Re: [Xen-users] VT-d CPU resources

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

On Thu, Jun 28, 2012 at 8:52 AM, amiard brice <perso@xxxxxxxxxxxxxxx> wrote:
> But as I said, my backplane ("motherboard extension") is composed with 4
> bridge "PCI-e to PCI". And I have one domU for each "PCI-e to PCI bridge",
> so according to the intel_VT-d pdf, it could be possible in my case to have
> 4 domU (one for each PCIe to PCI bridges).

This sounds like a question it would be useful to ask on xen-devel.
(Unfortuantely I'm not familiar enough with PCIe-to-PCI bridges to
give you a good answer.)

 -George

>
> In my opinion it could be due to the EPT table. In my "xm dmesg" I could see
> "EPT not enable" and "CPU capabilities :  EPT table 2Mo", but I can't active
> it (I've try different options in default/grub without succes)
>
> (if devices behind the same pci bridges could not be allocated to different
> VMs, it' simply because VT-d use specific interruption command call MSI-X in
> aim to identify a domU, and those interruptions commands  could be possible
> only with PCIe, you can have more information in the pdf intel VT-d).
>
> thank you for your help in advance
>
>
>
>
>
>
> Hi,
>
> I've never been successful with VT-d-style pci delegation, but I read
> devices behind pci bridges could not be allocated to different VMs in
> earlier times.
>
> Make sure this is supposed to work before you tackle the harder issues.
>
> 2012/6/22 amiard brice <perso@xxxxxxxxxxxxxxx>:
>> Hello
>>
>>
>>
>> I'm working on XEN since one month now.
>>
>>
>>
>> I want create four domU with 2 PCI device per dom.
>>
>> I've bought a backplane with 3 bridges PCIe 1x to PCI and 4 PCI
>> directly connected to the PCH (Q67).
>>
>> (Moreover PCI card (ethernet card) are composed with a PCI bridge)
>>
>>
>>
>> I've succefuly created 4 domU with bakend devices, with option
>> "pci-backend-strict-check" disable.
>>
>> I’ve try with it but even if all PCI ports behind PCIe to PCI bridge
>> appears in  pci-list-assignable-devices, domU won’t start, with an
>> error message "device XX:XX.X need to be co-assigned with XX:XX.X, but
>> it's not owned by pci-backend
>>
>>
>>
>> The probleme is :  even if my domU are configuer with 1 VCPUs for each
>> of them, when domU acces to I/O devices, VCPUs aren't separated (I've
>> notice this using virt-manager charts). During a basic CPU benchmark
>> on a domU, VCPUs are isolated.
>>
>>
>>
>> I Have attached "lspci-v", "xm dmesg", "xm
>> pci-list-assignable-devices", "default-grub", "xm info" and a “domU cfg
> file”
>>
>>
>>
>> A share core is very problematic my RT application
>>
>>
>>
>> thank you for your help in advance
>>
>>
>>
>>
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@xxxxxxxxxxxxx
>> http://lists.xen.org/xen-users
>
>
>
> --
> the purpose of libvirt is to provide an abstraction layer hiding all xen
> features added since 2006 until they were finally understood and copied by
> the kvm devs.
>
>
> _______________________________________________
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> Xen-users@xxxxxxxxxxxxx
> http://lists.xen.org/xen-users

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