From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric B Munson Subject: [PATCH 0/5 V4] Avoid soft lockup message when KVM is stopped by host Date: Tue, 29 Nov 2011 16:35:34 -0500 Message-ID: <1322602539-27004-1-git-send-email-emunson@mgebm.net> Return-path: Received: from oz.csail.mit.edu ([128.30.30.239]:41183 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756501Ab1K2Vft (ORCPT ); Tue, 29 Nov 2011 16:35:49 -0500 Sender: linux-arch-owner@vger.kernel.org List-ID: To: avi@redhat.com Cc: Eric B Munson , mingo@redhat.com, hpa@zytor.com, arnd@arndb.de, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, mtosatti@redhat.com, jeremy.fitzhardinge@citrix.com, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org 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: arnd@arndb.de Cc: ryanh@linux.vnet.ibm.com Cc: aliguori@us.ibm.com Cc: mtosatti@redhat.com Cc: jeremy.fitzhardinge@citrix.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Eric B Munson (5): 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 arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/include/asm/kvm_para.h | 1 + arch/x86/include/asm/pvclock-abi.h | 1 + arch/x86/kernel/kvmclock.c | 21 +++++++++++++++++++++ arch/x86/kvm/x86.c | 20 ++++++++++++++++++++ include/asm-generic/kvm_para.h | 14 ++++++++++++++ include/linux/kvm.h | 2 ++ kernel/watchdog.c | 12 ++++++++++++ 8 files changed, 73 insertions(+), 0 deletions(-) create mode 100644 include/asm-generic/kvm_para.h -- 1.7.5.4