[libvirt PATCH 3/3] qemu: Properly set //cpu/@migratable default value for running domains

[Jiri Denemark]

Since active domains which do not have the attribute already set were
not started by libvirt that probed for CPU migratable property, we need
to check this property on reconnect and update the domain definition
accordingly.

https://bugzilla.redhat.com/show_bug.cgi?id=1857967

Reported-by: Mark Mielke <mark.mielke at gmail.com>
Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
---
 src/qemu/qemu_process.c | 49 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 70fc24b993..d5ac8af37e 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -7755,6 +7755,52 @@ qemuProcessRefreshDisks(virQEMUDriverPtr driver,
 }
 
 
+static int
+qemuProcessRefreshCPUMigratability(virQEMUDriverPtr driver,
+                                   virDomainObjPtr vm,
+                                   qemuDomainAsyncJob asyncJob)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    virDomainDefPtr def = vm->def;
+    bool migratable;
+    int rc;
+
+    if (def->cpu->mode != VIR_CPU_MODE_HOST_PASSTHROUGH)
+        return 0;
+
+    /* If the cpu.migratable capability is present, the migratable attribute
+     * is set correctly. */
+    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_CPU_MIGRATABLE))
+        return 0;
+
+    if (!ARCH_IS_X86(def->os.arch))
+        return 0;
+
+    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
+        return -1;
+
+    rc = qemuMonitorGetCPUMigratable(priv->mon, &migratable);
+
+    if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
+        return -1;
+
+    if (rc == 1)
+        migratable = false;
+
+    /* Libvirt 6.5.0 would set migratable='off' for running domains even though
+     * the actual default used by QEMU was 'on'. */
+    if (def->cpu->migratable == VIR_TRISTATE_SWITCH_OFF && migratable) {
+        VIR_DEBUG("Fixing CPU migratable attribute");
+        def->cpu->migratable = VIR_TRISTATE_SWITCH_ON;
+    }
+
+    if (def->cpu->migratable == VIR_TRISTATE_SWITCH_ABSENT)
+        def->cpu->migratable = virTristateSwitchFromBool(migratable);
+
+    return 0;
+}
+
+
 static int
 qemuProcessRefreshCPU(virQEMUDriverPtr driver,
                       virDomainObjPtr vm)
@@ -7770,6 +7816,9 @@ qemuProcessRefreshCPU(virQEMUDriverPtr driver,
     if (!vm->def->cpu)
         return 0;
 
+    if (qemuProcessRefreshCPUMigratability(driver, vm, QEMU_ASYNC_JOB_NONE) < 0)
+        return -1;
+
     if (!(host = virQEMUDriverGetHostCPU(driver))) {
         virResetLastError();
         return 0;
-- 
2.27.0