[PATCH v3 4/6] KVM: x86: warn on incorrectly NULL members of kvm_x86_ops

From: Paolo Bonzini
Date: Thu Feb 17 2022 - 13:08:43 EST


Use the newly corrected KVM_X86_OP annotations to warn about possible
NULL pointer dereferences as soon as the vendor module is loaded.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7d733f601106..a7e82fc1f1f3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1545,10 +1545,13 @@ extern struct kvm_x86_ops kvm_x86_ops;

static inline void kvm_ops_static_call_update(void)
{
-#define KVM_X86_OP(func) \
+#define __KVM_X86_OP(func) \
static_call_update(kvm_x86_##func, kvm_x86_ops.func);
-#define KVM_X86_OP_OPTIONAL KVM_X86_OP
+#define KVM_X86_OP(func) \
+ WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
+#define KVM_X86_OP_OPTIONAL __KVM_X86_OP
#include <asm/kvm-x86-ops.h>
+#undef __KVM_X86_OP
}

#define __KVM_HAVE_ARCH_VM_ALLOC
--
2.31.1