On 2023-10-17 09:22, Alex Deucher wrote:
> On Tue, Oct 17, 2023 at 12:52 AM Luben Tuikov <luben.tuikov@xxxxxxx> wrote:
>>
>> A context priority value of AMD_CTX_PRIORITY_UNSET is now invalid--instead of
>> carrying it around and passing it to the Direct Rendering Manager--and it
>> becomes AMD_CTX_PRIORITY_NORMAL in amdgpu_ctx_ioctl(), the gateway to context
>> creation.
>>
>> Cc: Alex Deucher <Alexander.Deucher@xxxxxxx>
>> Cc: Christian König <christian.koenig@xxxxxxx>
>> Signed-off-by: Luben Tuikov <luben.tuikov@xxxxxxx>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>> index 0dc9c655c4fbdb..092962b93064fc 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>> @@ -47,7 +47,6 @@ const unsigned int amdgpu_ctx_num_entities[AMDGPU_HW_IP_NUM] = {
>> bool amdgpu_ctx_priority_is_valid(int32_t ctx_prio)
>> {
>> switch (ctx_prio) {
>> - case AMDGPU_CTX_PRIORITY_UNSET:
>> case AMDGPU_CTX_PRIORITY_VERY_LOW:
>> case AMDGPU_CTX_PRIORITY_LOW:
>> case AMDGPU_CTX_PRIORITY_NORMAL:
>> @@ -55,6 +54,7 @@ bool amdgpu_ctx_priority_is_valid(int32_t ctx_prio)
>> case AMDGPU_CTX_PRIORITY_VERY_HIGH:
>> return true;
>> default:
>> + case AMDGPU_CTX_PRIORITY_UNSET:
>> return false;
>
> I don't recall if any userspace uses this, but this would break
> userspace if it does.
This is shielded from user space in the following manner,
1) amdgpu_ctx_priority_is_valid() is called from amdgpu_ctx_ioctl() and
if amdgpu_ctx_priority_is_valid() returns false, we set the priority to NORMAL.
See the 2nd patch.
2) It is also called from amdgpu_ctx_priority_permit(), which is called
from amdgpu_ctx_init() which is called from amdgpu_ctx_alloc() which
is called from amdgpu_ctx_ioctl(), _after_ the call described above,
and thus priority is now NORMAL.
Plus I'm typing this on a running system with 6.6.0 + those two patches.
User space can send us down UNSET, but we set it to NORMAL.
Can I get an R-B?
>
> Alex
>
>> }
>> }
>>
>> base-commit: dc9b2e683bcba017588b9aaad80f442ad004a48f
>> --
>> 2.42.0
>>
--
Regards,
Luben
