JIRA: https://issues.redhat.com/browse/RHEL-27745
Conflicts:
* virt/kvm/guest_memfd.c: difference in the hunk due to RHEL missing upstream
commit 1d23040caa8b ("KVM: guest_memfd: Use AS_INACCESSIBLE when creating
guest_memfd inode") which would end up being reverted with this follow-up fix.
This patch is a backport of the following upstream commit:
commit 27e6a24a4cf3d25421c0f6ebb7c39f45fc14d20f
Author: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu Jul 11 13:56:54 2024 -0400
mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE
The flags AS_UNMOVABLE and AS_INACCESSIBLE were both added just for guest_memfd;
AS_UNMOVABLE is already in existing versions of Linux, while AS_INACCESSIBLE was
acked for inclusion in 6.11.
But really, they are the same thing: only guest_memfd uses them, at least for
now, and guest_memfd pages are unmovable because they should not be
accessed by the CPU.
So merge them into one; use the AS_INACCESSIBLE name which is more comprehensive.
At the same time, this fixes an embarrassing bug where AS_INACCESSIBLE was used
as a bit mask, despite it being just a bit index.
The bug was mostly benign, because AS_INACCESSIBLE's bit representation (1010)
corresponded to setting AS_UNEVICTABLE (which is already set) and AS_ENOSPC
(except no async writes can happen on the guest_memfd). So the AS_INACCESSIBLE
flag simply had no effect.
Fixes: 1d23040caa8b ("KVM: guest_memfd: Use AS_INACCESSIBLE when creating guest_memfd inode")
Fixes: c72ceafbd12c ("mm: Introduce AS_INACCESSIBLE for encrypted/confidential memory")
Cc: linux-mm@kvack.org
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Michael Roth <michael.roth@amd.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rafael Aquini <raquini@redhat.com>
288fab6492