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[PATCH v11 01/14] qdev: unplug blocker for devices
From: |
Jagannathan Raman |
Subject: |
[PATCH v11 01/14] qdev: unplug blocker for devices |
Date: |
Fri, 10 Jun 2022 15:50:28 -0400 |
Add blocker to prevent hot-unplug of devices
TYPE_VFIO_USER_SERVER, which is introduced shortly, attaches itself to a
PCIDevice on which it depends. If the attached PCIDevice gets removed
while the server in use, it could cause it crash. To prevent this,
TYPE_VFIO_USER_SERVER adds an unplug blocker for the PCIDevice.
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
include/hw/qdev-core.h | 29 +++++++++++++++++++++++++++++
hw/core/qdev.c | 24 ++++++++++++++++++++++++
softmmu/qdev-monitor.c | 4 ++++
3 files changed, 57 insertions(+)
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 92c3d65208..98774e2835 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -193,6 +193,7 @@ struct DeviceState {
int instance_id_alias;
int alias_required_for_version;
ResettableState reset;
+ GSList *unplug_blockers;
};
struct DeviceListener {
@@ -419,6 +420,34 @@ void qdev_simple_device_unplug_cb(HotplugHandler
*hotplug_dev,
void qdev_machine_creation_done(void);
bool qdev_machine_modified(void);
+/**
+ * qdev_add_unplug_blocker: Add an unplug blocker to a device
+ *
+ * @dev: Device to be blocked from unplug
+ * @reason: Reason for blocking
+ */
+void qdev_add_unplug_blocker(DeviceState *dev, Error *reason);
+
+/**
+ * qdev_del_unplug_blocker: Remove an unplug blocker from a device
+ *
+ * @dev: Device to be unblocked
+ * @reason: Pointer to the Error used with qdev_add_unplug_blocker.
+ * Used as a handle to lookup the blocker for deletion.
+ */
+void qdev_del_unplug_blocker(DeviceState *dev, Error *reason);
+
+/**
+ * qdev_unplug_blocked: Confirm if a device is blocked from unplug
+ *
+ * @dev: Device to be tested
+ * @reason: Returns one of the reasons why the device is blocked,
+ * if any
+ *
+ * Returns: true if device is blocked from unplug, false otherwise
+ */
+bool qdev_unplug_blocked(DeviceState *dev, Error **errp);
+
/**
* GpioPolarity: Polarity of a GPIO line
*
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 84f3019440..0806d8fcaa 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -468,6 +468,28 @@ char *qdev_get_dev_path(DeviceState *dev)
return NULL;
}
+void qdev_add_unplug_blocker(DeviceState *dev, Error *reason)
+{
+ dev->unplug_blockers = g_slist_prepend(dev->unplug_blockers, reason);
+}
+
+void qdev_del_unplug_blocker(DeviceState *dev, Error *reason)
+{
+ dev->unplug_blockers = g_slist_remove(dev->unplug_blockers, reason);
+}
+
+bool qdev_unplug_blocked(DeviceState *dev, Error **errp)
+{
+ ERRP_GUARD();
+
+ if (dev->unplug_blockers) {
+ error_propagate(errp, error_copy(dev->unplug_blockers->data));
+ return true;
+ }
+
+ return false;
+}
+
static bool device_get_realized(Object *obj, Error **errp)
{
DeviceState *dev = DEVICE(obj);
@@ -704,6 +726,8 @@ static void device_finalize(Object *obj)
DeviceState *dev = DEVICE(obj);
+ g_assert(!dev->unplug_blockers);
+
QLIST_FOREACH_SAFE(ngl, &dev->gpios, node, next) {
QLIST_REMOVE(ngl, node);
qemu_free_irqs(ngl->in, ngl->num_in);
diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
index bb5897fc76..4b0ef65780 100644
--- a/softmmu/qdev-monitor.c
+++ b/softmmu/qdev-monitor.c
@@ -899,6 +899,10 @@ void qdev_unplug(DeviceState *dev, Error **errp)
HotplugHandlerClass *hdc;
Error *local_err = NULL;
+ if (qdev_unplug_blocked(dev, errp)) {
+ return;
+ }
+
if (dev->parent_bus && !qbus_is_hotpluggable(dev->parent_bus)) {
error_setg(errp, QERR_BUS_NO_HOTPLUG, dev->parent_bus->name);
return;
--
2.20.1
- [PATCH v11 00/14] vfio-user server in QEMU, Jagannathan Raman, 2022/06/10
- [PATCH v11 01/14] qdev: unplug blocker for devices,
Jagannathan Raman <=
- [PATCH v11 03/14] remote/machine: add vfio-user property, Jagannathan Raman, 2022/06/10
- [PATCH v11 05/14] vfio-user: define vfio-user-server object, Jagannathan Raman, 2022/06/10
- [PATCH v11 04/14] vfio-user: build library, Jagannathan Raman, 2022/06/10
- [PATCH v11 02/14] remote/machine: add HotplugHandler for remote machine, Jagannathan Raman, 2022/06/10
- [PATCH v11 06/14] vfio-user: instantiate vfio-user context, Jagannathan Raman, 2022/06/10
- [PATCH v11 07/14] vfio-user: find and init PCI device, Jagannathan Raman, 2022/06/10
- [PATCH v11 08/14] vfio-user: run vfio-user context, Jagannathan Raman, 2022/06/10
- [PATCH v11 10/14] vfio-user: IOMMU support for remote device, Jagannathan Raman, 2022/06/10
- [PATCH v11 11/14] vfio-user: handle DMA mappings, Jagannathan Raman, 2022/06/10
- [PATCH v11 09/14] vfio-user: handle PCI config space accesses, Jagannathan Raman, 2022/06/10