qemu: Add support for sending capabilities in migration cookie

Some migration capabilities may be enabled automatically, but only if
both sides of migration support them. Thus we need to be able transfer
the list of supported migration capabilities in migration cookie.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_migration.c

@@ -1917,6 +1917,7 @@ qemuMigrationSrcBeginPhase(virQEMUDriverPtr driver,
         goto cleanup;
 
     if (qemuMigrationBakeCookie(mig, driver, vm,
+                                QEMU_MIGRATION_SOURCE,
                                 cookieout, cookieoutlen,
                                 cookieFlags) < 0)
         goto cleanup;
@@ -2429,8 +2430,9 @@ qemuMigrationDstPrepareAny(virQEMUDriverPtr driver,
         goto stopjob;
 
  done:
-    if (qemuMigrationBakeCookie(mig, driver, vm, cookieout,
+    if (qemuMigrationBakeCookie(mig, driver, vm,
-                                cookieoutlen, cookieFlags) < 0) {
+                                QEMU_MIGRATION_DESTINATION,
+                                cookieout, cookieoutlen, cookieFlags) < 0) {
         /* We could tear down the whole guest here, but
          * cookie data is (so far) non-critical, so that
          * seems a little harsh. We'll just warn for now.
@@ -3523,8 +3525,9 @@ qemuMigrationSrcRun(virQEMUDriverPtr driver,
                    QEMU_MIGRATION_COOKIE_STATS;
 
     if (qemuMigrationCookieAddPersistent(mig, &persistDef) < 0 ||
-        qemuMigrationBakeCookie(mig, driver, vm, cookieout,
+        qemuMigrationBakeCookie(mig, driver, vm,
-                                cookieoutlen, cookieFlags) < 0) {
+                                QEMU_MIGRATION_SOURCE,
+                                cookieout, cookieoutlen, cookieFlags) < 0) {
         VIR_WARN("Unable to encode migration cookie");
     }
 
@@ -5019,7 +5022,9 @@ qemuMigrationDstFinish(virQEMUDriverPtr driver,
             priv->job.completed->status = QEMU_DOMAIN_JOB_STATUS_COMPLETED;
         }
 
-        if (qemuMigrationBakeCookie(mig, driver, vm, cookieout, cookieoutlen,
+        if (qemuMigrationBakeCookie(mig, driver, vm,
+                                    QEMU_MIGRATION_DESTINATION,
+                                    cookieout, cookieoutlen,
                                     QEMU_MIGRATION_COOKIE_STATS) < 0)
             VIR_WARN("Unable to encode migration cookie");
 

src/qemu/qemu_migration_cookie.c

@@ -33,6 +33,7 @@
 
 #include "qemu_domain.h"
 #include "qemu_migration_cookie.h"
+#include "qemu_migration_params.h"
 
 
 #define VIR_FROM_THIS VIR_FROM_QEMU
@@ -50,7 +51,8 @@ VIR_ENUM_IMPL(qemuMigrationCookieFlag,
               "memory-hotplug",
               "cpu-hotplug",
               "cpu",
-              "allowReboot");
+              "allowReboot",
+              "capabilities");
 
 
 static void
@@ -94,6 +96,18 @@ qemuMigrationCookieNBDFree(qemuMigrationCookieNBDPtr nbd)
 }
 
 
+static void
+qemuMigrationCookieCapsFree(qemuMigrationCookieCapsPtr caps)
+{
+    if (!caps)
+        return;
+
+    virBitmapFree(caps->supported);
+    virBitmapFree(caps->automatic);
+    VIR_FREE(caps);
+}
+
+
 void
 qemuMigrationCookieFree(qemuMigrationCookiePtr mig)
 {
@@ -112,6 +126,7 @@ qemuMigrationCookieFree(qemuMigrationCookiePtr mig)
     VIR_FREE(mig->lockDriver);
     VIR_FREE(mig->jobInfo);
     virCPUDefFree(mig->cpu);
+    qemuMigrationCookieCapsFree(mig->caps);
     VIR_FREE(mig);
 }
 
@@ -550,6 +565,33 @@ qemuMigrationCookieAddAllowReboot(qemuMigrationCookiePtr mig,
 }
 
 
+static int
+qemuMigrationCookieAddCaps(qemuMigrationCookiePtr mig,
+                           virDomainObjPtr vm,
+                           qemuMigrationParty party)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+
+    qemuMigrationCookieCapsFree(mig->caps);
+    if (VIR_ALLOC(mig->caps) < 0)
+        return -1;
+
+    if (priv->migrationCaps)
+        mig->caps->supported = virBitmapNewCopy(priv->migrationCaps);
+    else
+        mig->caps->supported = virBitmapNew(0);
+
+    mig->caps->automatic = qemuMigrationParamsGetAlwaysOnCaps(party);
+
+    if (!mig->caps->supported || !mig->caps->automatic)
+        return -1;
+
+    mig->flags |= QEMU_MIGRATION_COOKIE_CAPS;
+
+    return 0;
+}
+
+
 static void
 qemuMigrationCookieGraphicsXMLFormat(virBufferPtr buf,
                                      qemuMigrationCookieGraphicsPtr grap)
@@ -710,6 +752,33 @@ qemuMigrationCookieStatisticsXMLFormat(virBufferPtr buf,
 }
 
