Re: [PATCH v5 1/2] x86/kexec: VMCLEAR vmcss on all cpus if necessary

[Zhang Yanfei <zhangyanfei@cn.fujitsu.com>]

于 2012年11月21日 18:33, Gleb Natapov 写道:
> On Wed, Nov 21, 2012 at 10:23:12AM +0800, Zhang Yanfei wrote:
>> This patch adds an atomic notifier list named crash_notifier_list.
>> When loading kvm-intel module, a notifier will be registered in
>> the list to enable vmcss loaded on all cpus to be VMCLEAR'd if
>> needed.
>>
>> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
>> ---
>>  arch/x86/include/asm/kexec.h |    2 ++
>>  arch/x86/kernel/crash.c      |   25 +++++++++++++++++++++++++
>>  2 files changed, 27 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 317ff17..5e22b00 100644
>> --- a/arch/x86/include/asm/kexec.h
>> +++ b/arch/x86/include/asm/kexec.h
>> @@ -163,6 +163,8 @@ struct kimage_arch {
>>  };
>>  #endif
>>  
>> +extern struct atomic_notifier_head crash_notifier_list;
>> +
>>  #endif /* __ASSEMBLY__ */
>>  
>>  #endif /* _ASM_X86_KEXEC_H */
>> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
>> index 13ad899..0f3d5b4 100644
>> --- a/arch/x86/kernel/crash.c
>> +++ b/arch/x86/kernel/crash.c
>> @@ -16,6 +16,8 @@
>>  #include <linux/delay.h>
>>  #include <linux/elf.h>
>>  #include <linux/elfcore.h>
>> +#include <linux/module.h>
>> +#include <linux/notifier.h>
>>  
>>  #include <asm/processor.h>
>>  #include <asm/hardirq.h>
>> @@ -30,6 +32,19 @@
>>  
>>  int in_crash_kexec;
>>  
>> +/*
>> + * The list is used to VMCLEAR vmcss loaded on all
>> + * cpus. And when loading kvm_intel module, the
>> + * vmclear function will be registered in the list.
>> + */
>> +ATOMIC_NOTIFIER_HEAD(crash_notifier_list);
>> +EXPORT_SYMBOL_GPL(crash_notifier_list);
>> +
>> +static inline void cpu_emergency_vmclear_loaded_vmcss(void)
>> +{
>> +	atomic_notifier_call_chain(&crash_notifier_list, 0, NULL);
>> +}
>> +
> The notifier list is not VMX specific. It may be used for other
> purposes, so please use better name or just open code it.

OK, thanks. crash_notifier_list --> vmclear_notifier_list?
the new v6 version has been sent, any comments are welcome.

> 
> ACKs from kexec side are needed.
> 
>>  #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
>>  
>>  static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
>> @@ -46,6 +61,11 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
>>  #endif
>>  	crash_save_cpu(regs, cpu);
>>  
>> +	/*
>> +	 * VMCLEAR vmcss loaded on all cpus if needed.
>> +	 */
>> +	cpu_emergency_vmclear_loaded_vmcss();
>> +
>>  	/* Disable VMX or SVM if needed.
>>  	 *
>>  	 * We need to disable virtualization on all CPUs.
>> @@ -88,6 +108,11 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
>>  
>>  	kdump_nmi_shootdown_cpus();
>>  
>> +	/*
>> +	 * VMCLEAR vmcss loaded on this cpu if needed.
>> +	 */
>> +	cpu_emergency_vmclear_loaded_vmcss();
>> +
>>  	/* Booting kdump kernel with VMX or SVM enabled won't work,
>>  	 * because (among other limitations) we can't disable paging
>>  	 * with the virt flags.
>> -- 
>> 1.7.1
>>
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> 
> --
> 			Gleb.
> 


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