Re: [Xen-devel] [PATCH] x86/vPMU: constrain MSR_IA32_DS_AREA loads

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 12/17/2015 09:18 AM, Jan Beulich wrote:
> > > > On 17.12.15 at 15:12, <boris.ostrovsky@xxxxxxxxxx> wrote:
> > On 12/17/2015 09:01 AM, Jan Beulich wrote:
> > > @@ -415,8 +416,10 @@ static int core2_vpmu_verify(struct vcpu
> > >                enabled_cntrs |= (1ULL << i);
> > >        }
> > >    
> > > -    if ( vpmu_is_set(vcpu_vpmu(v), VPMU_CPU_HAS_DS) &&
> > > -         !is_canonical_address(core2_vpmu_cxt->ds_area) )
> > > +    if ( vpmu_is_set(vpmu, VPMU_CPU_HAS_DS) &&
> > > +         !(has_hvm_container_vcpu(v)
> > > +           ? is_canonical_address(core2_vpmu_cxt->ds_area)
> > > +           : __addr_ok(core2_vpmu_cxt->ds_area)) )
> > Should we instead of (or in addition to) this also make the same change
> > in core2_vpmu_do_wrmsr()?
> Currently there's no need for this since - afaict - PV guests can't
> write this MSR directly (it's not among the white listed set in
> traps.c).
Then we probably shouldn't set VPMU_CPU_HAS_DS for PV guests.


-boris


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