From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: VPMU backports for 4.6
Date: Wed, 20 Jan 2016 12:36:51 -0500 [thread overview]
Message-ID: <569FC5B3.9050304@oracle.com> (raw)
In-Reply-To: <569FCE5E02000078000C94CC@prv-mh.provo.novell.com>
On 01/20/2016 12:13 PM, Jan Beulich wrote:
>>>> On 20.01.16 at 17:12, <boris.ostrovsky@oracle.com> wrote:
>> There two patches need to be backported to 4.6
>>
>> fb424bf x86/VPMU: don't allow any non-zero writes to MSR_IA32_PEBS_ENABLE
>> 31af0d7 x86/VPMU: check more carefully which bits are allowed to be
>> written to MSRs
> "Need to be" is pretty strong for an unsupported subsystem. In fact
> I had already considered those and then decided not to take them.
> So with you asking for them I'm not really sure what to do...
"Need to" may indeed have been a bit too much.
Since there is a potential for crashing the hypervisor I think we should
have those two in 4.6, even if we don't officially support VPMU.
(As a side --- XSA-163 says that VPMU is "unsupported security-wise". Do
we make any distinction between a feature being generally or
security-wise unsupported?)
-boris
next prev parent reply other threads:[~2016-01-20 17:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-20 16:12 VPMU backports for 4.6 Boris Ostrovsky
2016-01-20 17:13 ` Jan Beulich
2016-01-20 17:36 ` Boris Ostrovsky [this message]
2016-01-21 7:35 ` Jan Beulich
2016-01-21 10:10 ` Ian Campbell
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