[libvirt] [PATCH 05/10] support to pass VIR_DOMAIN_AFFECT_CURRENT to virDomainGetVcpusFlags()

[Wen Congyang]

We need this feature in the following patch.

---
 include/libvirt/libvirt.h.in |    3 ++-
 src/libvirt.c                |   12 ++++++------
 src/qemu/qemu_driver.c       |   18 ++++++++++--------
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index 8e20f75..14d6a88 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -1234,8 +1234,9 @@ typedef virVcpuInfo *virVcpuInfoPtr;
 
 /* Flags for controlling virtual CPU hot-plugging.  */
 typedef enum {
-    /* Must choose at least one of these two bits; SetVcpus can choose both;
+    /* Must choose at least one of these three bits; SetVcpus can choose both;
        see virDomainModificationImpact for details.  */
+    VIR_DOMAIN_VCPU_CURRENT = VIR_DOMAIN_AFFECT_CURRENT,
     VIR_DOMAIN_VCPU_LIVE    = VIR_DOMAIN_AFFECT_LIVE,
     VIR_DOMAIN_VCPU_CONFIG  = VIR_DOMAIN_AFFECT_CONFIG,
 
diff --git a/src/libvirt.c b/src/libvirt.c
index e00c64f..9857e3b 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -6923,13 +6923,18 @@ error:
  * @flags must include either VIR_DOMAIN_AFFECT_LIVE to query a
  * running domain (which will fail if domain is not active), or
  * VIR_DOMAIN_AFFECT_CONFIG to query the XML description of the
- * domain.  It is an error to set both flags.
+ * domain, or VIR_DOMAIN_AFFECT_CURRENT to query a running domain
+ * (if domain is active) or query the XML description of the domain
+ * (if domain is not active).
+ * It is an error to set two of these three flags.
  *
  * If @flags includes VIR_DOMAIN_VCPU_MAXIMUM, then the maximum
  * virtual CPU limit is queried.  Otherwise, this call queries the
  * current virtual CPU limit.
  *
  * Returns 0 in case of success, -1 in case of failure.
+ *
+ * NB. Not all hypervisor support VIR_DOMAIN_AFFECT_CURRENT.
  */
 
 int
@@ -6947,11 +6952,6 @@ virDomainGetVcpusFlags(virDomainPtr domain, unsigned int flags)
         return -1;
     }
 
-    /* Exactly one of these two flags should be set.  */
-    if (!(flags & VIR_DOMAIN_AFFECT_LIVE) == !(flags & VIR_DOMAIN_AFFECT_CONFIG)) {
-        virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);
-        goto error;
-    }
     conn = domain->conn;
 
     if (conn->driver->domainGetVcpusFlags) {
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 8b65c26..9ddbc0f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -3374,18 +3374,12 @@ qemudDomainGetVcpusFlags(virDomainPtr dom, unsigned int flags)
     virDomainObjPtr vm;
     virDomainDefPtr def;
     int ret = -1;
+    bool isActive;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
                   VIR_DOMAIN_AFFECT_CONFIG |
                   VIR_DOMAIN_VCPU_MAXIMUM, -1);
 
-    /* Exactly one of LIVE or CONFIG must be set.  */
-    if (!(flags & VIR_DOMAIN_AFFECT_LIVE) == !(flags & VIR_DOMAIN_AFFECT_CONFIG)) {
-        qemuReportError(VIR_ERR_INVALID_ARG,
-                        _("invalid flag combination: (0x%x)"), flags);
-        return -1;
-    }
-
     qemuDriverLock(driver);
     vm = virDomainFindByUUID(&driver->domains, dom->uuid);
     qemuDriverUnlock(driver);
@@ -3398,8 +3392,16 @@ qemudDomainGetVcpusFlags(virDomainPtr dom, unsigned int flags)
         goto cleanup;
     }
 
+    isActive = virDomainObjIsActive(vm);
+    if ((flags & ~VIR_DOMAIN_VCPU_MAXIMUM) == VIR_DOMAIN_AFFECT_CURRENT) {
+        if (isActive)
+            flags |= VIR_DOMAIN_AFFECT_LIVE;
+        else
+            flags |= VIR_DOMAIN_AFFECT_CONFIG;
+    }
+
     if (flags & VIR_DOMAIN_AFFECT_LIVE) {
-        if (!virDomainObjIsActive(vm)) {
+        if (!isActive) {
             qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
                             _("domain not active"));
             goto cleanup;
-- 
1.7.1