[PATCH v23 09/14] KVM: arm64: Consolidate stage2 unmap range into kvm_stage2_unmap_range

[Suzuki K Poulose <suzuki.poulose@arm.com>]

In preparation for adding VM specific backends for stage2 operations,
nuke __unmap_stage2_range() and fold the logic into
kvm_stage2_unmap_range(). Also, make kvm_unmap_gfn_range(), the only other
user of the __unmap_stage2_range() call the kvm_stage2_unmap_range(). Also,
while at it fix the comment to make it clear that mmu_lock must always be
held while unmapping. The code already mandates that and the two call paths
do have the write mmu_lock held.

Later we would replace the logic in kvm_stage2_unmap_range() with VM
specific backends.

No functional changes intended.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
Change since v21:
 - Nuke __unmap_stage2_range and consolidate the stage2_unmap_range logic
   into kvm_stage2_unmap_range(), in preparation for removing the KVM_PGT_FN()
   for stage2_unmap
---
 arch/arm64/kvm/mmu.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 9ba86450fe4af..3fef16393f568 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -314,36 +314,30 @@ static void invalidate_icache_guest_page(void *va, size_t size)
  * does.
  */
 /**
- * __unmap_stage2_range -- Clear stage2 page table entries to unmap a range
+ * kvm_stage2_unmap_range -- Clear stage2 page table entries to unmap a range
  * @mmu:   The KVM stage-2 MMU pointer
  * @start: The intermediate physical base address of the range to unmap
  * @size:  The size of the area to unmap
  * @may_block: Whether or not we are permitted to block
  *
  * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
- * be called while holding mmu_lock (unless for freeing the stage2 pgd before
- * destroying the VM), otherwise another faulting VCPU may come in and mess
- * with things behind our backs.
+ * be called while holding mmu_lock otherwise another faulting VCPU may
+ * come in and mess with things behind our backs.
  */
-static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size,
-				 bool may_block)
-{
-	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
-	phys_addr_t end = start + size;
-
-	lockdep_assert_held_write(&kvm->mmu_lock);
-	WARN_ON(size & ~PAGE_MASK);
-	WARN_ON(stage2_apply_range(mmu, start, end, KVM_PGT_FN(kvm_pgtable_stage2_unmap),
-				   may_block));
-}
-
 void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start,
 			    u64 size, bool may_block)
 {
-	if (kvm_vm_is_protected(kvm_s2_mmu_to_kvm(mmu)))
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
+
+	if (kvm_vm_is_protected(kvm))
 		return;
 
-	__unmap_stage2_range(mmu, start, size, may_block);
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	WARN_ON(size & ~PAGE_MASK);
+
+	WARN_ON(stage2_apply_range(mmu, start, start + size,
+				   KVM_PGT_FN(kvm_pgtable_stage2_unmap),
+				   may_block));
 }
 
 void kvm_stage2_flush_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
@@ -2436,12 +2430,12 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 
 bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
 {
-	if (!kvm->arch.mmu.pgt || kvm_vm_is_protected(kvm))
+	if (!kvm->arch.mmu.pgt)
 		return false;
 
-	__unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
-			     (range->end - range->start) << PAGE_SHIFT,
-			     range->may_block);
+	kvm_stage2_unmap_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
+			       (range->end - range->start) << PAGE_SHIFT,
+			       range->may_block);
 
 	kvm_nested_s2_unmap(kvm, range->may_block);
 	return false;
-- 
2.43.0