From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nadav Har'El" Subject: Re: [PATCH 0/30] nVMX: Nested VMX, v9 Date: Mon, 16 May 2011 02:11:40 +0300 Message-ID: <20110515231140.GA17294@fermat.math.technion.ac.il> References: <1304842511-nyh@il.ibm.com> <4DC7CD81.2070305@redhat.com> <20110511082027.GG19019@redhat.com> <20110512154228.GA7943@fermat.math.technion.ac.il> <20110512155727.GA20193@redhat.com> <20110512163115.GA13138@fermat.math.technion.ac.il> <20110512165157.GC20193@redhat.com> <4DCC123B.3080006@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Gleb Natapov , kvm@vger.kernel.org, abelg@il.ibm.com To: Avi Kivity Return-path: Received: from mailgw12.technion.ac.il ([132.68.225.12]:22779 "EHLO mailgw12.technion.ac.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753034Ab1EOXLo (ORCPT ); Sun, 15 May 2011 19:11:44 -0400 Content-Disposition: inline In-Reply-To: <4DCC123B.3080006@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, May 12, 2011, Avi Kivity wrote about "Re: [PATCH 0/30] nVMX: Nested VMX, v9": > Ah, yes. For live migration to work, all vmcb state must be accessible > via vendor-independent accessors once an exit is completely handled. > For example, GPRs are accessible via kvm_register_read(), and without > nesting, interrupt state is stowed in the interrupt queue, but if you > keep IDT_VECTORING_INFO live between exit and entry, you can lose it if > you migrate at this point. Hi, I can quite easily save this state in a different place which is saved - The easiest will just be to use vmcs12, which has place for exactly the fields we want to save (and they are rewritten anyway when we exit to L1). Avi, would you you like me use this sort of solution to avoid the extra state? Of course, considering that anyway, live migration with nested VMX probably still doesn't work for a dozen other reasons :( Or do you consider this not enough, and rather that it is necessary that nested VMX should use exactly the same logic as nested SVM does - namely, use tricks like SVM's "exit_required" instead of our different tricks? Nadav. -- Nadav Har'El | Monday, May 16 2011, 12 Iyyar 5771 nyh@math.technion.ac.il |----------------------------------------- Phone +972-523-790466, ICQ 13349191 |Corduroy pillows - they're making http://nadav.harel.org.il |headlines!