Commit 261cd5ed authored by Sean Christopherson's avatar Sean Christopherson
Browse files

x86/reboot: Expose VMCS crash hooks if and only if KVM_{INTEL,AMD} is enabled 



Expose the crash/reboot hooks used by KVM to disable virtualization in
hardware and unblock INIT only if there's a potential in-tree user,
i.e. either KVM_INTEL or KVM_AMD is enabled.

Reviewed-by: default avatarKai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-9-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 59765db5

arch/x86/include/asm/reboot.h

+4 −0
Original line number Diff line number Diff line
@@ -25,10 +25,14 @@ void __noreturn machine_real_restart(unsigned int type); 
#define MRR_BIOS	0

#define MRR_APM		1



#if IS_ENABLED(CONFIG_KVM_INTEL) || IS_ENABLED(CONFIG_KVM_AMD)

typedef void (cpu_emergency_virt_cb)(void);

void cpu_emergency_register_virt_callback(cpu_emergency_virt_cb *callback);

void cpu_emergency_unregister_virt_callback(cpu_emergency_virt_cb *callback);

void cpu_emergency_disable_virtualization(void);

#else

static inline void cpu_emergency_disable_virtualization(void) {}

#endif /* CONFIG_KVM_INTEL || CONFIG_KVM_AMD */



typedef void (*nmi_shootdown_cb)(int, struct pt_regs*);

void nmi_shootdown_cpus(nmi_shootdown_cb callback);

arch/x86/kernel/reboot.c

+4 −1
Original line number Diff line number Diff line
@@ -529,6 +529,7 @@ static inline void kb_wait(void) 


static inline void nmi_shootdown_cpus_on_restart(void);



#if IS_ENABLED(CONFIG_KVM_INTEL) || IS_ENABLED(CONFIG_KVM_AMD)

/* RCU-protected callback to disable virtualization prior to reboot. */

static cpu_emergency_virt_cb __rcu *cpu_emergency_virt_callback;
@@ -596,7 +597,9 @@ static void emergency_reboot_disable_virtualization(void) 
		nmi_shootdown_cpus_on_restart();

	}

}



#else

static void emergency_reboot_disable_virtualization(void) { }

#endif /* CONFIG_KVM_INTEL || CONFIG_KVM_AMD */



void __attribute__((weak)) mach_reboot_fixups(void)

{