[Intel-xe] [PATCH] drm/xe: Allow atomic operations in pages for Xe2

[Souza, Jose]

On Wed, 2023-10-04 at 23:29 -0500, Lucas De Marchi wrote:
> On Wed, Oct 04, 2023 at 02:06:24PM -0700, Jose Souza wrote:
> > Without this if a atomic operations is executed it causes engine
> > memory catastrophic error.
> > 
> > This bit was already being added in the pte_encode_vma() path but not
> > in the pde_encode_bo() path.
> > 
> > This fixes at least the 3 failures in piglit sanity and 2 failures in
> > crucible.
> > 
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> > ---
> > drivers/gpu/drm/xe/xe_vm.c | 3 +++
> > 1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> > index ea17d026546cd..6be5d92706932 100644
> > --- a/drivers/gpu/drm/xe/xe_vm.c
> > +++ b/drivers/gpu/drm/xe/xe_vm.c
> > @@ -1261,6 +1261,9 @@ static u64 xelp_pte_encode_bo(struct xe_bo *bo, u64 bo_offset,
> > 	pte |= pte_encode_cache(xe, cache);
> > 	pte |= pte_encode_ps(pt_level);
> > 
> > +	if (GRAPHICS_VERx100(xe) >= 20)
> > +		pte |= XE_USM_PPGTT_PTE_AE;
> 
> I think there's a clash with doing this here and doing it where it was
> done in commit 6193a2ba4704 ("drm/xe: set PTE_AE for all platforms supporting it")
> 
> There it's adding the flag  in the gpuva.flags which is later added to
> the pte. However, in xe_pt_stage_bind() that checks for XE_VMA_ATOMIC_PTE_BIT
> is only inside doing that for devmem. I was thinking that I might had screwed it
> with my recent refactors, but looking at the log it was always like
> that and the fix in the commit above didn't fix it for *all* the
> platforms.
> 
> Does it fix it if you simply change that function to consider system
> memory? Otherwise we should probably change it only in the pte encode
> instead of doing it in both places.

I thought it would be needed in pde_encode_bo() code paths but I have done your suggestions in the internal tree and it fixed Mesa tests.
Will send the updated version of this patch in a few minutes.

> 
> +Fei, +Matt Brost, +Matt Roper
> 
> Lucas De Marchi
> 
> > +
> > 	if (xe_bo_is_vram(bo) || xe_bo_is_stolen_devmem(bo))
> > 		pte |= XE_PPGTT_PTE_DM;
> > 
> > -- 
> > 2.42.0
> >