| Message ID | 20221104011041.290951-8-pcc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: permit MAP_SHARED mappings with MTE enabled | expand |
On Thu, Nov 03 2022, Peter Collingbourne <pcc@google.com> wrote: > Certain VMMs such as crosvm have features (e.g. sandboxing) that depend > on being able to map guest memory as MAP_SHARED. The current restriction > on sharing MAP_SHARED pages with the guest is preventing the use of > those features with MTE. Now that the races between tasks concurrently > clearing tags on the same page have been fixed, remove this restriction. > > Note that this is a relaxation of the ABI. > > Signed-off-by: Peter Collingbourne <pcc@google.com> > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > Reviewed-by: Steven Price <steven.price@arm.com> > --- > arch/arm64/kvm/mmu.c | 8 -------- > 1 file changed, 8 deletions(-) Reviewed-by: Cornelia Huck <cohuck@redhat.com>
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 9ff9a271cf01..b9402d8b5a90 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1110,14 +1110,6 @@ static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn, static bool kvm_vma_mte_allowed(struct vm_area_struct *vma) { - /* - * VM_SHARED mappings are not allowed with MTE to avoid races - * when updating the PG_mte_tagged page flag, see - * sanitise_mte_tags for more details. - */ - if (vma->vm_flags & VM_SHARED) - return false; - return vma->vm_flags & VM_MTE_ALLOWED; }