[Qemu-devel] [PATCH] watchdog: convert to QemuOpts

[Paolo Bonzini]

This makes it possible to specify a watchdog action in a configuration file.
The previous behavior of "-watchdog" is moved to the (implied) "-watchdog
model" suboption.  This is already more or less obsolete, since it is possible
to achieve the same effect with "-device", but "-watchdog-action does not have
an equivalent.

One alternative implementation is possible, namely to add an "action"
property to the watchdog device.  However, boards often have embedded
watchdog devices; even if they currently don't, these should call
watchdog_perform_action() so that they are affected by -watchdog-action.
(This is listed in our BiteSizedTasks wiki page).

For these boards, "-watchdog action=foo" has two advantages:

1) it is much easier to use than a "-global" option, and can be
configured globally for all boards.

2) it is harder to add a property to a device than it is to just
s/qemu_system_reset_request/watchdog_perform_action/; in some cases,
the devices are not even qdev-ified at all.  The chance of the conversion
happening then would basically be zero if one had to add a property as
a prerequisite.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 docs/qdev-device-use.txt |  4 ++++
 qemu-options.hx          | 36 ++++++++++++++--------------
 vl.c                     | 61 +++++++++++++++++++++++++++++++++++-------------
 3 files changed, 68 insertions(+), 33 deletions(-)

diff --git a/docs/qdev-device-use.txt b/docs/qdev-device-use.txt
index 136d271..1906b7d 100644
--- a/docs/qdev-device-use.txt
+++ b/docs/qdev-device-use.txt
@@ -365,6 +365,10 @@ The old way to define a guest watchdog device is -watchdog 
DEVNAME.
 The new way is -device DEVNAME.  For PCI devices, you can add
 bus=PCI-BUS,addr=DEVFN to control the PCI device address, as usual.
 
+No matter if you use -watchdog or -device to define the guest watchdog
+device, you can specify the watchdog action with "-watchdog-action ACTION"
+or "-watchdog action=ACTION".
+
 === Host Device Assignment ===
 
 QEMU supports assigning host PCI devices (qemu-kvm only at this time)
diff --git a/qemu-options.hx b/qemu-options.hx
index ec356f6..719253c 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3115,12 +3115,19 @@ when the shift value is high (how high depends on the 
host machine).
 ETEXI
 
 DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \
-    "-watchdog i6300esb|ib700\n" \
-    "                enable virtual hardware watchdog [default=none]\n",
+    "-watchdog 
[model=]i6300esb|ib700,action=reset|shutdown|poweroff|pause|debug|none\n" \
+    "                enable virtual hardware watchdog (default: 
model=none,action=reset)\n",
+    QEMU_ARCH_ALL)
+DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
+    "-watchdog-action reset|shutdown|poweroff|pause|debug|none\n" \
+    "                action when watchdog fires (default: reset)\n",
     QEMU_ARCH_ALL)
 STEXI
address@hidden -watchdog @var{model}
address@hidden -watchdog address@hidden,address@hidden
 @findex -watchdog
address@hidden -watchdog-action @var{action}
address@hidden -watchdog-action
+
 Create a virtual hardware watchdog device.  Once enabled (by a guest
 action), the watchdog must be periodically polled by an agent inside
 the guest or else the guest will be restarted.
@@ -3129,22 +3136,16 @@ The @var{model} is the model of hardware watchdog to 
emulate.  Choices
 for model are: @code{ib700} (iBASE 700) which is a very simple ISA
 watchdog with a single timer, or @code{i6300esb} (Intel 6300ESB I/O
 controller hub) which is a much more featureful PCI-based dual-timer
-watchdog.  Choose a model for which your guest has drivers.
-
-Use @code{-watchdog help} to list available hardware models.  Only one
+watchdog.  Choose a model for which your guest has drivers;
+use @code{-watchdog help} to list available hardware models.  Only one
 watchdog can be enabled for a guest.
-ETEXI
-
-DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \
-    "-watchdog-action reset|shutdown|poweroff|pause|debug|none\n" \
-    "                action when watchdog fires [default=reset]\n",
-    QEMU_ARCH_ALL)
-STEXI
address@hidden -watchdog-action @var{action}
address@hidden -watchdog-action
 
