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spice-qemu-char: Generate chardev open/close events

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Define a state callback and make that generate chardev open/close events when
called by the spice-server.

Notes:

1) For all but the newest spice-server versions (which have a fix for this)
the code ignores these events for a spicevmc with a subtype of vdagent, this
subtype specific knowledge is undesirable, but unavoidable for now, see:
http://lists.freedesktop.org/archives/spice-devel/2011-July/004837.html

2) This code deliberately sends the events immediately rather then from a
bh. This is done this way because:
a) There is no need to do it from a bh; and
b) Doing it from a bh actually causes issues because the spice-server may send
data immediately after the open and when the open runs from a bh, then
qemu_chr_be_can_write will return 0 for the first write which the spice-server
does not expect, when this happens the spice-server will never retry the write
causing communication to stall.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Hans de Goede 2011-11-19 10:22:44 +01:00 committed by Anthony Liguori
parent a425d23f8f
commit f76e4c7f16
1 changed files with 35 additions and 1 deletions
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36
spice-qemu-char.c
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@ -69,11 +69,40 @@ static int vmc_read(SpiceCharDeviceInstance *sin, uint8_t *buf, int len)
return bytes;
}
static void vmc_state(SpiceCharDeviceInstance *sin, int connected)
{
SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
#if SPICE_SERVER_VERSION < 0x000901
/*
* spice-server calls the state callback for the agent channel when the
* spice client connects / disconnects. Given that not the client but
* the server is doing the parsing of the messages this is wrong as the
* server is still listening. Worse, this causes the parser in the server
* to go out of sync, so we ignore state calls for subtype vdagent
* spicevmc chardevs. For the full story see:
* http://lists.freedesktop.org/archives/spice-devel/2011-July/004837.html
*/
if (strcmp(sin->subtype, "vdagent") == 0) {
return;
}
#endif
if ((scd->chr->opened && connected) ||
(!scd->chr->opened && !connected)) {
return;
}
qemu_chr_be_event(scd->chr,
connected ? CHR_EVENT_OPENED : CHR_EVENT_CLOSED);
}
static SpiceCharDeviceInterface vmc_interface = {
.base.type = SPICE_INTERFACE_CHAR_DEVICE,
.base.description = "spice virtual channel char device",
.base.major_version = SPICE_INTERFACE_CHAR_DEVICE_MAJOR,
.base.minor_version = SPICE_INTERFACE_CHAR_DEVICE_MINOR,
.state = vmc_state,
.write = vmc_write,
.read = vmc_read,
};
@ -197,7 +226,12 @@ int qemu_chr_open_spice(QemuOpts *opts, CharDriverState **_chr)
chr->chr_guest_open = spice_chr_guest_open;
chr->chr_guest_close = spice_chr_guest_close;
qemu_chr_generic_open(chr);
#if SPICE_SERVER_VERSION < 0x000901
/* See comment in vmc_state() */
if (strcmp(subtype, "vdagent") == 0) {
qemu_chr_generic_open(chr);
}
#endif
*_chr = chr;
return 0;