Add shared libvfio helpers used by the Live Update kexec selftest: - vfio_thp_memfd_alloc() and vfio_memfd_mmap_aligned() to allocate a shmem memfd, map it at a 2MB-aligned virtual address, and back it with 2MB THP folios via MADV_HUGEPAGE, write-fault population, and MADV_COLLAPSE. - __sysfs_iommu_group_get(), a variant of sysfs_iommu_group_get() that returns an error instead of asserting when the device has no IOMMU group. Signed-off-by: Vipin Sharma --- .../selftests/vfio/lib/include/libvfio.h | 3 ++ .../vfio/lib/include/libvfio/sysfs.h | 1 + tools/testing/selftests/vfio/lib/libvfio.c | 54 +++++++++++++++++++ tools/testing/selftests/vfio/lib/sysfs.c | 22 ++++++-- 4 files changed, 77 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/vfio/lib/include/libvfio.h b/tools/testing/selftests/vfio/lib/include/libvfio.h index 07862b470777..1c245962525b 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio.h @@ -33,4 +33,7 @@ char **vfio_selftests_get_bdfs(int *argc, char *argv[], int *nr_bdfs); */ void *mmap_reserve(size_t size, size_t align, size_t offset); +int vfio_thp_memfd_alloc(size_t size, void **vaddr_out); +void *vfio_memfd_mmap_aligned(int fd, size_t size, size_t align); + #endif /* SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_H */ diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h b/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h index c9ab1ea8f5a9..b9d6f6f69f88 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio/sysfs.h @@ -6,6 +6,7 @@ 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, int *group); int sysfs_iommu_group_get(const char *bdf); char *sysfs_driver_get(const char *bdf); diff --git a/tools/testing/selftests/vfio/lib/libvfio.c b/tools/testing/selftests/vfio/lib/libvfio.c index 3a3d1ed635c1..00369fe7d074 100644 --- a/tools/testing/selftests/vfio/lib/libvfio.c +++ b/tools/testing/selftests/vfio/lib/libvfio.c @@ -1,14 +1,23 @@ // SPDX-License-Identifier: GPL-2.0-only +#include #include #include +#include +#include #include #include +#include +#include #include "../../../kselftest.h" #include +#ifndef MADV_COLLAPSE +#define MADV_COLLAPSE 25 +#endif + static bool is_bdf(const char *str) { unsigned int s, b, d, f; @@ -101,3 +110,48 @@ void *mmap_reserve(size_t size, size_t align, size_t offset) return map_align; } + +void *vfio_memfd_mmap_aligned(int fd, size_t size, size_t align) +{ + void *vaddr; + + vaddr = mmap_reserve(size, align, 0); + vaddr = mmap(vaddr, size, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_FIXED, fd, 0); + VFIO_ASSERT_NE(vaddr, MAP_FAILED); + + return vaddr; +} + +int vfio_thp_memfd_alloc(size_t size, void **vaddr_out) +{ + void *vaddr; + int fd; + + VFIO_ASSERT_TRUE(IS_ALIGNED(size, SZ_2M)); + + fd = memfd_create("vfio-lu-dma", 0); + VFIO_ASSERT_GE(fd, 0); + + VFIO_ASSERT_EQ(ftruncate(fd, size), 0); + + vaddr = vfio_memfd_mmap_aligned(fd, size, SZ_2M); + + if (madvise(vaddr, size, MADV_HUGEPAGE)) + ksft_exit_skip("madvise(MADV_HUGEPAGE) failed: %s\n", + strerror(errno)); + + /* + * Write-fault the mapping rather than using fallocate() so that shmem + * allocates PMD-sized THP folios when shmem_enabled is always, + * within_size, or advise, then collapse in case shmem_enabled is never. + */ + memset(vaddr, 0, size); + + if (madvise(vaddr, size, MADV_COLLAPSE)) + ksft_exit_skip("madvise(MADV_COLLAPSE) failed: %s\n", + strerror(errno)); + + *vaddr_out = vaddr; + return fd; +} diff --git a/tools/testing/selftests/vfio/lib/sysfs.c b/tools/testing/selftests/vfio/lib/sysfs.c index 98a46a2543cd..219db6aaa101 100644 --- a/tools/testing/selftests/vfio/lib/sysfs.c +++ b/tools/testing/selftests/vfio/lib/sysfs.c @@ -115,14 +115,30 @@ char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i) return out_vf_bdf; } -int sysfs_iommu_group_get(const char *bdf) +int __sysfs_iommu_group_get(const char *bdf, int *group) { + char rl_path[PATH_MAX]; char path[PATH_MAX]; - int group; + char *end; + int ret; snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/iommu_group", bdf); - readlink_base(path, "%d", &group); + ret = readlink_safe(path, rl_path); + if (ret == -1) + return -errno; + + errno = 0; + *group = strtol(basename(rl_path), &end, 10); + VFIO_ASSERT_EQ(errno, 0); + VFIO_ASSERT_EQ(*end, '\0'); + return 0; +} + +int sysfs_iommu_group_get(const char *bdf) +{ + int group; + VFIO_ASSERT_EQ(__sysfs_iommu_group_get(bdf, &group), 0); return group; } -- 2.56.0.317.g454f8302e1-goog