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From: WANG Xuerui <kernel@xen0n.name>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Huacai Chen <chenhuacai@kernel.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>,
	Bibo Mao <maobibo@loongson.cn>,
	kvm@vger.kernel.org,
	loongarch@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	WANG Xuerui <git@xen0n.name>
Subject: [PATCH for-6.8 v2 1/4] KVM: LoongArch: Fix input value checking of _kvm_get_cpucfg
Date: Thu, 15 Feb 2024 00:33:54 +0800
Message-ID: <20240214163358.2913090-2-kernel@xen0n.name>
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From: WANG Xuerui <git@xen0n.name>

The range check for the CPUCFG ID is wrong (should have been a ||
instead of &&), and pointless, because the default case a few lines
below already serves to deny all unhandled cases.

Furthermore, the juggling of the temp return value is unnecessary,
because it is semantically equivalent and more readable to just
return at every switch case's end. This is done too to avoid potential
bugs in the future related to the unwanted complexity.

Fixes: db1ecca22edf ("LoongArch: KVM: Add LSX (128bit SIMD) support")
Signed-off-by: WANG Xuerui <git@xen0n.name>
---
 arch/loongarch/kvm/vcpu.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 27701991886d..c4a592623da6 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -300,11 +300,6 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
 
 static int _kvm_get_cpucfg(int id, u64 *v)
 {
-	int ret = 0;
-
-	if (id < 0 && id >= KVM_MAX_CPUCFG_REGS)
-		return -EINVAL;
-
 	switch (id) {
 	case 2:
 		/* Return CPUCFG2 features which have been supported by KVM */
@@ -324,12 +319,10 @@ static int _kvm_get_cpucfg(int id, u64 *v)
 		if (cpu_has_lasx)
 			*v |= CPUCFG2_LASX;
 
-		break;
+		return 0;
 	default:
-		ret = -EINVAL;
-		break;
+		return -EINVAL;
 	}
-	return ret;
 }
 
 static int kvm_check_cpucfg(int id, u64 val)
-- 
2.43.0