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    Subject[PATCH 0/4 V7] Avoid soft lockup message when KVM is stopped by host
    Date
    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: arnd@arndb.de
    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 <jan.kiszka@siemens.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

    Documentation/virtual/kvm/api.txt | 12 ++++++++++++
    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_host.h | 2 ++
    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 | 20 ++++++++++++++++++++
    include/asm-generic/kvm_para.h | 14 ++++++++++++++
    include/linux/kvm.h | 2 ++
    kernel/watchdog.c | 12 ++++++++++++
    12 files changed, 107 insertions(+), 0 deletions(-)
    create mode 100644 include/asm-generic/kvm_para.h

    --
    1.7.5.4



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