Commit 6e6a8ef0 authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Release mmap_lock when using VM_SHARED with MTE 



VM_SHARED mappings are currently forbidden in a memslot with MTE to
prevent two VMs racing to sanitise the same page. However, this check
is performed while holding current->mm's mmap_lock, but fails to release
it. Fix this by releasing the lock when needed.

Fixes: ea7fc1bb ("KVM: arm64: Introduce MTE VM feature")
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005122031.809857-1-qperret@google.com
parent 7615c2a5

arch/arm64/kvm/mmu.c

+4 −2
Original line number Diff line number Diff line
@@ -1529,8 +1529,10 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, 
		 * when updating the PG_mte_tagged page flag, see

		 * sanitise_mte_tags for more details.

		 */

		if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED)

			return -EINVAL;

		if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) {

			ret = -EINVAL;

			break;

		}



		if (vma->vm_flags & VM_PFNMAP) {

			/* IO region dirty page logging not allowed */