From nobody Sun Apr 5 13:22:51 2026 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 34F8028852E; Mon, 23 Mar 2026 02:56:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774234581; cv=none; b=Dnd/vAv5w9GEJVXcUlATYHR8WQgXQwWv6gOt63zX5JzKP6u4BvgxQTQpuYcTLoBb/bcitqnPl5TohgTRmsXyt3tiIkhf1kmXUSPZdbdCaQqXLAAJ4j2emgKuPYblko3ahx1kkuDW7ovqbhYG248QEkjCB9LeBF8UXpRDdIOXWkE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774234581; c=relaxed/simple; bh=CYX3G3ifnOGdRTffmuHm0LU74ney0de1dwmKeDVPgFY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HLBl2GZIZ1g1uu15c6P/+fQjg7pZpHCSQeB6F6nK3tCK6B1ot6GLKBZOs8OiQv4hJqo+iwqQL94G8B7txe2fXvX5CFq46GhGRCorDA9U3boKPYG4OJKgFJaXYew9iOv6QVHni2hRB2rnjT9e1FXxUOqetq7TissMZaEFkqxpsjY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8CxJMHRq8BpoaYdAA--.38171S3; Mon, 23 Mar 2026 10:56:17 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by front1 (Coremail) with SMTP id qMiowJBxbcLOq8Bpcg5bAA--.40805S4; Mon, 23 Mar 2026 10:56:16 +0800 (CST) From: Bibo Mao To: Tianrui Zhao , Huacai Chen Cc: kernel@xen0n.name, kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, Juergen Gross Subject: [PATCH v3 2/4] LoongArch: KVM: Move host CSR_EENTRY save and restore in context switch Date: Mon, 23 Mar 2026 10:56:11 +0800 Message-Id: <20260323025613.3260876-3-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20260323025613.3260876-1-maobibo@loongson.cn> References: <20260323025613.3260876-1-maobibo@loongson.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qMiowJBxbcLOq8Bpcg5bAA--.40805S4 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7 ZEXasCq-sGcSsGvfJ3UbIjqfuFe4nvWSU5nxnvy29KBjDU0xBIdaVrnUUvcSsGvfC2Kfnx nUUI43ZEXa7xR_UUUUUUUUU== Content-Type: text/plain; charset="utf-8" CSR register LOONGARCH_CSR_EENTRY is shared between host cpu and guest vCPU, KVM need save and restore LOONGARCH_CSR_EENTRY register. Here move CSR register LOONGARCH_CSR_EENTRY saving in context switch function, rather than VM enter entry. At most time VM enter/exit is much more frequent than vCPU thread context switch. Signed-off-by: Bibo Mao --- arch/loongarch/kvm/vcpu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 028eb3d5a33b..e82b2c84ce17 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -319,7 +319,6 @@ static int kvm_pre_enter_guest(struct kvm_vcpu *vcpu) * and it may also clear KVM_REQ_TLB_FLUSH_GPA pending bit */ kvm_late_check_requests(vcpu); - vcpu->arch.host_eentry =3D csr_read64(LOONGARCH_CSR_EENTRY); /* Clear KVM_LARCH_SWCSR_LATEST as CSR will change when enter guest */ vcpu->arch.aux_inuse &=3D ~KVM_LARCH_SWCSR_LATEST; =20 @@ -1624,9 +1623,11 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int= cpu) * If not, any old guest state from this vCPU will have been clobbered. */ context =3D per_cpu_ptr(vcpu->kvm->arch.vmcs, cpu); - if (migrated || (context->last_vcpu !=3D vcpu)) + if (migrated || (context->last_vcpu !=3D vcpu)) { vcpu->arch.aux_inuse &=3D ~KVM_LARCH_HWCSR_USABLE; - context->last_vcpu =3D vcpu; + context->last_vcpu =3D vcpu; + vcpu->arch.host_eentry =3D csr_read64(LOONGARCH_CSR_EENTRY); + } =20 /* Restore timer state regardless */ kvm_restore_timer(vcpu); --=20 2.39.3