virtio: console: tell host of open ports after resume from s3/s4
[linux-flexiantxendom0-3.2.10.git] / drivers / char / virtio_console.c
index fb68b12..cdf2f54 100644 (file)
  */
 #include <linux/cdev.h>
 #include <linux/debugfs.h>
+#include <linux/completion.h>
 #include <linux/device.h>
 #include <linux/err.h>
+#include <linux/freezer.h>
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/list.h>
@@ -32,6 +34,7 @@
 #include <linux/virtio_console.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
+#include <linux/module.h>
 #include "../tty/hvc/hvc_console.h"
 
 /*
@@ -73,6 +76,7 @@ struct ports_driver_data {
 static struct ports_driver_data pdrvdata;
 
 DEFINE_SPINLOCK(pdrvdata_lock);
+DECLARE_COMPLETION(early_console_added);
 
 /* This struct holds information that's relevant only for console ports */
 struct console {
@@ -151,6 +155,10 @@ struct ports_device {
        int chr_major;
 };
 
+struct port_stats {
+       unsigned long bytes_sent, bytes_received, bytes_discarded;
+};
+
 /* This struct holds the per-port data */
 struct port {
        /* Next port in the list, head is in the ports_device */
@@ -179,6 +187,13 @@ struct port {
        struct dentry *debugfs_file;
 
        /*
+        * Keep count of the bytes sent, received and discarded for
+        * this port for accounting and debugging purposes.  These
+        * counts are not reset across port open / close events.
+        */
+       struct port_stats stats;
+
+       /*
         * The entries in this struct will be valid if this port is
         * hooked up to an hvc console
         */
@@ -347,17 +362,19 @@ fail:
 }
 
 /* Callers should take appropriate locks */
-static void *get_inbuf(struct port *port)
+static struct port_buffer *get_inbuf(struct port *port)
 {
        struct port_buffer *buf;
-       struct virtqueue *vq;
        unsigned int len;
 
-       vq = port->in_vq;
-       buf = virtqueue_get_buf(vq, &len);
+       if (port->inbuf)
+               return port->inbuf;
+
+       buf = virtqueue_get_buf(port->in_vq, &len);
        if (buf) {
                buf->len = len;
                buf->offset = 0;
+               port->stats.bytes_received += len;
        }
        return buf;
 }
@@ -375,7 +392,7 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 
        sg_init_one(sg, buf->buf, buf->size);
 
-       ret = virtqueue_add_buf(vq, sg, 0, 1, buf);
+       ret = virtqueue_add_buf(vq, sg, 0, 1, buf, GFP_ATOMIC);
        virtqueue_kick(vq);
        return ret;
 }
@@ -384,32 +401,27 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 static void discard_port_data(struct port *port)
 {
        struct port_buffer *buf;
-       struct virtqueue *vq;
-       unsigned int len;
-       int ret;
+       unsigned int err;
 
        if (!port->portdev) {
                /* Device has been unplugged.  vqs are already gone. */
                return;
        }
-       vq = port->in_vq;
-       if (port->inbuf)
-               buf = port->inbuf;
-       else
-               buf = virtqueue_get_buf(vq, &len);
+       buf = get_inbuf(port);
 
-       ret = 0;
+       err = 0;
        while (buf) {
-               if (add_inbuf(vq, buf) < 0) {
-                       ret++;
+               port->stats.bytes_discarded += buf->len - buf->offset;
+               if (add_inbuf(port->in_vq, buf) < 0) {
+                       err++;
                        free_buf(buf);
                }
-               buf = virtqueue_get_buf(vq, &len);
+               port->inbuf = NULL;
+               buf = get_inbuf(port);
        }
-       port->inbuf = NULL;
-       if (ret)
+       if (err)
                dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
-                        ret);
+                        err);
 }
 
 static bool port_has_data(struct port *port)
@@ -417,18 +429,12 @@ static bool port_has_data(struct port *port)
        unsigned long flags;
        bool ret;
 
