From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH 0/5] KVM paravirt_ops implementation Date: Wed, 20 Jun 2007 13:53:05 -0700 Message-ID: <467993B1.6000307@goop.org> References: <4675F462.1010708@codemonkey.ws> <4675F9DE.6080806@goop.org> <4675FDCA.4040006@codemonkey.ws> <4676084F.3090901@goop.org> <46787325.30804@vmware.com> <4679381E.9090404@codemonkey.ws> <46794899.6070708@goop.org> <46798174.2060304@vmware.com> <46798597.4020903@codemonkey.ws> <4679882B.7070605@vmware.com> <46798B16.5090407@goop.org> <46798D9B.5000400@codemonkey.ws> <46799157.3070805@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <46799157.3070805-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Zachary Amsden Cc: kvm-devel , virtualization List-Id: virtualization@lists.linuxfoundation.org Zachary Amsden wrote: > Unless you also migrate the hypercall page itself and impose migration > restrictions on compatible hypercall pages. Seems unreasonable, especially if you support migration between VT and SVM machines. The whole point of a hypercall page is to give you a point of indirection in order to hide these kinds of hardware differences; migrating it would defeat the purpose. > Although I favor the guarantee that execution within the hypercall > page is finished - it is important for protecting against > non-reentrancy as well. Think about interrupts during batching / > queueing operations. Not quite sure that's specifically relevant to migration, but yes, its important to disable interrupts while doing the setup for a batch of stuff unless you want to see some surprises in your queue (and not "Oh, yay, a puppy!" kind of surprises). J ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/