From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ky Srinivasan" Subject: RE: hvm hibernate Date: Wed, 01 Apr 2009 14:43:28 -0600 Message-ID: <49D37D900200003000068687@lucius.provo.novell.com> References: <49D361C50200003000068642@lucius.provo.novell.com> <4FA716B1526C7C4DB0375C6DADBC4EA34172EC1B83@LONPMAILBOX01.citrite.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <4FA716B1526C7C4DB0375C6DADBC4EA34172EC1B83@LONPMAILBOX01.citrite.net> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ian Pratt , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org >>> On 4/1/2009 at 4:01 PM, in message <4FA716B1526C7C4DB0375C6DADBC4EA34172EC1B83@LONPMAILBOX01.citrite.net>, = Ian Pratt wrote:=20 >> With the support of S4 sleep state (hibernate) for HVM guests, we = now >> have a situation where the guest is resuming from hibernate while the >> hypervisor assumes that it is spinning up a new guest VM. And so, if >> the hypervisor maintains any guest specific state that needs to persist >> across a hibernate, there is no way to save and restore this state. I >> am running into this problem on win2k8 guests where the Hyperv shim has >> to maintain guest specific state that needs to persist across a >> hibernate. >> Given that we already support save/restore which is functionally >> equivalent to hibernate, do we need to support S4 sleep state? >=20 > It's needed for Microsoft WHQL logo tests. >=20 > Have you switched over to using the hyperv code in xen-unstable or are = you=20 > using the original Novell code? We have shipped the Novell shim in sles11. This issue came about while = running SVVP (MSFT's virtualization validation suite). If the firmware = supports s4 sleep state then and only then sleep related tests are run. As = I noted in my email, if the hypervisor needs to manage state that persists = across hibernate, you will have a problem. I suspect, the hyperv code in = xen-unstable will run into the same problem - for instance guest_os_id is = written by the guest via an MSR write and that is maintained by the = hypervisor. If this guest were to hibernate and come back, this state will = not be correctly set. Regards, K. Y >=20 > Ian=20 >=20 > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel