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Date: Mon, 20 Jun 2016 11:36:13 +0800
From: Peter Xu <peterx@redhat.com>
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Subject: Re: [Qemu-devel] [V11 2/4] hw/i386: ACPI IVRS table
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: David Kiarie <davidkiarie4@gmail.com>, Valentine Sinitsyn <valentine.sinitsyn@gmail.com>, QEMU Developers <qemu-devel@nongnu.org>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel@redhat.com>

On Sat, Jun 18, 2016 at 02:34:26PM +0200, Jan Kiszka wrote:
> On 2016-06-18 14:32, Peter Xu wrote:
> > On Sat, Jun 18, 2016 at 11:18:29AM +0300, David Kiarie wrote:
[...]
> >> I missed this is the last version of the patch I should fix it in next version.
> >>
> >> On taking a closer look at this there might be larger problem where
> >> with the advent of -device <iommu-type> users can possibly emulate two
> >> IOMMUs at the same time ? A proposed solution was to have
> >> pci_setup_iommu check that DMA hook as not been setup yet and fail if
> >> yes. I should send a fix for that too.
> > 
> > Currently we should only support single vIOMMU.  If you are going to
> > rebase to x86-iommu codes, there is a patch that includes the check:
> > 
> >   "[PATCH v9 02/25] x86-iommu: provide x86_iommu_get_default"
> > 
> > by:
> > 
> >   assert(x86_iommu_default == NULL);
> > 
> > Maybe we should print something more readable, like "multiple vIOMMUs
> > are not supported yet", rather than an assertion fail.
> 
> You need proper error handling and a readable error message because
> nothing else will stop the user from doing -device intel-iommu -device
> amd-iommu.

Will do.  Thanks.

-- peterx