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From: Juergen Gross <jgross@suse.com>
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Date: Mon, 4 Apr 2016 06:33:15 +0200
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Subject: Re: [Qemu-devel] [PATCH] xen: write information about supported
	backends
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To: Stefano Stabellini <sstabellini@kernel.org>
Cc: xen-devel@lists.xensource.com, qemu-devel@nongnu.org, konrad.wilk@oracle.com, kraxel@redhat.com

On 01/04/16 16:56, Stefano Stabellini wrote:
> On Wed, 30 Mar 2016, Juergen Gross wrote:
>> Add a Xenstore directory for each supported pv backend. This will allow
>> Xen tools to decide which backend type to use in case there are
>> multiple possibilities.
>>
>> The information is added under
>> /local/domain/<backend-domid>/device-model/<domid>/backends
>> before the "running" state is written to Xenstore. Using a directory
>> for each directory enables us to add parameters for specific backends
>> in the future.
>>
>> In order to reuse the Xenstore directory creation already present in
>> hw/xen/xen_devconfig.c move the related functions to
>> hw/xen/xen_backend.c where they fit better.
> 
> An interface change like this one, needs a new file under docs (in the
> Xen repository) to document it.  Please add a reference to it, in the
> commit message here.

Is the Xenstore path documentation enough? Or do you want something
like docs/misc/qemu-deprivilege.txt to be added?

> In addition please make sure that this can work with QEMU running as
> non-root. What are the permissions of the new xenstore directory?

Should work, as I'm using the same functions as any backend in qemu is
using. The new directory is read-only for the qemu target domain (same
as the backend directories).


Juergen