Re: [PATCH 1/3] iommu/vt-d: Remove redundant IOTLB flush

[Lu Baolu]

On 2020/3/24 23:31, Jacob Pan wrote:
> On Sat, 21 Mar 2020 09:32:45 +0800
> Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>  wrote:
>
> > On 2020/3/21 0:20, Jacob Pan wrote:
> > > On Fri, 20 Mar 2020 21:45:26 +0800
> > > Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>  wrote:
> > >    
> > > > On 2020/3/20 12:32, Jacob Pan wrote:
> > > > > IOTLB flush already included in the PASID tear down process. There
> > > > > is no need to flush again.
> > > > It seems that intel_pasid_tear_down_entry() doesn't flush the pasid
> > > > based device TLB?
> > > >   
> > > I saw this code in intel_pasid_tear_down_entry(). Isn't the last
> > > line flush the devtlb? Not in guest of course since the passdown
> > > tlb flush is inclusive.
> > >
> > > 	pasid_cache_invalidation_with_pasid(iommu, did, pasid);
> > > 	iotlb_invalidation_with_pasid(iommu, did, pasid);
> > >
> > > 	/* Device IOTLB doesn't need to be flushed in caching mode.
> > > */ if (!cap_caching_mode(iommu->cap))
> > > 		devtlb_invalidation_with_pasid(iommu, dev, pasid);
> > >    
> > But devtlb_invalidation_with_pasid() doesn't do the right thing, it
> > flushes the device tlb, instead of pasid-based device tlb.
> Hmm, you are right. But the function name is misleading, pasid argument
> is not used, is there a reason why?
> This is used for PASID based device IOTLB flush, right?

Yes. I will fix and put your patch after it.

Best regards,
baolu