linux-kernel - Re: [PATCH] Add MCE support to KVM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <49EDEE93.30103@codemonkey.ws>
Date:	Tue, 21 Apr 2009 11:04:35 -0500
From:	Anthony Liguori <anthony@...emonkey.ws>
To:	Avi Kivity <avi@...hat.com>
CC:	Huang Ying <ying.huang@...el.com>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH] Add MCE support to KVM

Avi Kivity wrote:
> Anthony Liguori wrote:
>> Avi Kivity wrote:
>>>
>>> Then we would need to tell which read-only MSRs are setup writeable 
>>> and which aren't...
>>>
>>> I'm okay with an ioctl to setup MCE, but just make sure userspace 
>>> has all the information to know what the kernel can do rather than 
>>> the try-and-see-if-it-works approach.  We can publish this 
>>> information via KVM_CAP things, or via another ioctl (see 
>>> KVM_GET_SUPPORTED_CPUID2 for an example).
>>
>> Why not introduce a new exit type for MSR reads/writes that aren't 
>> handled by the kernel?  You just need a bit on the return that 
>> indicates whether to GPF because of an invalid MSR access.
>>
>> KVM_SET_MSRs should be reserved for MSRs that are performance 
>> sensitive.  Not all of them will be.
>>
>
> Right now everything in the vcpu is emulated in the kernel.  
> Everything else is emulated either in the kernel (irqchip) or in 
> userspace.  This makes things easier to understand, and is more future 
> friendly if more cpu features become virtualized by hardware.

Except cpuid, which is handled in userspace, sort of :-)  I think the 
same arguments apply here too.

Regards,

Anthony Liguori
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/