KVM: arm64: Convert to the gfn-based MMU notifier callbacks

Move arm64 to the gfn-base MMU notifier APIs, which do the hva->gfn
lookup in common code.

No meaningful functional change intended, though the exact order of
operations is slightly different since the memslot lookups occur before
calling into arch code.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210402005658.3024832-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/arm64/include/asm/kvm_host.h

@@ -586,6 +586,7 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
 			      struct kvm_vcpu_events *events);
 
 #define KVM_ARCH_WANT_MMU_NOTIFIER
+#define KVM_ARCH_WANT_NEW_MMU_NOTIFIER_APIS
 
 void kvm_arm_halt_guest(struct kvm *kvm);
 void kvm_arm_resume_guest(struct kvm *kvm);

arch/arm64/kvm/mmu.c

@@ -839,7 +839,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 * gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk
 	 * the page we just got a reference to gets unmapped before we have a
 	 * chance to grab the mmu_lock, which ensure that if the page gets
-	 * unmapped afterwards, the call to kvm_unmap_hva will take it away
+	 * unmapped afterwards, the call to kvm_unmap_gfn will take it away
 	 * from us again properly. This smp_rmb() interacts with the smp_wmb()
 	 * in kvm_mmu_notifier_invalidate_<page|range_end>.
 	 */
@@ -1064,123 +1064,70 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
-static int handle_hva_to_gpa(struct kvm *kvm,
-			     unsigned long start,
-			     unsigned long end,
-			     int (*handler)(struct kvm *kvm,
-					    gpa_t gpa, u64 size,
-					    void *data),
-			     void *data)
+bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
 {
-	struct kvm_memslots *slots;
-	struct kvm_memory_slot *memslot;
-	int ret = 0;
-
-	slots = kvm_memslots(kvm);
-
-	/* we only care about the pages that the guest sees */
-	kvm_for_each_memslot(memslot, slots) {
-		unsigned long hva_start, hva_end;
-		gfn_t gpa;
-
-		hva_start = max(start, memslot->userspace_addr);
-		hva_end = min(end, memslot->userspace_addr +
-					(memslot->npages << PAGE_SHIFT));
-		if (hva_start >= hva_end)
-			continue;
-
-		gpa = hva_to_gfn_memslot(hva_start, memslot) << PAGE_SHIFT;
-		ret |= handler(kvm, gpa, (u64)(hva_end - hva_start), data);
-	}
-
-	return ret;
-}
+	if (!kvm->arch.mmu.pgt)
+		return 0;
 
-static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
-	unsigned flags = *(unsigned *)data;
-	bool may_block = flags & MMU_NOTIFIER_RANGE_BLOCKABLE;
+	__unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
+			     (range->end - range->start) << PAGE_SHIFT,
+			     range->may_block);
 
-	__unmap_stage2_range(&kvm->arch.mmu, gpa, size, may_block);
 	return 0;
 }
 
-int kvm_unmap_hva_range(struct kvm *kvm,
-			unsigned long start, unsigned long end, unsigned flags)
+bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 {
+	kvm_pfn_t pfn = pte_pfn(range->pte);
+
 	if (!kvm->arch.mmu.pgt)
 		return 0;
 
-	handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, &flags);
-	return 0;
-}
-
-static int kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
-	kvm_pfn_t *pfn = (kvm_pfn_t *)data;
+	WARN_ON(range->end - range->start != 1);
 
-	WARN_ON(size != PAGE_SIZE);
+	/*
+	 * We've moved a page around, probably through CoW, so let's treat it
+	 * just like a translation fault and clean the cache to the PoC.
+	 */
+	clean_dcache_guest_page(pfn, PAGE_SIZE);
 
 	/*
 	 * The MMU notifiers will have unmapped a huge PMD before calling
-	 * ->change_pte() (which in turn calls kvm_set_spte_hva()) and
+	 * ->change_pte() (which in turn calls kvm_set_spte_gfn()) and
 	 * therefore we never need to clear out a huge PMD through this
 	 * calling path and a memcache is not required.
 	 */
-	kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, gpa, PAGE_SIZE,
-			       __pfn_to_phys(*pfn), KVM_PGTABLE_PROT_R, NULL);
+	kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, range->start << PAGE_SHIFT,
+			       PAGE_SIZE, __pfn_to_phys(pfn),
+			       KVM_PGTABLE_PROT_R, NULL);
+
 	return 0;
 }
 
-int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
+bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 {
-	unsigned long end = hva + PAGE_SIZE;
-	kvm_pfn_t pfn = pte_pfn(pte);
+	u64 size = (range->end - range->start) << PAGE_SHIFT;
+	kvm_pte_t kpte;
+	pte_t pte;
 
 	if (!kvm->arch.mmu.pgt)
 		return 0;
 
-	/*
-	 * We've moved a page around, probably through CoW, so let's treat it
-	 * just like a translation fault and clean the cache to the PoC.
-	 */
-	clean_dcache_guest_page(pfn, PAGE_SIZE);
-	handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pfn);
-	return 0;
-}
-
-static int kvm_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
-	pte_t pte;
-	kvm_pte_t kpte;
-
 	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
-	kpte = kvm_pgtable_stage2_mkold(kvm->arch.mmu.pgt, gpa);
+
+	kpte = kvm_pgtable_stage2_mkold(kvm->arch.mmu.pgt,
+					range->start << PAGE_SHIFT);
 	pte = __pte(kpte);
 	return pte_valid(pte) && pte_young(pte);
 }
 
-static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
-{
-	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
-	return kvm_pgtable_stage2_is_young(kvm->arch.mmu.pgt, gpa);
-}
-
-int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
-{
-	if (!kvm->arch.mmu.pgt)
-		return 0;
-
-	return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
-}
-
-int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
+bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 {
 	if (!kvm->arch.mmu.pgt)
 		return 0;
 
-	return handle_hva_to_gpa(kvm, hva, hva + PAGE_SIZE,
-				 kvm_test_age_hva_handler, NULL);
+	return kvm_pgtable_stage2_is_young(kvm->arch.mmu.pgt,
+					   range->start << PAGE_SHIFT);
 }
 
 phys_addr_t kvm_mmu_get_httbr(void)