 
+static void
+qemuMigrationCookieCapsXMLFormat(virBufferPtr buf,
+                                 qemuMigrationCookieCapsPtr caps)
+{
+    qemuMigrationCapability cap;
+
+    virBufferAddLit(buf, "<capabilities>\n");
+    virBufferAdjustIndent(buf, 2);
+
+    for (cap = 0; cap < QEMU_MIGRATION_CAP_LAST; cap++) {
+        bool supported = false;
+        bool automatic = false;
+
+        ignore_value(virBitmapGetBit(caps->supported, cap, &supported));
+        ignore_value(virBitmapGetBit(caps->automatic, cap, &automatic));
+        if (supported) {
+            virBufferAsprintf(buf, "<cap name='%s' auto='%s'/>\n",
+                              qemuMigrationCapabilityTypeToString(cap),
+                              automatic ? "yes" : "no");
+        }
+    }
+
+    virBufferAdjustIndent(buf, -2);
+    virBufferAddLit(buf, "</capabilities>\n");
+}
+
+
 static int
 qemuMigrationCookieXMLFormat(virQEMUDriverPtr driver,
                              virBufferPtr buf,
@@ -793,6 +862,9 @@ qemuMigrationCookieXMLFormat(virQEMUDriverPtr driver,
     if (mig->flags & QEMU_MIGRATION_COOKIE_ALLOW_REBOOT)
         qemuDomainObjPrivateXMLFormatAllowReboot(buf, mig->allowReboot);
 
+    if (mig->flags & QEMU_MIGRATION_COOKIE_CAPS)
+        qemuMigrationCookieCapsXMLFormat(buf, mig->caps);
+
     virBufferAdjustIndent(buf, -2);
     virBufferAddLit(buf, "</qemu-migration>\n");
     return 0;
@@ -1067,6 +1139,59 @@ qemuMigrationCookieStatisticsXMLParse(xmlXPathContextPtr ctxt)
 }
 
 
+static qemuMigrationCookieCapsPtr
+qemuMigrationCookieCapsXMLParse(xmlXPathContextPtr ctxt)
+{
+    qemuMigrationCookieCapsPtr caps = NULL;
+    xmlNodePtr *nodes = NULL;
+    qemuMigrationCookieCapsPtr ret = NULL;
+    char *name = NULL;
+    char *automatic = NULL;
+    int cap;
+    size_t i;
+    int n;
+
+    if (VIR_ALLOC(caps) < 0)
+        return NULL;
+
+    if (!(caps->supported = virBitmapNew(QEMU_MIGRATION_CAP_LAST)) ||
+        !(caps->automatic = virBitmapNew(QEMU_MIGRATION_CAP_LAST)))
+        goto cleanup;
+
+    if ((n = virXPathNodeSet("./capabilities[1]/cap", ctxt, &nodes)) < 0)
+        goto cleanup;
+
+    for (i = 0; i < n; i++) {
+        if (!(name = virXMLPropString(nodes[i], "name"))) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("missing migration capability name"));
+            goto cleanup;
+        }
+
+        if ((cap = qemuMigrationCapabilityTypeFromString(name)) < 0)
+            VIR_DEBUG("unknown migration capability '%s'", name);
+        else
+            ignore_value(virBitmapSetBit(caps->supported, cap));
+
+        if ((automatic = virXMLPropString(nodes[i], "auto")) &&
+            STREQ(automatic, "yes"))
+            ignore_value(virBitmapSetBit(caps->automatic, cap));
+
+        VIR_FREE(name);
+        VIR_FREE(automatic);
+    }
+
+    VIR_STEAL_PTR(ret, caps);
+
+ cleanup:
+    qemuMigrationCookieCapsFree(caps);
+    VIR_FREE(nodes);
+    VIR_FREE(name);
+    VIR_FREE(automatic);
+    return ret;
+}
+
+
 static int
 qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig,
                             virQEMUDriverPtr driver,
@@ -1246,6 +1371,10 @@ qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig,
         qemuDomainObjPrivateXMLParseAllowReboot(ctxt, &mig->allowReboot) < 0)
         goto error;
 
+    if (flags & QEMU_MIGRATION_COOKIE_CAPS &&
+        !(mig->caps = qemuMigrationCookieCapsXMLParse(ctxt)))
+        goto error;
+
     virObjectUnref(caps);
     return 0;
 
@@ -1286,6 +1415,7 @@ int
 qemuMigrationBakeCookie(qemuMigrationCookiePtr mig,
                         virQEMUDriverPtr driver,
                         virDomainObjPtr dom,
+                        qemuMigrationParty party,
                         char **cookieout,
                         int *cookieoutlen,
                         unsigned int flags)
@@ -1329,6 +1459,10 @@ qemuMigrationBakeCookie(qemuMigrationCookiePtr mig,
     if (flags & QEMU_MIGRATION_COOKIE_ALLOW_REBOOT)
         qemuMigrationCookieAddAllowReboot(mig, dom);
 
