[PATCH v1 1/1] qemu: add support for zero-page-detection migration parameter

[Tejus GK]

QEMU supports a migration parameter to determine whether zero-page
checking should be performed and if yes, where it should be performed
(i.e., in the main migration thread or multifd threads). Add support for
this parameter in libvirt.

Signed-off-by: Tejus GK <tejus...@nutanix.com>
---
 include/libvirt/libvirt-domain.h | 11 +++++++++++
 src/qemu/qemu_migration.c        |  1 +
 src/qemu/qemu_migration_params.c |  8 ++++++++
 src/qemu/qemu_migration_params.h |  1 +
 tools/virsh-domain.c             | 13 +++++++++++++
 5 files changed, 34 insertions(+)

diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 99208137c3..5a4875770b 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -1468,6 +1468,17 @@ typedef enum {
  */
 # define VIR_MIGRATE_PARAM_TLS_DESTINATION          "tls.destination"
 
+/**
+ * VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION:
+ *
+ * virDomainMigrate* params field: zero page detection method as
+ * VIR_TYPED_PARAM_STRING. Supported values are 'none', 'legacy', and
+ * 'multifd'.
+ *
+ * Since: 12.8.0
+ */
+# define VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION      "zero_page_detection"
+
 /* Domain migration. */
 virDomainPtr virDomainMigrate (virDomainPtr domain, virConnectPtr dconn,
                                unsigned long flags, const char *dname,
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 4a43ab83b0..f25506e590 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -110,6 +110,7 @@ const virTypedParamValidationTemplate 
qemuMigrationParametersValidation[] = {
     { VIR_MIGRATE_PARAM_TLS_DESTINATION, VIR_TYPED_PARAM_STRING },
     { VIR_MIGRATE_PARAM_DISKS_URI, VIR_TYPED_PARAM_STRING },
     { VIR_MIGRATE_PARAM_BANDWIDTH_AVAIL_SWITCHOVER, VIR_TYPED_PARAM_ULLONG },
+    { VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION, VIR_TYPED_PARAM_STRING},
     { "", 0 }
 };
 
diff --git a/src/qemu/qemu_migration_params.c b/src/qemu/qemu_migration_params.c
index dd47516742..7064140379 100644
--- a/src/qemu/qemu_migration_params.c
+++ b/src/qemu/qemu_migration_params.c
@@ -131,6 +131,7 @@ VIR_ENUM_IMPL(qemuMigrationParam,
               "multifd-zstd-level",
               "avail-switchover-bandwidth",
               "direct-io",
+              "zero-page-detection",
 );
 
 typedef struct _qemuMigrationParamsAlwaysOnItem 
qemuMigrationParamsAlwaysOnItem;
@@ -274,6 +275,10 @@ static const qemuMigrationParamsTPMapItem 
qemuMigrationParamsTPMap[] = {
      .unit = 1024 * 1024, /* MiB/s */
      .param = QEMU_MIGRATION_PARAM_AVAIL_SWITCHOVER_BANDWIDTH,
      .party = QEMU_MIGRATION_SOURCE},
+
+    {.typedParam = VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION,
+     .param = QEMU_MIGRATION_PARAM_ZERO_PAGE_DETECTION,
+     .party = QEMU_MIGRATION_SOURCE},
 };
 
 static const qemuMigrationParamInfoItem qemuMigrationParamInfo[] = {
@@ -332,6 +337,9 @@ static const qemuMigrationParamInfoItem 
qemuMigrationParamInfo[] = {
     [QEMU_MIGRATION_PARAM_DIRECT_IO] = {
         .type = QEMU_MIGRATION_PARAM_TYPE_BOOL,
     },
+    [QEMU_MIGRATION_PARAM_ZERO_PAGE_DETECTION] = {
+        .type = QEMU_MIGRATION_PARAM_TYPE_STRING,
+    },
 };
 G_STATIC_ASSERT(G_N_ELEMENTS(qemuMigrationParamInfo) == 
QEMU_MIGRATION_PARAM_LAST);
 
diff --git a/src/qemu/qemu_migration_params.h b/src/qemu/qemu_migration_params.h
index b7a829b85a..131fe82fc0 100644
--- a/src/qemu/qemu_migration_params.h
+++ b/src/qemu/qemu_migration_params.h
@@ -67,6 +67,7 @@ typedef enum {
     QEMU_MIGRATION_PARAM_MULTIFD_ZSTD_LEVEL,
     QEMU_MIGRATION_PARAM_AVAIL_SWITCHOVER_BANDWIDTH,
     QEMU_MIGRATION_PARAM_DIRECT_IO,
+    QEMU_MIGRATION_PARAM_ZERO_PAGE_DETECTION,
 
     QEMU_MIGRATION_PARAM_LAST
 } qemuMigrationParam;
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 2c64f19a19..519d8427bd 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -11432,6 +11432,10 @@ static const vshCmdOptDef opts_migrate[] = {
      .type = VSH_OT_INT,
      .help = N_("bandwidth (in MiB/s) available for the final phase of 
migration")
     },
+    {.name = "zero-page-detection",
+     .type = VSH_OT_STRING,
+     .help = N_("zero page detection method for migration")
+    },
     {.name = NULL}
 };
 
@@ -11733,6 +11737,15 @@ doMigrate(void *opaque)
             goto save_error;
     }
 
+    if ((rv = vshCommandOptString(ctl, cmd, "zero-page-detection", &opt)) < 0) 
{
+        goto out;
+    } else if (rv > 0) {
+        if (virTypedParamsAddString(&params, &nparams, &maxparams,
+                                    VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION,
+                                    opt) < 0)
+            goto save_error;
+    }
+
     if ((rv = vshCommandOptInt(ctl, cmd, "comp-zlib-level", &intOpt)) < 0) {
         goto out;
     } else if (rv > 0) {
-- 
2.43.7