[libvirt] [PATCH] Add 'Hybrid-Suspend' power management discovery for the host

24 Nov 2011

Some systems support a feature known as 'Hybrid-Suspend', apart from the
usual system-wide sleep states such as Suspend-to-RAM (S3) or Suspend-to-Disk
(S4). Add the functionality to discover this power management feature and
export it in the capabilities XML under the <power_management> tag.

This addition was suggested in [1].

References:
1. http://www.redhat.com/archives/libvir-list/2011-November/msg01298.html

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---

 docs/formatcaps.html.in     |   12 +++--
 docs/schemas/capability.rng |    5 ++
 src/conf/capabilities.c     |    2 -
 src/util/util.c             |   99 ++++++++++++++++++++++++++++++-------------
 src/util/util.h             |    8 ++-
 5 files changed, 88 insertions(+), 38 deletions(-)

diff --git a/docs/formatcaps.html.in b/docs/formatcaps.html.in
index ce6f9a6..c5fb925 100644
--- a/docs/formatcaps.html.in
+++ b/docs/formatcaps.html.in
@@ -31,6 +31,7 @@ BIOS you will see</p>
     <power_management>
       <S3/>
       <S4/>
+      <Hybrid-Suspend/>
     <power_management/>
   </host></span>
 
@@ -70,11 +71,12 @@ the host platform, but other information may be available, it shows the CPU arch
 topology, model name, and additional features which are not included in the model but the
 CPU provides them. Features of the chip are shown within the feature block (the block is
 similar to what you will find in a Xen fully virtualized domain description). Further,
-the power management features supported by the host are shown, such as Suspend-to-RAM (S3)
-and Suspend-to-Disk (S4). In case the query for power management features succeeded but the
-host does not support any such feature, then an empty <power_management/>
-tag will be shown. Otherwise, if the query itself failed, no such tag will
-be displayed (i.e., there will not be any power_management block or empty tag in the XML).</p>
+the power management features supported by the host are shown, such as Suspend-to-RAM (S3),
+Suspend-to-Disk (S4) and Hybrid-Suspend (a combination of S3 and S4).
+In case the query for power management features succeeded but the host does not support
+any such feature, then an empty <power_management/> tag will be shown. Otherwise,
+if the query itself failed, no such tag will be displayed (i.e., there will not be any
+power_management block or empty tag in the XML).</p>
         <p>The second block (in blue) indicates the paravirtualization support of the
 Xen support, you will see the os_type of xen to indicate a paravirtual
 kernel, then architecture information and potential features.</p>
diff --git a/docs/schemas/capability.rng b/docs/schemas/capability.rng
index 645769e..6cf2188 100644
--- a/docs/schemas/capability.rng
+++ b/docs/schemas/capability.rng
@@ -121,6 +121,11 @@
             <empty/>
           </element>
         </optional>
+        <optional>
+          <element name='Hybrid-Suspend'>
+            <empty/>
+          </element>
+        </optional>
       </interleave>
     </element>
   </define>
diff --git a/src/conf/capabilities.c b/src/conf/capabilities.c
index 87b60b0..8468861 100644
--- a/src/conf/capabilities.c
+++ b/src/conf/capabilities.c
@@ -35,7 +35,7 @@
 #define VIR_FROM_THIS VIR_FROM_CAPABILITIES
 
 VIR_ENUM_IMPL(virHostPMCapability, VIR_HOST_PM_LAST,
-              "S3", "S4")
+              "S3", "S4", "Hybrid-Suspend")
 
 /**
  * virCapabilitiesNew:
diff --git a/src/util/util.c b/src/util/util.c
index ce697fb..ccd1a0e 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -2623,47 +2623,50 @@ virTypedParameterArrayClear(virTypedParameterPtr params, int nparams)
 }
 
 /**
- * Get the Power Management Capabilities of the host system.
- * The script 'pm-is-supported' (from the pm-utils package) is run
- * to find out all the power management features supported by the host,
- * such as Suspend-to-RAM (S3) and Suspend-to-Disk (S4).
+ * virDiscoverHostPMFeature:
+ * @bitmask: The bitmask which should be populated with the result of
+ *           the query
+ * @feature: The power management feature to check whether it is supported
+ *           by the host. Values could be:
+ *           VIR_HOST_PM_S3 for Suspend-to-RAM
+ *           VIR_HOST_PM_S4 for Suspend-to-Disk
+ *           VIR_HOST_PM_HYBRID_SUSPEND for Hybrid-Suspend
  *
- * @bitmask: Pointer to the bitmask which will be set appropriately to
- *           indicate all the supported host power management features.
+ * Run the script 'pm-is-supported' (from the pm-utils package)
+ * to find out if @feature is supported by the host.
  *
- * Returns 0 if the query was successful, -1 upon failure.
+ * Returns 0 if the query was successful, -1 on failure.
  */
 int
-virGetPMCapabilities(unsigned int *bitmask)
+virDiscoverHostPMFeature(unsigned int *bitmask, unsigned int feature)
 {
-    int ret = -1;
-    int status;
     virCommandPtr cmd;
+    int status;
+    int ret = -1;
 
