Re: [PATCH v11 0/2] x86: vmclear vmcss on all cpus when doing kdump if necessary

Gleb Natapov
2012-12-06T16:28:43Z

On Thu, Dec 06, 2012 at 11:36:48PM +0800, Zhang Yanfei wrote:
> 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.
>
Applied to queue. Thanks.

> Changelog from v10 to v11:
> 1. regenerate the patch set against current queue branch in
> git://git.kernel.org/pub/scm/virt/kvm/kvm.git
>
> Changelog from v9 to v10:
> 1. add rcu protect to the callback function
>
> Changelog from v8 to v9:
> 1. KEXEC: use a callback function instead of a notifier.
> 2. KVM-INTEL: use a new vmclear function instead of just calling
> vmclear_local_loaded_vmcss to make sure we just do the core vmclear
> operation in kdump.
>
> 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: VMCLEAR VMCSs loaded on all cpus if necessary
> KVM-INTEL: provide the vmclear function and a bitmap to support
> VMCLEAR in kdump
>
> arch/x86/include/asm/kexec.h | 2 +
> arch/x86/kernel/crash.c | 32 ++++++++++++++++++++
> arch/x86/kvm/vmx.c | 67 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 101 insertions(+), 0 deletions(-)

--
Gleb.