Shared IRQ with PCI Passthrough?

Shared IRQ with PCI Passthrough?

[Michael Sturm]

Hi,

back in Dec 2010 Jan Kiszka posted a number of patches that deal with 
IRQ sharing.

[PATCH 0/5] pci-assign: Host IRQ sharing suppport + some fixes and cleanups
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64601

[PATCH v3 0/4] KVM & genirq: Enable adaptive IRQ sharing for 
passed-through devices
http://thread.gmane.org/gmane.linux.kernel/1076440

[PATCH 0/2] Small KVM device assignment cleanups
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64515

What do I need to do to apply these patches to my system?

The server I'm working on is running Proxmox 1.8 with upgraded 
2.6.35-1-pve kernel (previously 2.6.32-4-pve) and qemu-kvm 0.14.1.

Do I need to upgrade to a newer kernel, or upgrade qemu-kvm (e.g. 
0.15.0), or both?

The problem that I'm hoping to solve is an IRQ conflict. The Intel 
DQ67SW motherboard only has 1 PCI slot and no BIOS support for assigning 
IRQs. KVM PCI passthrough only works with the nousb kernel parameter, 
otherwise the ehci_hcd:usb1 conflicts with the PCI's assigned IRQ 16. 
This is a problem because I also need to USB passthrough a dongle 
required by the software (in WinXP guest).

Thanks for any pointers,

Mick

RE: Shared IRQ with PCI Passthrough?

[Gardziejczyk, Kamil]

Hi,

Have you resolve your problem with shared IRQ lines? I have checked out qemu-kvm 0.15.0 and found that Jan Kiszka patch was applied to latest version of kvm. 
 
[PATCH 0/5] pci-assign: Host IRQ sharing suppport + some fixes and cleanups
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64601    

Which version of linux kernel do you use? I have tried with 3.0.0. It looks that Jan Kiszka`s patches were not added to that kernel version. Maybe it is in 2.6.xxx? 
Any ideas how to fix it? :) 
 

-----Original Message-----
From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On Behalf Of Michael Sturm
Sent: Saturday, August 13, 2011 7:05 AM
To: kvm@vger.kernel.org
Subject: Shared IRQ with PCI Passthrough?

Hi,

back in Dec 2010 Jan Kiszka posted a number of patches that deal with 
IRQ sharing.

[PATCH 0/5] pci-assign: Host IRQ sharing suppport + some fixes and cleanups
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64601

[PATCH v3 0/4] KVM & genirq: Enable adaptive IRQ sharing for 
passed-through devices
http://thread.gmane.org/gmane.linux.kernel/1076440

[PATCH 0/2] Small KVM device assignment cleanups
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64515

What do I need to do to apply these patches to my system?

The server I'm working on is running Proxmox 1.8 with upgraded 
2.6.35-1-pve kernel (previously 2.6.32-4-pve) and qemu-kvm 0.14.1.

Do I need to upgrade to a newer kernel, or upgrade qemu-kvm (e.g. 
0.15.0), or both?

The problem that I'm hoping to solve is an IRQ conflict. The Intel 
DQ67SW motherboard only has 1 PCI slot and no BIOS support for assigning 
IRQs. KVM PCI passthrough only works with the nousb kernel parameter, 
otherwise the ehci_hcd:usb1 conflicts with the PCI's assigned IRQ 16. 
This is a problem because I also need to USB passthrough a dongle 
required by the software (in WinXP guest).

Thanks for any pointers,

Mick

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Re: Shared IRQ with PCI Passthrough?

[Michael Sturm]

On 19-08-11 0:02, Gardziejczyk, Kamil wrote:
> Hi,
>
> Have you resolve your problem with shared IRQ lines? I have checked out qemu-kvm 0.15.0 and found that Jan Kiszka patch was applied to latest version of kvm.
>
> [PATCH 0/5] pci-assign: Host IRQ sharing suppport + some fixes and cleanups
> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64601
>
> Which version of linux kernel do you use? I have tried with 3.0.0. It looks that Jan Kiszka`s patches were not added to that kernel version. Maybe it is in 2.6.xxx?
> Any ideas how to fix it? :)
>
>

Hi Kamil,

Thanks for your reply.

For testing purposes, I've installed Ubuntu 11.04 Server (64-bit) on a 
separate physical disk. The default kernel of this setup is 
2.6.38-8-server (slightly newer than the Proxmox kernel 2.6.35-1-pve I 
was using previously).

As you suggested, I too have now tested qemu-kvm 0.15.0. (git clone 
git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git and compiling the 
stable-0.15 branch).

As before, using the nousb kernel option (with intel_iommu=on) my WinXP 
guest with pci-passthrough works fine, but without the nousb option, the 
guest cannot be started.

My next attempt will be to try the KVM external module kit, compiling 
the latest code from the git clone 
git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git. I think using the 
module kit rather than patching and compiling a custom kernel should 
work better in my case (if I'm moving back to Proxmox later), yet still 
update KVM to the latest code.

Hopefully this will resolve the IRQ conflict.

Any other ideas?

Mick

Re: Shared IRQ with PCI Passthrough?

