KVM: arm64: Update stale comment for sanitise_mte_tags()

Browse source

Commit c911f0d468 ("KVM: arm64: permit all VM_MTE_ALLOWED mappings
with MTE enabled") allowed VM_SHARED VMAs in a VM with MTE enabled, so
remove the comment to the contrary.

Commit d77e59a8fc ("arm64: mte: Lock a page for MTE tag initialisation")
removed the race that can lead to tags being zeroed more than once when
multiple threads attempt initialisation at the same time, so remove the
comment about mmap_lock too. Note that sanitise_mte_tags() was never called
with the mmap_lock held from user_mem_abort() and the race was prevented by
kvm->mmu_lock.

However, the function still requires to have the kvm->mmu_lock held to
ensure that the memory remains mapped in the userspace process while the
tags are zeroed. Document this in a comment.

CC: Peter Collingbourne <pcc@google.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Steven Price <steven.price@arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

...

This commit is contained in:

Alexandru Elisei 2025-09-15 16:52:34 +01:00 • committed by Marc Zyngier

parent 27d2b47eef

commit 597f41e174

1 changed files with 2 additions and 5 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

7

arch/arm64/kvm/mmu.c

View file