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From: Rusty Russell <rusty@rustcorp.com.au>
To: Jamie Lokier <jamie@shareable.org>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
	kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	virtualization@lists.linux-foundation.org
Subject: Re: [Qemu-devel] Using PCI config space to indicate config location
Date: Wed, 10 Oct 2012 14:14:47 +1030	[thread overview]
Message-ID: <87txu36le8.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20121009210901.GY14867@jl-vm1.vm.bytemark.co.uk>

Jamie Lokier <jamie@shareable.org> writes:

> Rusty Russell wrote:
>> I don't think it'll be that bad; reset clears the device to unknown,
>> bar0 moves it from unknown->legacy mode, bar1/2/3 changes it from
>> unknown->modern mode, and anything else is bad (I prefer being strict so
>> we catch bad implementations from the beginning).
>
> Will that work, if the guest with kernel that uses modern mode, kexecs
> to an older (but presumed reliable) kernel that only knows about legacy mode?
>
> I.e. will the replacement kernel, or (ideally) replacement driver on
> the rare occasion that is needed on a running kernel, be able to reset
> the device hard enough?

Well, you need to reset the device, so yes.

Cheers,
Rusty.

WARNING: multiple messages have this Message-ID (diff)
From: Rusty Russell <rusty@rustcorp.com.au>
To: Jamie Lokier <jamie@shareable.org>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
	kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	virtualization@lists.linux-foundation.org,
	Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: [Qemu-devel] Using PCI config space to indicate config location
Date: Wed, 10 Oct 2012 14:14:47 +1030	[thread overview]
Message-ID: <87txu36le8.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20121009210901.GY14867@jl-vm1.vm.bytemark.co.uk>

Jamie Lokier <jamie@shareable.org> writes:

> Rusty Russell wrote:
>> I don't think it'll be that bad; reset clears the device to unknown,
>> bar0 moves it from unknown->legacy mode, bar1/2/3 changes it from
>> unknown->modern mode, and anything else is bad (I prefer being strict so
>> we catch bad implementations from the beginning).
>
> Will that work, if the guest with kernel that uses modern mode, kexecs
> to an older (but presumed reliable) kernel that only knows about legacy mode?
>
> I.e. will the replacement kernel, or (ideally) replacement driver on
> the rare occasion that is needed on a running kernel, be able to reset
> the device hard enough?

Well, you need to reset the device, so yes.

Cheers,
Rusty.

  reply	other threads:[~2012-10-10  3:44 UTC|newest]

