[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2 for-4.15] x86/msr: introduce an option for HVM relaxed rdmsr behavior
On 3/4/21 9:47 AM, Roger Pau Monne wrote: > Introduce an option to allow selecting a less strict behaviour for > rdmsr accesses targeting a MSR not explicitly handled by Xen. Since > commit 84e848fd7a162f669 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 commit attempts to offer a fallback option similar to the > previous behavior. Note however that the value of the underlying MSR > is never leaked to the guest, as the newly introduced option only > changes whether a #GP is injected or not. > > Long term the plan is to properly handle all the MSRs, so the option > introduced here should be considered a temporary resort for OSes that > don't work properly with the new MSR policy. Any OS that requires this > option to be enabled should be reported to > xen-devel@xxxxxxxxxxxxxxxxxxxx. > > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> > --- > Changes since v1: > - Only apply the option to HVM guests. > - Only apply the special handling to MSR reads. > - Sanitize the newly introduced flags field. > - Print a warning message when the option is used. > --- > Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > --- > Boris, could you please test with Solaris to see if this fixes the > issue? Yes, still works. (It worked especially well after I noticed new option name ;-)) -boris
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