Re: [PATCH v3 3/3] QEMU-AER: Qemu changes to support AER for VFIO-PCI devices

Gleb Natapov
2013-02-05T09:21:20Z

On Tue, Feb 05, 2013 at 09:05:19AM +0000, Pandarathil, Vijaymohan R wrote:
>
>
> > -----Original Message-----
> > From: Gleb Natapov [mailto:gleb@redhat.com]
> > Sent: Tuesday, February 05, 2013 12:05 AM
> > To: Blue Swirl
> > Cc: Pandarathil, Vijaymohan R; Alex Williamson; Bjorn Helgaas; Ortiz, Lance
> > E; kvm@vger.kernel.org; qemu-devel@nongnu.org; linux-pci@vger.kernel.org;
> > linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH v3 3/3] QEMU-AER: Qemu changes to support AER for VFIO-
> > PCI devices
> >
> > On Sun, Feb 03, 2013 at 04:36:11PM +0000, Blue Swirl wrote:
> > > On Sun, Feb 3, 2013 at 2:10 PM, Pandarathil, Vijaymohan R
> > > <vijaymohan.pandarathil@hp.com> wrote:
> > > > - Create eventfd per vfio device assigned to a guest and
> > register an
> > > > event handler
> > > >
> > > > - This fd is passed to the vfio_pci driver through the SET_IRQ
> > ioctl
> > > >
> > > > - When the device encounters an error, the eventfd is signalled
> > > > and the qemu eventfd handler gets invoked.
> > > >
> > > > - In the handler decide what action to take. Current action
> > taken
> > > > is to terminate the guest.
> > >
> > > Usually this is not OK, but I guess this is not guest triggerable.
> > >
> > Still not OK. Why not stop a guest with appropriate stop reason?
>
> The thinking was that since this is a hardware error, we would want to stop the guest at the earliest. The hw_error() routine which aborts the qemu process was suggested by Alex and that seemed appropriate. Earlier I was using qemu_system_shutdown_request(). Any suggestions ?
>
I am thinking vm_stop(). Stopping SMP guest (and UP too in fact)
involves sending IPIs to other cpus running guest's vcpus. Both exit()
and vm_stop() will do it, but former is implicitly in the kernel and
later is explicitly in QEMU.

--
Gleb.