linux-kernel - [PATCH v3 3/4] LoongArch: KVM: Move LBT capability checking in LBT exception handler

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Message-Id: <20260203033131.3372834-4-maobibo@loongson.cn>
Date: Tue,  3 Feb 2026 11:31:30 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Huacai Chen <chenhuacai@...nel.org>,
	WANG Xuerui <kernel@...0n.name>,
	Tianrui Zhao <zhaotianrui@...ngson.cn>
Cc: loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Subject: [PATCH v3 3/4] LoongArch: KVM: Move LBT capability checking in LBT exception handler

Like FPU exception handler, check LBT capability in LBT exception
handler rather than function kvm_own_lbt().

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 arch/loongarch/kvm/exit.c | 4 +++-
 arch/loongarch/kvm/vcpu.c | 3 ---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index 74b427287e96..65ec10a7245a 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -820,8 +820,10 @@ static int kvm_handle_lasx_disabled(struct kvm_vcpu *vcpu, int ecode)
 
 static int kvm_handle_lbt_disabled(struct kvm_vcpu *vcpu, int ecode)
 {
-	if (kvm_own_lbt(vcpu))
+	if (!kvm_guest_has_lbt(&vcpu->arch))
 		kvm_queue_exception(vcpu, EXCCODE_INE, 0);
+	else
+		kvm_own_lbt(vcpu);
 
 	return RESUME_GUEST;
 }
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index d91a1160a309..995461d724b5 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -1286,9 +1286,6 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
 #ifdef CONFIG_CPU_HAS_LBT
 int kvm_own_lbt(struct kvm_vcpu *vcpu)
 {
-	if (!kvm_guest_has_lbt(&vcpu->arch))
-		return -EINVAL;
-
 	preempt_disable();
 	if (!(vcpu->arch.aux_inuse & KVM_LARCH_LBT)) {
 		set_csr_euen(CSR_EUEN_LBTEN);
-- 
2.39.3