linux-kernel - [PATCH] KVM: x86: Fix pointer mistmatch warning when patching RET0 static calls

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Message-Id: <20220223162355.3174907-1-seanjc@google.com>
Date:   Wed, 23 Feb 2022 16:23:55 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        llvm@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Like Xu <like.xu.linux@...il.com>
Subject: [PATCH] KVM: x86: Fix pointer mistmatch warning when patching RET0
 static calls

Cast kvm_x86_ops.func to 'void *' when updating KVM static calls that are
conditionally patched to __static_call_return0().  clang complains about
using mismatching pointers in the ternary operator, which breaks the
build when compiling with CONFIG_KVM_WERROR=y.

  >> arch/x86/include/asm/kvm-x86-ops.h:82:1: warning: pointer type mismatch
  ('bool (*)(struct kvm_vcpu *)' and 'void *') [-Wpointer-type-mismatch]

Fixes: 5be2226f417d ("KVM: x86: allow defining return-0 static calls")
Reported-by: Like Xu <like.xu.linux@...il.com>
Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/include/asm/kvm_host.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 713e08f62385..f285ddb8b66b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1547,8 +1547,8 @@ static inline void kvm_ops_static_call_update(void)
 	WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
 #define KVM_X86_OP_OPTIONAL __KVM_X86_OP
 #define KVM_X86_OP_OPTIONAL_RET0(func) \
-	static_call_update(kvm_x86_##func, kvm_x86_ops.func ? : \
-			   (void *) __static_call_return0);
+	static_call_update(kvm_x86_##func, (void *)kvm_x86_ops.func ? : \
+					   (void *)__static_call_return0);
 #include <asm/kvm-x86-ops.h>
 #undef __KVM_X86_OP
 }

base-commit: f4bc051fc91ab9f1d5225d94e52d369ef58bec58
-- 
2.35.1.473.g83b2b277ed-goog