[PATCH 2/4] KVM: arm64: MMU: Add kvm_stage2_unmap_all() helper

[Marc Zyngier <maz@kernel.org>]

Build on top of kvm_pgtable_stage2_unmap_notlbi() to provide a primitive
tearing down a whole Stage-2 MMU and invalidating the corresponding TLBs
by VMID, which is far more efficient than performing range invalidation
(or even worse, single mappings).

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_mmu.h |  1 +
 arch/arm64/kvm/mmu.c             | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 6eae7e7e2a684..f450557d4b7b3 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -171,6 +171,7 @@ void __init free_hyp_pgds(void);
 
 void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start,
 			    u64 size, bool may_block);
+void kvm_stage2_unmap_all(struct kvm_s2_mmu *mmu, bool may_block);
 void kvm_stage2_flush_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end);
 void kvm_stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end);
 
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 9ba86450fe4af..68bfd09870b76 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -346,6 +346,21 @@ void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start,
 	__unmap_stage2_range(mmu, start, size, may_block);
 }
 
+void kvm_stage2_unmap_all(struct kvm_s2_mmu *mmu, bool may_block)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
+
+	if (kvm_vm_is_protected(kvm))
+		return;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	WARN_ON(stage2_apply_range(mmu, 0, kvm_phys_size(mmu),
+				   KVM_PGT_FN(kvm_pgtable_stage2_unmap_notlbi),
+				   may_block));
+
+	kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
+}
+
 void kvm_stage2_flush_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
 {
 	stage2_apply_range_resched(mmu, addr, end, KVM_PGT_FN(kvm_pgtable_stage2_flush));
-- 
2.47.3