+       ret = false;
        spin_lock_irqsave(&port->inbuf_lock, flags);
-       if (port->inbuf) {
-               ret = true;
-               goto out;
-       }
        port->inbuf = get_inbuf(port);
-       if (port->inbuf) {
+       if (port->inbuf)
                ret = true;
-               goto out;
-       }
-       ret = false;
-out:
+
        spin_unlock_irqrestore(&port->inbuf_lock, flags);
        return ret;
 }
@@ -451,7 +457,7 @@ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
        vq = portdev->c_ovq;
 
        sg_init_one(sg, &cpkt, sizeof(cpkt));
-       if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
+       if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) >= 0) {
                virtqueue_kick(vq);
                while (!virtqueue_get_buf(vq, &len))
                        cpu_relax();
@@ -500,7 +506,7 @@ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
        reclaim_consumed_buffers(port);
 
        sg_init_one(sg, in_buf, in_count);
-       ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf);
+       ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf, GFP_ATOMIC);
 
        /* Tell Host to go! */
        virtqueue_kick(out_vq);
@@ -529,6 +535,8 @@ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
                cpu_relax();
 done:
        spin_unlock_irqrestore(&port->outvq_lock, flags);
+
+       port->stats.bytes_sent += in_count;
        /*
         * We're expected to return the amount of data we wrote -- all
         * of it
@@ -633,8 +641,8 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
                if (filp->f_flags & O_NONBLOCK)
                        return -EAGAIN;
 
-               ret = wait_event_interruptible(port->waitqueue,
-                                              !will_read_block(port));
+               ret = wait_event_freezable(port->waitqueue,
+                                          !will_read_block(port));
                if (ret < 0)
                        return ret;
        }
@@ -677,8 +685,8 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
                if (nonblock)
                        return -EAGAIN;
 
-               ret = wait_event_interruptible(port->waitqueue,
-                                              !will_write_block(port));
+               ret = wait_event_freezable(port->waitqueue,
+                                          !will_write_block(port));
                if (ret < 0)
                        return ret;
        }
@@ -1030,12 +1038,6 @@ static struct attribute_group port_attribute_group = {
        .attrs = port_sysfs_entries,
 };
 
-static int debugfs_open(struct inode *inode, struct file *filp)
-{
-       filp->private_data = inode->i_private;
-       return 0;
-}
-
 static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
                            size_t count, loff_t *offp)
 {
@@ -1059,6 +1061,14 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "outvq_full: %d\n", port->outvq_full);
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
+                              "bytes_sent: %lu\n", port->stats.bytes_sent);
+       out_offset += snprintf(buf + out_offset, out_count - out_offset,
+                              "bytes_received: %lu\n",
+                              port->stats.bytes_received);
+       out_offset += snprintf(buf + out_offset, out_count - out_offset,
+                              "bytes_discarded: %lu\n",
+                              port->stats.bytes_discarded);
+       out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "is_console: %s\n",
                               is_console_port(port) ? "yes" : "no");
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
@@ -1071,7 +1081,7 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
 
 static const struct file_operations port_debugfs_ops = {
        .owner = THIS_MODULE,
-       .open  = debugfs_open,
+       .open  = simple_open,
        .read  = debugfs_read,
 };
 
@@ -1143,6 +1153,7 @@ static int add_port(struct ports_device *portdev, u32 id)
        port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
 
        port->host_connected = port->guest_connected = false;
+       port->stats = (struct port_stats) { 0 };
 
        port->outvq_full = false;
 
@@ -1254,6 +1265,20 @@ static void remove_port(struct kref *kref)
        kfree(port);
 }
 
