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authorAlistair Popple <apopple@nvidia.com>2022-01-15 01:09:31 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-01-27 13:05:43 +0300
commit52b66f818916600098c7ea954d749f2307770d9f (patch)
treef573ed81188ea2557788f02c6eea0748c9ec8bcd /tools
parent42de0446a142354f98caa3cdf8f930ca1cac7b14 (diff)
downloadlinux-52b66f818916600098c7ea954d749f2307770d9f.tar.xz
mm/hmm.c: allow VM_MIXEDMAP to work with hmm_range_fault
commit 87c01d57fa23de82fff593a7d070933d08755801 upstream. hmm_range_fault() can be used instead of get_user_pages() for devices which allow faulting however unlike get_user_pages() it will return an error when used on a VM_MIXEDMAP range. To make hmm_range_fault() more closely match get_user_pages() remove this restriction. This requires dealing with the !ARCH_HAS_PTE_SPECIAL case in hmm_vma_handle_pte(). Rather than replicating the logic of vm_normal_page() call it directly and do a check for the zero pfn similar to what get_user_pages() currently does. Also add a test to hmm selftest to verify functionality. Link: https://lkml.kernel.org/r/20211104012001.2555676-1-apopple@nvidia.com Fixes: da4c3c735ea4 ("mm/hmm/mirror: helper to snapshot CPU page table") Signed-off-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/vm/hmm-tests.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index 864f126ffd78..203323967b50 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -1251,6 +1251,48 @@ TEST_F(hmm, anon_teardown)
/*
* Test memory snapshot without faulting in pages accessed by the device.
*/
+TEST_F(hmm, mixedmap)
+{
+ struct hmm_buffer *buffer;
+ unsigned long npages;
+ unsigned long size;
+ unsigned char *m;
+ int ret;
+
+ npages = 1;
+ size = npages << self->page_shift;
+
+ buffer = malloc(sizeof(*buffer));
+ ASSERT_NE(buffer, NULL);
+
+ buffer->fd = -1;
+ buffer->size = size;
+ buffer->mirror = malloc(npages);
+ ASSERT_NE(buffer->mirror, NULL);
+
+
+ /* Reserve a range of addresses. */
+ buffer->ptr = mmap(NULL, size,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE,
+ self->fd, 0);
+ ASSERT_NE(buffer->ptr, MAP_FAILED);
+
+ /* 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;
+ ASSERT_EQ(m[0], HMM_DMIRROR_PROT_READ);
+
+ hmm_buffer_free(buffer);
+}
+
+/*
+ * Test memory snapshot without faulting in pages accessed by the device.
+ */
TEST_F(hmm2, snapshot)
{
struct hmm_buffer *buffer;