[PATCH 2/3] migration: postcopy-uffd-usermode-only documentation

Lin Ma posted 3 patches 4 years, 3 months ago
Maintainers: "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Eric Blake <eblake@redhat.com>, Juan Quintela <quintela@redhat.com>, Thomas Huth <thuth@redhat.com>, Laurent Vivier <lvivier@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Markus Armbruster <armbru@redhat.com>
[PATCH 2/3] migration: postcopy-uffd-usermode-only documentation
Posted by Lin Ma 4 years, 3 months ago
Signed-off-by: Lin Ma <lma@suse.com>
---
 docs/devel/migration.rst | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst
index 2401253482..dfdd3f20b4 100644
--- a/docs/devel/migration.rst
+++ b/docs/devel/migration.rst
@@ -639,6 +639,15 @@ postcopy-blocktime value of qmp command will show overlapped blocking
 time for all vCPU, postcopy-vcpu-blocktime will show list of blocking
 time per vCPU.
 
+Since kernel v5.11, Unprivileged user (without SYS_CAP_PTRACE capability)
+must pass UFFD_USER_MODE_ONLY to userfaultd if the unprivileged_userfaultfd
+sysctl knob is 0.
+
+To allow unprivileged user postcopy, Issue this command on destination
+monitor prior to turning on postcopy-ram:
+
+``migrate_set_capability postcopy-uffd-usermode-only on``
+
 .. note::
   During the postcopy phase, the bandwidth limits set using
   ``migrate_set_parameter`` is ignored (to avoid delaying requested pages that
-- 
2.26.2