Test MMIO-backed DMA mappings by iommu_map()-ing mmap'ed BAR regions. Also update vfio_pci_bar_map() to align BAR mmaps for efficient huge page mappings.
Only vfio_type1 variants are tested; iommufd variants can be added once kernel support lands. The manual mmap alignment can be removed once mmap(!MAP_FIXED) on vfio device fds improves to automatically return well-aligned addresses. Signed-off-by: Alex Mastro <[email protected]> --- Sanity test run: $ ./vfio_dma_mapping_mmio_test 0000:05:00.0 TAP version 13 1..4 # Starting 4 tests from 2 test cases. # RUN vfio_dma_mapping_mmio_test.vfio_type1_iommu.map_full_bar ... Mapping BAR4: vaddr=0x7fad40000000 size=0x2000000000 iova=0x2000000000 # OK vfio_dma_mapping_mmio_test.vfio_type1_iommu.map_full_bar ok 1 vfio_dma_mapping_mmio_test.vfio_type1_iommu.map_full_bar # RUN vfio_dma_mapping_mmio_test.vfio_type1_iommu.map_partial_bar ... Mapping BAR4 (partial): vaddr=0x7fad40000000 size=0x1000 iova=0x0 # OK vfio_dma_mapping_mmio_test.vfio_type1_iommu.map_partial_bar ok 2 vfio_dma_mapping_mmio_test.vfio_type1_iommu.map_partial_bar # RUN vfio_dma_mapping_mmio_test.vfio_type1v2_iommu.map_full_bar ... Mapping BAR4: vaddr=0x7fad40000000 size=0x2000000000 iova=0x2000000000 # OK vfio_dma_mapping_mmio_test.vfio_type1v2_iommu.map_full_bar ok 3 vfio_dma_mapping_mmio_test.vfio_type1v2_iommu.map_full_bar # RUN vfio_dma_mapping_mmio_test.vfio_type1v2_iommu.map_partial_bar ... Mapping BAR4 (partial): vaddr=0x7fad40000000 size=0x1000 iova=0x0 # OK vfio_dma_mapping_mmio_test.vfio_type1v2_iommu.map_partial_bar ok 4 vfio_dma_mapping_mmio_test.vfio_type1v2_iommu.map_partial_bar # PASSED: 4 / 4 tests passed. # Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0 --- tools/testing/selftests/vfio/Makefile | 1 + tools/testing/selftests/vfio/lib/vfio_pci_device.c | 28 ++++- .../selftests/vfio/vfio_dma_mapping_mmio_test.c | 132 +++++++++++++++++++++ 3 files changed, 160 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/vfio/Makefile b/tools/testing/selftests/vfio/Makefile index 3c796ca99a50..ead27892ab65 100644 --- a/tools/testing/selftests/vfio/Makefile +++ b/tools/testing/selftests/vfio/Makefile @@ -1,5 +1,6 @@ CFLAGS = $(KHDR_INCLUDES) TEST_GEN_PROGS += vfio_dma_mapping_test +TEST_GEN_PROGS += vfio_dma_mapping_mmio_test TEST_GEN_PROGS += vfio_iommufd_setup_test TEST_GEN_PROGS += vfio_pci_device_test TEST_GEN_PROGS += vfio_pci_device_init_perf_test diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index 13fdb4b0b10f..6f29543856a5 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -12,10 +12,13 @@ #include <sys/mman.h> #include <uapi/linux/types.h> +#include <linux/align.h> #include <linux/iommufd.h> +#include <linux/kernel.h> #include <linux/limits.h> #include <linux/mman.h> #include <linux/overflow.h> +#include <linux/sizes.h> #include <linux/types.h> #include <linux/vfio.h> @@ -124,20 +127,43 @@ static void vfio_pci_region_get(struct vfio_pci_device *device, int index, static void vfio_pci_bar_map(struct vfio_pci_device *device, int index) { struct vfio_pci_bar *bar = &device->bars[index]; + size_t align, size; + void *map_base, *map_align; 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); + VFIO_ASSERT_GT(bar->info.size, 0); 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, + /* + * Align the mmap for more efficient IOMMU mapping. + * The largest PUD size supporting huge pfnmap is 1GiB. + */ + size = bar->info.size; + align = min_t(u64, 1ULL << __builtin_ctzll(size), SZ_1G); + + map_base = mmap(NULL, size + align, PROT_NONE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + VFIO_ASSERT_NE(map_base, MAP_FAILED); + + map_align = (void *)ALIGN((uintptr_t)map_base, align); + + if (map_align > map_base) + munmap(map_base, map_align - map_base); + if (align > (size_t)(map_align - map_base)) + munmap(map_align + size, align - (map_align - map_base)); + + bar->vaddr = mmap(map_align, size, prot, MAP_SHARED | MAP_FIXED, device->fd, bar->info.offset); VFIO_ASSERT_NE(bar->vaddr, MAP_FAILED); + + madvise(bar->vaddr, size, MADV_HUGEPAGE); } static void vfio_pci_bar_unmap(struct vfio_pci_device *device, int index) diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c new file mode 100644 index 000000000000..211fa4203b49 --- /dev/null +++ b/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stdio.h> +#include <sys/mman.h> +#include <unistd.h> + +#include <uapi/linux/types.h> +#include <linux/pci_regs.h> +#include <linux/sizes.h> +#include <linux/vfio.h> + +#include <libvfio.h> + +#include "../kselftest_harness.h" + +static const char *device_bdf; + +static int largest_mapped_bar(struct vfio_pci_device *device) +{ + int bar_idx = -1; + u64 bar_size = 0; + + for (int i = 0; i < PCI_STD_NUM_BARS; i++) { + struct vfio_pci_bar *bar = &device->bars[i]; + + if (!bar->vaddr) + continue; + + if (!(bar->info.flags & VFIO_REGION_INFO_FLAG_WRITE)) + continue; + + if (bar->info.size > bar_size) { + bar_size = bar->info.size; + bar_idx = i; + } + } + + return bar_idx; +} + +FIXTURE(vfio_dma_mapping_mmio_test) { + struct iommu *iommu; + struct vfio_pci_device *device; + struct iova_allocator *iova_allocator; + int bar_idx; +}; + +FIXTURE_VARIANT(vfio_dma_mapping_mmio_test) { + const char *iommu_mode; +}; + +#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode) \ +FIXTURE_VARIANT_ADD(vfio_dma_mapping_mmio_test, _iommu_mode) { \ + .iommu_mode = #_iommu_mode, \ +} + +FIXTURE_VARIANT_ADD_IOMMU_MODE(vfio_type1_iommu); +FIXTURE_VARIANT_ADD_IOMMU_MODE(vfio_type1v2_iommu); + +#undef FIXTURE_VARIANT_ADD_IOMMU_MODE + +FIXTURE_SETUP(vfio_dma_mapping_mmio_test) +{ + self->iommu = iommu_init(variant->iommu_mode); + self->device = vfio_pci_device_init(device_bdf, self->iommu); + self->iova_allocator = iova_allocator_init(self->iommu); + self->bar_idx = largest_mapped_bar(self->device); +} + +FIXTURE_TEARDOWN(vfio_dma_mapping_mmio_test) +{ + iova_allocator_cleanup(self->iova_allocator); + vfio_pci_device_cleanup(self->device); + iommu_cleanup(self->iommu); +} + +TEST_F(vfio_dma_mapping_mmio_test, map_full_bar) +{ + struct vfio_pci_bar *bar; + struct dma_region region; + + if (self->bar_idx < 0) + SKIP(return, "No mappable BAR found on device %s", device_bdf); + + bar = &self->device->bars[self->bar_idx]; + + region = (struct dma_region) { + .vaddr = bar->vaddr, + .size = bar->info.size, + .iova = iova_allocator_alloc(self->iova_allocator, bar->info.size), + }; + + printf("Mapping BAR%d: vaddr=%p size=0x%lx iova=0x%lx\n", + self->bar_idx, region.vaddr, region.size, region.iova); + + iommu_map(self->iommu, ®ion); + iommu_unmap(self->iommu, ®ion); +} + +TEST_F(vfio_dma_mapping_mmio_test, map_partial_bar) +{ + struct vfio_pci_bar *bar; + struct dma_region region; + size_t page_size; + + if (self->bar_idx < 0) + SKIP(return, "No mappable BAR found on device %s", device_bdf); + + bar = &self->device->bars[self->bar_idx]; + page_size = getpagesize(); + + if (bar->info.size < 2 * page_size) + SKIP(return, "BAR%d too small for partial mapping test (size=0x%llx)", + self->bar_idx, bar->info.size); + + region = (struct dma_region) { + .vaddr = bar->vaddr, + .size = page_size, + .iova = iova_allocator_alloc(self->iova_allocator, page_size), + }; + + printf("Mapping BAR%d (partial): vaddr=%p size=0x%lx iova=0x%lx\n", + self->bar_idx, region.vaddr, region.size, region.iova); + + iommu_map(self->iommu, ®ion); + iommu_unmap(self->iommu, ®ion); +} + +int main(int argc, char *argv[]) +{ + device_bdf = vfio_selftests_get_bdf(&argc, argv); + return test_harness_run(argc, argv); +} --- base-commit: d721f52e31553a848e0e9947ca15a49c5674aef3 change-id: 20260107-scratch-amastro-vfio-dma-mapping-mmio-test-eecf25d9a742 Best regards, -- Alex Mastro <[email protected]>
