[PATCH] virtio_mmio: fix endian-ness for mmio

Michael S. Tsirkin
2015-03-05T21:54:46Z

Going over the virtio mmio code, I noticed that it doesn't correctly
return device config values in LE format when using virtio 1.0.
Borrow code from virtio_pci_modern to do this correctly.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Note: untested: QEMU doesn't support virtio 1.0 for virtio-mmio.
Pawel, could you please confirm this patch makes sense?

drivers/virtio/virtio_mmio.c | 79 +++++++++++++++++++++++++++++++++++++++-----
1 file changed, 71 insertions(+), 8 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index cad5698..0375456 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -156,22 +156,85 @@ static void vm_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
- u8 *ptr = buf;
- int i;
+ void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
+ u8 b;
+ __le16 w;
+ __le32 l;

- for (i = 0; i < len; i++)
- ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
+ if (vm_dev->version == 1) {
+ u8 *ptr = buf;
+ int i;
+
+ for (i = 0; i < len; i++)
+ ptr[i] = readb(base + offset + i);
+ return;
+ }
+
+ switch (len) {
+ case 1:
+ b = readb(base + offset);
+ memcpy(buf, &b, sizeof b);
+ break;
+ case 2:
+ w = cpu_to_le16(readw(base + offset));
+ memcpy(buf, &w, sizeof w);
+ break;
+ case 4:
+ l = cpu_to_le32(readl(base + offset));
+ memcpy(buf, &l, sizeof l);
+ break;
+ case 8:
+ l = cpu_to_le32(readl(base + offset));
+ memcpy(buf, &l, sizeof l);
+ l = cpu_to_le32(ioread32(base + offset + sizeof l));
+ memcpy(buf + sizeof l, &l, sizeof l);
+ break;
+ default:
+ BUG();
+ }
}

static void vm_set(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
- const u8 *ptr = buf;
- int i;
+ void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
+ u8 b;
+ __le16 w;
+ __le32 l;

- for (i = 0; i < len; i++)
- writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
+ if (vm_dev->version == 1) {
+ const u8 *ptr = buf;
+ int i;
+
+ for (i = 0; i < len; i++)
+ writeb(ptr[i], base + offset + i);
+
+ return;
+ }
+
+ switch (len) {
+ case 1:
+ memcpy(&b, buf, sizeof b);
+ writeb(b, base + offset);
+ break;
+ case 2:
+ memcpy(&w, buf, sizeof w);
+ writew(le16_to_cpu(w), base + offset);
+ break;
+ case 4:
+ memcpy(&l, buf, sizeof l);
+ writel(le32_to_cpu(l), base + offset);
+ break;
+ case 8:
+ memcpy(&l, buf, sizeof l);
+ writel(le32_to_cpu(l), base + offset);
+ memcpy(&l, buf + sizeof l, sizeof l);
+ writel(le32_to_cpu(l), base + offset + sizeof l);
+ break;
+ default:
+ BUG();
+ }
}

static u8 vm_get_status(struct virtio_device *vdev)
--
MST