[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] RFC: chardev: mark the calls that allow an impl
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH] RFC: chardev: mark the calls that allow an implicit mux monitor |
Date: |
Wed, 22 Aug 2018 13:26:38 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 08/22/2018 01:02 PM, Marc-André Lureau wrote:
This is mostly for readability of the code. Let's make it clear which
callers can create an implicit monitor when the chardev is muxed.
This will also enforce a safer behaviour, as we don't really support
creating monitor anywhere/anytime at the moment.
There are documented cases, such as: -serial/-parallel/-virtioconsole
and to less extent -debugcon.
Less obvious and questionnable ones are -gdb and Xen console. Add a
s/questionnable/questionable/
FIXME note for those, but keep the support for now.
Other qemu_chr_new() callers either have a fixed parameter/filename
string, or do preliminary checks on the string (such as slirp), or do
not need it, such as -qtest.
On a related note, the list of monitor creation places:
- the chardev creators listed above: all from command line (except
perhaps Xen console?)
- -gdb & hmp gdbserver will create a "GDB monitor command" chardev
that is wired to an HMP monitor.
- -mon command line option
From this short study, I would like to think that a monitor may only
be created in the main thread today, though I remain skeptical :)
Signed-off-by: Marc-André Lureau <address@hidden>
---
include/chardev/char.h | 18 +++++++++++++++++-
chardev/char.c | 21 +++++++++++++++++----
gdbstub.c | 6 +++++-
hw/char/xen_console.c | 5 ++++-
vl.c | 8 ++++----
5 files changed, 47 insertions(+), 11 deletions(-)
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 6f0576e214..be2b9b817e 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -105,6 +105,7 @@ ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts,
* @qemu_chr_new:
*
* Create a new character backend from a URI.
+ * Do not implicitely initialize a monitor if the chardev is muxed.
s/implicitely/implicitly/
*
* @label the name of the backend
* @filename the URI
@@ -113,6 +114,19 @@ ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts,
*/
Chardev *qemu_chr_new(const char *label, const char *filename);
+/**
+ * @qemu_chr_new_mux_mon:
+ *
+ * Create a new character backend from a URI.
+ * Implicitely initialize a monitor if the chardev is muxed.
and again
+++ b/gdbstub.c
@@ -2038,7 +2038,11 @@ int gdbserver_start(const char *device)
sigaction(SIGINT, &act, NULL);
}
#endif
- chr = qemu_chr_new_noreplay("gdb", device);
+ /*
+ * FIXME: it's a bit weird to allow using a mux chardev here
+ * and setup implicitely a monitor. We may want to break this.
s/setup implicitely/implicitly set up/
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org