[Intel-xe] [PATCH] drm/xe: Implement HW workaround 14016763929

[Souza, Jose]

On Thu, 2023-08-03 at 15:01 -0400, Oak Zeng wrote:
> To workaround a HW bug on DG2, driver is required to map the whole
> ppgtt virtual address space before GPU workload submission. Thus
> set the XE_VM_FLAG_SCRATCH_PAGE flag during vm create so the whole
> address space is mapped to point to scratch page.
> 
> Signed-off-by: Oak Zeng <oak.zeng at intel.com>
> ---
>  drivers/gpu/drm/xe/Makefile        | 2 +-
>  drivers/gpu/drm/xe/xe_vm.c         | 5 +++++
>  drivers/gpu/drm/xe/xe_wa_oob.rules | 1 +
>  3 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index e79624ab2cb3..e6a05d35c931 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -37,7 +37,7 @@ quiet_cmd_wa_oob = GEN     $(notdir $(generated_oob))
>  $(generated_oob) &: $(obj)/xe_gen_wa_oob $(srctree)/$(src)/xe_wa_oob.rules
>  	$(call cmd,wa_oob)
>  
> -$(obj)/xe_guc.o $(obj)/xe_wa.o $(obj)/xe_ring_ops.o: $(generated_oob)
> +$(obj)/xe_guc.o $(obj)/xe_wa.o $(obj)/xe_ring_ops.o $(obj)/xe_vm.o: $(generated_oob)
>  
>  # Please keep these build lists sorted!
>  
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index cb28dbc2bdbb..b045bb341a5c 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -29,6 +29,8 @@
>  #include "xe_res_cursor.h"
>  #include "xe_sync.h"
>  #include "xe_trace.h"
> +#include "generated/xe_wa_oob.h"
> +#include "xe_wa.h"
>  
>  #define TEST_VM_ASYNC_OPS_ERROR
>  
> @@ -1235,6 +1237,9 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
>  
>  	INIT_LIST_HEAD(&vm->extobj.list);
>  
> +	if (XE_WA(xe_root_mmio_gt(xe), 14016763929))
> +		flags |= XE_VM_FLAG_SCRATCH_PAGE;

Isn't DRM_XE_VM_CREATE_FAULT_MODE incompatible with SCRATCH_PAGE?
What if user-space asks for fault mode in DG2?


> +
>  	if (!(flags & XE_VM_FLAG_MIGRATION))
>  		xe_device_mem_access_get(xe);
>  
> diff --git a/drivers/gpu/drm/xe/xe_wa_oob.rules b/drivers/gpu/drm/xe/xe_wa_oob.rules
> index 15c23813398a..6fc68c592ca8 100644
> --- a/drivers/gpu/drm/xe/xe_wa_oob.rules
> +++ b/drivers/gpu/drm/xe/xe_wa_oob.rules
> @@ -15,3 +15,4 @@
>  18020744125	PLATFORM(PVC)
>  1509372804	PLATFORM(PVC), GRAPHICS_STEP(A0, C0)
>  1409600907	GRAPHICS_VERSION_RANGE(1200, 1250)
> +14016763929	PLATFORM(DG2)