On 01/12/2021 09:41, Jan Beulich wrote: > --- a/xen/drivers/passthrough/vtd/iommu.c > +++ b/xen/drivers/passthrough/vtd/iommu.c > @@ -591,7 +591,8 @@ static int __must_check iommu_flush_all( > bool_t flush_dev_iotlb; > int rc = 0; > > - flush_all_cache(); > + flush_local(FLUSH_CACHE);
While I agree that the conversion is an improvement, the logic still looks totally bogus. I can believe that it might have been a stopgap to fix problems before we identified the need for sync_cache() for non-coherent IOMMUs, but there's no need I can spot for any WBINVDs on any of these paths. I'm fairly sure this should just be dropped, and Xen will get faster as a result. ~Andrew
