> -----Original Message----- > From: Jan Beulich [mailto:jbeul...@suse.com] > Sent: 21 March 2017 15:33 > To: Paul Durrant <paul.durr...@citrix.com> > Cc: Andrew Cooper <andrew.coop...@citrix.com>; xen- > de...@lists.xenproject.org > Subject: Re: [PATCH v2 4/6] x86/viridian: add warnings for unimplemented > hypercalls and MSRs > > >>> On 20.03.17 at 18:08, <paul.durr...@citrix.com> wrote: > > These warnings can be useful when Microsoft updates Windows. > > > > In the past there have been several cases when Windows erroneously uses > > hypercalls and MSRs that should be gated on CPUID flags than Xen does > > not set. The usual symptom is a guest crash with little or no information > > in the hypervisor log. Adding these warnings at least gives a clue as to > > what might be happening in such cases. > > > > Some versions of Windows do currently issue hypercalls that they should > > not, so this patch whitelists those to avoid the warnings as the lack > > of implementation is clearly proved not to be a problem to the guest. > > > > The warnings are rate limited so a malicious guest cannot use them to > > as a DoS. > > > > NOTE: Because the MSR warnings need to be gated on range checking the > > MSR address this patch imports the up-to-date definitions of all > > the viridian MSRs from the specification. > > > > Signed-off-by: Paul Durrant <paul.durr...@citrix.com> > > Reviewed-by: Jan Beulich <jbeul...@suse.com> > > with one remark: > > > @@ -552,6 +610,10 @@ int wrmsr_viridian_regs(uint32_t idx, uint64_t val) > > break; > > > > default: > > + if ( idx >= VIRIDIAN_MSR_MIN && idx <= VIRIDIAN_MSR_MAX ) > > + gprintk(XENLOG_WARNING, "write to unimplemented MSR > %08x\n", > > + idx); > > Mind if I shorten the string literal by one using %#x instead of > %08x (also on the read side) while committing?
No, I don't mind. Paul > > Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
