Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f23d1f4a authored by Zhang Yanfei's avatar Zhang Yanfei Committed by Gleb Natapov
Browse files

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: default avatarZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent c2193463

arch/x86/include/asm/kexec.h

+2 −0
Original line number Diff line number Diff line
@@ -163,6 +163,8 @@ struct kimage_arch { 
};

#endif



extern void (*crash_vmclear_loaded_vmcss)(void);



#endif /* __ASSEMBLY__ */



#endif /* _ASM_X86_KEXEC_H */

arch/x86/kernel/crash.c

+32 −0
Original line number Diff line number Diff line
@@ -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.