Re: [PATCH -v2] Add MCE support to KVM

From: Anthony Liguori <anthony@codemonkey.ws>
To: Huang Ying <ying.huang@intel.com>
Cc: Avi Kivity <avi@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH -v2] Add MCE support to KVM
Date: Sat, 18 Apr 2009 10:54:38 -0500	[thread overview]
Message-ID: <49E9F7BE.4090904@codemonkey.ws> (raw)
In-Reply-To: <1239953345.6842.3.camel@yhuang-dev.sh.intel.com>

Huang Ying wrote:
> The related MSRs are emulated. MCE capability is exported via
> extension KVM_CAP_MCE and ioctl KVM_X86_GET_MCE_CAP_SUPPORTED. A new
> vcpu ioctl command KVM_X86_SETUP_MCE is used to setup MCE emulation
> such as the mcg_cap. MCE is injected via vcpu ioctl command
> KVM_X86_SET_MCE. Extended machine-check state (MCG_EXT_P) and CMCI are
> not simulated.
>   

Maybe I'm missing something, but couldn't this be implemented entirely 
within userspace?  There's nothing VT/SVM specific about this.  If the 
issue is setting these MSRs from userspace via KVM_SET_MSRS isn't 
enough, perhaps we should add userspace MSR handling.

Also, if you implement the MSR logic in userspace, it's pretty simple to 
make it work in the non-TCG case which will be a requirement for 
upstream merging.

Regards,

Anthony LIguori