Re: [Qemu-devel] [PATCH v6 04/12] dataplane: add virtqueue vring code

[Michael S. Tsirkin]

On Mon, Dec 10, 2012 at 02:09:37PM +0100, Stefan Hajnoczi wrote:
> +        iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
> +                                       desc.flags & VRING_DESC_F_WRITE);
> +        if (!iov->iov_base) {
> +            error_report("Failed to map indirect descriptor"
> +                         "addr %#" PRIx64 " len %u",
> +                         (uint64_t)desc.addr, desc.len);
> +            vring->broken = true;
> +            return -EFAULT;
> +        }
> +        iov->iov_len = desc.len;
> +        iov++;

Hmm, this assumes a descriptor can not cross a memory
region boundary. Is this really guaranteed?
vhost does not make such assumptions.

-- 
MST