From: Alex Williamson <alex.williamson@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
izumi.taku@jp.fujitsu.com
Subject: Re: [PATCH] vfio/pci: Support error recovery
Date: Tue, 13 Dec 2016 09:27:59 -0700 [thread overview]
Message-ID: <20161213092759.50fbd7df@t450s.home> (raw)
In-Reply-To: <20161213181116-mutt-send-email-mst@kernel.org>
On Tue, 13 Dec 2016 18:12:34 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Mon, Dec 12, 2016 at 08:39:48PM -0700, Alex Williamson wrote:
> > On Tue, 13 Dec 2016 05:15:13 +0200
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> >
> > > On Mon, Dec 12, 2016 at 03:43:13PM -0700, Alex Williamson wrote:
> > > > > So just don't do it then. Topology must match between host and guest,
> > > > > except maybe for the case of devices with host driver (e.g. PF)
> > > > > which we might be able to synchronize against.
> > > >
> > > > We're talking about host kernel level handling here. The host kernel
> > > > cannot defer the link reset to the user under the assumption that the
> > > > user is handling the devices in a very specific way. The moment we do
> > > > that, we've lost.
> > >
> > > The way is same as baremetal though, so why not?
> >
> > How do we know this? What if the user is dpdk? The kernel is
> > responsible for maintaining the integrity of the system and devices,
> > not the user.
> >
> > > And if user doesn't do what's expected, we can
> > > do the full link reset on close.
> >
> > That's exactly my point, if we're talking about multiple devices,
> > there's no guarantee that the close() for each is simultaneous. If one
> > function is released before the other we cannot do a bus reset. If
> > that device is then opened by another user before its sibling is
> > released, then we once again cannot perform a link reset. I don't
> > think it would be reasonable to mark the released device quarantined
> > until the sibling is released, that would be a terrible user experience.
>
> Not sure why you find it so terrible, and I don't think there's another way.
If we can't do it without regressing the support we currently have,
let's not do it at all.
next prev parent reply other threads:[~2016-12-13 16:29 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-27 11:34 [PATCH] vfio/pci: Support error recovery Cao jin
2016-11-28 3:00 ` Michael S. Tsirkin
2016-11-28 9:32 ` Cao jin
2016-11-30 1:46 ` Michael S. Tsirkin
2016-12-01 13:38 ` Cao jin
2016-12-01 4:04 ` Alex Williamson
2016-12-01 4:51 ` Michael S. Tsirkin
2016-12-01 13:40 ` Cao jin
2016-12-06 3:46 ` Michael S. Tsirkin
2016-12-06 6:47 ` Cao jin
2016-12-01 13:40 ` Cao jin
2016-12-01 14:55 ` Alex Williamson
2016-12-04 12:16 ` Cao jin
2016-12-04 15:30 ` Alex Williamson
2016-12-05 5:52 ` Cao jin
2016-12-05 16:17 ` Alex Williamson
2016-12-06 3:55 ` Michael S. Tsirkin
2016-12-06 4:59 ` Alex Williamson
2016-12-06 10:46 ` Cao jin
2016-12-06 15:35 ` Alex Williamson
2016-12-07 2:49 ` Cao jin
2016-12-08 14:46 ` Cao jin
2016-12-08 16:30 ` Michael S. Tsirkin
2016-12-09 3:40 ` Cao jin
2016-12-09 3:40 ` Cao jin
2016-12-06 6:11 ` Cao jin
2016-12-06 15:25 ` Alex Williamson
2016-12-07 2:58 ` Cao jin
2016-12-12 13:49 ` Cao jin
2016-12-12 19:12 ` Alex Williamson
2016-12-12 22:29 ` Michael S. Tsirkin
2016-12-12 22:43 ` Alex Williamson
2016-12-13 3:15 ` Michael S. Tsirkin
2016-12-13 3:39 ` Alex Williamson
2016-12-13 16:12 ` Michael S. Tsirkin
2016-12-13 16:27 ` Alex Williamson [this message]
2016-12-14 1:58 ` Michael S. Tsirkin
2016-12-14 3:00 ` Alex Williamson
2016-12-14 22:20 ` Michael S. Tsirkin
2016-12-14 22:47 ` Alex Williamson
2016-12-14 23:00 ` Michael S. Tsirkin
2016-12-14 23:32 ` Alex Williamson
2016-12-14 10:24 ` Cao jin
2016-12-14 22:16 ` Alex Williamson
2016-12-14 22:25 ` Michael S. Tsirkin
2016-12-14 22:49 ` Alex Williamson
2016-12-15 13:56 ` Cao jin
2016-12-15 14:50 ` Michael S. Tsirkin
2016-12-15 22:01 ` Alex Williamson
2016-12-16 10:15 ` Cao jin
2016-12-16 10:15 ` Cao jin
2016-12-15 17:02 ` Alex Williamson
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