diff options
| -rw-r--r-- | hw/virtio-console.c | 38 | ||||
| -rw-r--r-- | hw/virtio-serial-bus.c | 123 | ||||
| -rw-r--r-- | hw/virtio-serial.h | 24 |
3 files changed, 139 insertions, 46 deletions
diff --git a/hw/virtio-console.c b/hw/virtio-console.c index caea11f3a8..62624ec780 100644 --- a/hw/virtio-console.c +++ b/hw/virtio-console.c @@ -20,11 +20,11 @@ typedef struct VirtConsole { /* Callback function that's called when the guest sends us data */ -static void flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) +static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) { VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port); - qemu_chr_write(vcon->chr, buf, len); + return qemu_chr_write(vcon->chr, buf, len); } /* Readiness of the guest to accept data on a port */ @@ -48,34 +48,37 @@ static void chr_event(void *opaque, int event) VirtConsole *vcon = opaque; switch (event) { - case CHR_EVENT_OPENED: { + case CHR_EVENT_OPENED: virtio_serial_open(&vcon->port); break; - } case CHR_EVENT_CLOSED: virtio_serial_close(&vcon->port); break; } } -/* Virtio Console Ports */ -static int virtconsole_initfn(VirtIOSerialDevice *dev) +static int generic_port_init(VirtConsole *vcon, VirtIOSerialDevice *dev) { - VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev); - VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port); - - port->info = dev->info; - - port->is_console = true; + vcon->port.info = dev->info; if (vcon->chr) { qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event, vcon); - port->info->have_data = flush_buf; + vcon->port.info->have_data = flush_buf; } return 0; } +/* Virtio Console Ports */ +static int virtconsole_initfn(VirtIOSerialDevice *dev) +{ + VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev); + VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port); + + port->is_console = true; + return generic_port_init(vcon, dev); +} + static int virtconsole_exitfn(VirtIOSerialDevice *dev) { VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev); @@ -115,14 +118,7 @@ static int virtserialport_initfn(VirtIOSerialDevice *dev) VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev); VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port); - port->info = dev->info; - - if (vcon->chr) { - qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event, - vcon); - port->info->have_data = flush_buf; - } - return 0; + return generic_port_init(vcon, dev); } static VirtIOSerialPortInfo virtserialport_info = { diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index b728040f3a..09e22aa44a 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -113,39 +113,74 @@ static size_t write_to_port(VirtIOSerialPort *port, return offset; } -static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, - VirtIODevice *vdev, bool discard) +static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev) { VirtQueueElement elem; - assert(port || discard); + while (virtqueue_pop(vq, &elem)) { + virtqueue_push(vq, &elem, 0); + } + virtio_notify(vdev, vq); +} + +static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, + VirtIODevice *vdev) +{ + assert(port); assert(virtio_queue_ready(vq)); - while ((discard || !port->throttled) && virtqueue_pop(vq, &elem)) { - uint8_t *buf; - size_t ret, buf_size; + while (!port->throttled) { + unsigned int i; - if (!discard) { - buf_size = iov_size(elem.out_sg, elem.out_num); - buf = qemu_malloc(buf_size); - ret = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, buf_size); + /* Pop an elem only if we haven't left off a previous one mid-way */ + if (!port->elem.out_num) { + if (!virtqueue_pop(vq, &port->elem)) { + break; + } + port->iov_idx = 0; + port->iov_offset = 0; + } - port->info->have_data(port, buf, ret); - qemu_free(buf); + for (i = port->iov_idx; i < port->elem.out_num; i++) { + size_t buf_size; + ssize_t ret; + + buf_size = port->elem.out_sg[i].iov_len - port->iov_offset; + ret = port->info->have_data(port, + port->elem.out_sg[i].iov_base + + port->iov_offset, + buf_size); + if (ret < 0 && ret != -EAGAIN) { + /* We don't handle any other type of errors here */ + abort(); + } + if (ret == -EAGAIN || (ret >= 0 && ret < buf_size)) { + virtio_serial_throttle_port(port, true); + port->iov_idx = i; + if (ret > 0) { + port->iov_offset += ret; + } + break; + } + port->iov_offset = 0; } - virtqueue_push(vq, &elem, 0); + if (port->throttled) { + break; + } + virtqueue_push(vq, &port->elem, 0); + port->elem.out_num = 0; } virtio_notify(vdev, vq); } -static void flush_queued_data(VirtIOSerialPort *port, bool discard) +static void flush_queued_data(VirtIOSerialPort *port) { assert(port); if (!virtio_queue_ready(port->ovq)) { return; } - do_flush_queued_data(port, port->ovq, &port->vser->vdev, discard); + do_flush_queued_data(port, port->ovq, &port->vser->vdev); } static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len) @@ -204,7 +239,7 @@ int virtio_serial_close(VirtIOSerialPort *port) * consume, reset the throttling flag and discard the data. */ port->throttled = false; - flush_queued_data(port, true); + discard_vq_data(port->ovq, &port->vser->vdev); send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0); @@ -258,7 +293,7 @@ void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle) return; } - flush_queued_data(port, false); + flush_queued_data(port); } /* Guest wants to notify us of some event */ @@ -414,11 +449,15 @@ static void handle_output(VirtIODevice *vdev, VirtQueue *vq) discard = true; } - if (!discard && port->throttled) { + if (discard) { + discard_vq_data(vq, vdev); + return; + } + if (port->throttled) { return; } - do_flush_queued_data(port, vq, vdev, discard); + do_flush_queued_data(port, vq, vdev); } static void handle_input(VirtIODevice *vdev, VirtQueue *vq) @@ -488,9 +527,24 @@ static void virtio_serial_save(QEMUFile *f, void *opaque) * Items in struct VirtIOSerialPort. */ QTAILQ_FOREACH(port, &s->ports, next) { + uint32_t elem_popped; + qemu_put_be32s(f, &port->id); qemu_put_byte(f, port->guest_connected); qemu_put_byte(f, port->host_connected); + + elem_popped = 0; + if (port->elem.out_num) { + elem_popped = 1; + } + qemu_put_be32s(f, &elem_popped); + if (elem_popped) { + qemu_put_be32s(f, &port->iov_idx); + qemu_put_be64s(f, &port->iov_offset); + + qemu_put_buffer(f, (unsigned char *)&port->elem, + sizeof(port->elem)); + } } } @@ -501,7 +555,7 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id) uint32_t max_nr_ports, nr_active_ports, ports_map; unsigned int i; - if (version_id > 2) { + if (version_id > 3) { return -EINVAL; } @@ -554,6 +608,29 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id) send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, port->host_connected); } + + if (version_id > 2) { + uint32_t elem_popped; + + qemu_get_be32s(f, &elem_popped); + if (elem_popped) { + qemu_get_be32s(f, &port->iov_idx); + qemu_get_be64s(f, &port->iov_offset); + + qemu_get_buffer(f, (unsigned char *)&port->elem, + sizeof(port->elem)); + virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr, + port->elem.in_num, 1); + virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr, + port->elem.out_num, 1); + + /* + * Port was throttled on source machine. Let's + * unthrottle it here so data starts flowing again. + */ + virtio_serial_throttle_port(port, false); + } + } } return 0; } @@ -634,7 +711,7 @@ static void remove_port(VirtIOSerial *vser, uint32_t port_id) port = find_port_by_id(vser, port_id); /* Flush out any unconsumed buffers first */ - flush_queued_data(port, true); + discard_vq_data(port->ovq, &port->vser->vdev); send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1); } @@ -695,6 +772,8 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base) port->guest_connected = true; } + port->elem.out_num = 0; + QTAILQ_INSERT_TAIL(&port->vser->ports, port, next); port->ivq = port->vser->ivqs[port->id]; port->ovq = port->vser->ovqs[port->id]; @@ -806,7 +885,7 @@ VirtIODevice *virtio_serial_init(DeviceState *dev, uint32_t max_nr_ports) * Register for the savevm section with the virtio-console name * to preserve backward compat */ - register_savevm(dev, "virtio-console", -1, 2, virtio_serial_save, + register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save, virtio_serial_load, vser); return vdev; diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h index ff08c40681..a308196786 100644 --- a/hw/virtio-serial.h +++ b/hw/virtio-serial.h @@ -102,6 +102,23 @@ struct VirtIOSerialPort { */ uint32_t id; + /* + * This is the elem that we pop from the virtqueue. A slow + * backend that consumes guest data (e.g. the file backend for + * qemu chardevs) can cause the guest to block till all the output + * is flushed. This isn't desired, so we keep a note of the last + * element popped and continue consuming it once the backend + * becomes writable again. + */ + VirtQueueElement elem; + + /* + * The index and the offset into the iov buffer that was popped in + * elem above. + */ + uint32_t iov_idx; + uint64_t iov_offset; + /* Identify if this is a port that binds with hvc in the guest */ uint8_t is_console; @@ -137,10 +154,11 @@ struct VirtIOSerialPortInfo { /* * Guest wrote some data to the port. This data is handed over to - * the app via this callback. The app is supposed to consume all - * the data that is presented to it. + * the app via this callback. The app can return a size less than + * 'len'. In this case, throttling will be enabled for this port. */ - void (*have_data)(VirtIOSerialPort *port, const uint8_t *buf, size_t len); + ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf, + size_t len); }; /* Interface to the virtio-serial bus */ |