[RFC v4 11/11] vduse: Support binding irq to the specified cpu

From: Xie Yongji <xieyongji@bytedance.com>
To: mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com,
	sgarzare@redhat.com, parav@nvidia.com, bob.liu@oracle.com,
	hch@infradead.org, rdunlap@infradead.org, willy@infradead.org,
	viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org,
	corbet@lwn.net
Cc: virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org,
	linux-fsdevel@vger.kernel.org
Subject: [RFC v4 11/11] vduse: Support binding irq to the specified cpu
Date: Tue, 23 Feb 2021 19:50:48 +0800	[thread overview]
Message-ID: <20210223115048.435-12-xieyongji@bytedance.com> (raw)
In-Reply-To: <20210223115048.435-1-xieyongji@bytedance.com>

Add a parameter for the ioctl VDUSE_INJECT_VQ_IRQ to support
injecting virtqueue's interrupt to the specified cpu.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 22 +++++++++++++++++-----
 include/uapi/linux/vduse.h         |  7 ++++++-
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index f5adeb9ee027..df3d467fff40 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -923,14 +923,27 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		break;
 	}
 	case VDUSE_INJECT_VQ_IRQ: {
+		struct vduse_vq_irq irq;
 		struct vduse_virtqueue *vq;
 
+		ret = -EFAULT;
+		if (copy_from_user(&irq, argp, sizeof(irq)))
+			break;
+
 		ret = -EINVAL;
-		if (arg >= dev->vq_num)
+		if (irq.index >= dev->vq_num)
+			break;
+
+		if (irq.cpu != -1 && (irq.cpu >= nr_cpu_ids ||
+		    !cpu_online(irq.cpu)))
 			break;
 
-		vq = &dev->vqs[arg];
-		queue_work(vduse_irq_wq, &vq->inject);
+		ret = 0;
+		vq = &dev->vqs[irq.index];
+		if (irq.cpu == -1)
+			queue_work(vduse_irq_wq, &vq->inject);
+		else
+			queue_work_on(irq.cpu, vduse_irq_wq, &vq->inject);
 		break;
 	}
 	case VDUSE_INJECT_CONFIG_IRQ:
@@ -1342,8 +1355,7 @@ static int vduse_init(void)
 	if (ret)
 		goto err_chardev;
 
-	vduse_irq_wq = alloc_workqueue("vduse-irq",
-				WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
+	vduse_irq_wq = alloc_workqueue("vduse-irq", WQ_HIGHPRI, 0);
 	if (!vduse_irq_wq)
 		goto err_wq;
 
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 9070cd512cb4..9c70fd842ce5 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -116,6 +116,11 @@ struct vduse_vq_eventfd {
 	int fd; /* eventfd, -1 means de-assigning the eventfd */
 };
 
+struct vduse_vq_irq {
+	__u32 index; /* virtqueue index */
+	int cpu; /* bind irq to the specified cpu, -1 means running on the current cpu */
+};
+
 #define VDUSE_BASE	0x81
 
 /* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */
@@ -131,7 +136,7 @@ struct vduse_vq_eventfd {
 #define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x04, struct vduse_vq_eventfd)
 
 /* Inject an interrupt for specific virtqueue */
-#define VDUSE_INJECT_VQ_IRQ	_IO(VDUSE_BASE, 0x05)
+#define VDUSE_INJECT_VQ_IRQ	_IOW(VDUSE_BASE, 0x05, struct vduse_vq_irq)
 
 /* Inject a config interrupt */
 #define VDUSE_INJECT_CONFIG_IRQ	_IO(VDUSE_BASE, 0x06)
-- 
2.11.0

