qemu: Ignore missing vm.unprivileged_userfaultfd sysctl

Older kernels did not support this sysctl, but they did not restrict
userfaultfd in any way so everything worked as if
vm.unprivileged_userfaultfd was set to 1. Thus we can safely ignore
errors when setting the value.

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

diff --git a/src/qemu/postcopy-migration.sysctl b/src/qemu/postcopy-migration.sysctl
index aa8f015ae0b8f0f7947311555c2ea33a7fbf8594..db3f11e49fa0a8c99b9bcd3d1fc148270f517226 100644 (file)
--- a/src/qemu/postcopy-migration.sysctl
+++ b/src/qemu/postcopy-migration.sysctl
@@ -3,4 +3,4 @@
 # privileged processes.
 # It can be safely overridden by a file in /etc/sysctl.d/ in case post-copy
 # migration is not used on the host.
-vm.unprivileged_userfaultfd = 1
+-vm.unprivileged_userfaultfd = 1