[Jan Kiszka]

On 2011-08-23 14:52, Michael Sturm wrote:
> On 19-08-11 0:02, Gardziejczyk, Kamil wrote:
>> Hi,
>>
>> Have you resolve your problem with shared IRQ lines? I have checked
>> out qemu-kvm 0.15.0 and found that Jan Kiszka patch was applied to
>> latest version of kvm.
>>
>> [PATCH 0/5] pci-assign: Host IRQ sharing suppport + some fixes and
>> cleanups
>> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/64601
>>
>> Which version of linux kernel do you use? I have tried with 3.0.0. It
>> looks that Jan Kiszka`s patches were not added to that kernel version.
>> Maybe it is in 2.6.xxx?
>> Any ideas how to fix it? :)
>>
>>
> 
> Hi Kamil,
> 
> Thanks for your reply.
> 
> For testing purposes, I've installed Ubuntu 11.04 Server (64-bit) on a
> separate physical disk. The default kernel of this setup is
> 2.6.38-8-server (slightly newer than the Proxmox kernel 2.6.35-1-pve I
> was using previously).
> 
> As you suggested, I too have now tested qemu-kvm 0.15.0. (git clone
> git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git and compiling the
> stable-0.15 branch).
> 
> As before, using the nousb kernel option (with intel_iommu=on) my WinXP
> guest with pci-passthrough works fine, but without the nousb option, the
> guest cannot be started.
> 
> My next attempt will be to try the KVM external module kit, compiling
> the latest code from the git clone
> git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git. I think using the
> module kit rather than patching and compiling a custom kernel should
> work better in my case (if I'm moving back to Proxmox later), yet still
> update KVM to the latest code.
> 
> Hopefully this will resolve the IRQ conflict.

Nope, there is no IRQ sharing support for assigned devices in any public
version so far. I'm on it, but some issues remain to be solved.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: Shared IRQ with PCI Passthrough?

[Marco]

Jan Kiszka <jan.kiszka <at> siemens.com> writes:

....

> 
> Nope, there is no IRQ sharing support for assigned devices in any public
> version so far. I'm on it, but some issues remain to be solved.
> 
> Jan
> 


Hi, any news on this? I own an Intel DQ67OW that has the same issue. No PCI 
passthrough possible with KVM when USB is active.

Marco

Re: Shared IRQ with PCI Passthrough?

[Jan Kiszka]

On 2012-10-15 11:07, Marco wrote:
> Jan Kiszka <jan.kiszka <at> siemens.com> writes:
> 
> ....
> 
>>
>> Nope, there is no IRQ sharing support for assigned devices in any public
>> version so far. I'm on it, but some issues remain to be solved.
>>
>> Jan
>>
> 
> 
> Hi, any news on this? I own an Intel DQ67OW that has the same issue. No PCI 
> passthrough possible with KVM when USB is active.

Supported by qemu-kvm-1.2 and Linux >= 3.4. But not all devices play
well with it, so your mileage may vary.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux

Re: Shared IRQ with PCI Passthrough?

[Marco]

Jan Kiszka <jan.kiszka <at> siemens.com> writes:

> 
> On 2012-10-15 11:07, Marco wrote:
> > Jan Kiszka <jan.kiszka <at> siemens.com> writes:
> > 
> > ....
> > 
> >>
> >> Nope, there is no IRQ sharing support for assigned devices in any public
> >> version so far. I'm on it, but some issues remain to be solved.
> >>
> >> Jan
> >>
> > 
> > 
> > Hi, any news on this? I own an Intel DQ67OW that has the same issue. No PCI 
> > passthrough possible with KVM when USB is active.
> 
> Supported by qemu-kvm-1.2 and Linux >= 3.4. But not all devices play
> well with it, so your mileage may vary.
> 
> Jan
> 


Unfortunately I had no luck trying on Ubuntu Quantal (qemu-kvm 1.2 and Linux 
3.5). Exactly the same error message than before:

Failed to assign irq for "hostdev0": Input/output error
Perhaps you are assigning a device that shares an IRQ with another device?

Marco

RE: Shared IRQ with PCI Passthrough?

[Veruca Salt]

----------------------------------------
> To: kvm@vger.kernel.org
> From: msch123@gmx.eu
> Subject: Re: Shared IRQ with PCI Passthrough?
> Date: Thu, 18 Oct 2012 20:09:56 +0000
>
> Jan Kiszka <jan.kiszka <at> siemens.com> writes:
>
> >
> > On 2012-10-15 11:07, Marco wrote:
> > > Jan Kiszka <jan.kiszka <at> siemens.com> writes:
> > >
> > > ....
> > >
> > >>
> > >> Nope, there is no IRQ sharing support for assigned devices in any public
> > >> version so far. I'm on it, but some issues remain to be solved.
> > >>
> > >> Jan
> > >>
> > >
> > >
> > > Hi, any news on this? I own an Intel DQ67OW that has the same issue. No PCI
> > > passthrough possible with KVM when USB is active.
> >
We encountered severe problems with the DQ67OW; it proved all but impossible to pass thru USB, as you have to pass both PCI bridges through also, in which case you get booting problems with actual PCI cards being bounced from host to guest and back several times.

We worked around this(our ultimate kernel was pretty unstable in any case and IOMMU crashed it) using the KVM ehci script file to load USB 2 emulation. We don't use passthru at all on the current iteration.

However, while our kernel is the main reason, the DQ67OW board has awkward IRQ's, particularly in 64 bit, which would have nixed IOMMU in any case for us.

> > Supported by qemu-kvm-1.2 and Linux >= 3.4. But not all devices play
> > well with it, so your mileage may vary.
> >
> > Jan
> >
>
>
> Unfortunately I had no luck trying on Ubuntu Quantal (qemu-kvm 1.2 and Linux
> 3.5). Exactly the same error message than before:
>
> Failed to assign irq for "hostdev0": Input/output error
> Perhaps you are assigning a device that shares an IRQ with another device?
>
> Marco
>
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