From dd9ada5627245a3441ebde00736dd63d09acc222 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 13 Feb 2020 14:26:46 +0100 Subject: 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: Johannes Berg Signed-off-by: Richard Weinberger --- arch/um/drivers/vhost_user.h | 12 ++++--- arch/um/drivers/virtio_uml.c | 85 ++++++++++++++++++++++++++++++++++---------- 2 files changed, 75 insertions(+), 22 deletions(-) diff --git a/arch/um/drivers/vhost_user.h b/arch/um/drivers/vhost_user.h index 45ff5ea22fea..6c71b6005177 100644 --- a/arch/um/drivers/vhost_user.h +++ b/arch/um/drivers/vhost_user.h @@ -10,9 +10,10 @@ /* Feature bits */ #define VHOST_USER_F_PROTOCOL_FEATURES 30 /* Protocol feature bits */ -#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_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 { diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c index 023ced2250ea..9b4c5b7c0f0d 100644 --- a/arch/um/drivers/virtio_uml.c +++ b/arch/um/drivers/virtio_uml.c @@ -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); @@ -749,10 +774,13 @@ static void vu_del_vq(struct virtqueue *vq) { struct virtio_uml_vq_info *info = vq->priv; - um_free_irq(VIRTIO_IRQ, vq); + if (info->call_fd >= 0) { + um_free_irq(VIRTIO_IRQ, vq); + os_close_file(info->call_fd); + } - os_close_file(info->call_fd); - os_close_file(info->kick_fd); + if (info->kick_fd >= 0) + os_close_file(info->kick_fd); vring_del_virtqueue(vq); kfree(info); @@ -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); - rc = os_eventfd(0, 0); - if (rc < 0) - goto error_kick; - info->kick_fd = rc; + 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) @@ -866,10 +908,13 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev, return vq; error_setup: - um_free_irq(VIRTIO_IRQ, vq); - os_close_file(info->call_fd); + if (info->call_fd >= 0) { + um_free_irq(VIRTIO_IRQ, vq); + os_close_file(info->call_fd); + } error_call: - os_close_file(info->kick_fd); + if (info->kick_fd >= 0) + os_close_file(info->kick_fd); error_kick: vring_del_virtqueue(vq); error_create: @@ -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; - rc = vhost_user_set_vring_kick(vu_dev, vq->index, - info->kick_fd); - if (rc) - goto error_setup; + 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; -- cgit v1.2.3