From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Jan Beulich <JBeulich@suse.com>, John Doe <securef33d@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
x86@kernel.org, xen-devel@lists.xen.org,
linux-kernel@vger.kernel.org
Subject: Re: [Xen-devel] PROBLEM: kernel panic xsave_init
Date: Tue, 20 Oct 2015 10:27:41 -0400 [thread overview]
Message-ID: <56264F5D.9000104@oracle.com> (raw)
In-Reply-To: <5626613002000078000ACE3B@prv-mh.provo.novell.com>
On 10/20/2015 09:43 AM, Jan Beulich wrote:
>>>> On 20.10.15 at 15:22, <boris.ostrovsky@oracle.com> wrote:
>> The reason I think its this commit is that RAX, RDX and RCX look very
>> much like arguments to xsetbv (which xstate_enable_boot_cpu() executes)
>> and RAX value is 0x1f, which has two new bits that this commit defined.
> That would be the two MPX related bits, yet us (luckily) white listing
> leaf 7 in pv_cpuid(), it is quite easy to validate that we don't expose
> this feature to PV(H) guests.
Oh, so something like
cpuid=['0x7:ebx=xxxxxxxxxxxxxxxxx0xxxxxxxxxxxxxx']
(bit 14 as zero) for John to try then.
-boris
> Sadly the story is different for HVM
> guests (where the leaf handling uses black listing), but the register
> dump here clearly points to a PV guest (or Dom0).
>
> Jan
>
next prev parent reply other threads:[~2015-10-20 14:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <562430E6.6010205@gmail.com>
[not found] ` <20151019075618.GA22488@gmail.com>
2015-10-19 10:16 ` John Doe
2015-10-19 16:25 ` [Xen-devel] " Boris Ostrovsky
2015-10-20 9:51 ` Jan Beulich
2015-10-20 12:11 ` John Doe
2015-10-20 13:22 ` Boris Ostrovsky
2015-10-20 13:43 ` Jan Beulich
2015-10-20 14:27 ` Boris Ostrovsky [this message]
2015-10-20 14:41 ` Jan Beulich
2015-10-21 0:17 ` John Doe
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