From patchwork Mon Feb 10 09:05:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zha Bin X-Patchwork-Id: 11373557 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 10C2A14B4 for ; Mon, 10 Feb 2020 15:35:02 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E570A20715 for ; Mon, 10 Feb 2020 15:35:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E570A20715 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:35114 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j1B5Q-0003gb-Ua for patchwork-qemu-devel@patchwork.kernel.org; Mon, 10 Feb 2020 10:35:00 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41635) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j150s-00078z-Sa for qemu-devel@nongnu.org; Mon, 10 Feb 2020 04:05:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j150o-0004Ih-6D for qemu-devel@nongnu.org; Mon, 10 Feb 2020 04:05:51 -0500 Received: from out4436.biz.mail.alibaba.com ([47.88.44.36]:53923) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j150n-0004Ep-Su for qemu-devel@nongnu.org; Mon, 10 Feb 2020 04:05:50 -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 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: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 47.88.44.36 X-Mailman-Approved-At: Mon, 10 Feb 2020 10:31:31 -0500 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-dev@lists.oasis-open.org, zhabin@linux.alibaba.com, slp@redhat.com, mst@redhat.com, jasowang@redhat.com, jing2.liu@linux.intel.com, qemu-devel@nongnu.org, chao.p.peng@linux.intel.com, gerry@linux.alibaba.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" 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 */