How gpu requests are trapped by kvmgt ?

[Adel Belkhiri]

Thank you for your replay,

What I wanted to say is that I found that the number of requests sent by
the VM to the vgpu is different from the number of requests received by
KVMGT. I used Ftrace to do the count.  I think the i915 driver of the VM
sometimes combine multiple requests in just one request sent to KVMGT.

Am I wrong ?


Le mer. 25 oct. 2017 à 22:47, Tian, Kevin <kevin.tian at intel.com> a écrit :

> it’s decided by KVMGT. the real recipe is EPT, which is a CPU hw
> virtualization feature to decide which access in VM is trapped or not.
>
>
>
> *From:* intel-gvt-dev [mailto:intel-gvt-dev-bounces at lists.freedesktop.org]
> *On Behalf Of *Adel Belkhiri
> *Sent:* Wednesday, October 25, 2017 11:06 PM
> *To:* intel-gvt-dev at lists.freedesktop.org
> *Subject:* How gpu requests are trapped by kvmgt ?
>
>
>
> Hi everybody,
>
> I have a question about the implementation of KVMGT. According to the
> documentation, the virtual machine, may send some requests to the gpu
> directly (Pass-through) and forward some other requests to the KVMGT
> module.
>
> I read the code of KVMGT but i didn't understand how requests are being
> sent directly to the gpu ? and who decide which request to be directly sent
> to the gpu or to be trapped by kvmgt ? Is it the graphics card driver of
> the VM (i915) or KVMGT ?
>
> Thanks a lot for your help.
>
> Yours.
>
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