RE: [PATCH 05/13] KVM: Update IRTE according to guest interrupt configuration changes

[Wu, Feng]

> -----Original Message-----
> From: Paolo Bonzini [mailto:pbonzini@xxxxxxxxxx]
> Sent: Wednesday, November 12, 2014 5:14 PM
> To: Zhang, Yang Z; Wu, Feng; Alex Williamson
> Cc: gleb@xxxxxxxxxx; dwmw2@xxxxxxxxxxxxx; joro@xxxxxxxxxx;
> tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx; x86@xxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 05/13] KVM: Update IRTE according to guest interrupt
> configuration changes
> 
> 
> 
> On 12/11/2014 04:42, Zhang, Yang Z wrote:
> > Personally, I think this feature will be helpful to the legacy device
> > assignment. Agree, vfio is the right solution for future feature
> > enabling. But the old kvm without the good vfio supporting is still
> > used largely today. The user really looking for this feature but they
> > will not upgrade their kernel. It's easy for us to backport this
> > feature to old kvm with the legacy device assignment, but it is
> > impossible to backport the whole vfio.
> 
> You can certainly backport these patches to distros that do not have
> VFIO.  But upstream we should work on VFIO first.  VFIO has feature
> parity with legacy device assignment, and adding a new feature that is
> not in VFIO would be a bad idea.
> 
> By the way, do you have benchmark results for it?  We have not been able
> to see any performance improvement for APICv on e.g. netperf.

Do you mean benchmark results for APICv itself or VT-d Posted-Interrtups?

Thanks,
Feng

> 
> Paolo