From: Eric Huang <jinhuieric.huang@amd.com>
Date: Sat, 27 Feb 2021 22:46:44 +0000 (-0500)
Subject: drm/amdgpu: set snoop bit in pde/pte entries for A+A
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2e2f197f4c994cf60ccd43a55b202bd0c5d679ba;p=linux.git

drm/amdgpu: set snoop bit in pde/pte entries for A+A

Page tables in vram mapping to cpu is changed from uncached to
cached in A+A, the snoop bit in VM_CONTEXTx_PAGE_TABLE_BASE_ADDR/
PDE0s/PDE1s/PDE2s/PTE.TFs has to be set so gpuvm walker snoop
page table data out of CPU cache.

Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index c5fea144b759d..feed820091f6f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1432,6 +1432,10 @@ uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt *ttm, struct ttm_resource *mem)
 			flags |= AMDGPU_PTE_SNOOPED;
 	}
 
+	if (mem && mem->mem_type == TTM_PL_VRAM &&
+			mem->bus.caching == ttm_cached)
+		flags |= AMDGPU_PTE_SNOOPED;
+
 	return flags;
 }