linux-kernel - [PATCH v3 4/4] LoongArch: KVM: Make function kvm_own

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Message-Id: <20250815022621.508174-5-maobibo@loongson.cn>
Date: Fri, 15 Aug 2025 10:26:21 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Tianrui Zhao <zhaotianrui@...ngson.cn>,
	Huacai Chen <chenhuacai@...nel.org>,
	Xianglai Li <lixianglai@...ngson.cn>
Cc: kvm@...r.kernel.org,
	loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH v3 4/4] LoongArch: KVM: Make function kvm_own_lbt() robust

Add flag KVM_LARCH_LBT checking in function kvm_own_lbt(), so that
it can be called safely rather than duplicated enabling again.

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 arch/loongarch/kvm/vcpu.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index d1b8c50941ca..ce478151466c 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -1283,9 +1283,11 @@ int kvm_own_lbt(struct kvm_vcpu *vcpu)
 		return -EINVAL;
 
 	preempt_disable();
-	set_csr_euen(CSR_EUEN_LBTEN);
-	_restore_lbt(&vcpu->arch.lbt);
-	vcpu->arch.aux_inuse |= KVM_LARCH_LBT;
+	if (!(vcpu->arch.aux_inuse & KVM_LARCH_LBT)) {
+		set_csr_euen(CSR_EUEN_LBTEN);
+		_restore_lbt(&vcpu->arch.lbt);
+		vcpu->arch.aux_inuse |= KVM_LARCH_LBT;
+	}
 	preempt_enable();
 
 	return 0;
-- 
2.39.3