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Date: Tue, 16 Jun 2009 23:11:22 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] Regression opening read-only cdroms
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel <qemu-devel@nongnu.org>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Avi Kivity <avi@redhat.com>, Christoph Hellwig <hch@lst.de>

On 06/16/09 18:28, Anthony Liguori wrote:
> Jamie Lokier wrote:
>> What's missing is a "ro" sub-option to "-drive".
>
> It only is useful if we can expose that read-only attribute to the
> guest. You can't do that consistently with all block devices so the
> result would be that you'll fail write operations causing a guest to crash.

Well, I think all except ide-disk can signal r/o medium to the guest.

> This is not friendly to a user who expects that ro would Just Work.

chmod a-w $diskimage
And you'll run into the same issue today.

cheers,
   Gerd