[libvirt] [PATCH 3/5] qemu: Implement individual vcpu hotplug API
Peter Krempa
pkrempa at redhat.com
Fri Feb 10 17:10:20 UTC 2017
Add code that validates user's selection of cores and then uses the
existing code to plug in the vCPU.
---
src/qemu/qemu_driver.c | 74 +++++++++++++++++++++++
src/qemu/qemu_hotplug.c | 153 ++++++++++++++++++++++++++++++++++++++++++++++++
src/qemu/qemu_hotplug.h | 7 +++
3 files changed, 234 insertions(+)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 89bc833de..2b875b3e9 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -20190,6 +20190,79 @@ qemuDomainSetGuestVcpus(virDomainPtr dom,
}
+static int
+qemuDomainSetVcpu(virDomainPtr dom,
+ const char *cpumap,
+ int state,
+ unsigned int flags)
+{
+ virQEMUDriverPtr driver = dom->conn->privateData;
+ virDomainObjPtr vm = NULL;
+ virDomainDefPtr def = NULL;
+ virDomainDefPtr persistentDef = NULL;
+ virBitmapPtr map = NULL;
+ ssize_t lastvcpu;
+ int ret = -1;
+
+ virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
+ VIR_DOMAIN_AFFECT_CONFIG, -1);
+
+ if (state != 0 && state != 1) {
+ virReportInvalidArg(state, "%s", _("unsupported state value"));
+ return -1;
+ }
+
+ if (virBitmapParse(cpumap, &map, QEMU_GUEST_VCPU_MAX_ID) < 0)
+ goto cleanup;
+
+ if ((lastvcpu = virBitmapLastSetBit(map)) < 0) {
+ virReportError(VIR_ERR_INVALID_ARG, "%s",
+ _("no vcpus selected for modification"));
+ goto cleanup;
+ }
+
+ if (!(vm = qemuDomObjFromDomain(dom)))
+ goto cleanup;
+
+ if (virDomainSetVcpuEnsureACL(dom->conn, vm->def, flags) < 0)
+ goto cleanup;
+
+ if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
+ goto cleanup;
+
+ if (virDomainObjGetDefs(vm, flags, &def, &persistentDef) < 0)
+ goto endjob;
+
+ if (persistentDef) {
+ if (lastvcpu >= virDomainDefGetVcpusMax(persistentDef)) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("vcpu %zd is not present in persistent config"),
+ lastvcpu);
+ goto endjob;
+ }
+ }
+
+ if (def) {
+ if (lastvcpu >= virDomainDefGetVcpusMax(def)) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("vcpu %zd is not present in live config"),
+ lastvcpu);
+ goto endjob;
+ }
+ }
+
+ ret = qemuDomainSetVcpuInternal(driver, vm, def, persistentDef, map, !!state);
+
+ endjob:
+ qemuDomainObjEndJob(driver, vm);
+
+ cleanup:
+ virBitmapFree(map);
+ virDomainObjEndAPI(&vm);
+ return ret;
+}
+
+
static virHypervisorDriver qemuHypervisorDriver = {
.name = QEMU_DRIVER_NAME,
.connectOpen = qemuConnectOpen, /* 0.2.0 */
@@ -20403,6 +20476,7 @@ static virHypervisorDriver qemuHypervisorDriver = {
.domainMigrateStartPostCopy = qemuDomainMigrateStartPostCopy, /* 1.3.3 */
.domainGetGuestVcpus = qemuDomainGetGuestVcpus, /* 2.0.0 */
.domainSetGuestVcpus = qemuDomainSetGuestVcpus, /* 2.0.0 */
+ .domainSetVcpu = qemuDomainSetVcpu, /* 3.1.0 */
};
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 2f209f12b..363d1070b 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -5700,3 +5700,156 @@ qemuDomainSetVcpusInternal(virQEMUDriverPtr driver,
virObjectUnref(cfg);
return ret;
}
+
+
+static void
+qemuDomainSetVcpuInactive(virDomainDefPtr def,
+ virBitmapPtr map,
+ bool state)
+{
+ virDomainVcpuDefPtr vcpu;
+ ssize_t next = -1;
+
+ def->individualvcpus = true;
+
+ while ((next = virBitmapNextSetBit(map, next)) > 0) {
+ if (!(vcpu = virDomainDefGetVcpu(def, next)))
+ continue;
+
+ vcpu->online = state;
+ vcpu->hotpluggable = VIR_TRISTATE_BOOL_YES;
+ vcpu->order = 0;
+ }
+}
+
+
+/**
+ * qemuDomainFilterHotplugVcpuEntities:
+ *
+ * Returns a bitmap of hotpluggable vcpu entities that correspond to the logical
+ * vcpus requested in @vcpus.
