From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753913Ab2AQSEy (ORCPT ); Tue, 17 Jan 2012 13:04:54 -0500 Received: from oz.csail.mit.edu ([128.30.30.239]:34388 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752393Ab2AQSEw (ORCPT ); Tue, 17 Jan 2012 13:04:52 -0500 From: Eric B Munson To: avi@redhat.com Cc: Eric B Munson , mingo@redhat.com, hpa@zytor.com, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, mtosatti@redhat.com, jeremy.fitzhardinge@citrix.com, levinsasha928@gmail.com, Jan Kiszka , kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/4 V9] Avoid soft lockup message when KVM is stopped by host Date: Tue, 17 Jan 2012 13:04:44 -0500 Message-Id: <1326823488-11413-1-git-send-email-emunson@mgebm.net> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changes from V8: Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu Changes from V7: Define KVM_CAP_GUEST_PAUSED and support check Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED Changes from V6: Use __this_cpu_and when clearing the PVCLOCK_GUEST_STOPPED flag Changes from V5: Collapse generic check_and_clear_guest_stopped into patch 2 Include check_and_clear_guest_stopped defintion to ia64, s390, and powerpc Change check_and_clear_guest_stopped to use __get_cpu_var instead of taking the cpuid arg. Protect check_and_clear_guest_stopped declaration with CONFIG_KVM_CLOCK check Changes from V4: Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED Add description of KVMCLOCK_GUEST_PAUSED ioctl to api.txt Changes from V3: Include CC's on patch 3 Drop clear flag ioctl and have the watchdog clear the flag when it is reset Changes from V2: A new kvm functions defined in kvm_para.h, the only change to pvclock is the initial flag definition Changes from V1: (Thanks Marcelo) Host code has all been moved to arch/x86/kvm/x86.c KVM_PAUSE_GUEST was renamed to KVM_GUEST_PAUSED 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. Cc: mingo@redhat.com Cc: hpa@zytor.com Cc: ryanh@linux.vnet.ibm.com Cc: aliguori@us.ibm.com Cc: mtosatti@redhat.com Cc: jeremy.fitzhardinge@citrix.com Cc: levinsasha928@gmail.com Cc: Jan Kiszka Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Eric B Munson (4): 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 KVMCLOCK_GUEST_STOPPED Add check for suspended vm in softlockup detector Documentation/virtual/kvm/api.txt | 13 +++++++++++++ arch/ia64/include/asm/kvm_para.h | 5 +++++ arch/powerpc/include/asm/kvm_para.h | 5 +++++ arch/s390/include/asm/kvm_para.h | 5 +++++ arch/x86/include/asm/kvm_para.h | 8 ++++++++ arch/x86/include/asm/pvclock-abi.h | 1 + arch/x86/kernel/kvmclock.c | 21 +++++++++++++++++++++ arch/x86/kvm/x86.c | 26 ++++++++++++++++++++++++++ include/asm-generic/kvm_para.h | 14 ++++++++++++++ include/linux/kvm.h | 3 +++ kernel/watchdog.c | 12 ++++++++++++ 11 files changed, 113 insertions(+), 0 deletions(-) create mode 100644 include/asm-generic/kvm_para.h -- 1.7.5.4