xen/virtio: use dom0 as default backend for CONFIG_XEN_VIRTIO_FORCE_GRANT

With CONFIG_XEN_VIRTIO_FORCE_GRANT set the default backend domid to 0,
enabling to use xen_grant_dma_ops for those devices.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>

diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index 7133272918f0ff01c90f2f9b872d3b1066cb2d06..3e4c590896d08038ac327ddcd5083bc515cbd02e 100644 (file)
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -365,6 +365,9 @@ void xen_grant_setup_dma_ops(struct device *dev)
        if (dev->of_node) {
                if (xen_dt_grant_init_backend_domid(dev, data))
                        goto err;
+       } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) {
+               dev_info(dev, "Using dom0 as backend\n");
+               data->backend_domid = 0;
        } else {
                /* XXX ACPI device unsupported for now */
                goto err;