From: Sayali Patil Date: Thu, 11 Jun 2026 03:41:00 +0000 (+0530) Subject: selftests/mm: allow PUD-level entries in compound testcase of hmm tests X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=224ed0e019b122d08580362abe57574a78f2b5fa;p=thirdparty%2Flinux.git selftests/mm: allow PUD-level entries in compound testcase of hmm tests Patch series "selftests/mm: assorted fixes for hmm-tests", v3. This series fixes a few issues in hmm-tests that show up when page-size and huge-page configuration differ from the hardcoded assumptions the tests were written for (PMD/THP sizing, default hugepage size, and related cases). It also includes a fix to exclusive_cow: the test ignored the return value of fork(), so both parent and child ran the same teardown path. This patch (of 3): The HMM compound testcase currently assumes only PMD-level mappings and fails on systems where default_hugepagesz=1G is set, because the region is then reported by the device at PUD level. Determine the mapping level (PMD or PUD) the device reports for the first page of the range and require every page to match that level exactly via ASSERT_EQ(). This accepts PUD-level mappings while preserving the expected/observed protection values printed on failure, and rejects a fragmented mapping that mixes PMD- and PUD-level entries within the same range (which a per-page OR check would have let pass). Link: https://lore.kernel.org/20260611034102.1030738-1-aboorvad@linux.ibm.com Link: https://lore.kernel.org/20260611034102.1030738-2-aboorvad@linux.ibm.com Fixes: e478425bec93 ("mm/hmm: add tests for hmm_pfn_to_map_order()") Signed-off-by: Sayali Patil Co-developed-by: Aboorva Devarajan Signed-off-by: Aboorva Devarajan Cc: Alex Sierra Cc: Alistair Popple Cc: Balbir Singh Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Ralph Campbell Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c index 46e0c8c921c3d..deb6a7485650f 100644 --- a/tools/testing/selftests/mm/hmm-tests.c +++ b/tools/testing/selftests/mm/hmm-tests.c @@ -1602,8 +1602,8 @@ TEST_F(hmm2, snapshot) } /* - * Test the hmm_range_fault() HMM_PFN_PMD flag for large pages that - * should be mapped by a large page table entry. + * Test the hmm_range_fault() handling of large pages (PMD or PUD) + * that should be mapped by a large page table entry. */ TEST_F(hmm, compound) { @@ -1613,6 +1613,7 @@ TEST_F(hmm, compound) unsigned long default_hsize = default_huge_page_size(); int *ptr; unsigned char *m; + unsigned char prot; int ret; unsigned long i; @@ -1648,11 +1649,20 @@ TEST_F(hmm, compound) ASSERT_EQ(ret, 0); ASSERT_EQ(buffer->cpages, npages); - /* Check what the device saw. */ + /* + * Check what the device saw. The region is backed by a single huge + * page that the device reports either at PMD or at PUD level depending + * on the configured default hugepage size. Determine that level from + * the first page and require every page in the range to match it + * exactly, so that a fragmented mapping mixing levels (or a missing + * large-page bit) is still caught and reported with its actual value. + */ m = buffer->mirror; + prot = HMM_DMIRROR_PROT_WRITE | + ((m[0] & HMM_DMIRROR_PROT_PUD) ? HMM_DMIRROR_PROT_PUD : + HMM_DMIRROR_PROT_PMD); for (i = 0; i < npages; ++i) - ASSERT_EQ(m[i], HMM_DMIRROR_PROT_WRITE | - HMM_DMIRROR_PROT_PMD); + ASSERT_EQ(m[i], prot); /* Make the region read-only. */ ret = mprotect(buffer->ptr, size, PROT_READ); @@ -1663,11 +1673,17 @@ TEST_F(hmm, compound) ASSERT_EQ(ret, 0); ASSERT_EQ(buffer->cpages, npages); - /* Check what the device saw. */ + /* + * Check what the device saw after mprotect(PROT_READ). Same + * approach as above: determine the mapping level from the first + * page and require every page to match it exactly. + */ m = buffer->mirror; + prot = HMM_DMIRROR_PROT_READ | + ((m[0] & HMM_DMIRROR_PROT_PUD) ? HMM_DMIRROR_PROT_PUD : + HMM_DMIRROR_PROT_PMD); for (i = 0; i < npages; ++i) - ASSERT_EQ(m[i], HMM_DMIRROR_PROT_READ | - HMM_DMIRROR_PROT_PMD); + ASSERT_EQ(m[i], prot); munmap(buffer->ptr, buffer->size); buffer->ptr = NULL;