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Date: Thu, 24 Nov 2016 13:29:31 +0800
From: Peter Xu <peterx@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v2] pci: relax pci_msi_get_message()
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To: qemu-devel@nongnu.org
Cc: mst@redhat.com, david@gibson.dropbear.id.au, QEMU Stable <qemu-stable@nongnu.org>

On Tue, Nov 22, 2016 at 04:08:50PM +0800, Peter Xu wrote:
> We are very strict in the past getting MSIs from commit
> d1f6af6a1 ("kvm-irqchip: simplify kvm_irqchip_add_msi_route"), assuming
> that MSI should be configured before hand when fetching. When we have
> unrecognized configurations, we panic the system. However looks like
> this is too strict to be working on some platform, and issues occured.
> Firstly it's found on a ppc case and fixed by David in:
>=20
>   6d17a01 vfio/pci: Fix regression in MSI routing configuration
>=20
> However we encountered another case now with windows virtio driver and
> reported (and possibly more):
>=20
>   http://bugs.debian.org/844361
>=20
> To make every driver/hardware happy, let's loosen the rule and go back
> to the original behavior - instead of panic the system, when we try to
> fetch MSI without configured MSI/MSI-X system, we just provide an empty
> message to make drivers happy.
>=20
> Reported-by: Maciej Kotli=C5=84ski <makotlinski@gmail.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Sorry I should mark this as "for-2.8". Also cc stable since this bug
exists since 2.7.0.

Michael, do you think it can be a material for 2.8 rc2?

Thanks,

-- peterx