The only way for chardev drivers to communicate an error was to return a NULL
pointer, which resulted in an error message that said _that_ something went
wrong, but not _why_.
This patch changes the interface to return 0/-errno and updates
qemu_chr_open_opts to use strerror to display a more helpful error message.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
In the old spice-vmc device we used to have:
last_out = virtio_serial_write(&svc->port, p, MIN(len, VMC_MAX_HOST_WRITE));
if (last_out > 0)
...
Now in the chardev backend we have:
last_out = MIN(len, VMC_MAX_HOST_WRITE);
qemu_chr_read(scd->chr, p, last_out);
if (last_out > 0) {
...
Which causes us to no longer detect if the virtio port is not ready
to receive data from us. chardev actually has a mechanism to detect this,
but it requires a separate call to qemu_chr_can_read, before calling
qemu_chr_read (which return void).
This patch uses qemu_chr_can_read to fix the flow control from client to
guest.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Note the vmc_register_interface() in spice_chr_write is left in place
in case someone uses spice-chardev with a frontend which does not have
guest open / close notification.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Alon Levy <alevy@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Adding a chardev backend for spice, where spice determines what
to do with it based on the name attribute given during chardev creation.
For usage by spice vdagent in conjunction with a properly named
virtio-serial device, and future smartcard channel usage.
Example usage:
qemu -device virtio-serial -chardev spicevmc,name=vdagent,id=vdagent \
-device virtserialport,chardev=vdagent,name=com.redhat.spice.0
v4->v5:
* add tracing events
* fix missing comma
* fix help string to show debug is optional
v3->v4:
* updated commit message
v1->v3 changes: (v2 had a wrong commit message)
* removed spice-qemu-char.h, folded into ui/qemu-spice.h
* removed dead IOCTL code
* removed comment
* removed ifdef CONFIG_SPICE from qemu-config.c and qemu-options.hx help.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Kevin Wolf
Hans de Goede
Alon Levy