From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric B Munson Subject: [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Date: Tue, 7 Feb 2012 16:28:16 -0500 Message-ID: <1328650100-19521-1-git-send-email-emunson@mgebm.net> Return-path: Sender: linux-kernel-owner@vger.kernel.org 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, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org List-Id: linux-arch.vger.kernel.org Changes from V11: Re-add asm-generic stub Correct api.txt typo add kvm_make_request() call after setting PVCLOCK_GUEST_STOPPED Changes from V10: Return ioctl to per vcpu instead of per vm Changes from V9: Use kvm_for_each_vcpu to iterate online vcpu's 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: 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 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 +++++++++++++++++++++ include/asm-generic/kvm_para.h | 14 ++++++++++++++ include/linux/kvm.h | 3 +++ kernel/watchdog.c | 12 ++++++++++++ 9 files changed, 74 insertions(+), 0 deletions(-) create mode 100644 include/asm-generic/kvm_para.h -- 1.7.5.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from oz.csail.mit.edu ([128.30.30.239]:53269 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756913Ab2BGV2Z (ORCPT ); Tue, 7 Feb 2012 16:28:25 -0500 From: Eric B Munson Subject: [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Date: Tue, 7 Feb 2012 16:28:16 -0500 Message-ID: <1328650100-19521-1-git-send-email-emunson@mgebm.net> Sender: linux-arch-owner@vger.kernel.org List-ID: 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, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Message-ID: <20120207212816.xnUvMkVq2889mmJG92dDmog0b4G2KASxgM7fn_OmqeI@z> Changes from V11: Re-add asm-generic stub Correct api.txt typo add kvm_make_request() call after setting PVCLOCK_GUEST_STOPPED Changes from V10: Return ioctl to per vcpu instead of per vm Changes from V9: Use kvm_for_each_vcpu to iterate online vcpu's 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: 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 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 +++++++++++++++++++++ include/asm-generic/kvm_para.h | 14 ++++++++++++++ include/linux/kvm.h | 3 +++ kernel/watchdog.c | 12 ++++++++++++ 9 files changed, 74 insertions(+), 0 deletions(-) create mode 100644 include/asm-generic/kvm_para.h -- 1.7.5.4