switch chardev to QemuOpts: infrastructure, null device

start switching chardevs to QemuOpts.  This patch adds the
infrastructure and converts the null device.

The patch brings two new functions:

qemu_chr_open_opts()
	same as qemu_chr_open(), but uses QemuOpts instead of a
	option char string.

qemu_chr_parse_compat()
	accepts a traditional chardev option string, returns the
	corresponding QemuOpts instance, to handle backward
	compatibility.

The patch also adds a new -chardev switch which can be used to create
named+unconnected chardevs, like this:

	-chardev null,id=test

This uses the new qemu_chr_open_opts.  Thus with this patch alone only
the null device works.  The other devices will follow ...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index ce38a3b62c..d3aa55b635 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1195,6 +1195,8 @@ STEXI
 @table @option
 ETEXI
 
+DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, \
+    "-chardev spec   create unconnected chardev\n")
 DEF("serial", HAS_ARG, QEMU_OPTION_serial, \
     "-serial dev     redirect the serial port to char device 'dev'\n")
 STEXI