Initial import

1 files changed, 1637 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
new file mode 100644
index 000000000..1a4acf8bf
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -0,0 +1,1637 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/highmem.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/hugetlb.h>
+#include <linux/vmalloc.h>
+#include <linux/srcu.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/debugfs.h>
+
+#include <asm/tlbflush.h>
+#include <asm/kvm_ppc.h>
+#include <asm/kvm_book3s.h>
+#include <asm/mmu-hash64.h>
+#include <asm/hvcall.h>
+#include <asm/synch.h>
+#include <asm/ppc-opcode.h>
+#include <asm/cputable.h>
+
+#include "trace_hv.h"
+
+/* Power architecture requires HPT is at least 256kB */
+#define PPC_MIN_HPT_ORDER	18
+
+static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
+				long pte_index, unsigned long pteh,
+				unsigned long ptel, unsigned long *pte_idx_ret);
+static void kvmppc_rmap_reset(struct kvm *kvm);
+
+long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
+{
+	unsigned long hpt = 0;
+	struct revmap_entry *rev;
+	struct page *page = NULL;
+	long order = KVM_DEFAULT_HPT_ORDER;
+
+	if (htab_orderp) {
+		order = *htab_orderp;
+		if (order < PPC_MIN_HPT_ORDER)
+			order = PPC_MIN_HPT_ORDER;
+	}
+
+	kvm->arch.hpt_cma_alloc = 0;
+	page = kvm_alloc_hpt(1ul << (order - PAGE_SHIFT));
+	if (page) {
+		hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+		memset((void *)hpt, 0, (1ul << order));
+		kvm->arch.hpt_cma_alloc = 1;
+	}
+
+	/* Lastly try successively smaller sizes from the page allocator */
+	while (!hpt && order > PPC_MIN_HPT_ORDER) {
+		hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|
+				       __GFP_NOWARN, order - PAGE_SHIFT);
+		if (!hpt)
+			--order;
+	}
+
+	if (!hpt)
+		return -ENOMEM;
+
+	kvm->arch.hpt_virt = hpt;
+	kvm->arch.hpt_order = order;
+	/* HPTEs are 2**4 bytes long */
+	kvm->arch.hpt_npte = 1ul << (order - 4);
+	/* 128 (2**7) bytes in each HPTEG */
+	kvm->arch.hpt_mask = (1ul << (order - 7)) - 1;
+
+	/* Allocate reverse map array */
+	rev = vmalloc(sizeof(struct revmap_entry) * kvm->arch.hpt_npte);
+	if (!rev) {
+		pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n");
+		goto out_freehpt;
+	}
+	kvm->arch.revmap = rev;
+	kvm->arch.sdr1 = __pa(hpt) | (order - 18);
+
+	pr_info("KVM guest htab at %lx (order %ld), LPID %x\n",
+		hpt, order, kvm->arch.lpid);
+
+	if (htab_orderp)
+		*htab_orderp = order;
+	return 0;
+
+ out_freehpt:
+	if (kvm->arch.hpt_cma_alloc)
+		kvm_release_hpt(page, 1 << (order - PAGE_SHIFT));
+	else
+		free_pages(hpt, order - PAGE_SHIFT);
+	return -ENOMEM;
+}
+
+long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp)
+{
+	long err = -EBUSY;
+	long order;
