linux-kernel - [PATCH v1] KVM: allow KVM_BUG/KVM_BUG

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Date:   Wed,  1 Mar 2023 21:38:41 +0800
From:   Wei Wang <wei.w.wang@...el.com>
To:     pbonzini@...hat.com, seanjc@...gle.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Wei Wang <wei.w.wang@...el.com>
Subject: [PATCH v1] KVM: allow KVM_BUG/KVM_BUG_ON to handle 64-bit cond

Current KVM_BUG and KVM_BUG_ON assumes that 'cond' passed from callers is
32-bit as it casts 'cond' to the type of int. This will be wrong if 'cond'
provided by a caller is 64-bit, e.g. an error code of 0xc0000d0300000000
will be converted to 0, which is not expected. Improves the implementation
by using !!(cond) in KVM_BUG and KVM_BUG_ON. Compared to changing 'int' to
'int64_t', this has less LOCs.

Fixes: 0b8f11737cff ("KVM: Add infrastructure and macro to mark VM as bugged")
Signed-off-by: Wei Wang <wei.w.wang@...el.com>
---
 include/linux/kvm_host.h | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f06635b24bd0..d77ddf82c5c8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -881,20 +881,16 @@ static inline void kvm_vm_bugged(struct kvm *kvm)
 
 #define KVM_BUG(cond, kvm, fmt...)				\
 ({								\
-	int __ret = (cond);					\
-								\
-	if (WARN_ONCE(__ret && !(kvm)->vm_bugged, fmt))		\
+	if (WARN_ONCE(!!cond && !(kvm)->vm_bugged, fmt))	\
 		kvm_vm_bugged(kvm);				\
-	unlikely(__ret);					\
+	unlikely(!!cond);					\
 })
 
 #define KVM_BUG_ON(cond, kvm)					\
 ({								\
-	int __ret = (cond);					\
-								\
-	if (WARN_ON_ONCE(__ret && !(kvm)->vm_bugged))		\
+	if (WARN_ON_ONCE(!!(cond) && !(kvm)->vm_bugged))	\
 		kvm_vm_bugged(kvm);				\
-	unlikely(__ret);					\
+	unlikely(!!(cond));					\
 })
 
 static inline void kvm_vcpu_srcu_read_lock(struct kvm_vcpu *vcpu)
-- 
2.27.0