The Chardev events are listed in the QEMUChrEvent enum. By using the enum in the IOEventHandler typedef we: - make the IOEventHandler type more explicit (this handler process out-of-band information, while the IOReadHandler is in-band), - help static code analyzers. This patch was produced with the following spatch script: @match@ expression backend, opaque, context, set_open; identifier fd_can_read, fd_read, fd_event, be_change; @@ qemu_chr_fe_set_handlers(backend, fd_can_read, fd_read, fd_event, be_change, opaque, context, set_open); @depends on match@ identifier opaque, event; identifier match.fd_event; @@ static -void fd_event(void *opaque, int event) +void fd_event(void *opaque, QEMUChrEvent event) { ... } Then the typedef was modified manually in include/chardev/char-fe.h. Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20191218172009.8868-15-philmd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
307 lines
9.4 KiB
C
307 lines
9.4 KiB
C
/*
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* Virtio Console and Generic Serial Port Devices
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*
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* Copyright Red Hat, Inc. 2009, 2010
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*
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* Authors:
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* Amit Shah <amit.shah@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "chardev/char-fe.h"
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#include "qemu/error-report.h"
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#include "qemu/module.h"
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#include "trace.h"
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#include "hw/qdev-properties.h"
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#include "hw/virtio/virtio-serial.h"
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#include "qapi/error.h"
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#include "qapi/qapi-events-char.h"
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#define TYPE_VIRTIO_CONSOLE_SERIAL_PORT "virtserialport"
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#define VIRTIO_CONSOLE(obj) \
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OBJECT_CHECK(VirtConsole, (obj), TYPE_VIRTIO_CONSOLE_SERIAL_PORT)
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typedef struct VirtConsole {
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VirtIOSerialPort parent_obj;
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CharBackend chr;
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guint watch;
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} VirtConsole;
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/*
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* Callback function that's called from chardevs when backend becomes
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* writable.
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*/
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static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond,
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void *opaque)
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{
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VirtConsole *vcon = opaque;
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vcon->watch = 0;
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virtio_serial_throttle_port(VIRTIO_SERIAL_PORT(vcon), false);
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return FALSE;
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}
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/* Callback function that's called when the guest sends us data */
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static ssize_t flush_buf(VirtIOSerialPort *port,
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const uint8_t *buf, ssize_t len)
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{
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VirtConsole *vcon = VIRTIO_CONSOLE(port);
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ssize_t ret;
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if (!qemu_chr_fe_backend_connected(&vcon->chr)) {
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/* If there's no backend, we can just say we consumed all data. */
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return len;
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}
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ret = qemu_chr_fe_write(&vcon->chr, buf, len);
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trace_virtio_console_flush_buf(port->id, len, ret);
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if (ret < len) {
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
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/*
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* Ideally we'd get a better error code than just -1, but
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* that's what the chardev interface gives us right now. If
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* we had a finer-grained message, like -EPIPE, we could close
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* this connection.
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*/
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if (ret < 0)
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ret = 0;
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/* XXX we should be queuing data to send later for the
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* console devices too rather than silently dropping
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* console data on EAGAIN. The Linux virtio-console
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* hvc driver though does sends with spinlocks held,
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* so if we enable throttling that'll stall the entire
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* guest kernel, not merely the process writing to the
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* console.
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*
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* While we could queue data for later write without
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* enabling throttling, this would result in the guest
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* being able to trigger arbitrary memory usage in QEMU
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* buffering data for later writes.
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*
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* So fixing this problem likely requires fixing the
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* Linux virtio-console hvc driver to not hold spinlocks
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* while writing, and instead merely block the process
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* that's writing. QEMU would then need some way to detect
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* if the guest had the fixed driver too, before we can
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* use throttling on host side.
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*/
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if (!k->is_console) {
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virtio_serial_throttle_port(port, true);
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if (!vcon->watch) {
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vcon->watch = qemu_chr_fe_add_watch(&vcon->chr,
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G_IO_OUT|G_IO_HUP,
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chr_write_unblocked, vcon);
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}
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}
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}
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return ret;
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}
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/* Callback function that's called when the guest opens/closes the port */
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static void set_guest_connected(VirtIOSerialPort *port, int guest_connected)
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{
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VirtConsole *vcon = VIRTIO_CONSOLE(port);
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DeviceState *dev = DEVICE(port);
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
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if (!k->is_console) {
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qemu_chr_fe_set_open(&vcon->chr, guest_connected);
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}
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if (dev->id) {
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qapi_event_send_vserport_change(dev->id, guest_connected);
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}
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}
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static void guest_writable(VirtIOSerialPort *port)
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{
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VirtConsole *vcon = VIRTIO_CONSOLE(port);
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qemu_chr_fe_accept_input(&vcon->chr);
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}
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/* Readiness of the guest to accept data on a port */
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static int chr_can_read(void *opaque)
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{
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VirtConsole *vcon = opaque;
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return virtio_serial_guest_ready(VIRTIO_SERIAL_PORT(vcon));
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}
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/* Send data from a char device over to the guest */
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static void chr_read(void *opaque, const uint8_t *buf, int size)
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{
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VirtConsole *vcon = opaque;
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VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
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trace_virtio_console_chr_read(port->id, size);
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virtio_serial_write(port, buf, size);
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}
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static void chr_event(void *opaque, QEMUChrEvent event)
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{
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VirtConsole *vcon = opaque;
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VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
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trace_virtio_console_chr_event(port->id, event);
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switch (event) {
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case CHR_EVENT_OPENED:
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virtio_serial_open(port);
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break;
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case CHR_EVENT_CLOSED:
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if (vcon->watch) {
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g_source_remove(vcon->watch);
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vcon->watch = 0;
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}
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virtio_serial_close(port);
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break;
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case CHR_EVENT_BREAK:
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case CHR_EVENT_MUX_IN:
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case CHR_EVENT_MUX_OUT:
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/* Ignore */
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break;
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}
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}
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static int chr_be_change(void *opaque)
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{
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VirtConsole *vcon = opaque;
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VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
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if (k->is_console) {
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qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
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NULL, chr_be_change, vcon, NULL, true);
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} else {
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qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
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chr_event, chr_be_change, vcon, NULL, false);
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}
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if (vcon->watch) {
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g_source_remove(vcon->watch);
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vcon->watch = qemu_chr_fe_add_watch(&vcon->chr,
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G_IO_OUT | G_IO_HUP,
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chr_write_unblocked, vcon);
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}
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return 0;
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}
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static void virtconsole_enable_backend(VirtIOSerialPort *port, bool enable)
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{
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VirtConsole *vcon = VIRTIO_CONSOLE(port);
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if (!qemu_chr_fe_backend_connected(&vcon->chr)) {
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return;
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}
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if (enable) {
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
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qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
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k->is_console ? NULL : chr_event,
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chr_be_change, vcon, NULL, false);
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} else {
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qemu_chr_fe_set_handlers(&vcon->chr, NULL, NULL, NULL,
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NULL, NULL, NULL, false);
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}
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}
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static void virtconsole_realize(DeviceState *dev, Error **errp)
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{
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VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
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VirtConsole *vcon = VIRTIO_CONSOLE(dev);
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
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if (port->id == 0 && !k->is_console) {
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error_setg(errp, "Port number 0 on virtio-serial devices reserved "
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"for virtconsole devices for backward compatibility.");
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return;
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}
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if (qemu_chr_fe_backend_connected(&vcon->chr)) {
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/*
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* For consoles we don't block guest data transfer just
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* because nothing is connected - we'll just let it go
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* whetherever the chardev wants - /dev/null probably.
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*
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* For serial ports we need 100% reliable data transfer
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* so we use the opened/closed signals from chardev to
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* trigger open/close of the device
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*/
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if (k->is_console) {
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qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
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NULL, chr_be_change,
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vcon, NULL, true);
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virtio_serial_open(port);
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} else {
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qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
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chr_event, chr_be_change,
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vcon, NULL, false);
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}
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}
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}
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static void virtconsole_unrealize(DeviceState *dev, Error **errp)
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{
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VirtConsole *vcon = VIRTIO_CONSOLE(dev);
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if (vcon->watch) {
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g_source_remove(vcon->watch);
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}
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}
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static void virtconsole_class_init(ObjectClass *klass, void *data)
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{
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
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k->is_console = true;
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}
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static const TypeInfo virtconsole_info = {
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.name = "virtconsole",
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.parent = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
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.class_init = virtconsole_class_init,
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};
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static Property virtserialport_properties[] = {
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DEFINE_PROP_CHR("chardev", VirtConsole, chr),
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DEFINE_PROP_END_OF_LIST(),
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};
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static void virtserialport_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
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k->realize = virtconsole_realize;
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k->unrealize = virtconsole_unrealize;
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k->have_data = flush_buf;
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k->set_guest_connected = set_guest_connected;
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k->enable_backend = virtconsole_enable_backend;
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k->guest_writable = guest_writable;
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dc->props = virtserialport_properties;
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}
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static const TypeInfo virtserialport_info = {
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.name = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
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.parent = TYPE_VIRTIO_SERIAL_PORT,
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.instance_size = sizeof(VirtConsole),
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.class_init = virtserialport_class_init,
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};
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static void virtconsole_register_types(void)
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{
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type_register_static(&virtserialport_info);
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type_register_static(&virtconsole_info);
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}
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type_init(virtconsole_register_types)
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