This is a note to let you know that I've just added the patch titled
drm/vmwgfx: Enable DMA mappings with SEV
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-vmwgfx-enable-dma-mappings-with-sev.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d28663255b361f779868e222ba5b4c8d80168fdc
Author: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
Date: Sun Apr 7 22:28:02 2024 -0400
drm/vmwgfx: Enable DMA mappings with SEV
[ Upstream commit 4c08f01934ab67d1d283d5cbaa52b923abcfe4cd ]
Enable DMA mappings in vmwgfx after TTM has been fixed in commit
3bf3710e3718 ("drm/ttm: Add a generic TTM memcpy move for page-based iomem")
This enables full guest-backed memory support and in particular allows
usage of screen targets as the presentation mechanism.
Signed-off-by: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
Reported-by: Ye Li <ye.li@xxxxxxxxxxxx>
Tested-by: Ye Li <ye.li@xxxxxxxxxxxx>
Fixes: 3b0d6458c705 ("drm/vmwgfx: Refuse DMA operation when SEV encryption is active")
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@xxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v6.6+
Reviewed-by: Martin Krastev <martin.krastev@xxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240408022802.358641-1-zack.rusin@xxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 9d7a1b710f48f..53f63ad656a41 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -663,11 +663,12 @@ static int vmw_dma_select_mode(struct vmw_private *dev_priv)
[vmw_dma_map_populate] = "Caching DMA mappings.",
[vmw_dma_map_bind] = "Giving up DMA mappings early."};
- /* TTM currently doesn't fully support SEV encryption. */
- if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
- return -EINVAL;
-
- if (vmw_force_coherent)
+ /*
+ * When running with SEV we always want dma mappings, because
+ * otherwise ttm tt pool pages will bounce through swiotlb running
+ * out of available space.
+ */
+ if (vmw_force_coherent || cc_platform_has(CC_ATTR_MEM_ENCRYPT))
dev_priv->map_mode = vmw_dma_alloc_coherent;
else if (vmw_restrict_iommu)
dev_priv->map_mode = vmw_dma_map_bind;
