On Wed, Nov 29, 2017 at 11:05:46AM -0800, Jim Mattson wrote: > An alternative is to give the L1 guest read permission for this MSR in > the MSR permission bitmaps. It's still going to be ~80 cycles, but > that's better than the cost of a VM-exit/VM-entry round-trip. It's a useful optimization, 80 cycles is 80 cycles. The cache invalidation could likely be really simple, like: have a global counter always check the counter before and after and don't use the cache if they don't match. change KDB etc. to increase the counter. -Andi
