From: Keir Fraser <keir.xen@gmail.com>
To: "Liu, Jinsong" <jinsong.liu@intel.com>,
Jan Beulich <JBeulich@novell.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"Shan, Haitao" <haitao.shan@intel.com>,
"Li, Xin" <xin.li@intel.com>
Subject: Re: [PATCH] X86: cpuid faulting feature enable
Date: Fri, 01 Jul 2011 19:02:51 +0100 [thread overview]
Message-ID: <CA33CA5B.1D5E2%keir.xen@gmail.com> (raw)
In-Reply-To: <BC00F5384FCFC9499AF06F92E8B78A9E22307FB535@shsmsx502.ccr.corp.intel.com>
On 01/07/2011 18:48, "Liu, Jinsong" <jinsong.liu@intel.com> wrote:
>> Down to a particular stepping? That surely doesn't make sense for
>> anything but your own experimenting.
>
> Yes, it's some ugly.
> Currently cpuid faulting is not a architecturally commited feature, and, some
> other Intel processors (which do not has cpuid faulting feature) also has
> 0xceh MSR.
> Hence I use current way for safe. However, I marked it as FIXME to update in
> the future accordingly.
But Intel's own supporting document states that bit 31 of the PLATFORM_INFO
MSR should be sufficient to identify the cpuid faulting feature. Do you
really need the stepping check as well? Could you just do a rdmsr_safe
read-and-check of PLATFORM_INFO_MSR[31] instead?
It would be okay for other Intel CPUs to have MSR 0xce, so long as they
don't set bit 31...
-- Keir
next prev parent reply other threads:[~2011-07-01 18:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-01 14:32 [PATCH] X86: cpuid faulting feature enable Liu, Jinsong
2011-07-01 15:48 ` Jan Beulich
2011-07-01 16:07 ` Keir Fraser
2011-07-02 3:04 ` Tian, Kevin
2011-07-01 17:48 ` Liu, Jinsong
2011-07-01 18:02 ` Keir Fraser [this message]
2011-07-01 18:12 ` Liu, Jinsong
2011-07-01 18:14 ` Liu, Jinsong
2011-07-01 21:31 ` Keir Fraser
2011-07-02 3:15 ` Tian, Kevin
2011-07-02 7:49 ` Keir Fraser
2011-07-04 1:06 ` Shan, Haitao
2011-07-04 6:58 ` Keir Fraser
2011-07-03 9:40 ` Liu, Jinsong
2011-07-04 3:19 ` Liu, Jinsong
2011-07-04 6:59 ` Keir Fraser
2011-07-04 8:10 ` Liu, Jinsong
-- strict thread matches above, loose matches on Subject: below --
2011-07-01 19:41 Liu, Jinsong
2011-07-01 21:32 ` Keir Fraser
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