qemu: Implement virDomain{Get,Set}Time

One caveat though, qemu-ga is expecting time and returning time
in nanoseconds. With all the buffering and propagation delay, the
time is already wrong once it gets to the qemu-ga, but there's
nothing we can do about it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_agent.c

@@ -1685,3 +1685,96 @@ qemuAgentUpdateCPUInfo(unsigned int nvcpus,
 
     return 0;
 }
+
+
+int
+qemuAgentGetTime(qemuAgentPtr mon,
+                 long long *seconds,
+                 unsigned int *nseconds)
+{
+    int ret = -1;
+    unsigned long long json_time;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+
+    cmd = qemuAgentMakeCommand("guest-get-time",
+                               NULL);
+    if (!cmd)
+        return ret;
+
+    if (qemuAgentCommand(mon, cmd, &reply, true,
+                         VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK) < 0)
+        goto cleanup;
+
+    if (virJSONValueObjectGetNumberUlong(reply, "return", &json_time) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("malformed return value"));
+        goto cleanup;
+    }
+
+    /* guest agent returns time in nanoseconds,
+     * we need it in seconds here */
+    *seconds = json_time / 1000000000LL;
+    *nseconds = json_time % 1000000000LL;
+    ret = 0;
+
+ cleanup:
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}
+
+
+/**
+ * qemuAgentSetTime:
+ * @setTime: time to set
+ * @sync: let guest agent to read domain's RTC (@setTime is ignored)
+ */
+int
+qemuAgentSetTime(qemuAgentPtr mon,
+                long long seconds,
+                unsigned int nseconds,
+                bool sync)
+{
+    int ret = -1;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+
+    if (sync) {
+        cmd = qemuAgentMakeCommand("guest-set-time", NULL);
+    } else {
+        /* guest agent expect time with nanosecond granularity.
+         * Impressing. */
+        long long json_time;
+
+        /* Check if we overflow. For some reason qemu doesn't handle unsigned
+         * long long on the monitor well as it silently truncates numbers to
+         * signed long long. Therefore we must check overflow against LLONG_MAX
+         * not ULLONG_MAX. */
+        if (seconds > LLONG_MAX / 1000000000LL) {
+            virReportError(VIR_ERR_INVALID_ARG,
+                           _("Time '%lld' is too big for guest agent"),
+                           seconds);
+            return ret;
+        }
+
+        json_time = seconds * 1000000000LL;
+        json_time += nseconds;
+        cmd = qemuAgentMakeCommand("guest-set-time",
+                                   "I:time", json_time,
+                                   NULL);
+    }
+
+    if (!cmd)
+        return ret;
+
+    if (qemuAgentCommand(mon, cmd, &reply, true,
+                         VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK) < 0)
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}

src/qemu/qemu_agent.h

@@ -98,4 +98,12 @@ int qemuAgentSetVCPUs(qemuAgentPtr mon, qemuAgentCPUInfoPtr cpus, size_t ncpus);
 int qemuAgentUpdateCPUInfo(unsigned int nvcpus,
                            qemuAgentCPUInfoPtr cpuinfo,
                            int ncpuinfo);
+
+int qemuAgentGetTime(qemuAgentPtr mon,
+                     long long *seconds,
+                     unsigned int *nseconds);
+int qemuAgentSetTime(qemuAgentPtr mon,
+                     long long seconds,
+                     unsigned int nseconds,
+                     bool sync);
 #endif /* __QEMU_AGENT_H__ */

src/qemu/qemu_driver.c

@@ -16536,6 +16536,113 @@ qemuConnectGetCPUModelNames(virConnectPtr conn,
     return cpuGetModels(arch, models);
 }
 
+static int
+qemuDomainGetTime(virDomainPtr dom,
+                  long long *seconds,
+                  unsigned int *nseconds,
+                  unsigned int flags)
+{
+    virQEMUDriverPtr driver = dom->conn->privateData;
+    virDomainObjPtr vm = NULL;
+    qemuDomainObjPrivatePtr priv;
+    int ret = -1;
+    int rv;
+
+    virCheckFlags(0, ret);
+
+    if (!(vm = qemuDomObjFromDomain(dom)))
+        return ret;
+
+    if (virDomainGetTimeEnsureACL(dom->conn, vm->def) < 0)
+        goto cleanup;
+
+    priv = vm->privateData;
+
+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0)
+        goto cleanup;
+
+    if (!virDomainObjIsActive(vm)) {
+        virReportError(VIR_ERR_OPERATION_INVALID,
+                       "%s", _("domain is not running"));
+        goto endjob;
+    }
+
+    if (!qemuDomainAgentAvailable(priv, true))
+        goto endjob;
+
+    qemuDomainObjEnterAgent(vm);
+    rv = qemuAgentGetTime(priv->agent, seconds, nseconds);
+    qemuDomainObjExitAgent(vm);
+
+    if (rv < 0)
+        goto endjob;
+
+    ret = 0;
+
+ endjob:
+    if (!qemuDomainObjEndJob(driver, vm))
+        vm = NULL;
+
+ cleanup:
+    if (vm)
+        virObjectUnlock(vm);
+    return ret;
+}
+
+static int
+qemuDomainSetTime(virDomainPtr dom,
+                  long long seconds,
+                  unsigned int nseconds,
+                  unsigned int flags)
+{
+    virQEMUDriverPtr driver = dom->conn->privateData;
+    qemuDomainObjPrivatePtr priv;
+    virDomainObjPtr vm;
+    bool sync = flags & VIR_DOMAIN_TIME_SYNC;
+    int ret = -1;
+    int rv;
+
+    virCheckFlags(VIR_DOMAIN_TIME_SYNC, ret);
+
+    if (!(vm = qemuDomObjFromDomain(dom)))
+        return ret;
+
+    if (virDomainSetTimeEnsureACL(dom->conn, vm->def) < 0)
+        goto cleanup;
+
+    priv = vm->privateData;
+
+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
+        goto cleanup;
+
+    if (!virDomainObjIsActive(vm)) {
+        virReportError(VIR_ERR_OPERATION_INVALID,
+                       "%s", _("domain is not running"));
+        goto endjob;
+    }
+
+    if (!qemuDomainAgentAvailable(priv, true))
+        goto endjob;
+
+    qemuDomainObjEnterAgent(vm);
+    rv = qemuAgentSetTime(priv->agent, seconds, nseconds, sync);
+    qemuDomainObjExitAgent(vm);
+
+    if (rv < 0)
+        goto endjob;
+
+    ret = 0;
+
+ endjob:
+    if (!qemuDomainObjEndJob(driver, vm))
+        vm = NULL;
+
+ cleanup:
+    if (vm)
+        virObjectUnlock(vm);
+    return ret;
+}
+
 
 static int
 qemuDomainFSFreeze(virDomainPtr dom,
@@ -16819,6 +16926,8 @@ static virDriver qemuDriver = {
     .connectGetCPUModelNames = qemuConnectGetCPUModelNames, /* 1.1.3 */
     .domainFSFreeze = qemuDomainFSFreeze, /* 1.2.5 */
     .domainFSThaw = qemuDomainFSThaw, /* 1.2.5 */
+    .domainGetTime = qemuDomainGetTime, /* 1.2.5 */
+    .domainSetTime = qemuDomainSetTime, /* 1.2.5 */
 };