Ping, for reviews :) regards, tejus

On 17 Sep 2026, at 11:50 AM, Tejus GK <tejus.gk@nutanix.com> wrote:

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.gk@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(¶ms, &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