monitor_qmp_dispatcher_co() runs in the iohandler AioContext that is not
polled during nested event loops. The coroutine currently reschedules
itself in the main loop's qemu_aio_context AioContext, which is polled
during nested event loops. One known problem is that QMP device-add
calls drain_call_rcu(), which temporarily drops the BQL, leading to all
sorts of havoc like other vCPU threads re-entering device emulation code
while another vCPU thread is waiting in device emulation code with
aio_poll().

Paolo Bonzini suggested running non-coroutine QMP handlers in the
iohandler AioContext. This avoids trouble with nested event loops. His
original idea was to move coroutine rescheduling to
monitor_qmp_dispatch(), but I resorted to moving it to qmp_dispatch()
because we don't know if the QMP handler needs to run in coroutine
context in monitor_qmp_dispatch(). monitor_qmp_dispatch() would have
been nicer since it's associated with the monitor implementation and not
as general as qmp_dispatch(), which is also used by qemu-ga.

A number of qemu-iotests need updated .out files because the order of
QMP events vs QMP responses has changed.

Solves Issue #1933.

Cc: qemu-stable@nongnu.org
Fixes: 7bed8995 ("device_core: use drain_call_rcu in in qmp_device_add")
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2215192
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2214985
Buglink: https://issues.redhat.com/browse/RHEL-17369


Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240118144823.1497953-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit effd60c878176bcaf97fa7ce2b12d04bb8ead6f7)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

Improve

    (qemu) sync-profile of
    Error: Invalid parameter 'of'

to

    Error: invalid parameter 'of', expecting 'on', 'off', or 'reset'

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20231031111059.3407803-3-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Dr. David Alan Gilbert <dave@treblig.org>

Used by the hv-balloon driver for (optional) guest memory status reports.

Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>

Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

GLib recommend to use G_SOURCE_REMOVE / G_SOURCE_CONTINUE
for GSourceFunc callbacks. Our FEWatchFunc is a GSourceFunc
returning such value. Use such definitions which are
"more memorable" [*].

[*] https://docs.gtk.org/glib/callback.SourceFunc.html#return-value



Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230705133139.54419-5-philmd@linaro.org>

We use the user_ss[] array to hold the user emulation sources,
and the softmmu_ss[] array to hold the system emulation ones.
Hold the latter in the 'system_ss[]' array for parity with user
emulation.

Mechanical change doing:

  $ sed -i -e s/softmmu_ss/system_ss/g $(git grep -l softmmu_ss)

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230613133347.82210-10-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Since we *might* have user emulation with softmmu,
use the clearer 'CONFIG_SYSTEM_ONLY' key to check
for system emulation.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230613133347.82210-9-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

qatomic_mb_read and qatomic_mb_set were the very first atomic primitives
introduced for QEMU; their semantics are unclear and they provide a false
sense of safety.

The last use of qatomic_mb_read() has been removed, so delete it.
qatomic_mb_set() instead can survive as an optimized
qatomic_set()+smp_mb(), similar to Linux's smp_store_mb(), but
rename it to qatomic_set_mb() to match the order of the two
operations.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Instead of relying on magic memory barriers, document the pattern that
is being used.  It is the one based on Dekker's algorithm, and in this
case it is embodied as follows:

    enqueue request;              sleeping = true;
    smp_mb();                     smp_mb();
    if (sleeping) kick();         if (!have a request) yield();

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This makes it possible to turn qmp_dispatcher_co_busy into a static
variable.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Use a continue statement so that "after going to sleep" is treated the same
way as "after processing a request".  Pull the monitor_lock critical
section out of monitor_qmp_requests_pop_any_with_lock() and protect
qmp_dispatcher_co_shutdown with the monitor_lock.

The two changes are complex to separate because monitor_qmp_dispatcher_co()
previously had a complicated logic to check for shutdown both before
and after going to sleep.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Instead of overloading qmp_dispatcher_co_busy, make the coroutine
pointer NULL.  This will make things break spectacularly if somebody
tries to start a request after monitor_cleanup().

AIO_WAIT_WHILE_UNLOCKED() does not need qatomic_mb_read(), because
the macro contains all the necessary memory barriers.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Clean up monitor_event to just use monitor_suspend/monitor_resume,
using mon->mux_out to protect against incorrect nesting (especially
on startup).

The only remaining case of reading suspend_cnt is in the can_read
callback, which is just advisory and can use qatomic_read.

