5 files changed, 69 insertions, 7 deletions
diff --git a/tools/testing/selftests/vfio/lib/include/libvfio.h b/tools/testing/selftests/vfio/lib/include/libvfio.h
index 279ddcd70194..1b6da54cc2cb 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio.h
@@ -23,4 +23,13 @@
 const char *vfio_selftests_get_bdf(int *argc, char *argv[]);
 char **vfio_selftests_get_bdfs(int *argc, char *argv[], int *nr_bdfs);
 
+/*
+ * Reserve virtual address space of size at an address satisfying
+ * (vaddr % align) == offset.
+ *
+ * Returns the reserved vaddr. The caller is responsible for unmapping
+ * the returned region.
+ */
+void *mmap_reserve(size_t size, size_t align, size_t offset);
+
 #endif /* SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_H */
diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
index 5c9b9dc6d993..e9a3386a4719 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/iommu.h
@@ -61,6 +61,12 @@ iova_t iommu_hva2iova(struct iommu *iommu, void *vaddr);
 
 struct iommu_iova_range *iommu_iova_ranges(struct iommu *iommu, u32 *nranges);
 
+#define MODE_VFIO_TYPE1_IOMMU "vfio_type1_iommu"
+#define MODE_VFIO_TYPE1V2_IOMMU "vfio_type1v2_iommu"
+#define MODE_IOMMUFD_COMPAT_TYPE1 "iommufd_compat_type1"
+#define MODE_IOMMUFD_COMPAT_TYPE1V2 "iommufd_compat_type1v2"
+#define MODE_IOMMUFD "iommufd"
+
 /*
  * Generator for VFIO selftests fixture variants that replicate across all
  * possible IOMMU modes. Tests must define FIXTURE_VARIANT_ADD_IOMMU_MODE()
diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c
index 58b7fb7430d4..035dac069d60 100644
--- a/tools/testing/selftests/vfio/lib/iommu.c
+++ b/tools/testing/selftests/vfio/lib/iommu.c
@@ -20,32 +20,32 @@
 #include "../../../kselftest.h"
 #include <libvfio.h>
 
-const char *default_iommu_mode = "iommufd";
+const char *default_iommu_mode = MODE_IOMMUFD;
 
 /* Reminder: Keep in sync with FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(). */
 static const struct iommu_mode iommu_modes[] = {
 	{
-		.name = "vfio_type1_iommu",
+		.name = MODE_VFIO_TYPE1_IOMMU,
 		.container_path = "/dev/vfio/vfio",
 		.iommu_type = VFIO_TYPE1_IOMMU,
 	},
 	{
-		.name = "vfio_type1v2_iommu",
+		.name = MODE_VFIO_TYPE1V2_IOMMU,
 		.container_path = "/dev/vfio/vfio",
 		.iommu_type = VFIO_TYPE1v2_IOMMU,
 	},
 	{
-		.name = "iommufd_compat_type1",
+		.name = MODE_IOMMUFD_COMPAT_TYPE1,
 		.container_path = "/dev/iommu",
 		.iommu_type = VFIO_TYPE1_IOMMU,
 	},
 	{
-		.name = "iommufd_compat_type1v2",
+		.name = MODE_IOMMUFD_COMPAT_TYPE1V2,
 		.container_path = "/dev/iommu",
 		.iommu_type = VFIO_TYPE1v2_IOMMU,
 	},
 	{
-		.name = "iommufd",
+		.name = MODE_IOMMUFD,
 	},
 };
 
diff --git a/tools/testing/selftests/vfio/lib/libvfio.c b/tools/testing/selftests/vfio/lib/libvfio.c
index a23a3cc5be69..3a3d1ed635c1 100644
--- a/tools/testing/selftests/vfio/lib/libvfio.c
+++ b/tools/testing/selftests/vfio/lib/libvfio.c
@@ -2,6 +2,9 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/mman.h>
+
+#include <linux/align.h>
 
 #include "../../../kselftest.h"
 #include <libvfio.h>
@@ -76,3 +79,25 @@ const char *vfio_selftests_get_bdf(int *argc, char *argv[])
 
 	return vfio_selftests_get_bdfs(argc, argv, &nr_bdfs)[0];
 }
+
+void *mmap_reserve(size_t size, size_t align, size_t offset)
+{
+	void *map_base, *map_align;
+	size_t delta;
+
+	VFIO_ASSERT_GT(align, offset);
+	delta = align - offset;
+
+	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 + delta, align) - delta);
+
+	if (map_align > map_base)
+		VFIO_ASSERT_EQ(munmap(map_base, map_align - map_base), 0);
+
+	VFIO_ASSERT_EQ(munmap(map_align + size, map_base + align - map_align), 0);
+
+	return map_align;
+}
diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
index fac4c0ecadef..4e5871f1ebc3 100644
--- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
@@ -11,10 +11,14 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 
+#include <linux/align.h>
 #include <linux/iommufd.h>
+#include <linux/kernel.h>
 #include <linux/limits.h>
+#include <linux/log2.h>
 #include <linux/mman.h>
 #include <linux/overflow.h>
+#include <linux/sizes.h>
 #include <linux/types.h>
 #include <linux/vfio.h>
 
@@ -123,20 +127,38 @@ 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;
 	int prot = 0;
+	void *vaddr;
 
 	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_TRUE(is_power_of_2(bar->info.size));
 
 	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,
+	size = bar->info.size;
+
+	/*
+	 * Align BAR mmaps to improve page fault granularity during potential
+	 * subsequent IOMMU mapping of these BAR vaddr. 1G for x86 is the
+	 * largest hugepage size across any architecture, so no benefit from
+	 * larger alignment. BARs smaller than 1G will be aligned by their
+	 * power-of-two size, guaranteeing sufficient alignment for smaller
+	 * hugepages, if present.
+	 */
+	align = min_t(size_t, size, SZ_1G);
+
+	vaddr = mmap_reserve(size, align, 0);
+	bar->vaddr = mmap(vaddr, 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)