[libvirt] [PATCHv3 12/12] qemu: Implement memory device hotunplug

[Peter Krempa]

Add code to hot-remove memory devices from qemu. Unfortunately QEMU
doesn't support this right now, so this is just for completenes.
---

Notes:
    Version 3:
    - moved check for the "-device" capability before any other code
    Version 2:
    - no change

 src/qemu/qemu_driver.c  |  4 ++-
 src/qemu/qemu_hotplug.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++-
 src/qemu/qemu_hotplug.h |  3 ++
 3 files changed, 96 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index cbdf279..9731b5f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -7733,7 +7733,9 @@ qemuDomainDetachDeviceLive(virDomainObjPtr vm,
         ret = qemuDomainDetachRNGDevice(driver, vm, dev->data.rng);
         break;
     case VIR_DOMAIN_DEVICE_MEMORY:
-        /* TODO: Implement later */
+        ret = qemuDomainDetachMemoryDevice(driver, vm, dev->data.memory);
+        break;
+
     case VIR_DOMAIN_DEVICE_FS:
     case VIR_DOMAIN_DEVICE_INPUT:
     case VIR_DOMAIN_DEVICE_SOUND:
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 88c5e3c..3365982 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -2828,6 +2828,44 @@ qemuDomainRemoveControllerDevice(virQEMUDriverPtr driver,
 }


+static int
+qemuDomainRemoveMemoryDevice(virQEMUDriverPtr driver,
+                             virDomainObjPtr vm,
+                             virDomainMemoryDefPtr mem)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    virObjectEventPtr event;
+    char *backendAlias = NULL;
+    int rc;
+    int idx;
+
+    VIR_DEBUG("Removing memory device %s from domain %p %s",
+              mem->info.alias, vm, vm->def->name);
+
+    if ((event = virDomainEventDeviceRemovedNewFromObj(vm, mem->info.alias)))
+        qemuDomainEventQueue(driver, event);
+
+    if (virAsprintf(&backendAlias, "mem%s", mem->info.alias) < 0)
+        goto error;
+
+    qemuDomainObjEnterMonitor(driver, vm);
+    rc = qemuMonitorDelObject(priv->mon, backendAlias);
+    if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
+        goto error;
+
+    if ((idx = virDomainMemoryFindByDef(vm->def, mem)) >= 0)
+        virDomainMemoryRemove(vm->def, idx);
+
+    virDomainMemoryDefFree(mem);
+    VIR_FREE(backendAlias);
+    return 0;
+
+ error:
+    VIR_FREE(backendAlias);
+    return -1;
+}
+
+
 static void
 qemuDomainRemovePCIHostDevice(virQEMUDriverPtr driver,
                               virDomainObjPtr vm,
@@ -3165,8 +3203,9 @@ qemuDomainRemoveDevice(virQEMUDriverPtr driver,
         qemuDomainRemoveRNGDevice(driver, vm, dev->data.rng);
         break;

-    /* TODO: implement later */
     case VIR_DOMAIN_DEVICE_MEMORY:
+        ret = qemuDomainRemoveMemoryDevice(driver, vm, dev->data.memory);
+        break;

     case VIR_DOMAIN_DEVICE_NONE:
     case VIR_DOMAIN_DEVICE_LEASE:
@@ -4118,3 +4157,53 @@ qemuDomainDetachRNGDevice(virQEMUDriverPtr driver,
     qemuDomainResetDeviceRemoval(vm);
     return ret;
 }
+
+
+int
+qemuDomainDetachMemoryDevice(virQEMUDriverPtr driver,
+                             virDomainObjPtr vm,
+                             virDomainMemoryDefPtr memdef)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    virDomainMemoryDefPtr mem;
+    int idx;
+    int rc;
+    int ret = -1;
+
+    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("qemu does not support -device"));
+        return -1;
+    }
+
+    if ((idx = virDomainMemoryFindByDef(vm->def, memdef)) < 0) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("device not present in domain configuration"));
+        return -1;
+    }
+
+    mem = vm->def->mems[idx];
+
+    if (!mem->info.alias) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("alias for the memory device was not found"));
+        return -1;
+    }
+
+    qemuDomainMarkDeviceForRemoval(vm, &mem->info);
+
+    qemuDomainObjEnterMonitor(driver, vm);
+    rc = qemuMonitorDelDevice(priv->mon, mem->info.alias);
+    if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
+        goto cleanup;
+
+    rc = qemuDomainWaitForDeviceRemoval(vm);
+    if (rc == 0 || rc == 1)
+        ret = qemuDomainRemoveMemoryDevice(driver, vm, mem);
+    else
+        ret = 0;
+
+ cleanup:
+    qemuDomainResetDeviceRemoval(vm);
+    return ret;
+}
diff --git a/src/qemu/qemu_hotplug.h b/src/qemu/qemu_hotplug.h
index ad4ff38..4140da3 100644
--- a/src/qemu/qemu_hotplug.h
+++ b/src/qemu/qemu_hotplug.h
@@ -60,6 +60,9 @@ int qemuDomainFindGraphicsIndex(virDomainDefPtr def,
 int qemuDomainAttachMemory(virQEMUDriverPtr driver,
                            virDomainObjPtr vm,
                            virDomainMemoryDefPtr mem);
+int qemuDomainDetachMemoryDevice(virQEMUDriverPtr driver,
+                                 virDomainObjPtr vm,
+                                 virDomainMemoryDefPtr memdef);
 int qemuDomainChangeGraphics(virQEMUDriverPtr driver,
                              virDomainObjPtr vm,
                              virDomainGraphicsDefPtr dev);
-- 
2.2.2

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