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@r... 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;