From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: Userspace MSR handling
Date: Mon, 25 May 2009 13:16:22 +0200
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To: Ed Swierk <eswierk@aristanetworks.com>
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On 05/22/09 22:11, Ed Swierk wrote:
> Does it make sense to implement a generic mechanism for handling MSRs
> in userspace?

I see no other way to handle the xen pv msr writes.

> I imagine a mechanism analogous to PIO, adding a
> KVM_EXIT_MSR code and a msr type in the kvm_run struct.

Sounds sensible to me.  Probably must be off by default for backward 
compatibility, then enabled by ioctl.  I think it would be best to 
enable it for specific msrs.  We probably also want to have a way for 
userspace to figure whenever some specific msr is implemented in-kernel 
to handle the case of an msr emulation moving from userspace to 
kernelspace gracefully.

> I'm happy to take a stab at implementing this if no one else is
> already working on it.

I is somewhere on my todo list, but I didn't looked at it (yet).
Feel free to go ahead ;)

cheers,
   Gerd