Re: [PATCH] mm/hmm: fault non-owner device private entries

[Ralph Campbell <rcampbell@nvidia.com>]

On 7/23/22 06:32, Jason Gunthorpe wrote:
> On Fri, Jul 22, 2022 at 03:56:32PM -0700, Ralph Campbell wrote:
>> If hmm_range_fault() is called with the HMM_PFN_REQ_FAULT flag and a
>> device private PTE is found, the hmm_range::dev_private_owner page is
>> used to determine if the device private page should not be faulted in.
>> However, if the device private page is not owned by the caller,
>> hmm_range_fault() returns an error instead of calling migrate_to_ram()
>> to fault in the page.
>>
>> Cc: stable@vger.kernel.org
>> Fixes: 76612d6ce4cc ("mm/hmm: reorganize how !pte_present is handled in hmm_vma_handle_pte()")
>> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
>> Reported-by: Felix Kuehling <felix.kuehling@amd.com>
>> ---
>>   mm/hmm.c | 3 +++
>>   1 file changed, 3 insertions(+)
> Should we have a test for this ?
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
>
> Jason

Sure, I'll add something to tools/testing/selftests/vm/hmm-tests.c