From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric B Munson Subject: [PATCH 0/6] Avoid soft lockup message when KVM is stopped by host Date: Tue, 25 Oct 2011 15:26:13 -0400 Message-ID: <1319570779-8907-1-git-send-email-emunson@mgebm.net> Return-path: Received: from oz.csail.mit.edu ([128.30.30.239]:57209 "EHLO ozymandias.localdomain" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751019Ab1JYT0W (ORCPT ); Tue, 25 Oct 2011 15:26:22 -0400 Sender: linux-arch-owner@vger.kernel.org List-ID: To: avi@redhat.com Cc: mingo@redhat.com, x86@kernel.org, hpa@zytor.com, mtosatti@redhat.com, arnd@arndb.de, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-arch@vger.kernel.org, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, Eric B Munson When a guest kernel is stopped by the host hypervisor it can look like a soft lockup to the guest kernel. This false warning can mask later soft lockup warnings which may be real. This patch series adds a method for a host hypervisor to communicate to a guest kernel that it is being stopped. The final patch in the series has the watchdog check this flag when it goes to issue a soft lockup warning and skip the warning if the guest knows it was stopped. It was attempted to solve this in Qemu, but the side effects of saving and restoring the clock and tsc for each vcpu put the wall clock of the guest behind by the amount of time of the pause. This forces a guest to have ntp running in order to keep the wall clock accurate. Eric B Munson (6): Add flag to indicate that a vm was stopped by the host Add functions to check if the host has stopped the vm Add ioctl for KVM_GUEST_STOPPED Add generic stubs for kvm stop check functions Add check for suspended vm in softlockup detector Add age out of guest paused flag arch/x86/include/asm/pvclock-abi.h | 1 + arch/x86/include/asm/pvclock.h | 7 ++++ arch/x86/kernel/kvmclock.c | 55 ++++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 14 +++++++++ include/asm-generic/pvclock.h | 19 ++++++++++++ include/linux/kvm.h | 4 ++ include/linux/kvm_host.h | 2 + kernel/watchdog.c | 9 ++++++ 8 files changed, 111 insertions(+), 0 deletions(-) create mode 100644 include/asm-generic/pvclock.h -- 1.7.5.4