Commit e478425b authored by Ralph Campbell's avatar Ralph Campbell Committed by Jason Gunthorpe
Browse files

mm/hmm: add tests for hmm_pfn_to_map_order() 

Add a sanity test for hmm_range_fault() returning the page mapping size
order.

Link: https://lore.kernel.org/r/20200701225352.9649-6-rcampbell@nvidia.com


Signed-off-by: default avatarRalph Campbell <rcampbell@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 3b50a6e5

lib/test_hmm.c

+4 −0
Original line number Diff line number Diff line
@@ -766,6 +766,10 @@ static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range, 
		*perm |= HMM_DMIRROR_PROT_WRITE;

	else

		*perm |= HMM_DMIRROR_PROT_READ;

	if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PMD_SHIFT)

		*perm |= HMM_DMIRROR_PROT_PMD;

	else if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PUD_SHIFT)

		*perm |= HMM_DMIRROR_PROT_PUD;

}



static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni,

lib/test_hmm_uapi.h

+4 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ struct hmm_dmirror_cmd { 
 * HMM_DMIRROR_PROT_NONE: unpopulated PTE or PTE with no access

 * HMM_DMIRROR_PROT_READ: read-only PTE

 * HMM_DMIRROR_PROT_WRITE: read/write PTE

 * HMM_DMIRROR_PROT_PMD: PMD sized page is fully mapped by same permissions

 * HMM_DMIRROR_PROT_PUD: PUD sized page is fully mapped by same permissions

 * HMM_DMIRROR_PROT_ZERO: special read-only zero page

 * HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL: Migrated device private page on the

 *					device the ioctl() is made
@@ -51,6 +53,8 @@ enum { 
	HMM_DMIRROR_PROT_NONE			= 0x00,

	HMM_DMIRROR_PROT_READ			= 0x01,

	HMM_DMIRROR_PROT_WRITE			= 0x02,

	HMM_DMIRROR_PROT_PMD			= 0x04,

	HMM_DMIRROR_PROT_PUD			= 0x08,

	HMM_DMIRROR_PROT_ZERO			= 0x10,

	HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL	= 0x20,

	HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE	= 0x30,

tools/testing/selftests/vm/hmm-tests.c

+76 −0
Original line number Diff line number Diff line
@@ -1291,6 +1291,82 @@ TEST_F(hmm2, snapshot) 
	hmm_buffer_free(buffer);

}



/*

 * Test the hmm_range_fault() HMM_PFN_PMD flag for large pages that

 * should be mapped by a large page table entry.

 */

TEST_F(hmm, compound)

{

	struct hmm_buffer *buffer;

	unsigned long npages;

	unsigned long size;

	int *ptr;

	unsigned char *m;

	int ret;

	long pagesizes[4];

	int n, idx;

	unsigned long i;



	/* Skip test if we can't allocate a hugetlbfs page. */



	n = gethugepagesizes(pagesizes, 4);

	if (n <= 0)

		return;

	for (idx = 0; --n > 0; ) {

		if (pagesizes[n] < pagesizes[idx])

			idx = n;

	}

	size = ALIGN(TWOMEG, pagesizes[idx]);

	npages = size >> self->page_shift;



	buffer = malloc(sizeof(*buffer));

	ASSERT_NE(buffer, NULL);



	buffer->ptr = get_hugepage_region(size, GHR_STRICT);

	if (buffer->ptr == NULL) {

		free(buffer);

		return;

	}



	buffer->size = size;

	buffer->mirror = malloc(npages);

	ASSERT_NE(buffer->mirror, NULL);



	/* Initialize the pages the device will snapshot in buffer->ptr. */

	for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)

		ptr[i] = i;



	/* Simulate a device snapshotting CPU pagetables. */

	ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);

	ASSERT_EQ(ret, 0);

	ASSERT_EQ(buffer->cpages, npages);



	/* Check what the device saw. */

	m = buffer->mirror;

	for (i = 0; i < npages; ++i)

		ASSERT_EQ(m[i], HMM_DMIRROR_PROT_WRITE |

				HMM_DMIRROR_PROT_PMD);



	/* Make the region read-only. */

	ret = mprotect(buffer->ptr, size, PROT_READ);

	ASSERT_EQ(ret, 0);



	/* Simulate a device snapshotting CPU pagetables. */

	ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);

	ASSERT_EQ(ret, 0);

	ASSERT_EQ(buffer->cpages, npages);



	/* Check what the device saw. */

	m = buffer->mirror;

	for (i = 0; i < npages; ++i)

		ASSERT_EQ(m[i], HMM_DMIRROR_PROT_READ |

				HMM_DMIRROR_PROT_PMD);



	free_hugepage_region(buffer->ptr);

	buffer->ptr = NULL;

	hmm_buffer_free(buffer);

}



/*

 * Test two devices reading the same memory (double mapped).

 */