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From: "Liu, Jinsong" <jinsong.liu@intel.com>
To: "Luck, Tony" <tony.luck@intel.com>, Borislav Petkov <bp@amd64.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: "x86@kernel.org" <x86@kernel.org>,
        "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: RE: [Xen-devel] [PATCH 1/3] Add mcelog support for xen platform
Thread-Topic: [Xen-devel] [PATCH 1/3] Add mcelog support for xen platform
Thread-Index: AQHNH3YME+T8UaKT7UOvaY1icgqRWJaljggAgAL9hUCAAAEvAA==
Date: Mon, 23 Apr 2012 15:43:47 +0000
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Luck, Tony wrote:
>> Because, if you'd hooked into it, just imagine one fine day, when we
>> remove mcelog support, what screaming the xen people will be doing
>> when mcelog doesn't work anymore.
> 
> Agreed. Even before we get to deleting mcelog, "struct mce" can
> change (new fields could be added) ... and you don't want to have
> your hypervisor to have to know which version of Linux it is talking
> to. 
> 

Hmm, adding new fields block neither native nor xen -- xen just ignore new added fields, that would be no problem for xen:
/* Fields are zero when not available */
struct mce {
	...
}

and, hypervisor only record error into its mc_info cookie (in its own format), it doesn't care what's dom0's version and how dom0 translate it -- that's dom0's business. The role of hypervisor is virtual 'platform', just like h/w platform don't care what linux version runs over it.


Thanks,
Jinsong