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authorJohannes Berg <johannes.berg@intel.com>2020-02-13 14:26:46 +0100
committerRichard Weinberger <richard@nod.at>2020-03-29 23:29:00 +0200
commitdd9ada5627245a3441ebde00736dd63d09acc222 (patch)
treecd2d4d19d19f2f3830e28b26026e156d0d8d144e /arch/um
parent4b786e24ca80a492736b359b3d1a8d07612a78e5 (diff)
downloadlinux-dd9ada5627245a3441ebde00736dd63d09acc222.tar.bz2
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 <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/drivers/vhost_user.h12
-rw-r--r--arch/um/drivers/virtio_uml.c85
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;