> -----Original Message-----
> From: Michael S. Tsirkin [mailto:m...@redhat.com]
> Sent: Saturday, March 17, 2018 2:20 AM
> To: qemu-devel@nongnu.org
> Cc: Zhoujian (jay) <jianjay.z...@huawei.com>
> Subject: [PATCH] vhost-user: avoid misaligned access
>
> We can't pass a pointer to memory field directly since it's within a packed
> structure, so isn't aligned.
> Pass a pointer on stack and copy.
>
> Fixes: 30c4cc7 ("vhost: used_memslots refactoring")
> Cc: Jay Zhou <jianjay.z...@huawei.com>
> Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> ---
>
> I had to apply this to fix make check errors with clang.
> Pls review, test and ack.
>
> Thanks!
>
> hw/virtio/vhost-user.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index
> c12fdd9..a44ee7f 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -396,6 +396,7 @@ static int vhost_user_set_mem_table_postcopy(struct
> vhost_dev *dev,
> bool reply_supported = virtio_has_feature(dev->protocol_features,
>
> VHOST_USER_PROTOCOL_F_REPLY_ACK);
> VhostUserMsg msg_reply;
> + VhostUserMemory memory = {};
> int region_i, msg_i;
>
> VhostUserMsg msg = {
> @@ -407,10 +408,11 @@ static int vhost_user_set_mem_table_postcopy(struct
> vhost_dev *dev,
> msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> }
>
> - if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> + if (vhost_user_prepare_msg(dev, &memory, fds) < 0) {
> error_report("Failed preparing vhost-user memory table msg");
> return -1;
> }
> + msg.payload.memory = memory;
>
> fd_num = msg.payload.memory.nregions;
>
> @@ -549,16 +551,19 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
> .hdr.request = VHOST_USER_SET_MEM_TABLE,
> .hdr.flags = VHOST_USER_VERSION,
> };
> + VhostUserMemory memory = {};
>
> if (reply_supported) {
> msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> }
>
> - if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> + if (vhost_user_prepare_msg(dev, &memory, fds) < 0) {
> error_report("Failed preparing vhost-user memory table msg");
> return -1;
> }
>
> + msg.payload.memory = memory;
> +
> fd_num = msg.payload.memory.nregions;
>
> if (!fd_num) {
> @@ -1575,8 +1580,11 @@ static void vhost_user_set_used_memslots(struct
> vhost_dev *dev) {
> int fds[VHOST_MEMORY_MAX_NREGIONS];
> VhostUserMsg msg;
> + VhostUserMemory memory = {};
> +
> + vhost_user_prepare_msg(dev, &memory, fds);
>
> - vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> + msg.payload.memory = memory;
> }
Hi Michael, here should be like this:
static void vhost_user_set_used_memslots(struct vhost_dev *dev)
{
int fds[VHOST_MEMORY_MAX_NREGIONS];
- VhostUserMsg msg;
+ VhostUserMemory memory = {};
- vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
+ vhost_user_prepare_msg(dev, &memory, fds);
}
Regards,
Jay
>
> const VhostOps user_ops = {
> --
> MST
