linux-kernel - [PATCH 2/2] x86/reboot: emergency callbacks are now registered by common KVM code

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Message-ID: <20241003230806.229001-3-pbonzini@redhat.com>
Date: Thu,  3 Oct 2024 19:08:06 -0400
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: seanjc@...gle.com,
	torvalds@...ux-foundation.org
Subject: [PATCH 2/2] x86/reboot: emergency callbacks are now registered by common KVM code

Guard them with CONFIG_KVM_X86_COMMON rather than the two vendor modules.
In practice this has no functional change, because CONFIG_KVM_X86_COMMON
is set if and only if at least one vendor-specific module is being built.
However, it is cleaner to specify CONFIG_KVM_X86_COMMON for functions that
are used in kvm.ko.

Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
Fixes: 590b09b1d88e ("KVM: x86: Register "emergency disable" callbacks when virt is enabled")
Fixes: 6d55a94222db ("x86/reboot: Unconditionally define cpu_emergency_virt_cb typedef")
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/include/asm/reboot.h | 4 ++--
 arch/x86/kernel/reboot.c      | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/reboot.h b/arch/x86/include/asm/reboot.h
index d0ef2a678d66..7ec4c4d12277 100644
--- a/arch/x86/include/asm/reboot.h
+++ b/arch/x86/include/asm/reboot.h
@@ -26,13 +26,13 @@ void __noreturn machine_real_restart(unsigned int type);
 #define MRR_APM		1
 
 typedef void (cpu_emergency_virt_cb)(void);
-#if IS_ENABLED(CONFIG_KVM_INTEL) || IS_ENABLED(CONFIG_KVM_AMD)
+#if IS_ENABLED(CONFIG_KVM_X86_COMMON)
 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 */
+#endif /* CONFIG_KVM_X86_COMMON */
 
 typedef void (*nmi_shootdown_cb)(int, struct pt_regs*);
 void nmi_shootdown_cpus(nmi_shootdown_cb callback);
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 0e0a4cf6b5eb..0e3f9479ccc8 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -530,7 +530,7 @@ 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)
+#if IS_ENABLED(CONFIG_KVM_X86_COMMON)
 /* RCU-protected callback to disable virtualization prior to reboot. */
 static cpu_emergency_virt_cb __rcu *cpu_emergency_virt_callback;
 
@@ -600,7 +600,7 @@ static void emergency_reboot_disable_virtualization(void)
 }
 #else
 static void emergency_reboot_disable_virtualization(void) { }
-#endif /* CONFIG_KVM_INTEL || CONFIG_KVM_AMD */
+#endif /* CONFIG_KVM_X86_COMMON */
 
 void __attribute__((weak)) mach_reboot_fixups(void)
 {
-- 
2.43.5