Re: [PATCH 0/4 V16] Avoid soft lockup message when KVM is stopped byhost

[Marcelo Tosatti]

Applied, thanks.

On Sat, Mar 10, 2012 at 02:37:24PM -0500, Eric B Munson wrote:
> Changes from V15:
> Add arch/*/include/asm/kvm_para.h that includes the asm-generic version
> 
> Changes from V14:
> Update documentation for the pvclock api
> 
> Changes from V13:
> Expand on KVM_KVMCLOCK_CTRL ioctl documentation
> 
> Changes from V12:
> Re-add missing kvm.c code after rebase
> Rename CAP to KVM_CAP_KVMCLOCK_CTRL
> Rename ioctl to KVM_KVMCLOCK_CTRL
> 
> 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@xxxxxxxxxx
> Cc: hpa@xxxxxxxxx
> Cc: ryanh@xxxxxxxxxxxxxxxxxx
> Cc: aliguori@xxxxxxxxxx
> Cc: mtosatti@xxxxxxxxxx
> Cc: kvm@xxxxxxxxxxxxxxx
> Cc: linux-arch@xxxxxxxxxxxxxxx
> Cc: x86@xxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> 
> 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 KVM_KVMCLOCK_CTRL
>   Add check for suspended vm in softlockup detector
> 
>  Documentation/virtual/kvm/api.txt      |   20 ++++++++++++++++++++
>  Documentation/virtual/kvm/msr.txt      |    4 ++++
>  arch/alpha/include/asm/kvm_para.h      |    1 +
>  arch/arm/include/asm/kvm_para.h        |    1 +
>  arch/avr32/include/asm/kvm_para.h      |    1 +
>  arch/blackfin/include/asm/kvm_para.h   |    1 +
>  arch/c6x/include/asm/kvm_para.h        |    1 +
>  arch/frv/include/asm/kvm_para.h        |    1 +
>  arch/h8300/include/asm/kvm_para.h      |    1 +
>  arch/hexagon/include/asm/kvm_para.h    |    1 +
>  arch/ia64/include/asm/kvm_para.h       |    5 +++++
>  arch/m68k/include/asm/kvm_para.h       |    1 +
>  arch/microblaze/include/asm/kvm_para.h |    1 +
>  arch/mips/include/asm/kvm_para.h       |    1 +
>  arch/mn10300/include/asm/kvm_para.h    |    1 +
>  arch/openrisc/include/asm/kvm_para.h   |    1 +
>  arch/parisc/include/asm/kvm_para.h     |    1 +
>  arch/powerpc/include/asm/kvm_para.h    |    5 +++++
>  arch/s390/include/asm/kvm_para.h       |    5 +++++
>  arch/score/include/asm/kvm_para.h      |    1 +
>  arch/sh/include/asm/kvm_para.h         |    1 +
>  arch/sparc/include/asm/kvm_para.h      |    1 +
>  arch/tile/include/asm/kvm_para.h       |    1 +
>  arch/um/include/asm/kvm_para.h         |    1 +
>  arch/unicore32/include/asm/kvm_para.h  |    1 +
>  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                     |   22 ++++++++++++++++++++++
>  arch/xtensa/include/asm/kvm_para.h     |    1 +
>  include/asm-generic/kvm_para.h         |   14 ++++++++++++++
>  include/linux/kvm.h                    |    3 +++
>  kernel/watchdog.c                      |   12 ++++++++++++
>  33 files changed, 141 insertions(+), 0 deletions(-)
>  create mode 100644 arch/alpha/include/asm/kvm_para.h
>  create mode 100644 arch/arm/include/asm/kvm_para.h
>  create mode 100644 arch/avr32/include/asm/kvm_para.h
>  create mode 100644 arch/blackfin/include/asm/kvm_para.h
>  create mode 100644 arch/c6x/include/asm/kvm_para.h
>  create mode 100644 arch/frv/include/asm/kvm_para.h
>  create mode 100644 arch/h8300/include/asm/kvm_para.h
>  create mode 100644 arch/hexagon/include/asm/kvm_para.h
>  create mode 100644 arch/m68k/include/asm/kvm_para.h
>  create mode 100644 arch/microblaze/include/asm/kvm_para.h
>  create mode 100644 arch/mips/include/asm/kvm_para.h
>  create mode 100644 arch/mn10300/include/asm/kvm_para.h
>  create mode 100644 arch/openrisc/include/asm/kvm_para.h
>  create mode 100644 arch/parisc/include/asm/kvm_para.h
>  create mode 100644 arch/score/include/asm/kvm_para.h
>  create mode 100644 arch/sh/include/asm/kvm_para.h
>  create mode 100644 arch/sparc/include/asm/kvm_para.h
>  create mode 100644 arch/tile/include/asm/kvm_para.h
>  create mode 100644 arch/um/include/asm/kvm_para.h
>  create mode 100644 arch/unicore32/include/asm/kvm_para.h
>  create mode 100644 arch/xtensa/include/asm/kvm_para.h
>  create mode 100644 include/asm-generic/kvm_para.h
> 
> -- 
> 1.7.5.4
> 
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