From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?TWFyY2luIEdpYnXFgmE=?= Subject: Re: [Qemu-devel] [PATCH] kvmclock: Ensure time in migration never goes backward Date: Tue, 06 May 2014 21:54:35 +0200 Message-ID: <53693DFB.3080108@beyond.pl> References: <1399297882-3444-1-git-send-email-agraf@suse.de> <20140505232343.GA20638@amt.cnet> <20140505233120.GA23113@amt.cnet> <53688CC3.7040001@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org To: Alexander Graf , Marcelo Tosatti Return-path: Received: from mx.beyond.pl ([92.43.117.49]:50302 "EHLO mx.beyond.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752886AbaEFTyo (ORCPT ); Tue, 6 May 2014 15:54:44 -0400 In-Reply-To: <53688CC3.7040001@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: > Yes, and it isn't. Any ideas why it's not? This patch really just uses > the guest visible kvmclock time rather than the host view of it on > migration. > > There is definitely something very broken on the host's side since it > does return a smaller time than the guest exposed interface indicates. Don't know if helps but here are example values from time_at_migration and s->clock from your patch. Tested on 5 restores of saved VM that (used to) hang: s->clock time_at_migration 157082235125698 157113284546655 157082235125698 157113298196976 157082235125698 157113284615117 157082235125698 157113284486601 157082235125698 157113284479740 Now, when I compare system time on guest with and without patch: On unpatched qemu vm restores with date: Apr 18 06:56:36 On patched qemu it says: Apr 18 06:57:06 -- mg