virtio: Don't use PAGE_SIZE for vring alignment in virtio_pci.
That doesn't work for non-4k guests which are now appearing.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index c2cd69b..f28643f 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -237,7 +237,7 @@
info->queue_index = index;
info->num = num;
- size = PAGE_ALIGN(vring_size(num, PAGE_SIZE));
+ size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
if (info->queue == NULL) {
err = -ENOMEM;
@@ -290,7 +290,7 @@
iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
- size = PAGE_ALIGN(vring_size(info->num, PAGE_SIZE));
+ size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN));
free_pages_exact(info->queue, size);
kfree(info);
}
diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h
index e13d7eb..cd0fd5d 100644
--- a/include/linux/virtio_pci.h
+++ b/include/linux/virtio_pci.h
@@ -57,4 +57,8 @@
/* How many bits to shift physical queue address written to QUEUE_PFN.
* 12 is historical, and due to x86 page size. */
#define VIRTIO_PCI_QUEUE_ADDR_SHIFT 12
+
+/* The alignment to use between consumer and producer parts of vring.
+ * x86 pagesize again. */
+#define VIRTIO_PCI_VRING_ALIGN 4096
#endif