From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Yang Zhang <yang.z.zhang@intel.com>,
Kevin Tian <kevin.tian@intel.com>,
Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH] x86/intel: Protect set_cpuidmask() against #GP faults
Date: Thu, 5 Jun 2014 16:00:56 +0100 [thread overview]
Message-ID: <53908628.60506@citrix.com> (raw)
In-Reply-To: <5390A1580200007800018508@mail.emea.novell.com>
On 05/06/14 15:56, Jan Beulich wrote:
>>>> On 05.06.14 at 16:24, <andrew.cooper3@citrix.com> wrote:
>> On 05/06/14 15:05, Jan Beulich wrote:
>>>>>> On 05.06.14 at 13:19, <andrew.cooper3@citrix.com> wrote:
>>>> * Call set_cpuidmask() unconditionally so faulting-capable hardware still gets
>>>> a log message indicating to the user why their command line arguments are
>>>> not taking effect.
>>> I don't think Intel will particularly like this part.
>> Why not?
> Because they try to deprecate masking in favor of CPUID faulting as
> much as they can.
>
> Jan
>
And that is a very good thing.
However, masking is only available SandyBridge and older (for a few
generations), whereas faulting is only available on IvyBridge and newer.
If the user tries setting the cpuid_mask_XXX in the hope that masking
occurs, It is kind to give them an error back explaining why nothing is
happening.
~Andrew
prev parent reply other threads:[~2014-06-05 15:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-05 11:19 [PATCH] x86/intel: Protect set_cpuidmask() against #GP faults Andrew Cooper
2014-06-05 14:05 ` Jan Beulich
2014-06-05 14:24 ` Andrew Cooper
2014-06-05 14:56 ` Jan Beulich
2014-06-05 15:00 ` Andrew Cooper [this message]
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