[libvirt] [PATCH v3 5/9] Implement public API for virDomainSetIOThreads

[John Ferlan]

https://bugzilla.redhat.com/show_bug.cgi?id=1135491

Add the libvirt API infrastructure to support setting IOThread data.
For now this is the pinned CPU information, but eventually will also
support hot plug add/del

The API will support the LIVE, CONFIG, or CURRENT flags.  If the
VIR_DOMAIN_IOTHREADS_PIN flag is not provided, it's left up to the
hypervisor to handle, but when not provided the cpumap/maplen arguments
are not checked.

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 include/libvirt/libvirt-domain.h | 16 ++++++++++
 src/driver-hypervisor.h          |  8 +++++
 src/libvirt-domain.c             | 69 ++++++++++++++++++++++++++++++++++++++++
 src/libvirt_public.syms          |  1 +
 4 files changed, 94 insertions(+)

diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 9dcc424..e07db16 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -1582,11 +1582,27 @@ struct _virDomainIOThreadsInfo {
     char **resources;                  /* array of resources using IOThread */
 };
 
+/* Flags for controlling virtual IOThread pinning.  */
+typedef enum {
+    /* See virDomainModificationImpact for these flags.  */
+    VIR_DOMAIN_IOTHREADS_CURRENT = VIR_DOMAIN_AFFECT_CURRENT,
+    VIR_DOMAIN_IOTHREADS_LIVE    = VIR_DOMAIN_AFFECT_LIVE,
+    VIR_DOMAIN_IOTHREADS_CONFIG  = VIR_DOMAIN_AFFECT_CONFIG,
+
+    /* Additionally, these flags may be bitwise-OR'd in.  */
+    VIR_DOMAIN_IOTHREADS_PIN = (1 << 2), /* thread_id to pin using cpumap */
+} virDomainIOThreadsFlags;
+
 void                 virDomainIOThreadsInfoFree(virDomainIOThreadsInfoPtr info);
 
 int                  virDomainGetIOThreadsInfo(virDomainPtr domain,
                                                virDomainIOThreadsInfoPtr **info,
                                                unsigned int flags);
+int                  virDomainSetIOThreads(virDomainPtr domain,
+                                           unsigned int iothread_val,
+                                           unsigned char *cpumap,
+                                           int maplen,
+                                           unsigned int flags);
 
 /**
  * VIR_USE_CPU:
diff --git a/src/driver-hypervisor.h b/src/driver-hypervisor.h
index 2ce1a51..120d761 100644
--- a/src/driver-hypervisor.h
+++ b/src/driver-hypervisor.h
@@ -386,6 +386,13 @@ typedef int
                                 unsigned int flags);
 
 typedef int
+(*virDrvDomainSetIOThreads)(virDomainPtr domain,
+                            unsigned int iothread_val,
+                            unsigned char *cpumap,
+                            int maplen,
+                            unsigned int flags);
+
+typedef int
 (*virDrvDomainGetSecurityLabel)(virDomainPtr domain,
                                 virSecurityLabelPtr seclabel);
 
@@ -1260,6 +1267,7 @@ struct _virHypervisorDriver {
     virDrvDomainGetVcpus domainGetVcpus;
     virDrvDomainGetMaxVcpus domainGetMaxVcpus;
     virDrvDomainGetIOThreadsInfo domainGetIOThreadsInfo;
+    virDrvDomainSetIOThreads domainSetIOThreads;
     virDrvDomainGetSecurityLabel domainGetSecurityLabel;
     virDrvDomainGetSecurityLabelList domainGetSecurityLabelList;
     virDrvNodeGetSecurityModel nodeGetSecurityModel;
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index f893b35..bf73773 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -7969,6 +7969,75 @@ virDomainIOThreadsInfoFree(virDomainIOThreadsInfoPtr info)
 
 
 /**
+ * virDomainSetIOThreads:
+ * @domain: a domain object
+ * @iothread_val: either the thread_id to modify or a count of IOThreads
+ *      to be added or removed from the domain depending on the @flags setting
+ * @cpumap: 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.
+ * @maplen: number of bytes in cpumap, from 1 up to size of CPU map in
+ *      underlying virtualization system (Xen...).
+ *      If maplen < size, missing bytes are set to zero.
+ *      If maplen > size, failure code is returned.
+ * @flags: bitwise-OR of supported virDomainIOThreadsFlags
+ *
+ * If the VIR_DOMAIN_IOTHREADS_PIN flag is set, the @iothread_val will be
+ * an existing IOThread to be pinned
+ *
+ * Returns 0 in case of success, -1 in case of failure.
+ */
+int
+virDomainSetIOThreads(virDomainPtr domain,
+                      unsigned int iothread_val,
+                      unsigned char *cpumap,
+                      int maplen,
+                      unsigned int flags)
+{
+    virConnectPtr conn;
+
+    VIR_DOMAIN_DEBUG(domain, "iothread_val=%u, cpumap=%p, maplen=%d",
+                     iothread_val, cpumap, maplen);
+
+    virResetLastError();
+
+    virCheckDomainReturn(domain, -1);
+    conn = domain->conn;
+
+    virCheckReadOnlyGoto(conn->flags, error);
+    if ((unsigned short) iothread_val != iothread_val) {
+        virReportError(VIR_ERR_OVERFLOW, _("input too large: %u"),
+                       iothread_val);
+        goto error;
+    }
+
+    virCheckPositiveArgGoto(iothread_val, error);
+
+    /* If we're pinning threads, then need to ensure cpumap/maplen are valid */
+    if (flags & VIR_DOMAIN_IOTHREADS_PIN) {
+        virCheckNonNullArgGoto(cpumap, error);
+        virCheckPositiveArgGoto(maplen, error);
+    }
+
+    if (conn->driver->domainSetIOThreads) {
+        int ret;
+        ret = conn->driver->domainSetIOThreads(domain, iothread_val,
+                                               cpumap, maplen, flags);
+        if (ret < 0)
+            goto error;
+        return ret;
+    }
+
+    virReportUnsupportedError();
+
+ error:
+    virDispatchError(domain->conn);
+    return -1;
+}
+
+
+/**
  * virDomainGetSecurityLabel:
  * @domain: a domain object
  * @seclabel: pointer to a virSecurityLabel structure
diff --git a/src/libvirt_public.syms b/src/libvirt_public.syms
index d3ddd24..b1a9e83 100644
--- a/src/libvirt_public.syms
+++ b/src/libvirt_public.syms
@@ -699,6 +699,7 @@ LIBVIRT_1.2.13 {
     global:
         virDomainIOThreadsInfoFree;
         virDomainGetIOThreadsInfo;
+        virDomainSetIOThreads;
 } LIBVIRT_1.2.12;
 
 # .... define new API here using predicted next version number ....
-- 
2.1.0