From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH v2 3/3] x86/viridian: Add partition time reference counter MSR support Date: Mon, 04 Aug 2014 16:15:57 +0100 Message-ID: <53DFBFCD020000780002920D@mail.emea.novell.com> References: <1407157961-7239-1-git-send-email-paul.durrant@citrix.com> <1407157961-7239-4-git-send-email-paul.durrant@citrix.com> <53DFAE4802000078000290F1@mail.emea.novell.com> <9AAE0902D5BC7E449B7C8E4E778ABCD03FFAEF@AMSPEX01CL01.citrite.net> <9AAE0902D5BC7E449B7C8E4E778ABCD03FFBF5@AMSPEX01CL01.citrite.net> <9AAE0902D5BC7E449B7C8E4E778ABCD03FFC91@AMSPEX01CL01.citrite.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9AAE0902D5BC7E449B7C8E4E778ABCD03FFC91@AMSPEX01CL01.citrite.net> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Paul Durrant Cc: Ian Jackson , "Keir (Xen.org)" , Stefano Stabellini , Ian Campbell , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org >>> On 04.08.14 at 17:11, wrote: >> From: Paul Durrant >> I think that hvm_get_guest_time() should have the right semantics after all, >> in that it appears to be ns since a vcpu was onlined and is preserved across >> save/restore. > > Actually, I'm no longer convinced about that second part. It looks like only > TSC is preserved across save/restore. Indeed the saving/restoring would need to be written, similar to what is done for the other virtual time sources. And just like for those other system wide time sources, you'd have to pick a reference vCPU. Jan