[Qemu-devel] [multiprocess RFC PATCH 21/37] multi-process: QMP/HMP commands to add a device to the remote process

[elena . ufimtseva]

From: Jagannathan Raman <address@hidden>

Adds rdevice_add QMP & HMP commands to hotplug device to a remote device.

Signed-off-by: Jagannathan Raman <address@hidden>
Signed-off-by: John G Johnson <address@hidden>
Signed-off-by: Elena Ufimtseva <address@hidden>
---
 hmp-commands.hx         | 14 ++++++++
 hmp.h                   |  1 +
 hw/proxy/monitor.c      | 92 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/io/proxy-link.h |  2 ++
 include/monitor/qdev.h  |  4 +++
 monitor.c               |  5 +++
 qapi/misc.json          | 22 ++++++++++++
 remote/remote-main.c    | 48 ++++++++++++++++++++++++++
 8 files changed, 188 insertions(+)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index fb3c8ba..7e8e8ab 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -727,6 +727,20 @@ ETEXI
 
 #if defined(CONFIG_MPQEMU)
     {
+        .name       = "rdevice_add",
+        .args_type  = "rdev_id:s,driver:s,id:s,drive:s,bus:s",
+        .params     = "rdev_id driver id drive bus",
+        .help       = "add device to remote proc, like -rdevice on the command 
line",
+        .cmd        = hmp_rdevice_add,
+    },
+
+STEXI
address@hidden rdevice_add @var{config}
address@hidden rdevice_add
+Add device to remote proc.
+ETEXI
+
+    {
         .name       = "remote_proc_list",
         .args_type  = "",
         .params     = "",
diff --git a/hmp.h b/hmp.h
index 0940634..355a27e 100644
--- a/hmp.h
+++ b/hmp.h
@@ -150,5 +150,6 @@ void hmp_info_vm_generation_id(Monitor *mon, const QDict 
*qdict);
 void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict);
 void hmp_info_sev(Monitor *mon, const QDict *qdict);
 void hmp_remote_proc_list(Monitor *mon, const QDict *qdict);
+void hmp_rdevice_add(Monitor *mon, const QDict *qdict);
 
 #endif
diff --git a/hw/proxy/monitor.c b/hw/proxy/monitor.c
index 3005eec..2e2cda0 100644
--- a/hw/proxy/monitor.c
+++ b/hw/proxy/monitor.c
@@ -23,6 +23,7 @@
  */
 
 #include <sys/types.h>
+#include <string.h>
 
 #include "qemu/osdep.h"
 #include "qapi/qapi-types-block-core.h"
@@ -33,6 +34,13 @@
 #include "hw/boards.h"
 #include "hw/i386/pc.h"
 #include "hw/proxy/qemu-proxy.h"
+#include "qapi/qapi-commands-misc.h"
+#include "monitor/qdev.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qjson.h"
+#include "qapi/qmp/qstring.h"
+#include "qapi/error.h"
+#include "io/proxy-link.h"
 
 /*
  * TODO: Is there a callback where the allocated memory for QMP could be free'd
@@ -87,3 +95,87 @@ void hmp_remote_proc_list(Monitor *mon, const QDict *qdict)
                        pdev->remote_pid, pdev->rid, id, k->command);
     }
 }
+
+static PCIProxyDev *get_proxy_device(QDict *qdict, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(current_machine);
+    PCIProxyDev *pdev = NULL;
+    const char *rdev_id;
+
+    if (!qdict_haskey(qdict, "rdev_id")) {
+        error_setg(errp, "Please specify a value for rdev_id");
+        return NULL;
+    }
+
+    rdev_id = qdict_get_str(qdict, "rdev_id");
+
+    pdev = (PCIProxyDev *)g_hash_table_lookup(pcms->remote_devs, rdev_id);
+    if (!pdev) {
+        error_setg(errp,
+                   "No remote device by ID %s. Use query-remote command to get 
remote devices",
+                   rdev_id);
+    }
+
+    return pdev;
+}
+
+static void rdevice_add_del(QDict *qdict, proc_cmd_t cmd, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(current_machine);
+    ProcMsg msg = {0};
+    PCIProxyDev *pdev = NULL;
+    const char *id;
+    QString *json;
+    int wait;
+
+    pdev = get_proxy_device(qdict, errp);
+    if (*errp) {
+        return;
+    }
+
+    qdict_del(qdict, "rdev_id");
+
+    id = qdict_get_str(qdict, "id");
+
+    json = qobject_to_json(QOBJECT(qdict));
+
+    wait = GET_REMOTE_WAIT;
+
+    msg.cmd = cmd;
+    msg.bytestream = 1;
+    msg.size = strlen(qstring_get_str(json));
+    msg.data2 = (uint8_t *)qstring_get_str(json);
+    msg.num_fds = 1;
+    msg.fds[0] = wait;
+
+    proxy_proc_send(pdev->proxy_link, &msg);
+    (void)wait_for_remote(wait);
+    PUT_REMOTE_WAIT(wait);
+
+    qstring_destroy_obj(QOBJECT(json));
+
+    /* TODO: Only on success */
+    if (cmd == DEVICE_ADD) {
+        (void)g_hash_table_insert(pcms->remote_devs, (gpointer)g_strdup(id),
+                                  (gpointer)pdev);
+    }
+}
+
+void qmp_rdevice_add(QDict *qdict, QObject **ret_data, Error **errp)
+{
+    rdevice_add_del(qdict, DEVICE_ADD, errp);
+}
+
+void hmp_rdevice_add(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+
+    /* TODO: Is it OK to modify the QDict argument from HMP? */
+    rdevice_add_del((QDict *)qdict, DEVICE_ADD, &err);
+
+    if (err) {
+        monitor_printf(mon, "rdevice_add error: %s\n",
+                       error_get_pretty(err));
+        error_free(err);
+    }
+}
diff --git a/include/io/proxy-link.h b/include/io/proxy-link.h
index 175e2f1..8781508 100644
--- a/include/io/proxy-link.h
+++ b/include/io/proxy-link.h
@@ -60,6 +60,7 @@ typedef struct ProxyLinkState ProxyLinkState;
  * BAR_READ         Reads from PCI BAR region
  * SET_IRQFD        Sets the IRQFD to be used to raise interrupts directly
  *                  from remote device
+ * DEVICE_ADD       QMP/HMP command to hotplug device
  *
  */
 typedef enum {
@@ -70,6 +71,7 @@ typedef enum {
     BAR_WRITE,
     BAR_READ,
     SET_IRQFD,
+    DEVICE_ADD,
     MAX,
 } proc_cmd_t;
 
