LoongArch: KVM: Make function kvm_own_lbt() robust

commit 4be8cefc132606b4a6e851f37f8e8c40c406c910 upstream.

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

Cc: stable@vger.kernel.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 4b0ae29b8acab8e56d283c6cd68b6d7d95c68589..b5439a10b7652beda93c7b0f545323f33284b5a2 100644 (file)
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -1249,9 +1249,11 @@ 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;