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From: Andreas Hartmann <andihartmann@01019freenet.de>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
	kvm@vger.kernel.org, aik@ozlabs.ru,
	Jan Kiszka <jan.kiszka@siemens.com>,
	qemu-devel@nongnu.org, Blue Swirl <blauwirbel@gmail.com>,
	Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 0/3] VFIO-based PCI device assignment for QEMU 1.2
Date: Mon, 13 Aug 2012 20:32:46 +0200	[thread overview]
Message-ID: <5029484E.2020808@01019freenet.de> (raw)
In-Reply-To: <1344877056.4683.55.camel@ul30vt.home>

Alex Williamson wrote:
> On Mon, 2012-08-13 at 18:36 +0200, Andreas Hartmann wrote:
[...]
>> If I'm using your qemu instead of qemu from kvm-0.15 (opensuse package),
>> this error comes up when passing through a PCIe device, which works
>> absolutely fine with kvm 0.15. I would have expected, that your qemu
>> works with the legacy way of handling pcie passthrough, too (with
>> pci-stub module).
> 
> VFIO cannot work with pci-stub, the backends are fundamentally
> different.  KVM making use pci-stub to hold onto a device is actually
> one of the design problems that VFIO is meant to correct.  The other
> significant interface change is use of IOMMU groups, which is actually
> why VFIO works for some of your uses while pci-assign does not.
> 
>> This would mean, that all users get errors if they use the traditional
>> way. IOW: there are changes needed (which?) to move from kvm 0.15 to
>> your qemu version.
> 
> But the way we solve this is to make libvirt understand how to do both.
> Then it can probe the qemu/kvm binary and host system to figure out
> which is supported and use the correct device options based on what it
> finds.  Trying to do both via the same qemu command line doesn't make
> sense to me, especially when the device setup is so different.

Ok! I thought your qemu version still would understand the old way via
pci-stub. But this obviously was a misunderstanding of mine :-(.


Thanks,
Andreas

  reply	other threads:[~2012-08-13 18:33 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-01  5:18 [Qemu-devel] [PATCH 0/3] VFIO-based PCI device assignment for QEMU 1.2 Alex Williamson
2012-08-01  5:18 ` [Qemu-devel] [PATCH 1/3] vfio: Import vfio kernel header Alex Williamson
2012-08-01  7:13   ` Jan Kiszka
2012-08-01 18:09     ` Alex Williamson
2012-08-02  9:02       ` Jan Kiszka
2012-08-02 16:37         ` Alex Williamson
2012-08-02 16:45           ` Jan Kiszka
2012-08-01  5:18 ` [Qemu-devel] [PATCH 2/3] vfio: vfio-pci device assignment driver Alex Williamson
2012-08-13 22:18   ` Anthony Liguori
2012-08-14  5:25     ` Alex Williamson
2012-08-14  7:12   ` Stefan Hajnoczi
2012-08-14 13:51     ` Alex Williamson
2012-08-14 15:53   ` Avi Kivity
2012-08-14 17:23     ` Alex Williamson
2012-08-15  8:56       ` Avi Kivity
2012-08-01  5:18 ` [Qemu-devel] [PATCH 3/3] vfio: Enable vfio-pci and mark supported Alex Williamson
2012-08-01  7:15   ` Jan Kiszka
2012-08-01 18:14     ` Alex Williamson
2012-08-01 19:40       ` Alex Williamson
2012-08-02  9:03         ` Jan Kiszka
2012-08-13 22:19     ` Anthony Liguori
2012-08-14  5:27       ` Alex Williamson
2012-08-14 14:35         ` Avi Kivity
2012-08-13 13:27 ` [Qemu-devel] [PATCH 0/3] VFIO-based PCI device assignment for QEMU 1.2 Anthony Liguori
2012-08-13 13:58   ` Avi Kivity
2012-08-13 14:04     ` Jan Kiszka
2012-08-13 19:31       ` Anthony Liguori
2012-08-14  7:19         ` Jan Kiszka
2012-08-14 14:42         ` Avi Kivity
2012-08-14 14:53         ` Cole Robinson
2012-08-14 15:04           ` Jan Kiszka
2012-08-14 15:28             ` Cole Robinson
2012-08-13 14:23   ` Alex Williamson
2012-08-13 15:48     ` Andreas Hartmann
2012-08-13 16:14       ` Alex Williamson
2012-08-13 16:36         ` Andreas Hartmann
2012-08-13 16:57           ` Alex Williamson
2012-08-13 18:32             ` Andreas Hartmann [this message]
2012-08-13 19:33     ` Anthony Liguori
2012-08-13 20:48       ` Blue Swirl
2012-08-13 20:56         ` Alex Williamson
2012-08-13 20:55       ` [Qemu-devel] VFIO: Call for reviewers (was Re: [PATCH 0/3] VFIO-based PCI device assignment for QEMU 1.2) Alex Williamson

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