Re: [PATCH v8 0/2] x86: vmclear vmcss on all cpus when doing kdump if necessary

Zhang Yanfei
2012-11-26T01:57:36Z

Hello Eric

Would you help review the patch, and give some comments, please ?

Thanks
Zhang

于 2012年11月22日 16:22, Zhang Yanfei 写道:
> Currently, kdump just makes all the logical processors leave VMX operation by
> executing VMXOFF instruction, so any VMCSs active on the logical processors may
> be corrupted. But, sometimes, we need the VMCSs to debug guest images contained
> in the host vmcore. To prevent the corruption, we should VMCLEAR the VMCSs before
> executing the VMXOFF instruction.
>
> The patch set provides a way to VMCLEAR vmcss related to guests on all cpus before
> executing the VMXOFF when doing kdump. This is used to ensure the VMCSs in the
> vmcore updated and non-corrupted.
>
> Changelog from v7 to v8:
> 1. KEXEC: regression for using name crash_notifier_list
> and remove comments related to KVM
> and just call function atomic_notifier_call_chain directly.
>
> Changelog from v6 to v7:
> 1. KVM-INTEL: in hardware_disable, we needn't disable the
> vmclear, so remove it.
>
> Changelog from v5 to v6:
> 1. KEXEC: the atomic notifier list renamed:
> crash_notifier_list --> vmclear_notifier_list
> 2. KVM-INTEL: provide empty functions if CONFIG_KEXEC is
> not defined and remove unnecessary #ifdef's.
>
> Changelog from v4 to v5:
> 1. use an atomic notifier instead of function call, so
> have all the vmclear codes in vmx.c.
>
> Changelog from v3 to v4:
> 1. add a new percpu variable vmclear_skipped to skip
> vmclear in kdump in some conditions.
>
> Changelog from v2 to v3:
> 1. remove unnecessary conditions in function
> cpu_emergency_clear_loaded_vmcss as Marcelo suggested.
>
> Changelog from v1 to v2:
> 1. remove the sysctl and clear VMCSs unconditionally.
>
> Zhang Yanfei (2):
> x86/kexec: add a new atomic notifier list for kdump
> KVM-INTEL: add a notifier and a bitmap to support VMCLEAR in kdump
>
> arch/x86/include/asm/kexec.h | 2 +
> arch/x86/kernel/crash.c | 9 +++++
> arch/x86/kvm/vmx.c | 70 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 81 insertions(+), 0 deletions(-)