+static void remove_port_data(struct port *port)
+{
+       struct port_buffer *buf;
+
+       /* Remove unused data this port might have received. */
+       discard_port_data(port);
+
+       reclaim_consumed_buffers(port);
+
+       /* Remove buffers we queued up for the Host to send us data in. */
+       while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
+               free_buf(buf);
+}
+
 /*
  * Port got unplugged.  Remove port from portdev's list and drop the
  * kref reference.  If no userspace has this port opened, it will
@@ -1261,8 +1286,6 @@ static void remove_port(struct kref *kref)
  */
 static void unplug_port(struct port *port)
 {
-       struct port_buffer *buf;
-
        spin_lock_irq(&port->portdev->ports_lock);
        list_del(&port->list);
        spin_unlock_irq(&port->portdev->ports_lock);
@@ -1283,14 +1306,7 @@ static void unplug_port(struct port *port)
                hvc_remove(port->cons.hvc);
        }
 
-       /* Remove unused data this port might have received. */
-       discard_port_data(port);
-
-       reclaim_consumed_buffers(port);
-
-       /* Remove buffers we queued up for the Host to send us data in. */
-       while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
-               free_buf(buf);
+       remove_port_data(port);
 
        /*
         * We should just assume the device itself has gone off --
@@ -1352,6 +1368,7 @@ static void handle_control_message(struct ports_device *portdev,
                        break;
 
                init_port_console(port);
+               complete(&early_console_added);
                /*
                 * Could remove the port here in case init fails - but
                 * have to notify the host first.
@@ -1394,6 +1411,13 @@ static void handle_control_message(struct ports_device *portdev,
                break;
        case VIRTIO_CONSOLE_PORT_NAME:
                /*
+                * If we woke up after hibernation, we can get this
+                * again.  Skip it in that case.
+                */
+               if (port->name)
+                       break;
+
+               /*
                 * Skip the size of the header and the cpkt to get the size
                 * of the name that was sent
                 */
@@ -1481,8 +1505,7 @@ static void in_intr(struct virtqueue *vq)
                return;
 
        spin_lock_irqsave(&port->inbuf_lock, flags);
-       if (!port->inbuf)
-               port->inbuf = get_inbuf(port);
+       port->inbuf = get_inbuf(port);
 
        /*
         * Don't queue up data when port is closed.  This condition
@@ -1563,7 +1586,7 @@ static int init_vqs(struct ports_device *portdev)
        portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
                                   GFP_KERNEL);
        if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
-                       !portdev->out_vqs) {
+           !portdev->out_vqs) {
                err = -ENOMEM;
                goto free;
        }
@@ -1635,6 +1658,28 @@ static const struct file_operations portdev_fops = {
        .owner = THIS_MODULE,
 };
 
+static void remove_vqs(struct ports_device *portdev)
+{
+       portdev->vdev->config->del_vqs(portdev->vdev);
+       kfree(portdev->in_vqs);
+       kfree(portdev->out_vqs);
+}
+
+static void remove_controlq_data(struct ports_device *portdev)
+{
+       struct port_buffer *buf;
+       unsigned int len;
+
+       if (!use_multiport(portdev))
+               return;
+
+       while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
+               free_buf(buf);
+
+       while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
+               free_buf(buf);
+}
+
 /*
  * Once we're further in boot, we get probed like any other virtio
  * device.
@@ -1648,6 +1693,10 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
        struct ports_device *portdev;
        int err;
        bool multiport;
+       bool early = early_put_chars != NULL;
+
+       /* Ensure to read early_put_chars now */
+       barrier();
 
        portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
        if (!portdev) {
@@ -1675,13 +1724,11 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
 
        multiport = false;
        portdev->config.max_nr_ports = 1;
-       if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
+       if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
+                             offsetof(struct virtio_console_config,
+                                      max_nr_ports),
+                             &portdev->config.max_nr_ports) == 0)
                multiport = true;
-               vdev->config->get(vdev, offsetof(struct virtio_console_config,
-                                                max_nr_ports),
-                                 &portdev->config.max_nr_ports,
-                                 sizeof(portdev->config.max_nr_ports));
-       }
 
        err = init_vqs(portdev);
        if (err < 0) {
@@ -1719,15 +1766,26 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
 
