Re: [libvirt] [Qemu-devel] [PATCH v2] Add support for fd: protocol

On 06/20/2011 08:40 AM, Avi Kivity wrote: > On 06/14/2011 04:31 PM, Corey Bryant wrote: >> - Starting Qemu with a backing file >> > > For this we could tell qemu that a file named "xyz" is available via fd > n, via an extension of the getfd command. > > For example > > (qemu) getfd path="/images/my-image.img" > (qemu) getfd path="/images/template.img" > (qemu) drive-add path="/images/my-image.img" > > The open() for my-image.img first looks up the name in the getfd > database, and finds it, so it returns the fd from there instead of > opening. It then opens the backing file ("template.img") and looks it up > again, and finds the second fd from the session. The way I've been thinking about this is: -blockdev id=hd0-back,file=fd:4,format=raw \ -blockdev file=fd:3,format=qcow2,backing=hd0-back While your proposal is clever, it makes me a little nervous about subtle security ramifications.