linux-kernel - Re: [PATCH v4 2/3] KVM-INTEL: Add new module vmcsinfo-intel to fill VMCSINFO

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Message-ID: <4FF6A0F3.2010201@cn.fujitsu.com>
Date:	Fri, 06 Jul 2012 16:25:23 +0800
From:	Wen Congyang <wency@...fujitsu.com>
To:	HATAYAMA Daisuke <d.hatayama@...fujitsu.com>
CC:	zhangyanfei@...fujitsu.com, dzickus@...hat.com, luto@....edu,
	kvm@...r.kernel.org, joerg.roedel@....com, mtosatti@...hat.com,
	kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
	paul.gortmaker@...driver.com, ludwig.nussel@...e.de,
	avi@...hat.com, gregkh@...uxfoundation.org, ebiederm@...ssion.com
Subject: Re: [PATCH v4 2/3] KVM-INTEL: Add new module vmcsinfo-intel to fill
 VMCSINFO

At 07/06/2012 04:04 PM, HATAYAMA Daisuke Wrote:
> From: Yanfei Zhang <zhangyanfei@...fujitsu.com>
> Subject: [PATCH v4 2/3] KVM-INTEL: Add new module vmcsinfo-intel to fill VMCSINFO
> Date: Wed, 4 Jul 2012 18:05:19 +0800
> 
>> Besides, this patch also exports vmcs revision identifier via
>> /sys/devices/system/cpu/vmcs_id and offsets of fields via
>> /sys/devices/system/cpu/vmcs/.
>> Individual offsets are contained in subfiles named by the filed's
>> encoding, e.g.: /sys/devices/cpu/vmcs/0800
> 
> According to the discussion starting from
> 
> http://lkml.indiana.edu/hypermail/linux/kernel/1105.3/00749.html

IIRC, kvm can not work in such environment. The vcpu can run on
different cpu. If the cpu's vmcs is different, I don't know what
will happen. So do we need to support for such environment now?
I think that if kvm can not work in such environment, we should
not provide vmcs information for each physical cpu.

Thanks
Wen Congyang

> 
> system can be composed of CPUs with different steppings or differnet
> microcode revisions. Becase of the nature that it's hided in the
> specification, I suspect layout of vmcs could change across different
> steppings or microcode revisions. Then, the interface needs to be
> changed as per-cpu like
> 
>    /sys/devices/cpu/cpu0/vmcs/0800
>    /sys/devices/cpu/cpu1/vmcs/0800
>    ...
>    /sys/devices/cpu/cpuN/vmcs/0800
> 
> Also, processing of vmcsinfo initialization needs to be done per cpu,
> and can be triggered when cpu is added not when kvm module is loaded.
> 
> Thanks.
> HATAYAMA, Daisuke
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
> 

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