iommufd/selftest: Add mock IO hugepages tests

Leverage previously added MOCK_FLAGS_DEVICE_HUGE_IOVA flag to create an
IOMMU domain with more than MOCK_IO_PAGE_SIZE supported.

Plumb the hugetlb backing memory for buffer allocation and change the
expected page size to MOCK_HUGE_PAGE_SIZE (1M) when hugepage variant test
cases are used. These so far are limited to 128M and 256M IOVA range tests
cases which is when 1M hugepages can be used.

Link: https://lore.kernel.org/r/20240202133415.23819-9-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: jpemartins

tools/testing/selftests/iommu/iommufd.c

@@ -12,6 +12,7 @@
 static unsigned long HUGEPAGE_SIZE;
 
 #define MOCK_PAGE_SIZE (PAGE_SIZE / 2)
+#define MOCK_HUGE_PAGE_SIZE (512 * MOCK_PAGE_SIZE)
 
 static unsigned long get_huge_page_size(void)
 {
@@ -1716,10 +1717,12 @@ FIXTURE(iommufd_dirty_tracking)
 FIXTURE_VARIANT(iommufd_dirty_tracking)
 {
 	unsigned long buffer_size;
+	bool hugepages;
 };
 
 FIXTURE_SETUP(iommufd_dirty_tracking)
 {
+	int mmap_flags;
 	void *vrc;
 	int rc;
 
@@ -1732,9 +1735,17 @@ FIXTURE_SETUP(iommufd_dirty_tracking)
 			   variant->buffer_size, rc);
 	}
 
+	mmap_flags = MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED;
+	if (variant->hugepages) {
+		/*
+		 * MAP_POPULATE will cause the kernel to fail mmap if THPs are
+		 * not available.
+		 */
+		mmap_flags |= MAP_HUGETLB | MAP_POPULATE;
+	}
 	assert((uintptr_t)self->buffer % HUGEPAGE_SIZE == 0);
 	vrc = mmap(self->buffer, variant->buffer_size, PROT_READ | PROT_WRITE,
-		   MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+		   mmap_flags, -1, 0);
 	assert(vrc == self->buffer);
 
 	self->page_size = MOCK_PAGE_SIZE;
@@ -1749,8 +1760,16 @@ FIXTURE_SETUP(iommufd_dirty_tracking)
 	assert((uintptr_t)self->bitmap % PAGE_SIZE == 0);
 
 	test_ioctl_ioas_alloc(&self->ioas_id);
-	test_cmd_mock_domain(self->ioas_id, &self->stdev_id, &self->hwpt_id,
-			     &self->idev_id);
+	/* Enable 1M mock IOMMU hugepages */
+	if (variant->hugepages) {
+		test_cmd_mock_domain_flags(self->ioas_id,
+					   MOCK_FLAGS_DEVICE_HUGE_IOVA,
+					   &self->stdev_id, &self->hwpt_id,
+					   &self->idev_id);
+	} else {
+		test_cmd_mock_domain(self->ioas_id, &self->stdev_id,
+				     &self->hwpt_id, &self->idev_id);
+	}
 }
 
 FIXTURE_TEARDOWN(iommufd_dirty_tracking)
@@ -1784,12 +1803,26 @@ FIXTURE_VARIANT_ADD(iommufd_dirty_tracking, domain_dirty128M)
 	.buffer_size = 128UL * 1024UL * 1024UL,
 };
 
+FIXTURE_VARIANT_ADD(iommufd_dirty_tracking, domain_dirty128M_huge)
+{
+	/* 4K bitmap (128M IOVA range) */
+	.buffer_size = 128UL * 1024UL * 1024UL,
+	.hugepages = true,
+};
+
 FIXTURE_VARIANT_ADD(iommufd_dirty_tracking, domain_dirty256M)
 {
 	/* 8K bitmap (256M IOVA range) */
 	.buffer_size = 256UL * 1024UL * 1024UL,
 };
 
+FIXTURE_VARIANT_ADD(iommufd_dirty_tracking, domain_dirty256M_huge)
+{
+	/* 8K bitmap (256M IOVA range) */
+	.buffer_size = 256UL * 1024UL * 1024UL,
+	.hugepages = true,
+};
+
 TEST_F(iommufd_dirty_tracking, enforce_dirty)
 {
 	uint32_t ioas_id, stddev_id, idev_id;
@@ -1853,6 +1886,9 @@ TEST_F(iommufd_dirty_tracking, get_dirty_bitmap)
 	uint32_t hwpt_id;
 	uint32_t ioas_id;
 
+	if (variant->hugepages)
+		page_size = MOCK_HUGE_PAGE_SIZE;
+
 	test_ioctl_ioas_alloc(&ioas_id);
 	test_ioctl_ioas_map_fixed_id(ioas_id, self->buffer,
 				     variant->buffer_size, MOCK_APERTURE_START);
@@ -1887,6 +1923,9 @@ TEST_F(iommufd_dirty_tracking, get_dirty_bitmap_no_clear)
 	uint32_t hwpt_id;
 	uint32_t ioas_id;
 
+	if (variant->hugepages)
+		page_size = MOCK_HUGE_PAGE_SIZE;
+
 	test_ioctl_ioas_alloc(&ioas_id);
 	test_ioctl_ioas_map_fixed_id(ioas_id, self->buffer,
 				     variant->buffer_size, MOCK_APERTURE_START);