ANDROID: KVM: arm64: Drop FOLL_FORCE when pinning guest memory pages
Passing FOLL_FORCE when pinning guest memory pages was intended to allow
the VMM to map guest memory as PROT_NONE without prohibiting access from
the guest. As it turns out, crosvm doesn't implement this, and since
the host kernel will inject a signal into the VMM on a bad access
irrespective of the stage-1 permissions, we can drop the FOLL_FORCE flag
altogether.
Bug: 226564150
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: If21091b6adf3dbe4155c5c840753c912d283b159
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 8e8d908..20249b7 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1163,10 +1163,7 @@
unsigned long hva)
{
struct mm_struct *mm = current->mm;
- unsigned int flags = FOLL_FORCE |
- FOLL_HWPOISON |
- FOLL_LONGTERM |
- FOLL_WRITE;
+ unsigned int flags = FOLL_HWPOISON | FOLL_LONGTERM | FOLL_WRITE;
struct kvm_pinned_page *ppage;
struct kvm *kvm = vcpu->kvm;
struct page *page;