As an extra benefit, mux_out is now simply protected by mon_lock.
Also, moving the prompt to the beginning of the main loop removes
it from the output in some error cases where QEMU does not actually
start successfully.  It is not a full fix and it would be nice to
also remove the monitor heading, but this is already a small (though
unintentional) improvement.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Allow flushing and printing to the monitor while mon->mon_lock is
held.  This will help cleaning up the locking of mon->mux_out and
mon->suspend_cnt.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Move monitor_resume()'s call to readline_show_prompt() outside the
potentially locked section.  Reuse the existing monitor_accept_input()
bottom half for this purpose.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

monitor_cleanup() is called from the main loop thread. Calling
AIO_WAIT_WHILE(qemu_get_aio_context(), ...) from the main loop thread is
equivalent to AIO_WAIT_WHILE_UNLOCKED(NULL, ...) because neither unlocks
the AioContext and the latter's assertion that we're in the main loop
succeeds.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230309190855.414275-7-stefanha@redhat.com>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

The HMP monitor runs in the main loop thread. Calling
AIO_WAIT_WHILE(qemu_get_aio_context(), ...) from the main loop thread is
equivalent to AIO_WAIT_WHILE_UNLOCKED(NULL, ...) because neither unlocks
the AioContext and the latter's assertion that we're in the main loop
succeeds.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230309190855.414275-6-stefanha@redhat.com>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Currently, the function will simply fail if ancillary fds are not
provided, for ex on unsupported platforms.

This changes the failure from:

    {"error": {"class": "GenericError", "desc": "No file descriptor
    supplied via SCM_RIGHTS"}}

to:

    {"error": {"class": "CommandNotFound", "desc": "The command getfd
    has not been found"}}

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

A process with enough capabilities can duplicate a socket to QEMU. Add a
QMP command to import it and add it to the monitor fd list, so it can be
later used by other commands.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230306122751.2355515-9-marcandre.lureau@redhat.com>

As per comment, presumably to avoid syscall in critical section.

Fixes: 0210c3b3 ("monitor: Use LOCK_GUARD macros")
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230306122751.2355515-7-marcandre.lureau@redhat.com>

Whether it is SPICE, VNC, D-Bus, or the socket chardev, they all
actually expect a socket kind or will fail in different ways at runtime.

Throw an error early if the given 'add_client' fd is not a socket, and
close it to avoid leaks.

This allows to replace the close() call with a more correct & portable
closesocket() version.

(this will allow importing sockets on Windows with a specialized command
in the following patch, while keeping the remaining monitor associated
sockets/add_client code & usage untouched)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230306122751.2355515-6-marcandre.lureau@redhat.com>

The auto completion does not work in some cases.

Case 1.

1. (qemu) info reg
2. Press 'Tab'.
3. It does not auto complete.

Case 2.

1. (qemu) block_resize flo
2. Press 'Tab'.
3. It does not auto complete 'floppy0'.

Since the readline_add_completion_of() may add any completion when
strlen(pfx) is zero, we remove the check with (name[0] == '\0') because
strlen() always returns zero in that case.

Fixes: 52f50b1e ("readline: Extract readline_add_completion_of() from monitor")
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

The auto completion does not work in some cases.

Case 1.

1. (qemu) info reg
2. Press 'Tab'.
3. It does not auto complete.

Case 2.

1. (qemu) block_resize flo
2. Press 'Tab'.
3. It does not auto complete 'floppy0'.

Since the readline_add_completion_of() may add any completion when
strlen(pfx) is zero, we remove the check with (name[0] == '\0') because
strlen() always returns zero in that case.

Fixes: 52f50b1e ("readline: Extract readline_add_completion_of() from monitor")
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Message-Id: <20230207045241.8843-1-dongli.zhang@oracle.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

What's left in misc.c is exactly the target-dependent part of the HMP
core.  Rename accordingly.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-33-armbru@redhat.com>

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-32-armbru@redhat.com>

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-31-armbru@redhat.com>

This requires giving them external linkage.  Rename do_help_cmd() to
hmp_help(), and do_print() to hmp_print().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-30-armbru@redhat.com>

Target-independent hmp_gpa2hva(), hmp_gpa2hpa() move along to stay
next to hmp_gva2gpa().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-29-armbru@redhat.com>

monitor_putc() will soon be used from more than one .c file.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-28-armbru@redhat.com>

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-27-armbru@redhat.com>

This moves the completion code from MAINTAINERS sections "Human
Monitor (HMP)" and "QMP" to section "QOM".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-26-armbru@redhat.com>

This moves the command from MAINTAINERS section "QMP" to section
"ACPI/SMBIOS)".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-25-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

This moves these commands from MAINTAINERS section "Human
Monitor (HMP)" to section "Stats".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-24-armbru@redhat.com>

This moves these commands from MAINTAINERS section "QMP" to new
section "Stats".  Status is Orphan.  Volunteers welcome!

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-23-armbru@redhat.com>

This moves these commands from MAINTAINERS section "Human
Monitor (HMP)" and "QMP" to "Main loop".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-22-armbru@redhat.com>

This moves these commands from MAINTAINERS section "Human
Monitor (HMP)" to "TPM".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-21-armbru@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>

This moves these commands from MAINTAINERS section "Human
Monitor (HMP)" to "virtio".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-20-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

This moves the command from MAINTAINERS sections "Human Monitor (HMP)"
and "QMP" to "Migration".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-19-armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>