From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] kvm: disable stealtime via reboot notifier to avoid mem corruption Date: Mon, 13 Aug 2012 18:52:31 -0300 Message-ID: <20120813215231.GA19294@amt.cnet> References: <1344594982-8516-1-git-send-email-fw@strlen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, avi@redhat.com, linux-kernel@vger.kernel.org To: Florian Westphal Return-path: Content-Disposition: inline In-Reply-To: <1344594982-8516-1-git-send-email-fw@strlen.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Aug 10, 2012 at 12:36:22PM +0200, Florian Westphal wrote: > else, we get memory corruption on reboot; found when tracking down > initramfs unpack error on initial reboot (with qemu-kvm -smp 2, > no problem with single-core). > > problem with doing it via kvm_shutdown() is that this file > depends on CONFIG_KVM_CLOCK, also its not enough to call it for one > cpu only. > > Signed-off-by: Florian Westphal > --- > not subscribed, please CC on replies. > Also, I don't know much about kvm or kexec, so its possible > that i missed something. > > In any case, this seems to fix the initramfs corruption for me. > patch is against virt/kvm/kvm.git. > > arch/x86/kernel/kvm.c | 1 + > arch/x86/kernel/kvmclock.c | 1 - > 2 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index c1d61ee..1596cc8 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -354,6 +354,7 @@ static void kvm_pv_guest_cpu_reboot(void *unused) > if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) > wrmsrl(MSR_KVM_PV_EOI_EN, 0); > kvm_pv_disable_apf(); > + kvm_disable_steal_time(); > } > > static int kvm_pv_reboot_notify(struct notifier_block *nb, This part below will introduce a bug for shutdown. Can you retest with the addition of kvm_disable_steal_time to kvm_pv_guest_cpu_reboot only, retest and resend please? Thanks > diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c > index f1b42b3..5a2fa7d 100644 > --- a/arch/x86/kernel/kvmclock.c > +++ b/arch/x86/kernel/kvmclock.c > @@ -191,7 +191,6 @@ static void kvm_crash_shutdown(struct pt_regs *regs) > static void kvm_shutdown(void) > { > native_write_msr(msr_kvm_system_time, 0, 0); > - kvm_disable_steal_time(); > native_machine_shutdown(); > } > > -- > 1.7.8.6 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html