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Date: Tue, 11 Dec 2012 16:18:20 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20121211141820.GB18753@redhat.com>
References: <1355144985-12897-1-git-send-email-stefanha@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v6 04/12] dataplane: add virtqueue vring
	code
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To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org, Blue Swirl <blauwirbel@gmail.com>, khoa@us.ibm.com, Paolo Bonzini <pbonzini@redhat.com>, Asias He <asias@redhat.com>

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