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From: Gerd Hoffmann <kraxel@redhat.com>
To: Ed Swierk <eswierk@aristanetworks.com>
Cc: kvm@vger.kernel.org
Subject: Re: Userspace MSR handling
Date: Mon, 25 May 2009 13:16:22 +0200	[thread overview]
Message-ID: <4A1A7E06.9080702@redhat.com> (raw)
In-Reply-To: <9ae48b020905221311h1859d5a1v3653404721d5208b@mail.gmail.com>

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

      parent reply	other threads:[~2009-05-25 11:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-22 20:11 Userspace MSR handling Ed Swierk
2009-05-23  8:57 ` Alexander Graf
2009-05-24 12:07   ` Avi Kivity
2009-05-24 16:15     ` Alexander Graf
2009-05-26 11:31       ` Avi Kivity
2009-05-25 11:03     ` Gerd Hoffmann
2009-05-25 11:20       ` Avi Kivity
2009-05-25 11:29         ` Gerd Hoffmann
2009-05-25 11:31           ` Avi Kivity
2009-05-27 16:12         ` Ed Swierk
2009-05-27 16:28           ` Avi Kivity
2009-05-27 17:09             ` Ed Swierk
2009-05-27 19:16               ` Gerd Hoffmann
2009-05-27 23:00                 ` Ed Swierk
2009-05-28  8:53                 ` Avi Kivity
2009-05-29  9:47                   ` Gerd Hoffmann
2009-05-31  8:21                     ` Avi Kivity
2009-05-25 11:16 ` Gerd Hoffmann [this message]

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