qemu: Ignore missing vm.unprivileged_userfaultfd sysctl

[libvirt PATCH] qemu: Ignore missing vm.unprivileged_userfaultfd sysctl

Jiri Denemark posted 1 patch 2 years, 2 months ago

Download mbox

Test syntax-check failed

Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/libvirt tags/patchew/67f443ee3961fc0c9d1efe5f9c14a75cc0e12595.1644401634.git.jdenemar@redhat.com

src/qemu/postcopy-migration.sysctl | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Expand all Fold all

[libvirt PATCH] qemu: Ignore missing vm.unprivileged_userfaultfd sysctl

Posted by Jiri Denemark 2 years, 2 months ago

Older kernels did not support this sysctl, but 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>
---
 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
-- 
2.35.1

Re: [libvirt PATCH] qemu: Ignore missing vm.unprivileged_userfaultfd sysctl

Posted by Ján Tomko 2 years, 2 months ago

On a Wednesday in 2022, Jiri Denemark wrote:
>Older kernels did not support this sysctl, but 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>
>---
> src/qemu/postcopy-migration.sysctl | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>

Reviewed-by: Ján Tomko <jtomko@redhat.com>

Jano