On Wed, 9 Nov 2016 14:49:02 +0000 Ilya Lesokhin <ilyal@xxxxxxxxxxxx> wrote: > I would virtualize the "ATS Control Register". And do what? > Regarding poor behavior, I couldn't really find what happens when ATS is misconfigured, but I would assume it can cause problems. > The scenarios I'm concerned about are: > 1. The guest enables translation caching, while the hypervisor thinks there are disabled -> Hypervisor won't issue invalidations. Aren't invalidations issued by the iommu, why does the hypervisor need to participate? How would a software entity induce an invalidation? > 2. Smallest Translation Unit misconfiguration. Not sure if it will cause invalid access or only poor caching behavior. > > Thanks, > Ilya > > > -----Original Message----- > > From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx] > > Sent: Sunday, November 06, 2016 7:09 PM > > To: Ilya Lesokhin <ilyal@xxxxxxxxxxxx> > > Cc: linux-pci@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx > > Subject: Re: Shouldn't VFIO virtualize the ATS capability? > > > > On Sun, 6 Nov 2016 11:13:09 +0000 > > Ilya Lesokhin <ilyal@xxxxxxxxxxxx> wrote: > > > > > Hi > > > I've noticed that VFIO doesn't virtualize the ATS capability. > > > It seems to me that translation caching and Smallest Translation Unit is > > something you would want to control on the host. Am I wrong? > > > > What about those fields would we virtualize? Why does the host need to be > > an intermediary? Can the user induce poor behavior with direct access to > > them? Thanks, > > > > Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
