[PATCH 7/7] qemu_hotplug: Generate thread-context object for memory device

[Michal Privoznik <mprivozn@xxxxxxxxxx>]

This is similar to one of previous commits which generated
thread-context object for memory devices at cmd line generation
phase. This one does the same for hotplug case, except it's doing
so iff QEMU sandboxing is turned off. The reason is that once
sandboxing is turned on, the __NR_sched_setaffinity syscall is
filtered by libseccomp and thus QEMU is unable to instantiate the
thread-context object.

Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
---
 src/qemu/qemu_hotplug.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index da92ced2f4..5c49da87ba 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -2240,11 +2240,13 @@ qemuDomainAttachMemory(virQEMUDriver *driver,
     g_autoptr(virJSONValue) devprops = NULL;
     g_autofree char *objalias = NULL;
     bool objAdded = false;
+    bool tcObjAdded = false;
     bool releaseaddr = false;
     bool teardownlabel = false;
     bool teardowncgroup = false;
     bool teardowndevice = false;
     g_autoptr(virJSONValue) props = NULL;
+    g_autoptr(virJSONValue) tcProps = NULL;
     virObjectEvent *event;
     int id;
     int ret = -1;
@@ -2273,6 +2275,11 @@ qemuDomainAttachMemory(virQEMUDriver *driver,
                                     priv, vm->def, mem, true, false) < 0)
         goto cleanup;
 
+    /* In case sandbox was turned on, thread-context won't work. */
+    if (cfg->seccompSandbox == 0 &&
+        qemuBuildThreadContextProps(&tcProps, &props, priv) < 0)
+        goto cleanup;
+
     if (qemuProcessBuildDestroyMemoryPaths(driver, vm, mem, true) < 0)
         goto cleanup;
 
@@ -2294,6 +2301,12 @@ qemuDomainAttachMemory(virQEMUDriver *driver,
         goto removedef;
 
     qemuDomainObjEnterMonitor(vm);
+    if (tcProps) {
+        if (qemuMonitorAddObject(priv->mon, &tcProps, NULL) < 0)
+            goto exit_monitor;
+        tcObjAdded = true;
+    }
+
     if (qemuMonitorAddObject(priv->mon, &props, NULL) < 0)
         goto exit_monitor;
     objAdded = true;
@@ -2301,6 +2314,12 @@ qemuDomainAttachMemory(virQEMUDriver *driver,
     if (qemuMonitorAddDeviceProps(priv->mon, &devprops) < 0)
         goto exit_monitor;
 
+    if (tcObjAdded) {
+        if (qemuProcessDeleteThreadContext(vm) < 0)
+            goto exit_monitor;
+        tcObjAdded = false;
+    }
+
     qemuDomainObjExitMonitor(vm);
 
     event = virDomainEventDeviceAddedNewFromObj(vm, objalias);
@@ -2339,6 +2358,8 @@ qemuDomainAttachMemory(virQEMUDriver *driver,
     virErrorPreserveLast(&orig_err);
     if (objAdded)
         ignore_value(qemuMonitorDelObject(priv->mon, objalias, false));
+    if (tcObjAdded)
+        ignore_value(qemuProcessDeleteThreadContext(vm));
     qemuDomainObjExitMonitor(vm);
 
     if (objAdded && mem)
@@ -4380,6 +4401,7 @@ qemuDomainRemoveMemoryDevice(virQEMUDriver *driver,
 
     qemuDomainObjEnterMonitor(vm);
     rc = qemuMonitorDelObject(priv->mon, backendAlias, true);
+    /* XXX remove TC object */
     qemuDomainObjExitMonitor(vm);
 
     virDomainAuditMemory(vm, oldmem, newmem, "update", rc == 0);
-- 
2.37.4