diff mbox

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

Message ID 5080E8BF.3020506@cn.fujitsu.com (mailing list archive)
State New, archived
Headers show

Commit Message

Yanfei Zhang Oct. 19, 2012, 5:44 a.m. UTC
This patch 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.

Signed-off-by: zhangyanfei <zhangyanfei@cn.fujitsu.com>
---
 arch/x86/include/asm/kexec.h |    2 ++
 arch/x86/kernel/crash.c      |   27 +++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 0 deletions(-)

Comments

Marcelo Tosatti Oct. 31, 2012, 12:18 a.m. UTC | #1
On Fri, Oct 19, 2012 at 01:44:31PM +0800, Zhang Yanfei wrote:
> This patch 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.
> 
> Signed-off-by: zhangyanfei <zhangyanfei@cn.fujitsu.com>
> ---
>  arch/x86/include/asm/kexec.h |    2 ++
>  arch/x86/kernel/crash.c      |   27 +++++++++++++++++++++++++++
>  2 files changed, 29 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 317ff17..fc05440 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -163,6 +163,8 @@ struct kimage_arch {
>  };
>  #endif
>  
> +extern void (*crash_clear_loaded_vmcss)(void);
> +
>  #endif /* __ASSEMBLY__ */
>  
>  #endif /* _ASM_X86_KEXEC_H */
> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
> index 13ad899..7289976 100644
> --- a/arch/x86/kernel/crash.c
> +++ b/arch/x86/kernel/crash.c
> @@ -16,6 +16,7 @@
>  #include <linux/delay.h>
>  #include <linux/elf.h>
>  #include <linux/elfcore.h>
> +#include <linux/module.h>
>  
>  #include <asm/processor.h>
>  #include <asm/hardirq.h>
> @@ -30,6 +31,22 @@
>  
>  int in_crash_kexec;
>  
> +/*
> + * This is used to VMCLEAR vmcss loaded on all
> + * cpus. And when loading kvm_intel module, the
> + * function pointer will be made valid.
> + */
> +void (*crash_clear_loaded_vmcss)(void) = NULL;
> +EXPORT_SYMBOL_GPL(crash_clear_loaded_vmcss);
> +
> +static void cpu_emergency_clear_loaded_vmcss(void)
> +{
> +	if (crash_clear_loaded_vmcss &&
> +	    cpu_has_vmx() && cpu_vmx_enabled()) {
> +		crash_clear_loaded_vmcss();
> +	}
> +}
> +

Are all this checks necessary? 

if (crash_clear_loaded_vmcss)
	crash_clear_loaded_vmcss();

Should be enough ? (callback only set if kvm-vmx module loaded).