+
+	mutex_lock(&kvm->lock);
+	if (kvm->arch.hpte_setup_done) {
+		kvm->arch.hpte_setup_done = 0;
+		/* order hpte_setup_done vs. vcpus_running */
+		smp_mb();
+		if (atomic_read(&kvm->arch.vcpus_running)) {
+			kvm->arch.hpte_setup_done = 1;
+			goto out;
+		}
+	}
+	if (kvm->arch.hpt_virt) {
+		order = kvm->arch.hpt_order;
+		/* Set the entire HPT to 0, i.e. invalid HPTEs */
+		memset((void *)kvm->arch.hpt_virt, 0, 1ul << order);
+		/*
+		 * Reset all the reverse-mapping chains for all memslots
+		 */
+		kvmppc_rmap_reset(kvm);
+		/* Ensure that each vcpu will flush its TLB on next entry. */
+		cpumask_setall(&kvm->arch.need_tlb_flush);
+		*htab_orderp = order;
+		err = 0;
+	} else {
+		err = kvmppc_alloc_hpt(kvm, htab_orderp);
+		order = *htab_orderp;
+	}
+ out:
+	mutex_unlock(&kvm->lock);
+	return err;
+}
+
+void kvmppc_free_hpt(struct kvm *kvm)
+{
+	kvmppc_free_lpid(kvm->arch.lpid);
+	vfree(kvm->arch.revmap);
+	if (kvm->arch.hpt_cma_alloc)
+		kvm_release_hpt(virt_to_page(kvm->arch.hpt_virt),
+				1 << (kvm->arch.hpt_order - PAGE_SHIFT));
+	else
+		free_pages(kvm->arch.hpt_virt,
+			   kvm->arch.hpt_order - PAGE_SHIFT);
+}
+
+/* Bits in first HPTE dword for pagesize 4k, 64k or 16M */
+static inline unsigned long hpte0_pgsize_encoding(unsigned long pgsize)
+{
+	return (pgsize > 0x1000) ? HPTE_V_LARGE : 0;
+}
+
+/* Bits in second HPTE dword for pagesize 4k, 64k or 16M */
+static inline unsigned long hpte1_pgsize_encoding(unsigned long pgsize)
+{
+	return (pgsize == 0x10000) ? 0x1000 : 0;
+}
+
+void kvmppc_map_vrma(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot,
+		     unsigned long porder)
+{
+	unsigned long i;
+	unsigned long npages;
+	unsigned long hp_v, hp_r;
+	unsigned long addr, hash;
+	unsigned long psize;
+	unsigned long hp0, hp1;
+	unsigned long idx_ret;
+	long ret;
+	struct kvm *kvm = vcpu->kvm;
+
+	psize = 1ul << porder;
+	npages = memslot->npages >> (porder - PAGE_SHIFT);
+
+	/* VRMA can't be > 1TB */
+	if (npages > 1ul << (40 - porder))
+		npages = 1ul << (40 - porder);
+	/* Can't use more than 1 HPTE per HPTEG */
+	if (npages > kvm->arch.hpt_mask + 1)
+		npages = kvm->arch.hpt_mask + 1;
+
+	hp0 = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
+		HPTE_V_BOLTED | hpte0_pgsize_encoding(psize);
+	hp1 = hpte1_pgsize_encoding(psize) |
+		HPTE_R_R | HPTE_R_C | HPTE_R_M | PP_RWXX;
+
+	for (i = 0; i < npages; ++i) {
+		addr = i << porder;
+		/* can't use hpt_hash since va > 64 bits */
+		hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & kvm->arch.hpt_mask;
+		/*
+		 * We assume that the hash table is empty and no
+		 * vcpus are using it at this stage.  Since we create
+		 * at most one HPTE per HPTEG, we just assume entry 7
+		 * is available and use it.
