Re: [PATCH v4 0/2] x86: clear vmcss on all cpus when doing kdumpif necessary

[zhangyanfei]

Hello Marcelo,

Any thoughts?


ä 2012å11æ14æ 17:29, zhangyanfei åé:
> 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 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: VMCLEAR vmcss on all cpus if necessary
>   KVM: set/unset crash_clear_loaded_vmcss and vmclear_skipped in
>     kvm_intel module
> 
>  arch/x86/include/asm/kexec.h |    3 +++ 
>  arch/x86/kernel/crash.c      |   32 ++++++++++++++++++++++++++++++++
>  arch/x86/kvm/vmx.c           |   32 ++++++++++++++++++++++++++++++++
>  3 files changed, 67 insertions(+), 0 deletions(-)
> 
> 
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