Re: [Xen-devel] [PATCH v5 0/7] VMX: Properly handle pi descriptor and per-cpu blocking list

["Wu, Feng" <feng.wu@xxxxxxxxx>]

> -----Original Message-----
> From: Tian, Kevin
> Sent: Tuesday, October 11, 2016 4:08 PM
> To: Wu, Feng <feng.wu@xxxxxxxxx>; xen-devel@xxxxxxxxxxxxx
> Cc: jbeulich@xxxxxxxx; andrew.cooper3@xxxxxxxxxx;
> george.dunlap@xxxxxxxxxxxxx; dario.faggioli@xxxxxxxxxx
> Subject: RE: [PATCH v5 0/7] VMX: Properly handle pi descriptor and per-cpu
> blocking list
> 
> > From: Wu, Feng
> > Sent: Tuesday, October 11, 2016 8:58 AM
> >
> > The current VT-d PI related code may operate incorrectly in the
> > following scenarios:
> > 1. When the last assigned device is dettached from the domain, all
> > the PI related hooks are removed then, however, the vCPU can be
> > blocked, switched to another pCPU, etc, all without the aware of
> > PI. After the next time we attach another device to the domain,
> > which makes the PI realted hooks avaliable again, the status
> > of the pi descriptor is not true. Besides that, the blocking vcpu
> > may still remain in the per-cpu blocking in this case. Patch [1/6]
> > and [2/6] handle this.
> 
> Your v5 series have 7 patches in total.

Oh, yes, forgot to update this. Should be [1/7] and [2/7]

> 
> >
> > 2. After the domain is destroyed, the the blocking vcpu may also
> > remain in the per-cpu blocking. Handled in patch [3/6].

[3/7]

> >
> > 3. When IRTE is in posted mode, we don't need to set the irq
> > affinity for it, since the destination of these interrupts is
> > vCPU and the vCPU affinity is set during vCPU scheduling. Patch
> > [5/6] handles this.

[5/7]

> >
> > 4. When a pCPU is unplugged, and there might be vCPUs on its
> > list. Since the pCPU is offline, those vCPUs might not be woken
> > up again. [6/6] addresses it.

[7/7]

Thanks,
Feng


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