From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] KVM: x86: fix kvmclock breakage from timers branch merge Date: Thu, 04 Sep 2014 21:42:44 +0200 Message-ID: <5408C0B4.5040207@redhat.com> References: <1409835487-14371-1-git-send-email-pbonzini@redhat.com> <54088CB5.6050406@canonical.com> <54089DDE.6010004@redhat.com> <5408AC76.6030404@canonical.com> <5408BA6D.1070602@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: kvm@vger.kernel.org, Thomas Gleixner , John Stultz To: Chris J Arges , linux-kernel@vger.kernel.org Return-path: In-Reply-To: <5408BA6D.1070602@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Il 04/09/2014 21:15, Paolo Bonzini ha scritto: > Il 04/09/2014 20:16, Chris J Arges ha scritto: >>> + boot_ns = timespec_to_ns(&tk->total_sleep_time) >>> + + tk->wall_to_monotonic.tv_sec * (u64)NSEC_PER_SEC >>> + + tk->wall_to_monotonic.tv_nsec >>> + + tk->xtime_sec * (u64)NSEC_PER_SEC; > > So this means that the above 3.16-based code is not the same as > > boot_ns = ktime_to_ns(ktime_add(tk->tkr.base_mono, tk->offs_boot)); > > in 3.17. Everything else in the patch you tested is the same as the > code that is in 3.17, so that's a start. > > Paolo > Based on commit 02cba1598a2a3b689e79ad6dad2532521f638271 we have: offs_real - offs_boot = wall_to_monotonic + total_sleep_time The patch I posted this morning separates tk->xtime_sec out of boot_ns, so all that is missing should be a change in boot_ns from base_mono + offs_boot to offs_real - offs_boot. Chris, can you try this patch on top of the previous one: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 92493e10937c..811eecc43fe8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1031,7 +1031,7 @@ static void update_pvclock_gtod(struct timekeeper *tk) struct pvclock_gtod_data *vdata = &pvclock_gtod_data; u64 boot_ns; - boot_ns = ktime_to_ns(ktime_add(tk->tkr.base_mono, tk->offs_boot)); + boot_ns = ktime_to_ns(ktime_sub(tk->offs_real, tk->offs_boot)); write_seqcount_begin(&vdata->seq); If it doesn't work, then commit 02cba1598a2a3b689e79ad6dad2532521f638271 is also broken. Paolo