Mesa (main): svga: finish readbacks before mapping resources

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Module: Mesa
Branch: main
Commit: c7b0309723721495edd318eb6ecd4446900d702b
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=c7b0309723721495edd318eb6ecd4446900d702b

Author: Zack Rusin <zackr at vmware.com>
Date:   Wed Mar  2 14:08:09 2022 -0500

svga: finish readbacks before mapping resources

Flushing the command queue before mapping a resource is not enough
to guaruantee that the mapped content is not stale. We have to finish
to make sure that the gb readback actually updated the guest surface.

This fixes races in direct maps (map reads raced with gb readbacks)

Signed-off-by: Zack Rusin <zackr at vmware.com>
Reviewed-by: Charmaine Lee <charmainel at vmware.com>
Reviewed-by: Neha Bhende <bhenden at vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16061>

---

 src/gallium/drivers/svga/svga_resource_texture.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/svga/svga_resource_texture.c b/src/gallium/drivers/svga/svga_resource_texture.c
index cc1514bff70..ff2c500dbb4 100644
--- a/src/gallium/drivers/svga/svga_resource_texture.c
+++ b/src/gallium/drivers/svga/svga_resource_texture.c
@@ -342,9 +342,9 @@ svga_texture_transfer_map_direct(struct svga_context *svga,
 
       if (!svga->swc->force_coherent || tex->imported) {
          /* Readback the whole surface */
-	 readback_texture_surface(svga, tex, surf);
+         readback_texture_surface(svga, tex, surf);
 
-         svga_context_flush(svga, NULL);
+         svga_context_finish(svga);
       }
       /*
        * Note: if PIPE_MAP_DISCARD_WHOLE_RESOURCE were specified