From 20c1c86f96dd7293734888ef6f8b75c11cda5fae Mon Sep 17 00:00:00 2001
Message-Id: <20c1c86f96dd7293734888ef6f8b75c11cda5fae@dist-git>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Wed, 22 Jun 2022 16:36:53 +0200
Subject: [PATCH] virsh: Add support for VIR_MIGRATE_ZEROCOPY flag
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Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
(cherry picked from commit efa3baeae70fbdf4ab032ca485cb9272ee96bd50)

https://bugzilla.redhat.com/show_bug.cgi?id=2089433

Conflicts:
	docs/manpages/virsh.rst
	tools/virsh-domain.c
            - post-copy recovery not backported

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 docs/manpages/virsh.rst | 8 +++++++-
 tools/virsh-domain.c    | 7 +++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index dd534c10cb..d24e7774a6 100644
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -3225,7 +3225,8 @@ migrate
    migrate [--live] [--offline] [--direct] [--p2p [--tunnelled]]
       [--persistent] [--undefinesource] [--suspend] [--copy-storage-all]
       [--copy-storage-inc] [--change-protection] [--unsafe] [--verbose]
-      [--rdma-pin-all] [--abort-on-error] [--postcopy] [--postcopy-after-precopy]
+      [--rdma-pin-all] [--abort-on-error] [--postcopy]
+      [--postcopy-after-precopy] [--zerocopy]
       domain desturi [migrateuri] [graphicsuri] [listen-address] [dname]
       [--timeout seconds [--timeout-suspend | --timeout-postcopy]]
       [--xml file] [--migrate-disks disk-list] [--disks-port port]
@@ -3298,6 +3299,11 @@ high (and thus allowing the domain to lock most of the host's memory). Doing so
 may be dangerous to both the domain and the host itself since the host's kernel
 may run out of memory.
 
+*--zerocopy* requests zero-copy mechanism to be used for migrating memory pages.
+For QEMU/KVM this means QEMU will be temporarily allowed to lock all guest
+pages in host's memory, although only those that are queued for transfer will
+be locked at the same time.
+
 ``Note``: Individual hypervisors usually do not support all possible types of
 migration. For example, QEMU does not support direct migration.
 
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index b56f6a90f5..c5bade1dbf 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -10730,6 +10730,10 @@ static const vshCmdOptDef opts_migrate[] = {
      .type = VSH_OT_BOOL,
      .help = N_("automatically switch to post-copy migration after one pass of pre-copy")
     },
+    {.name = "zerocopy",
+     .type = VSH_OT_BOOL,
+     .help = N_("use zero-copy mechanism for migrating memory pages")
+    },
     {.name = "migrateuri",
      .type = VSH_OT_STRING,
      .completer = virshCompleteEmpty,
@@ -11133,6 +11137,9 @@ doMigrate(void *opaque)
     if (vshCommandOptBool(cmd, "postcopy"))
         flags |= VIR_MIGRATE_POSTCOPY;
 
+    if (vshCommandOptBool(cmd, "zerocopy"))
+        flags |= VIR_MIGRATE_ZEROCOPY;
+
     if (vshCommandOptBool(cmd, "tls"))
         flags |= VIR_MIGRATE_TLS;
 
-- 
2.35.1