From a5cb43154905e2708bf90988bd2aa5f2fca6b935 Mon Sep 17 00:00:00 2001
Message-Id: <a5cb43154905e2708bf90988bd2aa5f2fca6b935@dist-git>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Mon, 24 Apr 2017 15:40:07 +0200
Subject: [PATCH] Add support for CPU cache specification

This patch introduces

    <cache level='N' mode='emulate'/>
    <cache mode='passthrough'/>
    <cache mode='disable'/>

sub element of /domain/cpu. Currently only a single <cache> element is
allowed.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
(cherry picked from commit a646a6016a7c62688988f7cfaa22e1340c2ce761)

https://bugzilla.redhat.com/show_bug.cgi?id=1428952

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 docs/formatdomain.html.in                          | 35 ++++++++++++
 docs/schemas/cputypes.rng                          | 21 ++++++++
 docs/schemas/domaincommon.rng                      |  3 ++
 src/conf/cpu_conf.c                                | 62 ++++++++++++++++++++++
 src/conf/cpu_conf.h                                | 19 +++++++
 src/libvirt_private.syms                           |  2 +
 .../generic-cpu-cache-disable.xml                  | 20 +++++++
 .../generic-cpu-cache-emulate.xml                  | 20 +++++++
 .../generic-cpu-cache-passthrough.xml              | 20 +++++++
 tests/genericxml2xmltest.c                         |  4 ++
 10 files changed, 206 insertions(+)
 create mode 100644 tests/genericxml2xmlindata/generic-cpu-cache-disable.xml
 create mode 100644 tests/genericxml2xmlindata/generic-cpu-cache-emulate.xml
 create mode 100644 tests/genericxml2xmlindata/generic-cpu-cache-passthrough.xml

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index aae5e9c07..aee1e1442 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1198,6 +1198,7 @@
   &lt;model fallback='allow'&gt;core2duo&lt;/model&gt;
   &lt;vendor&gt;Intel&lt;/vendor&gt;
   &lt;topology sockets='1' cores='2' threads='1'/&gt;
+  &lt;cache level='3' mode='emulate'/&gt;
   &lt;feature policy='disable' name='lahf_lm'/&gt;
 &lt;/cpu&gt;
 ...</pre>
@@ -1211,6 +1212,7 @@
 
 <pre>
 &lt;cpu mode='host-passthrough'&gt;
+  &lt;cache mode='passthrough'/&gt;
   &lt;feature policy='disable' name='lahf_lm'/&gt;
 ...</pre>
 
@@ -1431,6 +1433,39 @@
         <span class="since">Since 0.8.5</span> the <code>policy</code>
         attribute can be omitted and will default to <code>require</code>.
       </dd>
+
+      <dt><code>cache</code></dt>
+      <dd><span class="since">Since 3.3.0</span> the <code>cache</code>
+        element describes the virtual CPU cache. If the element is missing,
+        the hypervisor will use a sensible default.
+
+        <dl>
+          <dt><code>level</code></dt>
+          <dd>This optional attribute specifies which cache level is described
+            by the element. Missing attribute means the element describes all
+            CPU cache levels at once. Mixing <code>cache</code> elements with
+            the <code>level</code> attribute set and those without the
+            attribute is forbidden.</dd>
+
+          <dt><code>mode</code></dt>
+          <dd>
+            The following values are supported:
+            <dl>
+              <dt><code>emulate</code></dt>
+              <dd>The hypervisor will provide a fake CPU cache data.</dd>
+
+              <dt><code>passthrough</code></dt>
+              <dd>The real CPU cache data reported by the host CPU will be
+                passed through to the virtual CPU.</dd>
+
+              <dt><code>disable</code></dt>
+              <dd>The virtual CPU will report no CPU cache of the specified
+                level (or no cache at all if the <code>level</code> attribute
+                is missing).</dd>
+            </dl>
+          </dd>
+        </dl>
+      </dd>
     </dl>
 
     <p>
diff --git a/docs/schemas/cputypes.rng b/docs/schemas/cputypes.rng
index 8189114e3..3eef16abc 100644
--- a/docs/schemas/cputypes.rng
+++ b/docs/schemas/cputypes.rng
@@ -142,4 +142,25 @@
     </data>
   </define>
 
