On Wed, Apr 27, 2022, David Woodhouse wrote: > On Wed, 2022-04-27 at 01:40 +0000, Sean Christopherson wrote: > > Add a VM-wide gfn=>pfn cache and a fake MSR to let userspace control the > > cache. On writes, reflect the value of the MSR into the backing page of > > a gfn=>pfn cache so that userspace can detect if a value was written to > > the wrong page, i.e. to a stale mapping. > > > > Spin up 16 vCPUs (arbitrary) to use/refresh the cache, and another thread > > to trigger mmu_notifier events and memslot updates. > > Do you need the MSR hack? Can't you exercise this using Xen interrupt > delivery or runstate information and the same kind of thread setup? Yeah, I asumme it's possible, and medium/long term I definitely want to have a proper test. I went the hack route to get something that could hammer a cache with minimal chance of a test bug. I only have a rough idea of what the Xen stuff does.
