Re: [PATCH v2 1/6] hw/xen: Set XenBackendInstance in the XenDevice before realizing it

["Woodhouse, David" <dwmw@xxxxxxxxxxxx>]

On Wed, 2023-11-22 at 17:05 +0000, Paul Durrant wrote:
> On 21/11/2023 22:10, Volodymyr Babchuk wrote:
> > From: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > 
> > This allows a XenDevice implementation to know whether it was created
> > by QEMU, or merely discovered in XenStore after the toolstack created
> > it. This will allow us to create frontend/backend nodes only when we
> > should, rather than unconditionally attempting to overwrite them from
> > a driver domain which doesn't have privileges to do so.
> > 
> > As an added benefit, it also means we no longer have to call the
> > xen_backend_set_device() function from the device models immediately
> > after calling qdev_realize_and_unref(). Even though we could make
> > the argument that it's safe to do so, and the pointer to the unreffed
> > device *will* actually still be valid, it still made my skin itch to
> > look at it.
> > 
> > Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > ---
> >   hw/block/xen-block.c         | 3 +--
> >   hw/char/xen_console.c        | 2 +-
> >   hw/net/xen_nic.c             | 2 +-
> >   hw/xen/xen-bus.c             | 4 ++++
> >   include/hw/xen/xen-backend.h | 2 --
> >   include/hw/xen/xen-bus.h     | 2 ++
> >   6 files changed, 9 insertions(+), 6 deletions(-)
> > 
> 
> Actually, I think you should probably update
> xen_backend_try_device_destroy() in this patch too. It currently uses
> xen_backend_list_find() to check whether the specified XenDevice has an
> associated XenBackendInstance.

I think I did that in
https://git.infradead.org/users/dwmw2/qemu.git/commitdiff/94f1b474478ce0ede
but didn't get round to sending it out again because of travel.

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