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From 6a2ee1fd8d36ed8407b403a7307de1633462759c Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Wed, 9 Oct 2019 12:39:45 +0100
Subject: [PATCH 19/22] qdev/machine: Introduce hotplug_allowed hook

RH-Author: Peter Xu <peterx@redhat.com>
Message-id: <20191009123947.21505-4-peterx@redhat.com>
Patchwork-id: 91351
O-Subject: [RHEL-8.2.0 qemu-kvm PATCH 3/5] qdev/machine: Introduce hotplug_allowed hook
Bugzilla: 1738440
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Auger Eric <eric.auger@redhat.com>
RH-Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

Conflicts:

  hw/core/qdev.c: don't have 14405c274e86e ("qdev: Provide
    qdev_get_bus_hotplug_handler()")

  include/hw/boards: plenty of new things missing in
    MachineClass (kvm_type, numa_mem_supported, smp_parse)

  include/hw/qdev-core.h: don't have 17cc0128da3 ("qdev: Let machine
    hotplug handler to override bus hotplug handler")

Introduce this new per-machine hook to give any machine class a chance
to do a sanity check on the to-be-hotplugged device as a sanity test.
This will be used for x86 to try to detect some illegal configuration
of devices, e.g., possible conflictions between vfio-pci and x86
vIOMMU.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20190916080718.3299-3-peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit d2321d31ff98b75b652c2b1594f00a4cfd48102a)
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 hw/core/qdev.c         | 17 +++++++++++++++++
 include/hw/boards.h    |  9 +++++++++
 include/hw/qdev-core.h |  1 +
 qdev-monitor.c         |  7 +++++++
 4 files changed, 34 insertions(+)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 24f1ae7..5971242 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -259,6 +259,23 @@ HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev)
     return NULL;
 }
 
+bool qdev_hotplug_allowed(DeviceState *dev, Error **errp)
+{
+    MachineState *machine;
+    MachineClass *mc;
+    Object *m_obj = qdev_get_machine();
+
+    if (object_dynamic_cast(m_obj, TYPE_MACHINE)) {
+        machine = MACHINE(m_obj);
+        mc = MACHINE_GET_CLASS(machine);
+        if (mc->hotplug_allowed) {
+            return mc->hotplug_allowed(machine, dev, errp);
+        }
+    }
+
+    return true;
+}
+
 HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev)
 {
     HotplugHandler *hotplug_ctrl;
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 9b4a69b..e568a3c 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -156,6 +156,13 @@ typedef struct {
  *    should instead use "unimplemented-device" for all memory ranges where
  *    the guest will attempt to probe for a device that QEMU doesn't
  *    implement and a stub device is required.
+ * @hotplug_allowed:
+ *    If the hook is provided, then it'll be called for each device
+ *    hotplug to check whether the device hotplug is allowed.  Return
+ *    true to grant allowance or false to reject the hotplug.  When
+ *    false is returned, an error must be set to show the reason of
+ *    the rejection.  If the hook is not provided, all hotplug will be
+ *    allowed.
  */
 struct MachineClass {
     /*< private >*/
@@ -210,6 +217,8 @@ struct MachineClass {
 
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
                                            DeviceState *dev);
+    bool (*hotplug_allowed)(MachineState *state, DeviceState *dev,
+                            Error **errp);
     CpuInstanceProperties (*cpu_index_to_instance_props)(MachineState *machine,
                                                          unsigned cpu_index);
     const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine);
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 9453588..b8d1cac 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -286,6 +286,7 @@ void qdev_init_nofail(DeviceState *dev);
 void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id,
                                  int required_for_version);
 HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev);
+bool qdev_hotplug_allowed(DeviceState *dev, Error **errp);
 HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev);
 void qdev_unplug(DeviceState *dev, Error **errp);
 void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev,
diff --git a/qdev-monitor.c b/qdev-monitor.c
index f439b83..70bce8f 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -606,6 +606,13 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
     /* create device */
     dev = DEVICE(object_new(driver));
 
+    /* Check whether the hotplug is allowed by the machine */
+    if (qdev_hotplug && !qdev_hotplug_allowed(dev, &err)) {
+        /* Error must be set in the machine hook */
+        assert(err);
+        goto err_del_dev;
+    }
+
     if (bus) {
         qdev_set_parent_bus(dev, bus);
     } else if (qdev_hotplug && !qdev_get_machine_hotplug_handler(dev)) {
-- 
1.8.3.1