Commit dd9ada56 authored by Johannes Berg's avatar Johannes Berg Committed by Richard Weinberger
Browse files

um: virtio: Implement VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS 



Implement in-band notifications that are necessary for running
vhost-user devices under externally synchronized time-travel
mode (which is in a follow-up patch). This feature makes what
usually should be eventfd notifications in-band messages.

We'll prefer this feature, under the assumption that only a
few (simulation) devices will ever support it, since it's not
very efficient.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 4b786e24

arch/um/drivers/vhost_user.h

+8 −4
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define VHOST_USER_PROTOCOL_F_REPLY_ACK			3

#define VHOST_USER_PROTOCOL_F_SLAVE_REQ			5

#define VHOST_USER_PROTOCOL_F_CONFIG			9

#define VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS	14

/* Vring state index masks */

#define VHOST_USER_VRING_INDEX_MASK	0xff

#define VHOST_USER_VRING_POLL_MASK	BIT(8)
@@ -24,7 +25,8 @@ 
/* Supported protocol features */

#define VHOST_USER_SUPPORTED_PROTOCOL_F	(BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK) | \

					 BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ) | \

					 BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG))

					 BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG) | \

					 BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS))



enum vhost_user_request {

	VHOST_USER_GET_FEATURES = 1,
@@ -52,12 +54,14 @@ enum vhost_user_request { 
	VHOST_USER_SET_VRING_ENDIAN = 23,

	VHOST_USER_GET_CONFIG = 24,

	VHOST_USER_SET_CONFIG = 25,

	VHOST_USER_VRING_KICK = 35,

};



enum vhost_user_slave_request {

	VHOST_USER_SLAVE_IOTLB_MSG = 1,

	VHOST_USER_SLAVE_CONFIG_CHANGE_MSG = 2,

	VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3,

	VHOST_USER_SLAVE_VRING_CALL = 4,

};



struct vhost_user_header {

arch/um/drivers/virtio_uml.c

+67 −18
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ struct virtio_uml_device { 
	struct virtio_device vdev;

	struct platform_device *pdev;



	spinlock_t sock_lock;

	int sock, req_fd;

	u64 features;

	u64 protocol_features;
@@ -189,6 +190,7 @@ static int vhost_user_send(struct virtio_uml_device *vu_dev, 
			   int *fds, size_t num_fds)

{

	size_t size = sizeof(msg->header) + msg->header.size;

	unsigned long flags;

	bool request_ack;

	int rc;
@@ -207,24 +209,28 @@ static int vhost_user_send(struct virtio_uml_device *vu_dev, 
	if (request_ack)

		msg->header.flags |= VHOST_USER_FLAG_NEED_REPLY;



	spin_lock_irqsave(&vu_dev->sock_lock, flags);

	rc = full_sendmsg_fds(vu_dev->sock, msg, size, fds, num_fds);

	if (rc < 0)

		return rc;

		goto out;



	if (request_ack) {

		uint64_t status;



		rc = vhost_user_recv_u64(vu_dev, &status);

		if (rc)

			return rc;

			goto out;



		if (status) {

			vu_err(vu_dev, "slave reports error: %llu\n", status);

			return -EIO;

			rc = -EIO;

			goto out;

		}

	}



	return 0;

out:

	spin_unlock_irqrestore(&vu_dev->sock_lock, flags);

	return rc;

}



static int vhost_user_send_no_payload(struct virtio_uml_device *vu_dev,
@@ -324,6 +330,7 @@ static void vhost_user_reply(struct virtio_uml_device *vu_dev, 
static irqreturn_t vu_req_interrupt(int irq, void *data)

{

	struct virtio_uml_device *vu_dev = data;

	struct virtqueue *vq;

	int response = 1;

	struct {

		struct vhost_user_msg msg;
@@ -343,6 +350,15 @@ static irqreturn_t vu_req_interrupt(int irq, void *data) 
		virtio_config_changed(&vu_dev->vdev);

		response = 0;

		break;

	case VHOST_USER_SLAVE_VRING_CALL:

		virtio_device_for_each_vq((&vu_dev->vdev), vq) {

			if (vq->index == msg.msg.payload.vring_state.index) {

				response = 0;

				vring_interrupt(0 /* ignored */, vq);

				break;

			}

		}

		break;

	case VHOST_USER_SLAVE_IOTLB_MSG:

		/* not supported - VIRTIO_F_IOMMU_PLATFORM */

	case VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG:
@@ -684,6 +700,15 @@ static bool vu_notify(struct virtqueue *vq) 
	const uint64_t n = 1;

	int rc;



	if (info->kick_fd < 0) {

		struct virtio_uml_device *vu_dev;



		vu_dev = to_virtio_uml_device(vq->vdev);



		return vhost_user_set_vring_state(vu_dev, VHOST_USER_VRING_KICK,

						  vq->index, 0) == 0;

	}



	do {

		rc = os_write_file(info->kick_fd, &n, sizeof(n));

	} while (rc == -EINTR);
@@ -749,9 +774,12 @@ static void vu_del_vq(struct virtqueue *vq) 
{

	struct virtio_uml_vq_info *info = vq->priv;



	if (info->call_fd >= 0) {

		um_free_irq(VIRTIO_IRQ, vq);



		os_close_file(info->call_fd);

	}



	if (info->kick_fd >= 0)

		os_close_file(info->kick_fd);



	vring_del_virtqueue(vq);
@@ -782,6 +810,15 @@ static int vu_setup_vq_call_fd(struct virtio_uml_device *vu_dev, 
	int call_fds[2];

	int rc;



	/* no call FD needed/desired in this case */

	if (vu_dev->protocol_features &

			BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS) &&

	    vu_dev->protocol_features &

			BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {

		info->call_fd = -1;

		return 0;

	}



	/* Use a pipe for call fd, since SIGIO is not supported for eventfd */

	rc = os_pipe(call_fds, true, true);

	if (rc < 0)
@@ -838,10 +875,15 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev, 
	vq->priv = info;

	num = virtqueue_get_vring_size(vq);



	if (vu_dev->protocol_features &

			BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS)) {

		info->kick_fd = -1;

	} else {

		rc = os_eventfd(0, 0);

		if (rc < 0)

			goto error_kick;

		info->kick_fd = rc;

	}



	rc = vu_setup_vq_call_fd(vu_dev, vq);

	if (rc)
@@ -866,9 +908,12 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev, 
	return vq;



error_setup:

	if (info->call_fd >= 0) {

		um_free_irq(VIRTIO_IRQ, vq);

		os_close_file(info->call_fd);

	}

error_call:

	if (info->kick_fd >= 0)

		os_close_file(info->kick_fd);

error_kick:

	vring_del_virtqueue(vq);
@@ -908,10 +953,12 @@ static int vu_find_vqs(struct virtio_device *vdev, unsigned nvqs, 
	list_for_each_entry(vq, &vdev->vqs, list) {

		struct virtio_uml_vq_info *info = vq->priv;



		if (info->kick_fd >= 0) {

			rc = vhost_user_set_vring_kick(vu_dev, vq->index,

						       info->kick_fd);

			if (rc)

				goto error_setup;

		}



		rc = vhost_user_set_vring_enable(vu_dev, vq->index, true);

		if (rc)
@@ -1008,6 +1055,8 @@ static int virtio_uml_probe(struct platform_device *pdev) 
		return rc;

	vu_dev->sock = rc;



	spin_lock_init(&vu_dev->sock_lock);



	rc = vhost_user_init(vu_dev);

	if (rc)

		goto error_init;

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