        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
                           VIRTIO_CONSOLE_DEVICE_READY, 1);
+
+       /*
+        * If there was an early virtio console, assume that there are no
+        * other consoles. We need to wait until the hvc_alloc matches the
+        * hvc_instantiate, otherwise tty_open will complain, resulting in
+        * a "Warning: unable to open an initial console" boot failure.
+        * Without multiport this is done in add_port above. With multiport
+        * this might take some host<->guest communication - thus we have to
+        * wait.
+        */
+       if (multiport && early)
+               wait_for_completion(&early_console_added);
+
        return 0;
 
 free_vqs:
        /* The host might want to notify mgmt sw about device add failure */
        __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
                           VIRTIO_CONSOLE_DEVICE_READY, 0);
-       vdev->config->del_vqs(vdev);
-       kfree(portdev->in_vqs);
-       kfree(portdev->out_vqs);
+       remove_vqs(portdev);
 free_chrdev:
        unregister_chrdev(portdev->chr_major, "virtio-portsdev");
 free:
@@ -1765,21 +1823,8 @@ static void virtcons_remove(struct virtio_device *vdev)
         * have to just stop using the port, as the vqs are going
         * away.
         */
-       if (use_multiport(portdev)) {
-               struct port_buffer *buf;
-               unsigned int len;
-
-               while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
-                       free_buf(buf);
-
-               while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
-                       free_buf(buf);
-       }
-
-       vdev->config->del_vqs(vdev);
-       kfree(portdev->in_vqs);
-       kfree(portdev->out_vqs);
-
+       remove_controlq_data(portdev);
+       remove_vqs(portdev);
        kfree(portdev);
 }
 
@@ -1793,6 +1838,75 @@ static unsigned int features[] = {
        VIRTIO_CONSOLE_F_MULTIPORT,
 };
 
+#ifdef CONFIG_PM
+static int virtcons_freeze(struct virtio_device *vdev)
+{
+       struct ports_device *portdev;
+       struct port *port;
+
+       portdev = vdev->priv;
+
+       vdev->config->reset(vdev);
+
+       virtqueue_disable_cb(portdev->c_ivq);
+       cancel_work_sync(&portdev->control_work);
+       /*
+        * Once more: if control_work_handler() was running, it would
+        * enable the cb as the last step.
+        */
+       virtqueue_disable_cb(portdev->c_ivq);
+       remove_controlq_data(portdev);
+
+       list_for_each_entry(port, &portdev->ports, list) {
+               virtqueue_disable_cb(port->in_vq);
+               virtqueue_disable_cb(port->out_vq);
+               /*
+                * We'll ask the host later if the new invocation has
+                * the port opened or closed.
+                */
+               port->host_connected = false;
+               remove_port_data(port);
+       }
+       remove_vqs(portdev);
+
+       return 0;
+}
+
+static int virtcons_restore(struct virtio_device *vdev)
+{
+       struct ports_device *portdev;
+       struct port *port;
+       int ret;
+
+       portdev = vdev->priv;
+
+       ret = init_vqs(portdev);
+       if (ret)
+               return ret;
+
+       if (use_multiport(portdev))
+               fill_queue(portdev->c_ivq, &portdev->cvq_lock);
+
+       list_for_each_entry(port, &portdev->ports, list) {
+               port->in_vq = portdev->in_vqs[port->id];
+               port->out_vq = portdev->out_vqs[port->id];
+
+               fill_queue(port->in_vq, &port->inbuf_lock);
+
+               /* Get port open/close status on the host */
+               send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+
+               /*
+                * If a port was open at the time of suspending, we
+                * have to let the host know that it's still open.
+                */
+               if (port->guest_connected)
+                       send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
+       }
+       return 0;
+}
+#endif
+
 static struct virtio_driver virtio_console = {
        .feature_table = features,
        .feature_table_size = ARRAY_SIZE(features),
@@ -1802,6 +1916,10 @@ static struct virtio_driver virtio_console = {
        .probe =        virtcons_probe,
        .remove =       virtcons_remove,
        .config_changed = config_intr,
+#ifdef CONFIG_PM
+       .freeze =       virtcons_freeze,
+       .restore =      virtcons_restore,
+#endif
 };
 
 static int __init init(void)