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Commit 7389e826 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Alistair Strachan
Browse files

UPSTREAM: vring: Use the DMA API on Xen 



Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: default avatarWei Liu <wei.liu2@citrix.com>
(cherry picked from commit 78fe39872378b0bef00a91181f1947acb8a08500)
Bug: 121166534
Test: Ran cuttlefish with android-4.4 + VSOCKETS, VMWARE_VMCI_VSOCKETS
Signed-off-by: default avatarAlistair Strachan <astrachan@google.com>

Change-Id: Ibf85aad139f319354cd2ee8833ca9434c15640d8
parent 6bb68f96

drivers/virtio/virtio_ring.c

+12 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/hrtimer.h>

#include <linux/kmemleak.h>

#include <linux/dma-mapping.h>

#include <xen/xen.h>



#ifdef DEBUG

/* For development, we want to crash whenever the ring is screwed. */
@@ -131,6 +132,17 @@ struct vring_virtqueue { 


static bool vring_use_dma_api(struct virtio_device *vdev)

{

	/*

	 * In theory, it's possible to have a buggy QEMU-supposed

	 * emulated Q35 IOMMU and Xen enabled at the same time.  On

	 * such a configuration, virtio has never worked and will

	 * not work without an even larger kludge.  Instead, enable

	 * the DMA API if we're a Xen guest, which at least allows

	 * all of the sensible Xen configurations to work correctly.

	 */

	if (xen_domain())

		return true;



	return false;

}