[Qemu-devel] [PATCH] fixup! virtio: introduce virtio_map

[Qemu-devel] [PATCH] fixup! virtio: introduce virtio_map

[Michael S. Tsirkin]

Stefan noticed that we must use memmove, not memcpy,
as arguments overlap.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index ed1f274..939f802 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -481,8 +481,8 @@ static void virtqueue_map_iovec(struct iovec *sg, hwaddr *addr,
             error_report("virtio: memory split makes iovec too large");
             exit(1);
         }
-        memcpy(sg + i + 1, sg + i, sizeof(*sg) * (*num_sg - i));
-        memcpy(addr + i + 1, addr + i, sizeof(*addr) * (*num_sg - i));
+        memmove(sg + i + 1, sg + i, sizeof(*sg) * (*num_sg - i));
+        memmove(addr + i + 1, addr + i, sizeof(*addr) * (*num_sg - i));
         assert(len < sg[i + 1].iov_len);
         sg[i].iov_len = len;
         addr[i + 1] += len;
-- 
MST

Re: [Qemu-devel] [PATCH] fixup! virtio: introduce virtio_map

[Stefan Hajnoczi]

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On Tue, Oct 27, 2015 at 11:00:36PM +0200, Michael S. Tsirkin wrote:
> Stefan noticed that we must use memmove, not memcpy,
> as arguments overlap.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  hw/virtio/virtio.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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[Qemu-devel] [PATCH] fixup! virtio: introduce virtio_map

[Michael S. Tsirkin]

---

This will fix the issue reported by Cornelia.

 hw/virtio/virtio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index be32145..ed1f274 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -449,7 +449,7 @@ int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
 }
 
 static void virtqueue_map_iovec(struct iovec *sg, hwaddr *addr,
-                                size_t *num_sg, size_t max_size,
+                                unsigned int *num_sg, unsigned int max_size,
                                 int is_write)
 {
     unsigned int i;
-- 
MST

Re: [Qemu-devel] [PATCH] fixup! virtio: introduce virtio_map

[Cornelia Huck]

On Tue, 27 Oct 2015 14:30:05 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> ---
> 
> This will fix the issue reported by Cornelia.
> 
>  hw/virtio/virtio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index be32145..ed1f274 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -449,7 +449,7 @@ int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
>  }
> 
>  static void virtqueue_map_iovec(struct iovec *sg, hwaddr *addr,
> -                                size_t *num_sg, size_t max_size,
> +                                unsigned int *num_sg, unsigned int max_size,
>                                  int is_write)
>  {
>      unsigned int i;

With this fixup applied, both s390 machines come up. virtio-serial and
virtio-blk with and without dataplane seem fine.

At a first glance, the code seems fine as well.