x2apic issues with Solaris and Xen guests

x2apic issues with Solaris and Xen guests

[Stefan Hajnoczi]

I wonder whether the following two x2apic issues are related:

Solaris 10 U11 network doesn't work
https://bugzilla.redhat.com/show_bug.cgi?id=1040500

kvm - fails to setup timer interrupt via io-apic
(Thanks to Michael Tokarev for posting this link)
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=528077#68

It seems KVM's x2apic emulation works with regular Linux and Windows
guests, but not necessarily with other OSes.

Has anyone looked into this?

Stefan

Re: x2apic issues with Solaris and Xen guests

[Jan Kiszka]

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On 2015-04-20 19:07, Stefan Hajnoczi wrote:
> I wonder whether the following two x2apic issues are related:
> 
> Solaris 10 U11 network doesn't work
> https://bugzilla.redhat.com/show_bug.cgi?id=1040500
> 
> kvm - fails to setup timer interrupt via io-apic
> (Thanks to Michael Tokarev for posting this link)
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=528077#68
> 
> It seems KVM's x2apic emulation works with regular Linux and Windows
> guests, but not necessarily with other OSes.

KVM's x2apic is kind of paravirtual - without VT-d interrupt remapping.
That may confuse the guest, though it should work. But Xen already
refuses to pick it according to the second report:

| (XEN) Not enabling x2APIC: depends on iommu_supports_eim.

> 
> Has anyone looked into this?

Not yet. Is there a handy reproduction guest image? Or maybe someone
would like to start with tracing what the guest and the host do.

Jan



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Re: x2apic issues with Solaris and Xen guests

[Michael Tokarev]

20.04.2015 20:29, Jan Kiszka wrote:
> On 2015-04-20 19:07, Stefan Hajnoczi wrote:
>> I wonder whether the following two x2apic issues are related:
>>
>> Solaris 10 U11 network doesn't work
>> https://bugzilla.redhat.com/show_bug.cgi?id=1040500
>>
>> kvm - fails to setup timer interrupt via io-apic
>> (Thanks to Michael Tokarev for posting this link)
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=528077#68
[]
>> Has anyone looked into this?
> 
> Not yet. Is there a handy reproduction guest image? Or maybe someone
> would like to start with tracing what the guest and the host do.

The second link gives a trivial reproducer, you need just the
xen hipervisor binary and some kernel.  This should be easy
too, because it happens right on boot.  But I guess it requires
some inner knowlege of xen early boot machinery.

Thanks,

/mjt

Re: x2apic issues with Solaris and Xen guests

[Bandan Das]

Michael Tokarev <mjt@tls.msk.ru> writes:

> 20.04.2015 20:29, Jan Kiszka wrote:
>> On 2015-04-20 19:07, Stefan Hajnoczi wrote:
>>> I wonder whether the following two x2apic issues are related:
>>>
>>> Solaris 10 U11 network doesn't work
>>> https://bugzilla.redhat.com/show_bug.cgi?id=1040500
>>>
>>> kvm - fails to setup timer interrupt via io-apic
>>> (Thanks to Michael Tokarev for posting this link)
>>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=528077#68
> []
>>> Has anyone looked into this?
>> 
>> Not yet. Is there a handy reproduction guest image? Or maybe someone
>> would like to start with tracing what the guest and the host do.
>
> The second link gives a trivial reproducer, you need just the
> xen hipervisor binary and some kernel.  This should be easy
> too, because it happens right on boot.  But I guess it requires
> some inner knowlege of xen early boot machinery.

Have you tried Radim's patch ?

commit c806a6ad35bfa6c92249cd0ca4772d5ac3f8cb68
Author: Radim Krčmář <rkrcmar@redhat.com>
Date:   Wed Mar 18 19:38:22 2015 +0100

    KVM: x86: call irq notifiers with directed EOI
    

> Thanks,
>
> /mjt
>
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