+  <define name="cpuCache">
+    <element name="cache">
+      <optional>
+        <attribute name="level">
+          <choice>
+            <value>1</value>
+            <value>2</value>
+            <value>3</value>
+          </choice>
+        </attribute>
+      </optional>
+      <attribute name="mode">
+        <choice>
+          <value>emulate</value>
+          <value>passthrough</value>
+          <value>disable</value>
+        </choice>
+      </attribute>
+    </element>
+  </define>
+
 </grammar>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index edc225fe5..d5c28ee3c 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -4545,6 +4545,9 @@
         <optional>
           <ref name="cpuNuma"/>
         </optional>
+        <optional>
+          <ref name="cpuCache"/>
+        </optional>
       </interleave>
     </element>
   </define>
diff --git a/src/conf/cpu_conf.c b/src/conf/cpu_conf.c
index 623b1699f..1b098c476 100644
--- a/src/conf/cpu_conf.c
+++ b/src/conf/cpu_conf.c
@@ -62,6 +62,12 @@ VIR_ENUM_IMPL(virCPUFeaturePolicy, VIR_CPU_FEATURE_LAST,
               "disable",
               "forbid")
 
+VIR_ENUM_IMPL(virCPUCacheMode, VIR_CPU_CACHE_MODE_LAST,
+              "emulate",
+              "passthrough",
+              "disable")
+
+
 void
 virCPUDefFreeFeatures(virCPUDefPtr def)
 {
@@ -92,6 +98,7 @@ virCPUDefFree(virCPUDefPtr def)
         return;
 
     virCPUDefFreeModel(def);
+    VIR_FREE(def->cache);
     VIR_FREE(def);
 }
 
@@ -204,7 +211,18 @@ virCPUDefCopyWithoutModel(const virCPUDef *cpu)
     copy->threads = cpu->threads;
     copy->arch = cpu->arch;
 
+    if (cpu->cache) {
+        if (VIR_ALLOC(copy->cache) < 0)
+            goto error;
+
+        *copy->cache = *cpu->cache;
+    }
+
     return copy;
+
+ error:
+    virCPUDefFree(copy);
+    return NULL;
 }
 
 
@@ -489,6 +507,41 @@ virCPUDefParseXML(xmlNodePtr node,
         def->features[i].policy = policy;
     }
 
+    if (virXPathInt("count(./cache)", ctxt, &n) < 0) {
+        goto cleanup;
+    } else if (n > 1) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("at most one CPU cache element may be specified"));
+        goto cleanup;
+    } else if (n == 1) {
+        int level = -1;
+        char *strmode;
+        int mode;
+
+        if (virXPathBoolean("boolean(./cache[1]/@level)", ctxt) == 1 &&
+            (virXPathInt("string(./cache[1]/@level)", ctxt, &level) < 0 ||
+             level < 1 || level > 3)) {
+            virReportError(VIR_ERR_XML_ERROR, "%s",
+                           _("invalid CPU cache level, must be in range [1,3]"));
+            goto cleanup;
+        }
+
+        if (!(strmode = virXPathString("string(./cache[1]/@mode)", ctxt)) ||
+            (mode = virCPUCacheModeTypeFromString(strmode)) < 0) {
+            VIR_FREE(strmode);
+            virReportError(VIR_ERR_XML_ERROR, "%s",
+                           _("missing or invalid CPU cache mode"));
+            goto cleanup;
+        }
+        VIR_FREE(strmode);
+
+        if (VIR_ALLOC(def->cache) < 0)
+            goto cleanup;
+
+        def->cache->level = level;
+        def->cache->mode = mode;
+    }
+
  cleanup:
     ctxt->node = oldnode;
     VIR_FREE(fallback);
@@ -662,6 +715,15 @@ virCPUDefFormatBuf(virBufferPtr buf,
         virBufferAddLit(buf, "/>\n");
     }
 