-    *bitmask = 0;
-
-    /* Check support for Suspend-to-RAM (S3) */
-    cmd = virCommandNewArgList("pm-is-supported", "--suspend", NULL);
-    if (virCommandRun(cmd, &status) < 0)
-        goto cleanup;
-
-    /* Check return code of command == 0 for success
-     * (i.e., the PM capability is supported)
-     */
-    if (status == 0)
-        *bitmask |= 1U << VIR_HOST_PM_S3;
-    virCommandFree(cmd);
+    switch (feature) {
+    case VIR_HOST_PM_S3:
+        cmd = virCommandNewArgList("pm-is-supported", "--suspend", NULL);
+        break;
+    case VIR_HOST_PM_S4:
+        cmd = virCommandNewArgList("pm-is-supported", "--hibernate", NULL);
+        break;
+    case VIR_HOST_PM_HYBRID_SUSPEND:
+        cmd = virCommandNewArgList("pm-is-supported", "--suspend-hybrid", NULL);
+        break;
+    default:
+        return ret;
+    }
 
-    /* Check support for Suspend-to-Disk (S4) */
-    cmd = virCommandNewArgList("pm-is-supported", "--hibernate", NULL);
     if (virCommandRun(cmd, &status) < 0)
         goto cleanup;
 
-    /* Check return code of command == 0 for success
-     * (i.e., the PM capability is supported)
-     */
+   /*
+    * Check return code of command == 0 for success
+    * (i.e., the PM capability is supported)
+    */
     if (status == 0)
-        *bitmask |= 1U << VIR_HOST_PM_S4;
+        *bitmask |= 1U << feature;
 
     ret = 0;
 
@@ -2671,3 +2674,41 @@ cleanup:
     virCommandFree(cmd);
     return ret;
 }
+
+/**
+ * virGetPMCapabilities:
+ *
+ * Get the Power Management Capabilities that the host system supports,
+ * such as Suspend-to-RAM (S3), Suspend-to-Disk (S4) and Hybrid-Suspend
+ * (a combination of S3 and S4).
+ *
+ * @bitmask: Pointer to the bitmask which will be set appropriately to
+ *           indicate all the supported host power management features.
+ *
+ * Returns 0 if the query was successful, -1 on failure.
+ */
+int
+virGetPMCapabilities(unsigned int *bitmask)
+{
+    int ret;
+
+    *bitmask = 0;
+
+    /* Check support for Suspend-to-RAM (S3) */
+    ret = virDiscoverHostPMFeature(bitmask, VIR_HOST_PM_S3);
+    if (ret < 0)
+        return -1;
+
+    /* Check support for Suspend-to-Disk (S4) */
+    ret = virDiscoverHostPMFeature(bitmask, VIR_HOST_PM_S4);
+    if (ret < 0)
+        return -1;
+
+    /* Check support for Hybrid-Suspend */
+    ret = virDiscoverHostPMFeature(bitmask, VIR_HOST_PM_HYBRID_SUSPEND);
+    if (ret < 0)
+        return -1;
+
+    return 0;
+}
+
diff --git a/src/util/util.h b/src/util/util.h
index 5afcf58..eda60d2 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -264,14 +264,16 @@ void virTypedParameterArrayClear(virTypedParameterPtr params, int nparams);
 /* Power Management Capabilities of the host system */
 
 enum virHostPMCapability {
-    VIR_HOST_PM_S3,  /* Suspend-to-RAM */
-    VIR_HOST_PM_S4,  /* Suspend-to-Disk */
+    VIR_HOST_PM_S3,              /* Suspend-to-RAM */
+    VIR_HOST_PM_S4,              /* Suspend-to-Disk */
+    VIR_HOST_PM_HYBRID_SUSPEND,  /* Hybrid-Suspend */
 
     VIR_HOST_PM_LAST
 };
 
 VIR_ENUM_DECL(virHostPMCapability)
 
-int virGetPMCapabilities(unsigned int *);
+int virDiscoverHostPMFeature(unsigned int *bitmask, unsigned int feature);
+int virGetPMCapabilities(unsigned int *bitmask);
 
 #endif /* __VIR_UTIL_H__ */

    

Srivatsa S. Bhat

Daniel Veillard

Srivatsa S. Bhat

Daniel P. Berrange

Daniel P. Berrange

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