fd; + + VFIO_ASSERT_GT(read(fd, buf, ARRAY_SIZE(buf)), 0); + VFIO_ASSERT_EQ(close(fd), 0); + + errno = 0; + ret = strtol(buf, NULL, 0); + VFIO_ASSERT_EQ(errno, 0, "sysfs path \"%s\" is not an integer: \"%s\"\n", path, buf); + + return ret; +} + +static void sysfs_val_set(const char *component, const char *name, + const char *file, const char *val) +{ + char path[PATH_MAX]; + int fd; + + snprintf_assert(path, PATH_MAX, "/sys/bus/pci/%s/%s/%s", component, name, file); + VFIO_ASSERT_GT(fd = open(path, O_WRONLY), 0); + + VFIO_ASSERT_EQ(write(fd, val, strlen(val)), strlen(val)); + VFIO_ASSERT_EQ(close(fd), 0); +} + +static int sysfs_device_val_get(const char *bdf, const char *file) +{ + return sysfs_val_get_int("devices", bdf, file); +} + +static void sysfs_device_val_set(const char *bdf, const char *file, const char *val) +{ + sysfs_val_set("devices", bdf, file, val); +} + +static void sysfs_device_val_set_int(const char *bdf, const char *file, int val) +{ + char val_str[32]; + + snprintf_assert(val_str, sizeof(val_str), "%d", val); + sysfs_device_val_set(bdf, file, val_str); +} + +int sysfs_sriov_totalvfs_get(const char *bdf) +{ + return sysfs_device_val_get(bdf, "sriov_totalvfs"); +} + +int sysfs_sriov_numvfs_get(const char *bdf) +{ + return sysfs_device_val_get(bdf, "sriov_numvfs"); +} + +void sysfs_sriov_numvfs_set(const char *bdf, int numvfs) +{ + sysfs_device_val_set_int(bdf, "sriov_numvfs", numvfs); +} + +char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i) +{ + char path[PATH_MAX]; + char *out_vf_bdf; + + /* Fit "0000:00:00.0" */ + out_vf_bdf = calloc(16, sizeof(char)); + VFIO_ASSERT_NOT_NULL(out_vf_bdf); + + snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/virtfn%d", pf_bdf, i); + readlink_base(path, "%s", out_vf_bdf); + + return out_vf_bdf; +} + +int sysfs_iommu_group_get(const char *bdf) +{ + char path[PATH_MAX]; + int group; + + snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/iommu_group", bdf); + readlink_base(path, "%d", &group); + + return group; +} + +char *sysfs_driver_get(const char *bdf) +{ + char driver_path[PATH_MAX]; + char path[PATH_MAX]; + char *out_driver; + int ret; + + snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/driver", bdf); + ret = readlink_safe(path, driver_path); + if (ret == -1) { + if (errno == ENOENT) + return NULL; + + VFIO_FAIL("Failed to read %s\n", path); + } + + out_driver = strdup(basename(driver_path)); + VFIO_ASSERT_NOT_NULL(out_driver); + + return out_driver; +} diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index efbf9ab63cea7..80e8e5bebd7ca 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -25,8 +25,6 @@ #include "kselftest.h" #include -#define PCI_SYSFS_PATH "/sys/bus/pci/devices" - static void vfio_pci_irq_set(struct vfio_pci_device *device, u32 index, u32 vector, u32 count, int *fds) { @@ -204,24 +202,6 @@ void vfio_pci_device_reset(struct vfio_pci_device *device) ioctl_assert(device->fd, VFIO_DEVICE_RESET, NULL); } -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_assert(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_group_setup(struct vfio_pci_device *device, const char *bdf) { struct vfio_group_status group_status = { @@ -230,7 +210,7 @@ static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf char group_path[32]; int group; - group = vfio_pci_get_group_from_dev(bdf); + group = sysfs_iommu_group_get(bdf); snprintf_assert(group_path, sizeof(group_path), "/dev/vfio/%d", group); device->group_fd = open(group_path, O_RDWR);