[PATCH AUTOSEL 5.2 36/94] drm/virtio: use virtio_max_dma_size

Sasha Levin
2019-09-04T15:58:36Z

From: Gerd Hoffmann <kraxel@redhat.com>

[ Upstream commit 9b2a0a1ef66f96bf34921a3865581eca32ff05ec ]

We must make sure our scatterlist segments are not too big, otherwise
we might see swiotlb failures (happens with sev, also reproducable with
swiotlb=force).

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190821111210.27165-1-kraxel@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/virtio/virtgpu_object.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index b2da31310d24c..09b526518f5a6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -204,6 +204,7 @@ int virtio_gpu_object_get_sg_table(struct virtio_gpu_device *qdev,
.interruptible = false,
.no_wait_gpu = false
};
+ size_t max_segment;

/* wtf swapping */
if (bo->pages)
@@ -215,8 +216,13 @@ int virtio_gpu_object_get_sg_table(struct virtio_gpu_device *qdev,
if (!bo->pages)
goto out;

- ret = sg_alloc_table_from_pages(bo->pages, pages, nr_pages, 0,
- nr_pages << PAGE_SHIFT, GFP_KERNEL);
+ max_segment = virtio_max_dma_size(qdev->vdev);
+ max_segment &= PAGE_MASK;
+ if (max_segment > SCATTERLIST_MAX_SEGMENT)
+ max_segment = SCATTERLIST_MAX_SEGMENT;
+ ret = __sg_alloc_table_from_pages(bo->pages, pages, nr_pages, 0,
+ nr_pages << PAGE_SHIFT,
+ max_segment, GFP_KERNEL);
if (ret)
goto out;
return 0;
--
2.20.1