On Mon, May 20, 2013 at 01:50:39PM +0000, Alexey E. Suslikov wrote: > Jonathan Gray <jsg <at> jsg.id.au> writes: > > > That is quite a large hammer. It would be preferable to > > find out which msr it objects to and guard it with a specific cpuid > > check, and/or fix the hypervisor. > > >From NetBSD PR/47677 (http://gnats.netbsd.org/47677) > > "I think x86_errata should be avoided if NetBSD running > on virtual machine because accesses to MSR may be restricted" > > While above statement is an assumption, it is highly possible > for hypervisor to restrict operations on model-specific regs. > > For me it's kinda grounded approach, because erratas applied > on "host level" may conflict with what guests want, increasing > a possibility of screwing up things. > > So what is the point for guest to run erratas if hypervisor > may already done that upwards?
Filling the kernel full of if not really running on hardware do something else paths is asking for trouble. If a hypervisor claims to be a specific model of a processor it should not be surprised when it gets msrs that processor can handle.