[Intel-xe] [PATCH 1/1] drm/xe: set PTE_AE for all platforms supporting it

[Matt Roper]

On Wed, Sep 27, 2023 at 09:43:35PM -0700, fei.yang at intel.com wrote:
> From: Fei Yang <fei.yang at intel.com>
> 
> Atomic access is supported by PVC, and became a common feature for all
> platforms starting from Xe2. To enable that XE_VMA_ATOMIC_PTE_BIT needs
> to be set, then pte encode will eventually set PTE_AE for devmem.
> 
> Signed-off-by: Fei Yang <fei.yang at intel.com>

Matches the PTEs for Xe2 documented on bspec 67095, so

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

It seems strange to be setting this flag at this layer of the driver
before we know whether it's even the correct setting for atomic enable
(i.e., we don't know yet at this point whether we want to get pagefaults
for atomics or not).  At some point in the future we may want to move
the platform checks down to the same layer of the code where the actual
atomic enable logic happens, but that can wait until later.


Matt

> ---
>  drivers/gpu/drm/xe/xe_vm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index beffbb1039d3..5f700c0d5ef9 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -897,7 +897,7 @@ static struct xe_vma *xe_vma_create(struct xe_vm *vm,
>  			vma->tile_mask |= 0x1 << id;
>  	}
>  
> -	if (vm->xe->info.platform == XE_PVC)
> +	if (vm->xe->info.platform == XE_PVC || GRAPHICS_VER(vm->xe) >= 20)
>  		vma->gpuva.flags |= XE_VMA_ATOMIC_PTE_BIT;
>  
>  	if (bo) {
> -- 
> 2.25.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation