Commit 2cf1ba9a authored by Zhu Lingshan's avatar Zhu Lingshan Committed by Michael S. Tsirkin
Browse files

vhost_vdpa: implement IRQ offloading in vhost_vdpa 



This patch introduce a set of functions for setup/unsetup
and update irq offloading respectively by register/unregister
and re-register the irq_bypass_producer.

With these functions, this commit can setup/unsetup
irq offloading through setting DRIVER_OK/!DRIVER_OK, and
update irq offloading through SET_VRING_CALL.

Signed-off-by: default avatarZhu Lingshan <lingshan.zhu@intel.com>
Suggested-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20200731065533.4144-5-lingshan.zhu@intel.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 7164675a

drivers/vhost/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ config VHOST_VDPA 
	tristate "Vhost driver for vDPA-based backend"

	depends on EVENTFD

	select VHOST

	select IRQ_BYPASS_MANAGER

	depends on VDPA

	help

	  This kernel module can be loaded in host kernel to accelerate

drivers/vhost/vdpa.c

+62 −1
Original line number Diff line number Diff line
@@ -82,6 +82,39 @@ static irqreturn_t vhost_vdpa_config_cb(void *private) 
	return IRQ_HANDLED;

}



static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)

{

	struct vhost_virtqueue *vq = &v->vqs[qid];

	const struct vdpa_config_ops *ops = v->vdpa->config;

	struct vdpa_device *vdpa = v->vdpa;

	int ret, irq;



	if (!ops->get_vq_irq)

		return;



	irq = ops->get_vq_irq(vdpa, qid);

	spin_lock(&vq->call_ctx.ctx_lock);

	irq_bypass_unregister_producer(&vq->call_ctx.producer);

	if (!vq->call_ctx.ctx || irq < 0) {

		spin_unlock(&vq->call_ctx.ctx_lock);

		return;

	}



	vq->call_ctx.producer.token = vq->call_ctx.ctx;

	vq->call_ctx.producer.irq = irq;

	ret = irq_bypass_register_producer(&vq->call_ctx.producer);

	spin_unlock(&vq->call_ctx.ctx_lock);

}



static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid)

{

	struct vhost_virtqueue *vq = &v->vqs[qid];



	spin_lock(&vq->call_ctx.ctx_lock);

	irq_bypass_unregister_producer(&vq->call_ctx.producer);

	spin_unlock(&vq->call_ctx.ctx_lock);

}



static void vhost_vdpa_reset(struct vhost_vdpa *v)

{

	struct vdpa_device *vdpa = v->vdpa;
@@ -121,11 +154,15 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp) 
{

	struct vdpa_device *vdpa = v->vdpa;

	const struct vdpa_config_ops *ops = vdpa->config;

	u8 status;

	u8 status, status_old;

	int nvqs = v->nvqs;

	u16 i;



	if (copy_from_user(&status, statusp, sizeof(status)))

		return -EFAULT;



	status_old = ops->get_status(vdpa);



	/*

	 * Userspace shouldn't remove status bits unless reset the

	 * status to 0.
@@ -135,6 +172,15 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp) 


	ops->set_status(vdpa, status);



	/* vq irq is not expected to be changed once DRIVER_OK is set */

	if ((status & VIRTIO_CONFIG_S_DRIVER_OK) && !(status_old & VIRTIO_CONFIG_S_DRIVER_OK))

		for (i = 0; i < nvqs; i++)

			vhost_vdpa_setup_vq_irq(v, i);



	if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) && !(status & VIRTIO_CONFIG_S_DRIVER_OK))

		for (i = 0; i < nvqs; i++)

			vhost_vdpa_unsetup_vq_irq(v, i);



	return 0;

}
@@ -293,6 +339,7 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp) 


	return 0;

}



static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,

				   void __user *argp)

{
@@ -351,6 +398,7 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, 
			cb.private = NULL;

		}

		ops->set_vq_cb(vdpa, idx, &cb);

		vhost_vdpa_setup_vq_irq(v, idx);

		break;



	case VHOST_SET_VRING_NUM:
@@ -726,6 +774,18 @@ err: 
	return r;

}



static void vhost_vdpa_clean_irq(struct vhost_vdpa *v)

{

	struct vhost_virtqueue *vq;

	int i;



	for (i = 0; i < v->nvqs; i++) {

		vq = &v->vqs[i];

		if (vq->call_ctx.producer.irq)

			irq_bypass_unregister_producer(&vq->call_ctx.producer);

	}

}



static int vhost_vdpa_release(struct inode *inode, struct file *filep)

{

	struct vhost_vdpa *v = filep->private_data;
@@ -738,6 +798,7 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep) 
	vhost_vdpa_iotlb_free(v);

	vhost_vdpa_free_domain(v);

	vhost_vdpa_config_put(v);

	vhost_vdpa_clean_irq(v);

	vhost_dev_cleanup(&v->vdev);

	kfree(v->vdev.vqs);

	mutex_unlock(&d->mutex);

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