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From:   Tianrui Zhao <zhaotianrui@loongson.cn>
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
        Mark Brown <broonie@kernel.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Oliver Upton <oliver.upton@linux.dev>, maobibo@loongson.cn,
        Xi Ruoyao <xry111@xry111.site>, zhaotianrui@loongson.cn
Subject: [PATCH v6 22/30] LoongArch: KVM: Implement handle idle exception
Date:   Wed, 12 Apr 2023 16:30:15 +0800
Message-Id: <20230412083023.1693910-23-zhaotianrui@loongson.cn>
In-Reply-To: <20230412083023.1693910-1-zhaotianrui@loongson.cn>
References: <20230412083023.1693910-1-zhaotianrui@loongson.cn>
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Implement kvm handle loongarch vcpu idle exception, using kvm_vcpu_block
to emulate it.

Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
---
 arch/loongarch/kvm/exit.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index f151cc2dd0b9..3de08a4798fc 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -190,3 +190,23 @@ int _kvm_complete_iocsr_read(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 	return er;
 }
+
+int _kvm_emu_idle(struct kvm_vcpu *vcpu)
+{
+	++vcpu->stat.idle_exits;
+	trace_kvm_exit_idle(vcpu, KVM_TRACE_EXIT_IDLE);
+
+	if (!kvm_arch_vcpu_runnable(vcpu)) {
+		/*
+		 * Switch to the software timer before halt-polling/blocking as
+		 * the guest's timer may be a break event for the vCPU, and the
+		 * hypervisor timer runs only when the CPU is in guest mode.
+		 * Switch before halt-polling so that KVM recognizes an expired
+		 * timer before blocking.
+		 */
+		kvm_save_timer(vcpu);
+		kvm_vcpu_block(vcpu);
+	}
+
+	return EMULATE_DONE;
+}
-- 
2.31.1