 The @var{action} controls what QEMU will do when the watchdog timer
-expires.
+expires.  It can be specified directly in the @option{-watchdog} option,
+or as the argument of a separate @option{-watchdog-action} parameter.
+The effect is the same.  The watchdog action can be specified even if
+the watchdog is enabled through the @option{-device} option.
+
 The default is
 @code{reset} (forcefully reset the guest).
 Other possible actions are:
@@ -3162,8 +3163,9 @@ situations where the watchdog would have expired, and thus
 Examples:
 
 @table @code
address@hidden -watchdog i6300esb -watchdog-action pause
address@hidden -watchdog i6300esb,action=pause
 @item -watchdog ib700
address@hidden -device ib700 -watchdog action=poweroff
 @end table
 ETEXI
 
diff --git a/vl.c b/vl.c
index 9a04ad4..b76919e 100644
--- a/vl.c
+++ b/vl.c
@@ -168,7 +168,6 @@ static int no_reboot;
 int no_shutdown = 0;
 int cursor_hide = 1;
 int graphic_rotate = 0;
-const char *watchdog;
 QEMUOptionRom option_rom[MAX_OPTION_ROMS];
 int nb_option_roms;
 int semihosting_enabled = 0;
@@ -475,6 +474,23 @@ static QemuOptsList qemu_icount_opts = {
     },
 };
 
+static QemuOptsList qemu_watchdog_opts = {
+    .name = "watchdog",
+    .implied_opt_name = "model",
+    .merge_lists = true,
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_watchdog_opts.head),
+    .desc = {
+        {
+            .name = "model",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "action",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
 static QemuOptsList qemu_semihosting_config_opts = {
     .name = "semihosting-config",
     .implied_opt_name = "enable",
@@ -1224,6 +1240,26 @@ static void configure_msg(QemuOpts *opts)
     enable_timestamp_msg = qemu_opt_get_bool(opts, "timestamp", true);
 }
 
+static void configure_watchdog(QemuOpts *opts)
+{
+    const char *s;
+
+    s = qemu_opt_get(opts, "model");
+    if (s) {
+        int i = select_watchdog(s);
+        if (i > 0) {
+            exit (i == 1 ? 1 : 0);
+        }
+    }
+    s = qemu_opt_get(opts, "action");
+    if (s) {
+        int i = select_watchdog_action(s);
+        if (i > 0) {
+            exit (i == 1 ? 1 : 0);
+        }
+    }
+}
+
 /***********************************************************/
 /* USB devices */
 
@@ -2739,7 +2775,6 @@ static void set_memory_options(uint64_t *ram_slots, 
ram_addr_t *maxram_size)
 
 int main(int argc, char **argv, char **envp)
 {
-    int i;
     int snapshot, linux_boot;
     const char *initrd_filename;
     const char *kernel_filename, *kernel_cmdline;
@@ -2815,6 +2850,7 @@ int main(int argc, char **argv, char **envp)
     qemu_add_opts(&qemu_name_opts);
     qemu_add_opts(&qemu_numa_opts);
     qemu_add_opts(&qemu_icount_opts);
+    qemu_add_opts(&qemu_watchdog_opts);
     qemu_add_opts(&qemu_semihosting_config_opts);
 
     runstate_init();
@@ -3343,18 +3379,15 @@ int main(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_watchdog:
-                if (watchdog) {
-                    fprintf(stderr,
-                            "qemu: only one watchdog option may be given\n");
-                    return 1;
+                olist = qemu_find_opts("watchdog");
+                opts = qemu_opts_parse(olist, optarg, 1);
+                if (!opts) {
+                    exit(1);
                 }
-                watchdog = optarg;
                 break;
             case QEMU_OPTION_watchdog_action:
-                if (select_watchdog_action(optarg) == -1) {
-                    fprintf(stderr, "Unknown -watchdog-action parameter\n");
-                    exit(1);
-                }
+                qemu_opts_set(qemu_find_opts("watchdog"), 0, "action", optarg,
+                              &error_abort);
                 break;
             case QEMU_OPTION_virtiocon:
                 add_device_config(DEV_VIRTCON, optarg);
@@ -4227,11 +4260,7 @@ int main(int argc, char **argv, char **envp)
         select_vgahw(vga_model);
     }
 
-    if (watchdog) {
-        i = select_watchdog(watchdog);
-        if (i > 0)
-            exit (i == 1 ? 1 : 0);
-    }
+    configure_watchdog(qemu_find_opts_singleton("watchdog"));
 
     if (machine_class->compat_props) {
         qdev_prop_register_global_list(machine_class->compat_props);
-- 
1.8.3.1