Re: Nested SVM and migration

Joerg Roedel
2010-02-21T13:09:16Z

On Sun, Feb 21, 2010 at 02:54:01PM +0200, Avi Kivity wrote:
> So, if some other cpu (or the guest itself, with appropriate
> permissions) modifies the msr permission bitmap, svm will not notice
> this? svm loads the bitmap during entry?

Yes.

> I don't think you can tell, unless the host cpu modifying the vmcb is
> synchronized with the guest (or the guest modifies its own vmcb). But
> this is all academic.

Hmm, another thing comes to mind. We would need some redesign of the
nested_svm code to allow userspace to put a vcpu directly into nested
state. With the MSR approach, all userspace does is to write MSRs into
the vcpu before the first run?

Joerg