3 files changed, 22 insertions, 3 deletions
diff --git a/src/gallium/drivers/virgl/virgl_context.c b/src/gallium/drivers/virgl/virgl_context.c
index 9964520d5e7..f1b35fd1257 100644
--- a/src/gallium/drivers/virgl/virgl_context.c
+++ b/src/gallium/drivers/virgl/virgl_context.c
@@ -778,6 +778,11 @@ static void virgl_flush_eq(struct virgl_context *ctx, void *closure,
    virgl_encoder_set_sub_ctx(ctx, ctx->hw_sub_ctx_id);
 
    ctx->cbuf_initial_cdw = ctx->cbuf->cdw;
+
+   /* We have flushed the command queue, including any pending copy transfers
+    * involving staging resources.
+    */
+   ctx->queued_staging_res_size = 0;
 }
 
 static void virgl_flush_from_st(struct pipe_context *ctx,
diff --git a/src/gallium/drivers/virgl/virgl_context.h b/src/gallium/drivers/virgl/virgl_context.h
index 1449c64189a..b0fa03ca499 100644
--- a/src/gallium/drivers/virgl/virgl_context.h
+++ b/src/gallium/drivers/virgl/virgl_context.h
@@ -97,6 +97,9 @@ struct virgl_context {
 
    struct primconvert_context *primconvert;
    uint32_t hw_sub_ctx_id;
+
+   /* The total size of staging resources used in queued copy transfers. */
+   uint64_t queued_staging_res_size;
 };
 
 static inline struct virgl_sampler_view *
diff --git a/src/gallium/drivers/virgl/virgl_resource.c b/src/gallium/drivers/virgl/virgl_resource.c
index 879c3fb359a..e8baa4368e2 100644
--- a/src/gallium/drivers/virgl/virgl_resource.c
+++ b/src/gallium/drivers/virgl/virgl_resource.c
@@ -28,6 +28,12 @@
 #include "virgl_resource.h"
 #include "virgl_screen.h"
 
+/* A (soft) limit for the amount of memory we want to allow for queued staging
+ * resources. This is used to decide when we should force a flush, in order to
+ * avoid exhausting virtio-gpu memory.
+ */
+#define VIRGL_QUEUED_STAGING_RES_SIZE_LIMIT (128 * 1024 * 1024)
+
 /* We need to flush to properly sync the transfer with the current cmdbuf.
  * But there are cases where the flushing can be skipped:
  *
@@ -132,11 +138,13 @@ virgl_resource_transfer_prepare(struct virgl_context *vctx,
       copy_transfer = false;
    }
 
-   /* When performing a copy transfer there is no need to flush or wait for
-    * the target resource.
+   /* When performing a copy transfer there is no need wait for the target
+    * resource. There is normally no need to flush either, unless the amount of
+    * memory we are using for staging resources starts growing, in which case
+    * we want to flush to keep our memory consumption in check.
     */
    if (copy_transfer) {
-      flush = false;
+      flush = (vctx->queued_staging_res_size > VIRGL_QUEUED_STAGING_RES_SIZE_LIMIT);
       wait = false;
    }
 
@@ -572,6 +580,9 @@ void *virgl_transfer_uploader_map(struct virgl_context *vctx,
        */
       vtransfer->base.stride = stride;
       vtransfer->base.layer_stride = layer_stride;
+
+      /* Track the total size of active staging resources. */
+      vctx->queued_staging_res_size += size + align_offset;
    }
 
    return map_addr;