Re: [PATCH 10/17] KVM: PPC: Add support for Book3S processors in hypervisor mode

+struct kvmppc_pginfo {
+	unsigned long pfn;
+	atomic_t refcnt;
+};

+long kvmppc_alloc_hpt(struct kvm *kvm)
+{
+	unsigned long hpt;
+	unsigned long lpid;
+
+	hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|__GFP_NOWARN,
+			       HPT_ORDER - PAGE_SHIFT);
+	if (!hpt) {
+		pr_err("kvm_alloc_hpt: Couldn't alloc HPT\n");
+		return -ENOMEM;
+	}
+	kvm->arch.hpt_virt = hpt;
+
+	do {
+		lpid = find_first_zero_bit(lpid_inuse, NR_LPIDS);
+		if (lpid >= NR_LPIDS) {
+			pr_err("kvm_alloc_hpt: No LPIDs free\n");
+			free_pages(hpt, HPT_ORDER - PAGE_SHIFT);
+			return -ENOMEM;
+		}
+	} while (test_and_set_bit(lpid, lpid_inuse));
+
+	kvm->arch.sdr1 = __pa(hpt) | (HPT_ORDER - 18);
+	kvm->arch.lpid = lpid;
+	kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);
+	kvm->arch.host_lpid = mfspr(SPRN_LPID);
+	kvm->arch.host_lpcr = mfspr(SPRN_LPCR);
+
+	pr_info("KVM guest htab at %lx, LPID %lx\n", hpt, lpid);
+	return 0;
+}

+static unsigned long user_page_size(unsigned long addr)
+{
+	struct vm_area_struct *vma;
+	unsigned long size = PAGE_SIZE;
+
+	down_read(&current->mm->mmap_sem);
+	vma = find_vma(current->mm, addr);
+	if (vma)
+		size = vma_kernel_pagesize(vma);
+	up_read(&current->mm->mmap_sem);
+	return size;
+}

+void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem)
+{
+	unsigned long i;
+	unsigned long npages = kvm->arch.ram_npages;
+	unsigned long pfn;
+	unsigned long *hpte;
+	unsigned long hash;
+	struct kvmppc_pginfo *pginfo = kvm->arch.ram_pginfo;
+
+	if (!pginfo)
+		return;
+
+	/* VRMA can't be > 1TB */
+	if (npages > 1ul << (40 - kvm->arch.ram_porder))
+		npages = 1ul << (40 - kvm->arch.ram_porder);

+	/* Can't use more than 1 HPTE per HPTEG */
+	if (npages > HPT_NPTEG)
+		npages = HPT_NPTEG;
+
+	for (i = 0; i < npages; ++i) {
+		pfn = pginfo[i].pfn;
+		/* can't use hpt_hash since va > 64 bits */
+		hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & HPT_HASH_MASK;