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x86/kexec: VMCLEAR VMCSs loaded on all cpus if necessary 

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: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Zhang Yanfei 2012-12-06 23:40:47 +08:00 committed by Gleb Natapov
parent c219346325
commit f23d1f4a11
2 changed files with 34 additions and 0 deletions
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2
arch/x86/include/asm/kexec.h
View File

@ -163,6 +163,8 @@ struct kimage_arch {
};
#endif
extern void (*crash_vmclear_loaded_vmcss)(void);
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_KEXEC_H */

32
arch/x86/kernel/crash.c
View File

@ -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 +31,27 @@
int in_crash_kexec;
/*
* This is used to VMCLEAR all VMCSs loaded on the
* processor. And when loading kvm_intel module, the
* callback function pointer will be assigned.
*
* protected by rcu.
*/
void (*crash_vmclear_loaded_vmcss)(void) = NULL;
EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
static inline void cpu_crash_vmclear_loaded_vmcss(void)
{
void (*do_vmclear_operation)(void) = NULL;
rcu_read_lock();
do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
if (do_vmclear_operation)
do_vmclear_operation();
rcu_read_unlock();
}
#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
@ -46,6 +68,11 @@ 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_crash_vmclear_loaded_vmcss();
/* Disable VMX or SVM if needed.
*
* We need to disable virtualization on all CPUs.
@ -88,6 +115,11 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
kdump_nmi_shootdown_cpus();
/*
* VMCLEAR VMCSs loaded on this cpu if needed.
*/
cpu_crash_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.