From: Igor Mammedov <imammedo@redhat.com>
To: Markus Armbruster <armbru@redhat.com>
Cc: "Daniel P . Berrangé" <berrange@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
"Jason Wang" <jasowang@redhat.com>,
qemu-devel@nongnu.org, "Peter Xu" <peterx@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
"Eric Auger" <eric.auger@redhat.com>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [PATCH 4/4] vl: Prioritize realizations of devices
Date: Thu, 26 Aug 2021 13:36:29 +0200 [thread overview]
Message-ID: <20210826133629.2ddd3b88@redhat.com> (raw)
In-Reply-To: <87y28oy6rm.fsf@dusky.pond.sub.org>
On Thu, 26 Aug 2021 10:01:01 +0200
Markus Armbruster <armbru@redhat.com> wrote:
> Peter Xu <peterx@redhat.com> writes:
>
> > On Wed, Aug 25, 2021 at 05:50:23PM -0400, Peter Xu wrote:
> >> On Wed, Aug 25, 2021 at 02:28:55PM +0200, Markus Armbruster wrote:
> >> > Having thought about this a bit more...
...
> > Any further thoughts will be greatly welcomed.
>
> I'd like to propose a more modest solution: detect the problem and fail.
That's or proper dependency tracking (which stands chance to work with QMP,
but like it was said it's complex)
> A simple state machine can track "has IOMMU" state. It has three states
> "no so far", "yes", and "no", and two events "add IOMMU" and "add device
> that needs to know". State diagram:
>
> no so far
> +--- (start state) ---+
> | |
> add IOMMU | | add device that
> | | needs to know
> v v
> +--> yes no <--+
> | | add device that | |
> +-----+ needs to know +-----+
>
> "Add IOMMU" in state "no" is an error.
question is how we distinguish "device that needs to know"
from device that doesn't need to know, and then recently
added feature 'bypass IOMMU' adds more fun to this.
> "Add IOMMU" in state "yes" stays in state "yes" if multiple IOMMU make
> sense. Else it's an error.
>
> The state machine could be owned by the machine type.
>
>
next prev parent reply other threads:[~2021-08-26 11:37 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-18 19:42 [PATCH 0/4] vl: Prioritize device realizations Peter Xu
2021-08-18 19:42 ` [PATCH 1/4] qdev-monitor: Trace qdev creation Peter Xu
2021-08-18 19:43 ` [PATCH 2/4] qemu-config: Allow in-place sorting of QemuOptsList Peter Xu
2021-08-18 19:43 ` [PATCH 3/4] qdev: Export qdev_get_device_class() Peter Xu
2021-08-18 19:43 ` [PATCH 4/4] vl: Prioritize realizations of devices Peter Xu
2021-08-23 18:49 ` Eduardo Habkost
2021-08-23 19:18 ` Peter Xu
2021-08-23 21:07 ` Eduardo Habkost
2021-08-23 21:31 ` Peter Xu
2021-08-23 21:54 ` Michael S. Tsirkin
2021-08-23 22:51 ` Peter Xu
2021-08-23 21:56 ` Eduardo Habkost
2021-08-23 23:05 ` Peter Xu
2021-08-25 9:39 ` Markus Armbruster
2021-08-25 12:28 ` Markus Armbruster
2021-08-25 21:50 ` Peter Xu
2021-08-26 3:50 ` Peter Xu
2021-08-26 8:01 ` Markus Armbruster
2021-08-26 11:36 ` Igor Mammedov [this message]
2021-08-26 13:43 ` Peter Xu
2021-08-30 19:02 ` Peter Xu
2021-08-31 11:35 ` Markus Armbruster
2021-09-02 8:26 ` Igor Mammedov
2021-09-02 13:45 ` Peter Xu
2021-09-02 13:53 ` Daniel P. Berrangé
2021-09-02 14:21 ` Peter Xu
2021-09-02 14:57 ` Markus Armbruster
2021-09-03 15:48 ` Peter Xu
2021-09-02 15:06 ` Daniel P. Berrangé
2021-09-02 15:26 ` Markus Armbruster
2021-09-03 13:00 ` Igor Mammedov
2021-09-03 16:03 ` Peter Xu
2021-09-06 8:49 ` Igor Mammedov
2021-09-02 7:46 ` Igor Mammedov
2021-08-26 4:57 ` Markus Armbruster
2021-08-23 22:05 ` Michael S. Tsirkin
2021-08-23 22:36 ` Peter Xu
2021-08-24 2:52 ` Jason Wang
2021-08-24 15:50 ` Peter Xu
2021-08-25 4:23 ` Jason Wang
2021-09-06 9:22 ` Eric Auger
2021-08-24 16:24 ` David Hildenbrand
2021-08-24 19:52 ` Peter Xu
2021-08-25 8:08 ` David Hildenbrand
2021-08-24 2:51 ` Jason Wang
2021-10-20 13:44 ` [PATCH 0/4] vl: Prioritize device realizations David Hildenbrand
2021-10-20 13:48 ` Daniel P. Berrangé
2021-10-20 13:58 ` David Hildenbrand
2021-10-21 4:20 ` Peter Xu
2021-10-21 7:17 ` David Hildenbrand
2021-10-21 8:00 ` Peter Xu
2021-10-21 16:54 ` David Hildenbrand
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