From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: "Michael S. Tsirkin" <mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Kevin Wolf <kwolf-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Anthony PERARD
<anthony.perard-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>,
cornelia.huck-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org,
Wei Liu <wei.liu2-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>,
Stefan Hajnoczi
<stefanha-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
qemu-block-qX2TKyscuCcdnm+yROfE0A@public.gmane.org,
Stefano Stabellini
<stefano.stabellini-mvvWK6WmYclDPfheJLI6IQ@public.gmane.org>,
Jason Wang <jasowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org,
peterx-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Christian Borntraeger
<borntraeger-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Amit Shah <amit.shah-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
virtualization-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api
Date: Wed, 27 Apr 2016 16:56:32 +0200 [thread overview]
Message-ID: <20160427145632.GI17926@8bytes.org> (raw)
In-Reply-To: <20160427172630-mutt-send-email-mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
On Wed, Apr 27, 2016 at 05:34:30PM +0300, Michael S. Tsirkin wrote:
> On Wed, Apr 27, 2016 at 04:23:32PM +0200, Joerg Roedel wrote:
> QEMU can choose to bypass IOMMU for one device and not the other.
> IOMMU in QEMU isn't involved when it's bypassed.
And it is QEMU's task to tell the OS, right? And the correct way to do
this is via the firmware ACPI tables.
> Fine but this is beside the point. Almost all virtio devices
> bypass IOMMU and what this patch does is create a way
> to detect devices that don't. This code can maybe go into
> platform.
Again, the way to detect this is in platform code must not be device
specific. This is what the DMAR and IVRS tables on x86 are for.
When there is no way to do this in the firmware (or there is no firmware
at all), we have to do a quirk in the platform code for it.
Joerg
next prev parent reply other threads:[~2016-04-27 14:56 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1461245745-6710-1-git-send-email-mst@redhat.com>
[not found] ` <20160421135416.GE11775@citrix.com>
2016-04-27 12:18 ` [PATCH V2 RFC] fixup! virtio: convert to use DMA api David Woodhouse
2016-04-27 13:37 ` Michael S. Tsirkin
[not found] ` <20160427153345-mutt-send-email-mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-04-27 14:23 ` Joerg Roedel
2016-04-27 14:31 ` Andy Lutomirski
[not found] ` <CALCETrVkSSJbjoK8i7pLsSYR0o=Wy1UP-mrmn2uxYUd81g18dg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-27 14:38 ` Michael S. Tsirkin
2016-04-27 14:43 ` Andy Lutomirski
2016-04-27 14:54 ` Michael S. Tsirkin
2016-04-27 14:58 ` Joerg Roedel
2016-04-27 15:09 ` Michael S. Tsirkin
2016-04-27 15:10 ` Andy Lutomirski
2016-04-27 14:34 ` Michael S. Tsirkin
[not found] ` <20160427172630-mutt-send-email-mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-04-27 14:56 ` Joerg Roedel [this message]
[not found] ` <20160427145632.GI17926-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-04-27 15:05 ` Michael S. Tsirkin
2016-04-27 15:15 ` David Woodhouse
2016-04-27 18:17 ` Michael S. Tsirkin
2016-04-27 19:16 ` David Woodhouse
[not found] ` <1461784617.118304.181.camel-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2016-04-28 14:34 ` Michael S. Tsirkin
2016-04-28 15:11 ` David Woodhouse
[not found] ` <1461856314.33870.98.camel-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2016-04-28 15:37 ` Michael S. Tsirkin
2016-04-28 15:48 ` David Woodhouse
2016-05-01 10:37 ` Michael S. Tsirkin
[not found] ` <20160428182341-mutt-send-email-mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-05-09 11:09 ` Paolo Bonzini
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