From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH] x86/vPMU: constrain MSR_IA32_DS_AREA loads
Date: Thu, 17 Dec 2015 09:26:22 -0500
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To: Jan Beulich <JBeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>, Jun Nakajima <jun.nakajima@intel.com>, xen-devel <xen-devel@lists.xenproject.org>
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On 12/17/2015 09:18 AM, Jan Beulich wrote:
>>>> On 17.12.15 at 15:12, <boris.ostrovsky@oracle.com> 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