+    if (def->cache) {
+        virBufferAddLit(buf, "<cache ");
+        if (def->cache->level != -1)
+            virBufferAsprintf(buf, "level='%d' ", def->cache->level);
+        virBufferAsprintf(buf, "mode='%s'",
+                          virCPUCacheModeTypeToString(def->cache->mode));
+        virBufferAddLit(buf, "/>\n");
+    }
+
     for (i = 0; i < def->nfeatures; i++) {
         virCPUFeatureDefPtr feature = def->features + i;
 
diff --git a/src/conf/cpu_conf.h b/src/conf/cpu_conf.h
index 3e02deed4..09438b68b 100644
--- a/src/conf/cpu_conf.h
+++ b/src/conf/cpu_conf.h
@@ -103,6 +103,24 @@ struct _virCPUFeatureDef {
 };
 
 
+typedef enum {
+    VIR_CPU_CACHE_MODE_EMULATE,
+    VIR_CPU_CACHE_MODE_PASSTHROUGH,
+    VIR_CPU_CACHE_MODE_DISABLE,
+
+    VIR_CPU_CACHE_MODE_LAST
+} virCPUCacheMode;
+
+VIR_ENUM_DECL(virCPUCacheMode);
+
+typedef struct _virCPUCacheDef virCPUCacheDef;
+typedef virCPUCacheDef *virCPUCacheDefPtr;
+struct _virCPUCacheDef {
+    int level;          /* -1 for unspecified */
+    virCPUCacheMode mode;
+};
+
+
 typedef struct _virCPUDef virCPUDef;
 typedef virCPUDef *virCPUDefPtr;
 struct _virCPUDef {
@@ -121,6 +139,7 @@ struct _virCPUDef {
     size_t nfeatures;
     size_t nfeatures_max;
     virCPUFeatureDefPtr features;
+    virCPUCacheDefPtr cache;
 };
 
 
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index b551cb86a..9a334311d 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -67,6 +67,8 @@ virCapabilitiesSetNetPrefix;
 
 
 # conf/cpu_conf.h
+virCPUCacheModeTypeFromString;
+virCPUCacheModeTypeToString;
 virCPUDefAddFeature;
 virCPUDefCopy;
 virCPUDefCopyModel;
diff --git a/tests/genericxml2xmlindata/generic-cpu-cache-disable.xml b/tests/genericxml2xmlindata/generic-cpu-cache-disable.xml
new file mode 100644
index 000000000..25f65cc6e
--- /dev/null
+++ b/tests/genericxml2xmlindata/generic-cpu-cache-disable.xml
@@ -0,0 +1,20 @@
+<domain type='kvm'>
+  <name>foo</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu mode='host-passthrough'>
+    <cache mode='disable'/>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+  </devices>
+</domain>
diff --git a/tests/genericxml2xmlindata/generic-cpu-cache-emulate.xml b/tests/genericxml2xmlindata/generic-cpu-cache-emulate.xml
new file mode 100644
index 000000000..6ea57cbf6
--- /dev/null
+++ b/tests/genericxml2xmlindata/generic-cpu-cache-emulate.xml
@@ -0,0 +1,20 @@
+<domain type='kvm'>
+  <name>foo</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu mode='host-passthrough'>
+    <cache level='3' mode='emulate'/>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+  </devices>
+</domain>
diff --git a/tests/genericxml2xmlindata/generic-cpu-cache-passthrough.xml b/tests/genericxml2xmlindata/generic-cpu-cache-passthrough.xml
new file mode 100644
index 000000000..8d4c186c9
--- /dev/null
+++ b/tests/genericxml2xmlindata/generic-cpu-cache-passthrough.xml
@@ -0,0 +1,20 @@
+<domain type='kvm'>
+  <name>foo</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu mode='host-passthrough'>
+    <cache mode='passthrough'/>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+  </devices>
+</domain>
diff --git a/tests/genericxml2xmltest.c b/tests/genericxml2xmltest.c
index 488190270..ab1ebce9f 100644
--- a/tests/genericxml2xmltest.c
+++ b/tests/genericxml2xmltest.c
@@ -100,6 +100,10 @@ mymain(void)
 
     DO_TEST("vcpus-individual");
 
+    DO_TEST("cpu-cache-emulate");
+    DO_TEST("cpu-cache-passthrough");
+    DO_TEST("cpu-cache-disable");
+
     virObjectUnref(caps);
     virObjectUnref(xmlopt);
 
-- 
2.12.2