From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47344C352A4 for ; Mon, 10 Feb 2020 09:05:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2743A2080C for ; Mon, 10 Feb 2020 09:05:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727477AbgBJJFh (ORCPT ); Mon, 10 Feb 2020 04:05:37 -0500 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:60945 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726796AbgBJJFh (ORCPT ); Mon, 10 Feb 2020 04:05:37 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07417;MF=zhabin@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0Tpb7N0C_1581325531; Received: from localhost(mailfrom:zhabin@linux.alibaba.com fp:SMTPD_---0Tpb7N0C_1581325531) by smtp.aliyun-inc.com(127.0.0.1); Mon, 10 Feb 2020 17:05:31 +0800 From: Zha Bin To: linux-kernel@vger.kernel.org Cc: mst@redhat.com, jasowang@redhat.com, slp@redhat.com, virtio-dev@lists.oasis-open.org, qemu-devel@nongnu.org, gerry@linux.alibaba.com, zhabin@linux.alibaba.com, jing2.liu@linux.intel.com, chao.p.peng@linux.intel.com Subject: [PATCH v2 1/5] virtio-mmio: add notify feature for per-queue Date: Mon, 10 Feb 2020 17:05:17 +0800 Message-Id: <8a4ea95d6d77a2814aaf6897b5517353289a098e.1581305609.git.zhabin@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liu Jiang The standard virtio-mmio devices use notification register to signal backend. This will cause vmexits and slow down the performance when we passthrough the virtio-mmio devices to guest virtual machines. We proposed to update virtio over MMIO spec to add the per-queue notify feature VIRTIO_F_MMIO_NOTIFICATION[1]. It can allow the VMM to configure notify location for each queue. [1] https://lkml.org/lkml/2020/1/21/31 Signed-off-by: Liu Jiang Co-developed-by: Zha Bin Signed-off-by: Zha Bin Co-developed-by: Jing Liu Signed-off-by: Jing Liu Co-developed-by: Chao Peng Signed-off-by: Chao Peng --- drivers/virtio/virtio_mmio.c | 37 +++++++++++++++++++++++++++++++++++-- include/uapi/linux/virtio_config.h | 8 +++++++- 2 files changed, 42 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 97d5725..1733ab97 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -90,6 +90,9 @@ struct virtio_mmio_device { /* a list of queues so we can dispatch IRQs */ spinlock_t lock; struct list_head virtqueues; + + unsigned short notify_base; + unsigned short notify_multiplier; }; struct virtio_mmio_vq_info { @@ -98,6 +101,9 @@ struct virtio_mmio_vq_info { /* the list node for the virtqueues list */ struct list_head node; + + /* Notify Address*/ + unsigned int notify_addr; }; @@ -119,13 +125,23 @@ static u64 vm_get_features(struct virtio_device *vdev) return features; } +static void vm_transport_features(struct virtio_device *vdev, u64 features) +{ + if (features & BIT_ULL(VIRTIO_F_MMIO_NOTIFICATION)) + __virtio_set_bit(vdev, VIRTIO_F_MMIO_NOTIFICATION); +} + static int vm_finalize_features(struct virtio_device *vdev) { struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); + u64 features = vdev->features; /* Give virtio_ring a chance to accept features. */ vring_transport_features(vdev); + /* Give virtio_mmio a chance to accept features. */ + vm_transport_features(vdev, features); + /* Make sure there is are no mixed devices */ if (vm_dev->version == 2 && !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) { @@ -272,10 +288,13 @@ static void vm_reset(struct virtio_device *vdev) static bool vm_notify(struct virtqueue *vq) { struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); + struct virtio_mmio_vq_info *info = vq->priv; - /* We write the queue's selector into the notification register to + /* We write the queue's selector into the Notify Address to * signal the other end */ - writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY); + if (info) + writel(vq->index, vm_dev->base + info->notify_addr); + return true; } @@ -434,6 +453,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, vq->priv = info; info->vq = vq; + if (__virtio_test_bit(vdev, VIRTIO_F_MMIO_NOTIFICATION)) + info->notify_addr = vm_dev->notify_base + + vm_dev->notify_multiplier * vq->index; + else + info->notify_addr = VIRTIO_MMIO_QUEUE_NOTIFY; + spin_lock_irqsave(&vm_dev->lock, flags); list_add(&info->node, &vm_dev->virtqueues); spin_unlock_irqrestore(&vm_dev->lock, flags); @@ -471,6 +496,14 @@ static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs, return irq; } + if (__virtio_test_bit(vdev, VIRTIO_F_MMIO_NOTIFICATION)) { + unsigned int notify = readl(vm_dev->base + + VIRTIO_MMIO_QUEUE_NOTIFY); + + vm_dev->notify_base = notify & 0xffff; + vm_dev->notify_multiplier = (notify >> 16) & 0xffff; + } + err = request_irq(irq, vm_interrupt, IRQF_SHARED, dev_name(&vdev->dev), vm_dev); if (err) diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h index ff8e7dc..5d93c01 100644 --- a/include/uapi/linux/virtio_config.h +++ b/include/uapi/linux/virtio_config.h @@ -52,7 +52,7 @@ * rest are per-device feature bits. */ #define VIRTIO_TRANSPORT_F_START 28 -#define VIRTIO_TRANSPORT_F_END 38 +#define VIRTIO_TRANSPORT_F_END 40 #ifndef VIRTIO_CONFIG_NO_LEGACY /* Do we get callbacks when the ring is completely used, even if we've @@ -88,4 +88,10 @@ * Does the device support Single Root I/O Virtualization? */ #define VIRTIO_F_SR_IOV 37 + +/* + * This feature indicates the enhanced notification support on MMIO transport + * layer. + */ +#define VIRTIO_F_MMIO_NOTIFICATION 39 #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */ -- 1.8.3.1