diff --git a/include/monitor/qdev.h b/include/monitor/qdev.h
index 0ff3331..065701c 100644
--- a/include/monitor/qdev.h
+++ b/include/monitor/qdev.h
@@ -10,6 +10,10 @@ void hmp_info_qdm(Monitor *mon, const QDict *qdict);
 void hmp_info_qom_tree(Monitor *mon, const QDict *dict);
 void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp);
 
+#ifdef CONFIG_MPQEMU
+void qmp_rdevice_add(QDict *qdict, QObject **ret_data, Error **errp);
+#endif
+
 int qdev_device_help(QemuOpts *opts);
 DeviceState *qdev_device_add(QemuOpts *opts, Error **errp);
 void qdev_set_id(DeviceState *dev, const char *id);
diff --git a/monitor.c b/monitor.c
index defa129..0ad52e5 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1155,6 +1155,11 @@ static void monitor_init_qmp_commands(void)
     qmp_register_command(&qmp_commands, "netdev_add", qmp_netdev_add,
                          QCO_NO_OPTIONS);
 
+#ifdef CONFIG_MPQEMU
+    qmp_register_command(&qmp_commands, "rdevice_add", qmp_rdevice_add,
+                         QCO_NO_OPTIONS);
+#endif
+
     QTAILQ_INIT(&qmp_cap_negotiation_commands);
     qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
                          qmp_marshal_qmp_capabilities, QCO_ALLOW_PRECONFIG);
diff --git a/qapi/misc.json b/qapi/misc.json
index 8b3ca4f..28d49ea 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -1663,6 +1663,28 @@
   'gen': false } # so we can get the additional arguments
 
 ##
+# @rdevice_add:
+#
+# @rdev_id: ID of the remote device root
+#
+# @driver: the name of the new device's driver
+#
+# @bus: the device's parent bus (device tree path)
+#
+# @id: the device's ID, must be unique
+#
+# Additional arguments depend on the type.
+#
+# Add a device.
+#
+# Since: 3.0
+##
+{ 'command': 'rdevice_add',
+  'data': {'rdev_id': 'str', 'driver': 'str', '*bus': 'str', '*id': 'str'},
+  'if': 'defined(CONFIG_MPQEMU)',
+  'gen': false } # so we can get the additional arguments
+
+##
 # @device_del:
 #
 # Remove a device from a guest
diff --git a/remote/remote-main.c b/remote/remote-main.c
index 4683e7d..03c14de 100644
--- a/remote/remote-main.c
+++ b/remote/remote-main.c
@@ -48,6 +48,11 @@
 #include "exec/memattrs.h"
 #include "exec/address-spaces.h"
 #include "remote/iohub.h"
+#include "qapi/qmp/qjson.h"
+#include "qapi/qmp/qobject.h"
+#include "qemu/option.h"
+#include "qemu/config-file.h"
+#include "monitor/qdev.h"
 
 static ProxyLinkState *proxy_link;
 PCIDevice *remote_pci_dev;
@@ -138,6 +143,44 @@ fail:
     PUT_REMOTE_WAIT(wait);
 }
 
+static void process_device_add_msg(ProcMsg *msg)
+{
+    Error *local_err = NULL;
+    const char *json = (const char *)msg->data2;
+    int wait = msg->fds[0];
+    QObject *qobj = NULL;
+    QDict *qdict = NULL;
+    QemuOpts *opts = NULL;
+
+    qobj = qobject_from_json(json, &local_err);
+    if (local_err) {
+        goto fail;
+    }
+
+    qdict = qobject_to(QDict, qobj);
+    assert(qdict);
+
+    opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, &local_err);
+    if (local_err) {
+        goto fail;
+    }
+
+    (void)qdev_device_add(opts, &local_err);
+    if (local_err) {
+        goto fail;
+    }
+
+fail:
+    if (local_err) {
+        error_report_err(local_err);
+        /* TODO: communicate the exact error message to proxy */
+    }
+
+    notify_proxy(wait, 1);
+
+    PUT_REMOTE_WAIT(wait);
+}
+
 static void process_msg(GIOCondition cond)
 {
     ProcMsg *msg = NULL;
@@ -189,6 +232,9 @@ static void process_msg(GIOCondition cond)
     case SET_IRQFD:
         process_set_irqfd_msg(remote_pci_dev, msg);
         break;
+    case DEVICE_ADD:
+        process_device_add_msg(msg);
+        break;
     default:
         error_setg(&err, "Unknown command");
         goto finalize_loop;
@@ -225,6 +271,8 @@ int main(int argc, char *argv[])
 
     bdrv_init_with_whitelist();
 
+    qemu_add_opts(&qemu_device_opts);
+
     if (qemu_init_main_loop(&err)) {
         error_report_err(err);
         return -EBUSY;
-- 
1.8.3.1