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@xxxxxxxxxxxxxx>
> ---
> 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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