+ */
+static virBitmapPtr
+qemuDomainFilterHotplugVcpuEntities(virDomainDefPtr def,
+ virBitmapPtr vcpus,
+ bool state)
+{
+ qemuDomainVcpuPrivatePtr vcpupriv;
+ virDomainVcpuDefPtr vcpu;
+ virBitmapPtr map = NULL;
+ virBitmapPtr ret = NULL;
+ ssize_t next = -1;
+ size_t i;
+
+ if (!(map = virBitmapNewCopy(vcpus)))
+ return NULL;
+
+ /* make sure that all selected vcpus are in the correct state */
+ while ((next = virBitmapNextSetBit(map, next)) > 0) {
+ if (!(vcpu = virDomainDefGetVcpu(def, next)))
+ continue;
+
+ if (vcpu->online == state) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("vcpu '%zu' is already in requested state"), next);
+ goto cleanup;
+ }
+
+ if (vcpu->online && !vcpu->hotpluggable) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("vcpu '%zu' can't be hotunplugged"), next);
+ goto cleanup;
+ }
+ }
+
+ /* Make sure that all vCPUs belonging to a single hotpluggable entity were
+ * selected and then de-select any sub-threads of it. */
+ next = -1;
+ while ((next = virBitmapNextSetBit(map, next)) > 0) {
+ if (!(vcpu = virDomainDefGetVcpu(def, next)))
+ continue;
+
+ vcpupriv = QEMU_DOMAIN_VCPU_PRIVATE(vcpu);
+
+ if (vcpupriv->vcpus == 0) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("vcpu '%zu' belongs to a larger hotpluggable entity, "
+ "but siblings were not selected"), next);
+ goto cleanup;
+ }
+
+ for (i = next + 1; i < next + vcpupriv->vcpus; i++) {
+ if (!virBitmapIsBitSet(map, i)) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("vcpu '%zu' was not selected but it belongs to "
+ "hotpluggable entity '%zu-%zu' which was "
+ "partially selected"),
+ i, next, next + vcpupriv->vcpus - 1);
+ goto cleanup;
+ }
+
+ /* clear the subthreads */
+ ignore_value(virBitmapClearBit(map, i));
+ }
+ }
+
+ VIR_STEAL_PTR(ret, map);
+
+ cleanup:
+ virBitmapFree(map);
+ return ret;
+}
+
+
+int
+qemuDomainSetVcpuInternal(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDefPtr def,
+ virDomainDefPtr persistentDef,
+ virBitmapPtr map,
+ bool state)
+{
+ virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+ virBitmapPtr livevcpus = NULL;
+ int ret = -1;
+
+ if (def) {
+ if (!qemuDomainSupportsNewVcpuHotplug(vm)) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("this qemu version does not support specific "
+ "vCPU hotplug"));
+ goto cleanup;
+ }
+
+ if (!(livevcpus = qemuDomainFilterHotplugVcpuEntities(def, map, state)))
+ goto cleanup;
+
+ /* Make sure that only one hotpluggable entity is selected.
+ * qemuDomainSetVcpusLive allows setting more at once but error
+ * resolution in case of a partial failure is hard, so don't let users
+ * do so */
+ if (virBitmapCountBits(livevcpus) != 1) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("only one hotpluggable entity can be selected"));
+ goto cleanup;
+ }
+ }
+
+ if (livevcpus &&
+ qemuDomainSetVcpusLive(driver, cfg, vm, livevcpus, state) < 0)
+ goto cleanup;
+
+ if (persistentDef) {
+ qemuDomainSetVcpuInactive(persistentDef, map, state);
+
+ if (virDomainSaveConfig(cfg->configDir, driver->caps, persistentDef) < 0)
+ goto cleanup;
+ }
+
+ ret = 0;
+
+ cleanup:
+ virBitmapFree(livevcpus);
+ virObjectUnref(cfg);
+ return ret;
+}
diff --git a/src/qemu/qemu_hotplug.h b/src/qemu/qemu_hotplug.h
index 13242eec9..0b11c1ed9 100644
--- a/src/qemu/qemu_hotplug.h
+++ b/src/qemu/qemu_hotplug.h
@@ -143,4 +143,11 @@ int qemuDomainSetVcpusInternal(virQEMUDriverPtr driver,
unsigned int nvcpus,
bool hotpluggable);
+int qemuDomainSetVcpuInternal(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDefPtr def,
+ virDomainDefPtr persistentDef,
+ virBitmapPtr vcpus,
+ bool state);
+
#endif /* __QEMU_HOTPLUG_H__ */
--
2.11.0
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