From patchwork Tue Feb 28 09:39:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Denis V. Lunev\" via" X-Patchwork-Id: 13154616 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8BA37C64EC7 for ; Tue, 28 Feb 2023 09:40:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pWwSo-0002N3-Dx; Tue, 28 Feb 2023 04:40:02 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pWwSm-0002Kn-HO for qemu-devel@nongnu.org; Tue, 28 Feb 2023 04:40:00 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pWwSi-0003Be-CK for qemu-devel@nongnu.org; Tue, 28 Feb 2023 04:40:00 -0500 Received: from kwepemi100025.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4PQsjM4WG4z9tD0; Tue, 28 Feb 2023 17:37:43 +0800 (CST) Received: from DESKTOP-27KDQMV.china.huawei.com (10.174.148.223) by kwepemi100025.china.huawei.com (7.221.188.158) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Tue, 28 Feb 2023 17:39:41 +0800 To: , , CC: , , , , , , , Longpeng Subject: [PATCH v1 1/3] virtio-pci: submit msi route changes in batch Date: Tue, 28 Feb 2023 17:39:35 +0800 Message-ID: <20230228093937.2515-2-longpeng2@huawei.com> X-Mailer: git-send-email 2.25.0.windows.1 In-Reply-To: <20230228093937.2515-1-longpeng2@huawei.com> References: <20230228093937.2515-1-longpeng2@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.148.223] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemi100025.china.huawei.com (7.221.188.158) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.188; envelope-from=longpeng2@huawei.com; helo=szxga02-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: "Longpeng(Mike)" X-Patchwork-Original-From: "Longpeng(Mike)" via From: "Denis V. Lunev\" via" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Longpeng The kvm_irqchip_commit_routes() is a time-intensive operation, it needs scan and update all irqfds that are already assigned during each invocation, so more vectors means need more time to process them. For virtio-pci, we can just submit once when enabling vectors of a virtio-pci device. This can reduce the downtime when migrating a VM with vhost-vdpa devices. Signed-off-by: Longpeng --- hw/virtio/virtio-pci.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index 247325c193..22e76e3902 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -49,6 +49,19 @@ * configuration space */ #define VIRTIO_PCI_CONFIG_SIZE(dev) VIRTIO_PCI_CONFIG_OFF(msix_enabled(dev)) +/* Protected by the BQL */ +static KVMRouteChange virtio_pci_route_change; + +static inline void virtio_pci_begin_route_changes(void) +{ + virtio_pci_route_change = kvm_irqchip_begin_route_changes(kvm_state); +} + +static inline void virtio_pci_commit_route_changes(void) +{ + kvm_irqchip_commit_route_changes(&virtio_pci_route_change); +} + static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size, VirtIOPCIProxy *dev); static void virtio_pci_reset(DeviceState *qdev); @@ -790,12 +803,11 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy, int ret; if (irqfd->users == 0) { - KVMRouteChange c = kvm_irqchip_begin_route_changes(kvm_state); - ret = kvm_irqchip_add_msi_route(&c, vector, &proxy->pci_dev); + ret = kvm_irqchip_add_msi_route(&virtio_pci_route_change, vector, + &proxy->pci_dev); if (ret < 0) { return ret; } - kvm_irqchip_commit_route_changes(&c); irqfd->virq = ret; } irqfd->users++; @@ -903,12 +915,18 @@ static int kvm_virtio_pci_vector_vq_use(VirtIOPCIProxy *proxy, int nvqs) int ret = 0; VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); + virtio_pci_begin_route_changes(); + for (queue_no = 0; queue_no < nvqs; queue_no++) { if (!virtio_queue_get_num(vdev, queue_no)) { + virtio_pci_commit_route_changes(); return -1; } ret = kvm_virtio_pci_vector_use_one(proxy, queue_no); } + + virtio_pci_commit_route_changes(); + return ret; }