The patch titled
Subject: mm/hmm: add a test for cross device private faults
has been added to the -mm mm-unstable branch. Its filename is
mm-hmm-add-a-test-for-cross-device-private-faults.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hmm-add-a-test-for-cross-device-private-faults.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ralph Campbell <rcampbell@xxxxxxxxxx>
Subject: mm/hmm: add a test for cross device private faults
Date: Mon, 25 Jul 2022 11:36:15 -0700
Add a simple test case for when hmm_range_fault() is called with the
HMM_PFN_REQ_FAULT flag and a device private PTE is found for a device
other than the hmm_range::dev_private_owner. This should cause the page
to be faulted back to system memory from the other device and the PFN
returned in the output array.
Link: https://lkml.kernel.org/r/20220725183615.4118795-3-rcampbell@xxxxxxxxxx
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Felix Kuehling <felix.kuehling@xxxxxxx>
Cc: Philip Yang <Philip.Yang@xxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/hmm-tests.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/tools/testing/selftests/vm/hmm-tests.c~mm-hmm-add-a-test-for-cross-device-private-faults
+++ a/tools/testing/selftests/vm/hmm-tests.c
@@ -1603,9 +1603,19 @@ TEST_F(hmm2, double_map)
for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
ASSERT_EQ(ptr[i], i);
- /* Punch a hole after the first page address. */
- ret = munmap(buffer->ptr + self->page_size, self->page_size);
+ /* Migrate pages to device 1 and try to read from device 0. */
+ ret = hmm_dmirror_cmd(self->fd1, HMM_DMIRROR_MIGRATE, buffer, npages);
ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+
+ ret = hmm_dmirror_cmd(self->fd0, HMM_DMIRROR_READ, buffer, npages);
+ ASSERT_EQ(ret, 0);
+ ASSERT_EQ(buffer->cpages, npages);
+ ASSERT_EQ(buffer->faults, 1);
+
+ /* Check what device 0 read. */
+ for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
+ ASSERT_EQ(ptr[i], i);
hmm_buffer_free(buffer);
}
_
Patches currently in -mm which might be from rcampbell@xxxxxxxxxx are
mm-hmm-fault-non-owner-device-private-entries.patch
mm-hmm-add-a-test-for-cross-device-private-faults.patch
