From 08fef741d85ecfb3493c47f5f1334f91c30e3233 Mon Sep 17 00:00:00 2001
Message-Id: <08fef741d85ecfb3493c47f5f1334f91c30e3233@dist-git>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Wed, 9 Feb 2022 11:08:42 +0100
Subject: [PATCH] qemu: Ignore missing vm.unprivileged_userfaultfd sysctl
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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>
(cherry picked from commit 558f00397a0d46ad22bf53a22a40ed6fc4fdb5eb)

https://bugzilla.redhat.com/show_bug.cgi?id=2148578

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/postcopy-migration.sysctl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/qemu/postcopy-migration.sysctl b/src/qemu/postcopy-migration.sysctl
index aa8f015ae0..db3f11e49f 100644
--- 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
-- 
2.39.0