From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russ Blaine Subject: Re: shutdown question - PV vs HVM Date: Wed, 03 Sep 2008 11:01:30 -0700 Message-ID: <48BED0FA.5070409@sun.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: James Harper , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Have a question on this old thread: Keir Fraser wrote: > For a PV guest, a shutdown node is written into xenstore which the guest > picks up. The guest will then usually initiate a clean shutdown. > > The same happens for an HVM guest with PV drivers installed. If an HVM guest > has no PV drivers (And so will obviously not be watching xenstore) then xend > notifies the shutdown immediately to Xen. This causes Xen to immediately > transition the guest to shutdown state, and no longer execute the guest, > with no chance for clean shutdown. If there are no PV drivers installed, > clean shutdown needs to be initiated from within the guest. Why are HVM domains treated differently for shutdown? Guest OSes already know how to do a clean ACPI-initiated shutdown, so why not use that for shutdown in the presence of PV drivers? The current method requires extra complexity in PV drivers. I imagine that it either fell out of porting PV drivers from PV domains to HVM domains or is just paranoia about losing data during ACPI shutdown. - R > > -- Keir > > On 1/10/07 02:13, "James Harper" wrote: > >> I've had a bit of a look through the code but can't seem to find the >> answer to this question... what is the method by which 'xm' tells a >> domain to shutdown? >> >> What is different about HVM that means it just powers straight off? >> >> Looking at the Linux source, it appears that something is done with >> 'platform-feature-multiprocessor-suspend' in the store, but it isn't >> clear to me what... >> >> Thanks >> >> James >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xensource.com >> http://lists.xensource.com/xen-devel > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel -- ----------------------------------------------------- Russ Blaine | Solaris Kernel | russell.blaine@sun.com