Re: [PATCH v2 03/30] KVM: arm64: Extract PFN resolution in user_mem_abort()

---
 arch/arm64/kvm/mmu.c | 105 ++++++++++++++++++++++++-------------------
 1 file changed, 59 insertions(+), 46 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index b366bde15a429..5079a58b65b14 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c

@@ -1740,55 +1740,11 @@ struct kvm_s2_fault {
 	vm_flags_t vm_flags;
 };
 
-static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
-			  struct kvm_s2_trans *nested,
-			  struct kvm_memory_slot *memslot, unsigned long hva,
-			  bool fault_is_perm)
+static int kvm_s2_fault_pin_pfn(struct kvm_s2_fault *fault)
 {
-	int ret = 0;
-	struct kvm_s2_fault fault_data = {
-		.vcpu = vcpu,
-		.fault_ipa = fault_ipa,
-		.nested = nested,
-		.memslot = memslot,
-		.hva = hva,
-		.fault_is_perm = fault_is_perm,
-		.ipa = fault_ipa,
-		.logging_active = memslot_is_logging(memslot),
-		.force_pte = memslot_is_logging(memslot),
-		.s2_force_noncacheable = false,
-		.vfio_allow_any_uc = false,
-		.prot = KVM_PGTABLE_PROT_R,
-	};
-	struct kvm_s2_fault *fault = &fault_data;
-	struct kvm *kvm = vcpu->kvm;
 	struct vm_area_struct *vma;
-	void *memcache;
-	struct kvm_pgtable *pgt;
-	enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
-
-	if (fault->fault_is_perm)
-		fault->fault_granule = kvm_vcpu_trap_get_perm_fault_granule(fault->vcpu);
-	fault->write_fault = kvm_is_write_fault(fault->vcpu);
-	fault->exec_fault = kvm_vcpu_trap_is_exec_fault(fault->vcpu);
-	VM_WARN_ON_ONCE(fault->write_fault && fault->exec_fault);
+	struct kvm *kvm = fault->vcpu->kvm;
 
-	/*
-	 * Permission faults just need to update the existing leaf entry,
-	 * and so normally don't require allocations from the memcache. The
-	 * only exception to this is when dirty logging is enabled at runtime
-	 * and a write fault needs to collapse a block entry into a table.
-	 */
-	fault->topup_memcache = !fault->fault_is_perm ||
-				(fault->logging_active && fault->write_fault);
-	ret = prepare_mmu_memcache(fault->vcpu, fault->topup_memcache, &memcache);
-	if (ret)
-		return ret;
-
-	/*
-	 * Let's check if we will get back a huge page backed by hugetlbfs, or
-	 * get block mapping for device MMIO region.
-	 */
 	mmap_read_lock(current->mm);
 	vma = vma_lookup(current->mm, fault->hva);
 	if (unlikely(!vma)) {

@@ -1842,6 +1798,63 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (is_error_noslot_pfn(fault->pfn))
 		return -EFAULT;
 
+	return 1;
+}
+
+static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
+			  struct kvm_s2_trans *nested,
+			  struct kvm_memory_slot *memslot, unsigned long hva,
+			  bool fault_is_perm)
+{
+	int ret = 0;
+	struct kvm_s2_fault fault_data = {
+		.vcpu = vcpu,
+		.fault_ipa = fault_ipa,
+		.nested = nested,
+		.memslot = memslot,
+		.hva = hva,
+		.fault_is_perm = fault_is_perm,
+		.ipa = fault_ipa,
+		.logging_active = memslot_is_logging(memslot),
+		.force_pte = memslot_is_logging(memslot),
+		.s2_force_noncacheable = false,
+		.vfio_allow_any_uc = false,
+		.prot = KVM_PGTABLE_PROT_R,
+	};
+	struct kvm_s2_fault *fault = &fault_data;
+	struct kvm *kvm = vcpu->kvm;
+	void *memcache;
+	struct kvm_pgtable *pgt;
+	enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
+
+	if (fault->fault_is_perm)
+		fault->fault_granule = kvm_vcpu_trap_get_perm_fault_granule(fault->vcpu);
+	fault->write_fault = kvm_is_write_fault(fault->vcpu);
+	fault->exec_fault = kvm_vcpu_trap_is_exec_fault(fault->vcpu);
+	VM_WARN_ON_ONCE(fault->write_fault && fault->exec_fault);
+
+	/*
+	 * Permission faults just need to update the existing leaf entry,
+	 * and so normally don't require allocations from the memcache. The
+	 * only exception to this is when dirty logging is enabled at runtime
+	 * and a write fault needs to collapse a block entry into a table.
+	 */
+	fault->topup_memcache = !fault->fault_is_perm ||
+				(fault->logging_active && fault->write_fault);
+	ret = prepare_mmu_memcache(fault->vcpu, fault->topup_memcache, &memcache);
+	if (ret)
+		return ret;
+
+	/*
+	 * Let's check if we will get back a huge page backed by hugetlbfs, or
+	 * get block mapping for device MMIO region.
+	 */
+	ret = kvm_s2_fault_pin_pfn(fault);
+	if (ret != 1)
+		return ret;
+
+	ret = 0;
+
 	/*
 	 * Check if this is non-struct page memory PFN, and cannot support
 	 * CMOs. It could potentially be unsafe to access as cacheable.