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    Subject[PATCH 0/6 V3] Avoid soft lockup message when KVM is stopped by host
    Date
    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 (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/kvm_host.h | 3 ++
    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 | 52 ++++++++++++++++++++++++++++++++++++
    include/asm-generic/kvm_para.h | 14 +++++++++
    include/linux/kvm.h | 4 +++
    include/linux/kvm_host.h | 2 +
    kernel/watchdog.c | 9 ++++++
    9 files changed, 107 insertions(+), 0 deletions(-)
    create mode 100644 include/asm-generic/kvm_para.h

    --
    1.7.5.4



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