linux-kernel - [PATCH 06/13] KVM: monolithic: x86: remove __exit section prefix from machine

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Date:   Mon,  4 Nov 2019 17:59:54 -0500
From:   Andrea Arcangeli <aarcange@...hat.com>
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH 06/13] KVM: monolithic: x86: remove __exit section prefix from machine_unsetup

Adjusts the section prefixes of some KVM x86 code function because
with the monolithic KVM model the section checker can now do a more
accurate static analysis at build time and it found a potentially
kernel crashing bug. This also allows to build without
CONFIG_SECTION_MISMATCH_WARN_ONLY=n.

The __exit removed from machine_unsetup is because
kvm_arch_hardware_unsetup() is called by kvm_init() which is in the
__init section. It's not allowed to call a function located in the
__exit section and dropped during the kernel link from the __init
section or the kernel will crash if that call is made.

Signed-off-by: Andrea Arcangeli <aarcange@...hat.com>
---
 arch/x86/include/asm/kvm_host.h | 4 ++--
 arch/x86/kvm/svm.c              | 2 +-
 arch/x86/kvm/vmx/vmx.c          | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b36dd3265036..2b03ec80f6d7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1004,7 +1004,7 @@ extern int kvm_x86_hardware_enable(void);
 extern void kvm_x86_hardware_disable(void);
 extern __init int kvm_x86_check_processor_compatibility(void);
 extern __init int kvm_x86_hardware_setup(void);
-extern __exit void kvm_x86_hardware_unsetup(void);
+extern void kvm_x86_hardware_unsetup(void);
 extern bool kvm_x86_cpu_has_accelerated_tpr(void);
 extern bool kvm_x86_has_emulated_msr(int index);
 extern void kvm_x86_cpuid_update(struct kvm_vcpu *vcpu);
@@ -1196,7 +1196,7 @@ struct kvm_x86_ops {
 	void (*hardware_disable)(void);
 	int (*check_processor_compatibility)(void);/* __init */
 	int (*hardware_setup)(void);               /* __init */
-	void (*hardware_unsetup)(void);            /* __exit */
+	void (*hardware_unsetup)(void);
 	bool (*cpu_has_accelerated_tpr)(void);
 	bool (*has_emulated_msr)(int index);
 	void (*cpuid_update)(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1705608246fb..4ce102f6f075 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1412,7 +1412,7 @@ __init int kvm_x86_hardware_setup(void)
 	return r;
 }
 
-__exit void kvm_x86_hardware_unsetup(void)
+void kvm_x86_hardware_unsetup(void)
 {
 	int cpu;
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9c5f0c67b899..e406707381a4 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7737,7 +7737,7 @@ __init int kvm_x86_hardware_setup(void)
 	return r;
 }
 
-__exit void kvm_x86_hardware_unsetup(void)
+void kvm_x86_hardware_unsetup(void)
 {
 	if (nested)
 		nested_vmx_hardware_unsetup();