When running on Xen inside as virtual machine (nested virt scenario),
memory allocated by alloc_pages_exact might not actually be contiguous.
Call xen_swiotlb_alloc_coherent instead, which is going to take care of
making the buffer contiguous in machine memory.
No changes in behavior for the non-Xen case.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
Alternatively we could call dma_alloc_coherent in all cases, but that
would make the non-Xen code path more complex.
---
drivers/virtio/virtio_pci_legacy.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index 48bc979..27359ac 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -18,6 +18,8 @@
*/
#include "virtio_pci_common.h"
+#include <xen/xen.h>
+#include <xen/swiotlb-xen.h>
/* virtio config->get_features() implementation */
static u64 vp_get_features(struct virtio_device *vdev)
@@ -122,6 +124,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
unsigned long size;
u16 num;
int err;
+ dma_addr_t dma_addr;
/* Select the queue we're interested in */
iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
@@ -135,12 +138,20 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
info->msix_vector = msix_vec;
size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
- info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
+ /* activate the queue */
+ if (xen_domain()) {
+ info->queue = xen_swiotlb_alloc_coherent(NULL,
+ size,
+ &dma_addr,
+ GFP_KERNEL|__GFP_ZERO,
+ NULL);
+ } else {
+ info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
+ dma_addr = virt_to_phys(info->queue);
+ }
if (info->queue == NULL)
return ERR_PTR(-ENOMEM);
-
- /* activate the queue */
- iowrite32(virt_to_phys(info->queue) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
+ iowrite32(dma_addr >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
/* create the vring */
--
1.7.10.4
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