On 01/03/2021 19:33, Boris Ostrovsky wrote: > On 3/1/21 11:23 AM, Roger Pau Monne wrote: >> Introduce an option to allow selecting the legacy behavior for >> accesses to MSRs not explicitly handled. Since commit >> 84e848fd7a162f669 and 322ec7c89f6640e accesses to MSRs not explicitly >> handled by Xen result in the injection of a #GP to the guest. This is >> a behavior change since previously a #GP was only injected if >> accessing the MSR on the real hardware will also trigger a #GP. >> >> This seems to be problematic for some guests, so introduce an option >> to fallback to this legacy behavior. The main difference between what >> was previously done is that the hardware MSR value is not leaked to >> the guests on reads. >> >> Signed-off-by: Roger Pau Monné <roger....@citrix.com> >> --- >> Cc: Boris Ostrovsky <boris.ostrov...@oracle.com> >> --- >> Note that this option is not made available to dom0. I'm not sure >> whether it makes sense to do so, since anyone updating Xen to such >> newer version will also likely pair it with a newish kernel that >> doesn't require such workarounds. >> >> RFC because there's still some debate as to how we should solve the >> MSR issue, this is one possible way, but IMO we need to make a >> decision soon-ish because of the release timeline. >> >> Boris, could you please test with Solaris to see if this fixes the >> issue? > > Yes, it does. Thanks.
Really? This doesn't stop #GP being raised for RAPL_POWER_LIMIT AFAICT. Or am I mistaken about how the bug manifested? ~Andrew
