virtio: Don't use PAGE_SIZE for vring alignment in virtio_pci.

PATCH New Rusty Russell 1 participant 1 message Nov 12, 2008

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Rusty Russell

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2008-11-12 12:22 UTC #0 lore raw

PATCH 3/7 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 <[email protected]>

---
 drivers/virtio/virtio_pci.c |    5 +++--
 include/linux/virtio_pci.h  |    4 ++++
 2 files changed, 7 insertions(+), 2 deletions(-)

drivers/virtio/virtio_pci.c +3 -2

diff -r c6f6a3ab173b drivers/virtio/virtio_pci.c
@@ -216,7 +216,7 @@
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	struct virtio_pci_vq_info *info;
 	struct virtqueue *vq;
-	unsigned long flags;
+	unsigned long flags, size;
 	u16 num;
 	int err;

@@ -237,7 +237,8 @@
 	info->queue_index = index;
 	info->num = num;
 
-	info->queue = kzalloc(PAGE_ALIGN(vring_size(num,PAGE_SIZE)), GFP_KERNEL);
+	size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
+	info->queue = kzalloc(size, GFP_KERNEL);
 	if (info->queue == NULL) {
 		err = -ENOMEM;
 		goto out_info;

include/linux/virtio_pci.h +4 -0

diff -r c6f6a3ab173b 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