From nobody Tue Feb 10 04:32:52 2026 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 94DBE2D8393; Fri, 24 Oct 2025 07:20:15 +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=1761290418; cv=none; b=M8vjp/hFoCBw2cQeUGjVWBs2nAtmWlubNOZ/tn0z9lwiyGjHXyil9+oAnmWjiJinP/SnfQXO84WNNxvP1ZTIFrjdws8rFPSnIcZYclcVoGzuFdfJTKdl1iWAo27p8JU8lGvHzQlP2C4DhZrtC4N+ZP9m6cDcKIZAKuCBnHy4Evc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761290418; c=relaxed/simple; bh=FHPCUkF47wmXOUMYG5D5p7ycxQXyM3ejbPFjYjrSGIg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=g3U4vBKCQ60auo853dU6wYMPw7RZ4Outgu5+nQ3X8AVe4H7y0QG45znIrIgmZGOcu+jQQRmI3XYXErcBMiJX/qlDuke0Ewd4g8h9eHrk7yN+hWWA4WfRQkCc4c9tgMzmfPpFv6In3+AERc9kqGvQxL75WbYwYo7o9X9jebCnATI= 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 _____8Axz7+oKPto0hUaAA--.54356S3; Fri, 24 Oct 2025 15:20:08 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by front1 (Coremail) with SMTP id qMiowJCxocKiKPtojj4GAQ--.47710S4; Fri, 24 Oct 2025 15:20:08 +0800 (CST) From: Bibo Mao To: Huacai Chen , Xianglai Li , Song Gao Cc: kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] LoongArch: KVM: Skip PMU checking on vCPU context switch Date: Fri, 24 Oct 2025 15:20:01 +0800 Message-Id: <20251024072001.3164600-3-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20251024072001.3164600-1-maobibo@loongson.cn> References: <20251024072001.3164600-1-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: qMiowJCxocKiKPtojj4GAQ--.47710S4 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7 ZEXasCq-sGcSsGvfJ3UbIjqfuFe4nvWSU5nxnvy29KBjDU0xBIdaVrnUUvcSsGvfC2Kfnx nUUI43ZEXa7xR_UUUUUUUUU== Content-Type: text/plain; charset="utf-8" PMU hardware about VM is switched on VM exit to host rather than vCPU context sched off, PMU is checked and restored on return to VM. It is not necessary to check PMU on vCPU context sched on callback, since the request is made on VM exit entry or VM PMU CSR access abort routine already. Signed-off-by: Bibo Mao --- arch/loongarch/kvm/vcpu.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index bf56ad29ac15..dc35bf526fe9 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -148,12 +148,6 @@ static void kvm_lose_pmu(struct kvm_vcpu *vcpu) kvm_restore_host_pmu(vcpu); } =20 -static void kvm_restore_pmu(struct kvm_vcpu *vcpu) -{ - if ((vcpu->arch.aux_inuse & KVM_LARCH_PMU)) - kvm_make_request(KVM_REQ_PMU, vcpu); -} - static void kvm_check_pmu(struct kvm_vcpu *vcpu) { if (kvm_check_request(KVM_REQ_PMU, vcpu)) { @@ -304,7 +298,10 @@ static int kvm_pre_enter_guest(struct kvm_vcpu *vcpu) vcpu->arch.aux_inuse &=3D ~KVM_LARCH_SWCSR_LATEST; =20 if (kvm_request_pending(vcpu) || xfer_to_guest_mode_work_pending()) { - kvm_lose_pmu(vcpu); + if (vcpu->arch.aux_inuse & KVM_LARCH_PMU) { + kvm_lose_pmu(vcpu); + kvm_make_request(KVM_REQ_PMU, vcpu); + } /* make sure the vcpu mode has been written */ smp_store_mb(vcpu->mode, OUTSIDE_GUEST_MODE); local_irq_enable(); @@ -1609,9 +1606,6 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int = cpu) kvm_restore_timer(vcpu); kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu); =20 - /* Restore hardware PMU CSRs */ - kvm_restore_pmu(vcpu); - /* Don't bother restoring registers multiple times unless necessary */ if (vcpu->arch.aux_inuse & KVM_LARCH_HWCSR_USABLE) return 0; --=20 2.39.3