+    if (flags & QEMU_MIGRATION_COOKIE_CAPS &&
+        qemuMigrationCookieAddCaps(mig, dom, party) < 0)
+        return -1;
+
     if (!(*cookieout = qemuMigrationCookieXMLFormatStr(driver, mig)))
         return -1;
 

src/qemu/qemu_migration_cookie.h

@@ -19,6 +19,8 @@
 #ifndef __QEMU_MIGRATION_COOKIE_H__
 # define __QEMU_MIGRATION_COOKIE_H__
 
+# include "qemu_migration_params.h"
+
 typedef enum {
     QEMU_MIGRATION_COOKIE_FLAG_GRAPHICS,
     QEMU_MIGRATION_COOKIE_FLAG_LOCKSTATE,
@@ -30,6 +32,7 @@ typedef enum {
     QEMU_MIGRATION_COOKIE_FLAG_CPU_HOTPLUG,
     QEMU_MIGRATION_COOKIE_FLAG_CPU,
     QEMU_MIGRATION_COOKIE_FLAG_ALLOW_REBOOT,
+    QEMU_MIGRATION_COOKIE_FLAG_CAPS,
 
     QEMU_MIGRATION_COOKIE_FLAG_LAST
 } qemuMigrationCookieFlags;
@@ -47,6 +50,7 @@ typedef enum {
     QEMU_MIGRATION_COOKIE_CPU_HOTPLUG = (1 << QEMU_MIGRATION_COOKIE_FLAG_CPU_HOTPLUG),
     QEMU_MIGRATION_COOKIE_CPU = (1 << QEMU_MIGRATION_COOKIE_FLAG_CPU),
     QEMU_MIGRATION_COOKIE_ALLOW_REBOOT = (1 << QEMU_MIGRATION_COOKIE_FLAG_ALLOW_REBOOT),
+    QEMU_MIGRATION_COOKIE_CAPS = (1 << QEMU_MIGRATION_COOKIE_FLAG_CAPS),
 } qemuMigrationCookieFeatures;
 
 typedef struct _qemuMigrationCookieGraphics qemuMigrationCookieGraphics;
@@ -92,6 +96,13 @@ struct _qemuMigrationCookieNBD {
     } *disks;
 };
 
+typedef struct _qemuMigrationCookieCaps qemuMigrationCookieCaps;
+typedef qemuMigrationCookieCaps *qemuMigrationCookieCapsPtr;
+struct _qemuMigrationCookieCaps {
+    virBitmapPtr supported;
+    virBitmapPtr automatic;
+};
+
 typedef struct _qemuMigrationCookie qemuMigrationCookie;
 typedef qemuMigrationCookie *qemuMigrationCookiePtr;
 struct _qemuMigrationCookie {
@@ -132,6 +143,9 @@ struct _qemuMigrationCookie {
 
     /* If flags & QEMU_MIGRATION_COOKIE_ALLOW_REBOOT */
     virTristateBool allowReboot;
+
+    /* If flags & QEMU_MIGRATION_COOKIE_CAPS */
+    qemuMigrationCookieCapsPtr caps;
 };
 
 
@@ -139,6 +153,7 @@ int
 qemuMigrationBakeCookie(qemuMigrationCookiePtr mig,
                         virQEMUDriverPtr driver,
                         virDomainObjPtr dom,
+                        qemuMigrationParty party,
                         char **cookieout,
                         int *cookieoutlen,
                         unsigned int flags);

src/qemu/qemu_migration_params.c

@@ -153,6 +153,26 @@ static const qemuMigrationParamType qemuMigrationParamTypes[] = {
 verify(ARRAY_CARDINALITY(qemuMigrationParamTypes) == QEMU_MIGRATION_PARAM_LAST);
 
 
+virBitmapPtr
+qemuMigrationParamsGetAlwaysOnCaps(qemuMigrationParty party)
+{
+    virBitmapPtr caps = NULL;
+    size_t i;
+
+    if (!(caps = virBitmapNew(QEMU_MIGRATION_CAP_LAST)))
+        return NULL;
+
+    for (i = 0; i < ARRAY_CARDINALITY(qemuMigrationParamsAlwaysOn); i++) {
+        if (!(qemuMigrationParamsAlwaysOn[i].party & party))
+            continue;
+
+        ignore_value(virBitmapSetBit(caps, qemuMigrationParamsAlwaysOn[i].cap));
+    }
+
+    return caps;
+}
+
+
 static qemuMigrationParamsPtr
 qemuMigrationParamsNew(void)
 {

src/qemu/qemu_migration_params.h

@@ -65,6 +65,9 @@ typedef enum {
 } qemuMigrationParty;
 
 
+virBitmapPtr
+qemuMigrationParamsGetAlwaysOnCaps(qemuMigrationParty party);
+
 qemuMigrationParamsPtr
 qemuMigrationParamsFromFlags(virTypedParameterPtr params,
                              int nparams,