[PATCH v2 2/2] Support virDomainSetIOThreads

[John Ferlan <jferlan@xxxxxxxxxx>]

Support the libvirt_virDomainSetIOThreads method using code that mimics
the existing libvirt_virDomainPinVcpuFlags method

The following is a sample session assuming guest 'iothr-gst' has IOThreads
configured (it's currently running, too)

>>> import libvirt
>>> con=libvirt.open("qemu:///system")
>>> dom=con.lookupByName('iothr-gst')
>>> dom.ioThreadsInfo()
[(1, [False, False, True, False], ['/home/vm-images/iothr-vol1']), (2, [False, False, False, True], ['/home/vm-images/iothr-vol2']), (3, [False, False, False, True], [])]
>>> cpumap=(True,True,True,False)
>>> dom.setIOThreads(3,cpumap)
0
>>> print dom.ioThreadsInfo()
[(1, [False, False, True, False], ['/home/vm-images/iothr-vol1']), (2, [False, False, False, True], ['/home/vm-images/iothr-vol2']), (3, [True, True, True, False], [])]
>>>

Signed-off-by: John Ferlan <jferlan@xxxxxxxxxx>
---
 generator.py             |  1 +
 libvirt-override-api.xml |  8 ++++++
 libvirt-override.c       | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/generator.py b/generator.py
index 8165a18..aa140ed 100755
--- a/generator.py
+++ b/generator.py
@@ -436,6 +436,7 @@ skip_impl = (
     'virDomainGetEmulatorPinInfo',
     'virDomainPinEmulator',
     'virDomainGetIOThreadsInfo',
+    'virDomainSetIOThreads',
     'virSecretGetValue',
     'virSecretSetValue',
     'virSecretGetUUID',
diff --git a/libvirt-override-api.xml b/libvirt-override-api.xml
index e512311..19667b6 100644
--- a/libvirt-override-api.xml
+++ b/libvirt-override-api.xml
@@ -284,6 +284,14 @@
       <arg name='flags'  type='int' info='an OR&apos;ed set of virDomainModificationImpact'/>
       <return type='char *' info="list of IOThreads information including the iothread_id, the cpumap, the cpumap length, number of associated resources, and a list of each resource assigned to the iothread_id."/>
     </function>
+    <function name='virDomainSetIOThreads' file='python'>
+      <info>Dynamically change the real CPUs which can be allocated to an IOThread. This function requires privileged access to the hypervisor.</info>
+      <return type='int' info='0 in case of success, -1 in case of failure.'/>
+      <arg name='domain' type='virDomainPtr' info='pointer to domain object'/>
+      <arg name='iothread_val' type='unsigned int' info='iothread_id number'/>
+      <arg name='cpumap' type='unsigned char *' info='pointer to a bit map of real CPUs (in 8-bit bytes) (IN) Each bit set to 1 means that corresponding CPU is usable. Bytes are stored in little-endian order: CPU0-7, 8-15... In each byte, lowest CPU number is least significant bit.'/>
+      <arg name='flags'  type='int' info='an OR&apos;ed set of virDomainIOThreadsFlags'/>
+    </function>
     <function name='virDomainSetSchedulerParameters' file='python'>
       <info>Change the scheduler parameters</info>
       <return type='int' info='-1 in case of error, 0 in case of success.'/>
diff --git a/libvirt-override.c b/libvirt-override.c
index 580a1b2..8823a39 100644
--- a/libvirt-override.c
+++ b/libvirt-override.c
@@ -2100,6 +2100,71 @@ cleanup:
     return error;
 }
 
+static PyObject *
+libvirt_virDomainSetIOThreads(PyObject *self ATTRIBUTE_UNUSED,
+                              PyObject *args)
+{
+    virDomainPtr domain;
+    PyObject *pyobj_domain, *pycpumap;
+    PyObject *ret = NULL;
+    unsigned char *cpumap;
+    int cpumaplen, iothread_val, tuple_size, cpunum;
+    size_t i;
+    unsigned int flags;
+    int i_retval;
+
+    if (!PyArg_ParseTuple(args, (char *)"OiOI:virDomainSetIOThread",
+                          &pyobj_domain, &iothread_val, &pycpumap, &flags))
+        return NULL;
+    domain = (virDomainPtr) PyvirDomain_Get(pyobj_domain);
+
+    if ((cpunum = getPyNodeCPUCount(virDomainGetConnect(domain))) < 0)
+        return VIR_PY_INT_FAIL;
+
+    if (PyTuple_Check(pycpumap)) {
+        if ((tuple_size = PyTuple_Size(pycpumap)) == -1)
+            return ret;
+    } else {
+       PyErr_SetString(PyExc_TypeError, "Unexpected type, tuple is required");
+       return ret;
+    }
+
+    cpumaplen = VIR_CPU_MAPLEN(cpunum);
+    if (VIR_ALLOC_N(cpumap, cpumaplen) < 0)
+        return PyErr_NoMemory();
+
+    for (i = 0; i < tuple_size; i++) {
+        PyObject *flag = PyTuple_GetItem(pycpumap, i);
+        bool b;
+
+        if (!flag || libvirt_boolUnwrap(flag, &b) < 0)
+            goto cleanup;
+
+        if (b)
+            VIR_USE_CPU(cpumap, i);
+        else
+            VIR_UNUSE_CPU(cpumap, i);
+    }
+
+    for (; i < cpunum; i++)
+        VIR_UNUSE_CPU(cpumap, i);
+
+    flags |= VIR_DOMAIN_IOTHREADS_PIN;
+    LIBVIRT_BEGIN_ALLOW_THREADS;
+    i_retval = virDomainSetIOThreads(domain, iothread_val,
+                                     cpumap, cpumaplen, flags);
+    LIBVIRT_END_ALLOW_THREADS;
+    if (i_retval < 0) {
+        ret = VIR_PY_INT_FAIL;
+        goto cleanup;
+    }
+    ret = VIR_PY_INT_SUCCESS;
+
+cleanup:
+    VIR_FREE(cpumap);
+    return ret;
+}
+
 #endif /* LIBVIR_CHECK_VERSION(1, 2, 13) */
 
 /************************************************************************
@@ -8596,6 +8661,7 @@ static PyMethodDef libvirtMethods[] = {
 #endif /* LIBVIR_CHECK_VERSION(0, 10, 0) */
 #if LIBVIR_CHECK_VERSION(1, 2, 13)
     {(char *) "virDomainGetIOThreadsInfo", libvirt_virDomainGetIOThreadsInfo, METH_VARARGS, NULL},
+    {(char *) "virDomainSetIOThreads", libvirt_virDomainSetIOThreads, METH_VARARGS, NULL},
 #endif /* LIBVIR_CHECK_VERSION(1, 2, 13) */
     {(char *) "virConnectListStoragePools", libvirt_virConnectListStoragePools, METH_VARARGS, NULL},
     {(char *) "virConnectListDefinedStoragePools", libvirt_virConnectListDefinedStoragePools, METH_VARARGS, NULL},
-- 
2.1.0

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