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-27  0:29 Proposal for virtio standardization Rusty Russell
2012-09-27  0:29 ` [Qemu-devel] " Rusty Russell
2012-09-27  0:29 ` Rusty Russell
2012-10-04 18:49 ` [Qemu-devel] " Anthony Liguori
2012-10-04 18:49 ` Anthony Liguori
2012-10-04 18:49   ` Anthony Liguori
2012-10-08  2:21   ` Using PCI config space to indicate config location Rusty Russell
2012-10-08  2:21   ` Rusty Russell
2012-10-08  2:21     ` [Qemu-devel] " Rusty Russell
2012-10-08 13:58     ` Anthony Liguori
2012-10-08 13:58       ` Anthony Liguori
2012-10-08 14:58       ` Gerd Hoffmann
2012-10-08 14:58         ` Gerd Hoffmann
2012-10-08 15:09         ` Anthony Liguori
2012-10-08 15:09           ` Anthony Liguori
2012-10-08 20:13           ` Gerd Hoffmann
2012-10-08 20:13             ` Gerd Hoffmann
2012-10-08 20:55             ` Anthony Liguori
2012-10-08 20:55               ` Anthony Liguori
2012-10-08 23:56               ` Rusty Russell
2012-10-09  1:51                 ` Anthony Liguori
2012-10-09  3:16                   ` Rusty Russell
2012-10-09  3:16                     ` Rusty Russell
2012-10-09 10:17                     ` Avi Kivity
2012-10-09 10:17                       ` Avi Kivity
2012-10-09 14:03                       ` Anthony Liguori
2012-10-09 14:03                         ` Anthony Liguori
2012-10-09 13:56                     ` Anthony Liguori
2012-10-09 13:56                       ` Anthony Liguori
2012-10-10  3:44                       ` Rusty Russell
2012-10-10  3:44                         ` Rusty Russell
2012-10-10 11:37                         ` Michael S. Tsirkin
2012-10-10 11:37                           ` Michael S. Tsirkin
2012-10-09 13:56                     ` Anthony Liguori
2012-10-09 21:09                     ` Jamie Lokier
2012-10-09 21:09                       ` [Qemu-devel] " Jamie Lokier
2012-10-10  3:44                       ` Rusty Russell [this message]
2012-10-10  3:44                         ` Rusty Russell
2012-10-11  0:08                         ` Rusty Russell
2012-10-11  0:08                         ` Rusty Russell
2012-10-11  0:08                           ` Rusty Russell
2012-10-09 21:09                     ` Jamie Lokier
2012-10-09  3:16                   ` Rusty Russell
2012-10-09  6:33                   ` Gerd Hoffmann
2012-10-09  6:33                     ` Gerd Hoffmann
2012-10-09 15:26                     ` Anthony Liguori
2012-10-09 15:26                       ` Anthony Liguori
2012-10-09 20:24                       ` Gerd Hoffmann
2012-10-09 20:24                         ` Gerd Hoffmann
2012-10-10  2:54                         ` Rusty Russell
2012-10-10  2:54                         ` Rusty Russell
2012-10-10  2:54                           ` Rusty Russell
2012-10-10 13:36                           ` Anthony Liguori
2012-10-10 13:41                             ` Michael S. Tsirkin
2012-10-10 13:41                               ` Michael S. Tsirkin
2012-10-11  0:43                               ` Rusty Russell
2012-10-11  0:43                               ` Rusty Russell
2012-10-11  0:43                                 ` [Qemu-devel] " Rusty Russell
2012-10-09 15:26                     ` Anthony Liguori
2012-10-10  8:34                 ` Michael S. Tsirkin
2012-10-10  8:34                   ` Michael S. Tsirkin
2012-10-08 13:58     ` Anthony Liguori
2012-10-10  8:30     ` Michael S. Tsirkin
2012-10-10  8:30       ` [Qemu-devel] " Michael S. Tsirkin
2012-10-11  1:18       ` Rusty Russell
2012-10-11  1:18         ` [Qemu-devel] " Rusty Russell
2012-10-11 10:23         ` Michael S. Tsirkin
2012-10-11 10:23           ` [Qemu-devel] " Michael S. Tsirkin
2012-10-11 22:29           ` Rusty Russell
2012-10-11 22:29             ` [Qemu-devel] " Rusty Russell
2012-10-12  9:33             ` Michael S. Tsirkin
2012-10-12  9:33               ` [Qemu-devel] " Michael S. Tsirkin
2012-10-12  9:51               ` Rusty Russell
2012-10-12  9:51                 ` [Qemu-devel] " Rusty Russell
2012-10-12 10:02                 ` Michael S. Tsirkin
2012-10-12 10:02                   ` [Qemu-devel] " Michael S. Tsirkin
2012-10-16 13:15                   ` Rusty Russell
2012-10-16 13:15                   ` Rusty Russell
2012-10-16 13:15                     ` [Qemu-devel] " Rusty Russell
2012-10-16 13:30                     ` Michael S. Tsirkin
2012-10-16 13:30                       ` [Qemu-devel] " Michael S. Tsirkin
2012-10-16 13:52                       ` Rusty Russell
2012-10-16 13:52                       ` Rusty Russell
2012-10-16 13:52                         ` [Qemu-devel] " Rusty Russell
2012-10-11 22:29           ` Rusty Russell
2012-10-09 14:02 ` Proposal for virtio standardization Cornelia Huck
2012-10-09 14:02 ` Cornelia Huck
2012-10-09 14:02   ` [Qemu-devel] " Cornelia Huck
2012-10-10  3:46   ` Rusty Russell
2012-10-10  3:46   ` Rusty Russell
2012-10-10  3:46     ` [Qemu-devel] " Rusty Russell

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