>  #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
>  
>  static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
> @@ -46,6 +63,11 @@ 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_clear_loaded_vmcss();
> +
>  	/* Disable VMX or SVM if needed.
>  	 *
>  	 * We need to disable virtualization on all CPUs.
> @@ -88,6 +110,11 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
>  
>  	kdump_nmi_shootdown_cpus();
>  
> +	/*
> +	 * VMCLEAR vmcss loaded on this cpu if needed.
> +	 */
> +	cpu_emergency_clear_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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Yanfei Zhang Oct. 31, 2012, 1:52 a.m. UTC | #2
? 2012?10?31? 08:18, Marcelo Tosatti ??:
> On Fri, Oct 19, 2012 at 01:44:31PM +0800, Zhang Yanfei wrote:
>> This patch 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.
>>
>> Signed-off-by: zhangyanfei <zhangyanfei@cn.fujitsu.com>
>> ---
>>  arch/x86/include/asm/kexec.h |    2 ++
>>  arch/x86/kernel/crash.c      |   27 +++++++++++++++++++++++++++
>>  2 files changed, 29 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 317ff17..fc05440 100644
>> --- a/arch/x86/include/asm/kexec.h
>> +++ b/arch/x86/include/asm/kexec.h
>> @@ -163,6 +163,8 @@ struct kimage_arch {
>>  };
>>  #endif
>>  
>> +extern void (*crash_clear_loaded_vmcss)(void);
>> +
>>  #endif /* __ASSEMBLY__ */
>>  
>>  #endif /* _ASM_X86_KEXEC_H */
>> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
>> index 13ad899..7289976 100644
>> --- a/arch/x86/kernel/crash.c
>> +++ b/arch/x86/kernel/crash.c
>> @@ -16,6 +16,7 @@
>>  #include <linux/delay.h>
>>  #include <linux/elf.h>
>>  #include <linux/elfcore.h>
>> +#include <linux/module.h>
>>  
>>  #include <asm/processor.h>
>>  #include <asm/hardirq.h>
>> @@ -30,6 +31,22 @@
>>  
>>  int in_crash_kexec;
>>  
>> +/*
>> + * This is used to VMCLEAR vmcss loaded on all
>> + * cpus. And when loading kvm_intel module, the
>> + * function pointer will be made valid.
>> + */
>> +void (*crash_clear_loaded_vmcss)(void) = NULL;
>> +EXPORT_SYMBOL_GPL(crash_clear_loaded_vmcss);
>> +
>> +static void cpu_emergency_clear_loaded_vmcss(void)
>> +{
>> +	if (crash_clear_loaded_vmcss &&
>> +	    cpu_has_vmx() && cpu_vmx_enabled()) {
>> +		crash_clear_loaded_vmcss();
>> +	}
>> +}
>> +
> 
> Are all this checks necessary? 
> 
> if (crash_clear_loaded_vmcss)
> 	crash_clear_loaded_vmcss();
> 
> Should be enough ? (callback only set if kvm-vmx module loaded).

Hmm, it is enough. Thanks.

> 
>>  #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
>>  
>>  static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
>> @@ -46,6 +63,11 @@ 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_clear_loaded_vmcss();
>> +
>>  	/* Disable VMX or SVM if needed.
>>  	 *
>>  	 * We need to disable virtualization on all CPUs.
>> @@ -88,6 +110,11 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
>>  
>>  	kdump_nmi_shootdown_cpus();
>>  
>> +	/*
>> +	 * VMCLEAR vmcss loaded on this cpu if needed.
>> +	 */
>> +	cpu_emergency_clear_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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diff mbox

Patch

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 317ff17..fc05440 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -163,6 +163,8 @@  struct kimage_arch {
 };
 #endif
 
+extern void (*crash_clear_loaded_vmcss)(void);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 13ad899..7289976 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -16,6 +16,7 @@ 
 #include <linux/delay.h>
 #include <linux/elf.h>
 #include <linux/elfcore.h>
+#include <linux/module.h>
 
 #include <asm/processor.h>
 #include <asm/hardirq.h>
@@ -30,6 +31,22 @@ 
 
 int in_crash_kexec;
 
+/*
+ * This is used to VMCLEAR vmcss loaded on all
+ * cpus. And when loading kvm_intel module, the
+ * function pointer will be made valid.
+ */
+void (*crash_clear_loaded_vmcss)(void) = NULL;
+EXPORT_SYMBOL_GPL(crash_clear_loaded_vmcss);
+
+static void cpu_emergency_clear_loaded_vmcss(void)
+{
+	if (crash_clear_loaded_vmcss &&
+	    cpu_has_vmx() && cpu_vmx_enabled()) {
+		crash_clear_loaded_vmcss();
+	}
+}
+
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 
 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
@@ -46,6 +63,11 @@  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_clear_loaded_vmcss();
+
 	/* Disable VMX or SVM if needed.
 	 *
 	 * We need to disable virtualization on all CPUs.
@@ -88,6 +110,11 @@  void native_machine_crash_shutdown(struct pt_regs *regs)
 
 	kdump_nmi_shootdown_cpus();
 
+	/*
+	 * VMCLEAR vmcss loaded on this cpu if needed.
+	 */
+	cpu_emergency_clear_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.