+		 */
+		hash = (hash << 3) + 7;
+		hp_v = hp0 | ((addr >> 16) & ~0x7fUL);
+		hp_r = hp1 | addr;
+		ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, hash, hp_v, hp_r,
+						 &idx_ret);
+		if (ret != H_SUCCESS) {
+			pr_err("KVM: map_vrma at %lx failed, ret=%ld\n",
+			       addr, ret);
+			break;
+		}
+	}
+}
+
+int kvmppc_mmu_hv_init(void)
+{
+	unsigned long host_lpid, rsvd_lpid;
+
+	if (!cpu_has_feature(CPU_FTR_HVMODE))
+		return -EINVAL;
+
+	/* POWER7 has 10-bit LPIDs (12-bit in POWER8) */
+	host_lpid = mfspr(SPRN_LPID);
+	rsvd_lpid = LPID_RSVD;
+
+	kvmppc_init_lpid(rsvd_lpid + 1);
+
+	kvmppc_claim_lpid(host_lpid);
+	/* rsvd_lpid is reserved for use in partition switching */
+	kvmppc_claim_lpid(rsvd_lpid);
+
+	return 0;
+}
+
+static void kvmppc_mmu_book3s_64_hv_reset_msr(struct kvm_vcpu *vcpu)
+{
+	unsigned long msr = vcpu->arch.intr_msr;
+
+	/* If transactional, change to suspend mode on IRQ delivery */
+	if (MSR_TM_TRANSACTIONAL(vcpu->arch.shregs.msr))
+		msr |= MSR_TS_S;
+	else
+		msr |= vcpu->arch.shregs.msr & MSR_TS_MASK;
+	kvmppc_set_msr(vcpu, msr);
+}
+
+long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
+				long pte_index, unsigned long pteh,
+				unsigned long ptel, unsigned long *pte_idx_ret)
+{
+	long ret;
+
+	/* Protect linux PTE lookup from page table destruction */
+	rcu_read_lock_sched();	/* this disables preemption too */
+	ret = kvmppc_do_h_enter(kvm, flags, pte_index, pteh, ptel,
+				current->mm->pgd, false, pte_idx_ret);
+	rcu_read_unlock_sched();
+	if (ret == H_TOO_HARD) {
+		/* this can't happen */
+		pr_err("KVM: Oops, kvmppc_h_enter returned too hard!\n");
+		ret = H_RESOURCE;	/* or something */
+	}
+	return ret;
+
+}
+
+static struct kvmppc_slb *kvmppc_mmu_book3s_hv_find_slbe(struct kvm_vcpu *vcpu,
+							 gva_t eaddr)
+{
+	u64 mask;
+	int i;
+
+	for (i = 0; i < vcpu->arch.slb_nr; i++) {
+		if (!(vcpu->arch.slb[i].orige & SLB_ESID_V))
+			continue;
+
+		if (vcpu->arch.slb[i].origv & SLB_VSID_B_1T)
+			mask = ESID_MASK_1T;
+		else
+			mask = ESID_MASK;
+
+		if (((vcpu->arch.slb[i].orige ^ eaddr) & mask) == 0)
+			return &vcpu->arch.slb[i];
+	}
+	return NULL;
+}
+
+static unsigned long kvmppc_mmu_get_real_addr(unsigned long v, unsigned long r,
+			unsigned long ea)
+{
+	unsigned long ra_mask;
+
+	ra_mask = hpte_page_size(v, r) - 1;
+	return (r & HPTE_R_RPN & ~ra_mask) | (ea & ra_mask);
+}
+
+static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
+			struct kvmppc_pte *gpte, bool data, bool iswrite)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvmppc_slb *slbe;
+	unsigned long slb_v;
+	unsigned long pp, key;
+	unsigned long v, gr;
+	__be64 *hptep;
+	int index;
+	int virtmode = vcpu->arch.shregs.msr & (data ? MSR_DR : MSR_IR);
+
+	/* Get SLB entry */
+	if (virtmode) {
+		slbe = kvmppc_mmu_book3s_hv_find_slbe(vcpu, eaddr);
+		if (!slbe)
+			return -EINVAL;
+		slb_v = slbe->origv;
+	} else {
+		/* real mode access */
+		slb_v = vcpu->kvm->arch.vrma_slb_v;
+	}
+
+	preempt_disable();
+	/* Find the HPTE in the hash table */
+	index = kvmppc_hv_find_lock_hpte(kvm, eaddr, slb_v,
+					 HPTE_V_VALID | HPTE_V_ABSENT);
+	if (index < 0) {
+		preempt_enable();
+		return -ENOENT;
+	}
+	hptep = (__be64 *)(kvm->arch.hpt_virt + (index << 4));
+	v = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
+	gr = kvm->arch.revmap[index].guest_rpte;
+
+	unlock_hpte(hptep, v);
+	preempt_enable();
+
+	gpte->eaddr = eaddr;
+	gpte->vpage = ((v & HPTE_V_AVPN) << 4) | ((eaddr >> 12) & 0xfff);
+
+	/* Get PP bits and key for permission check */
+	pp = gr & (HPTE_R_PP0 | HPTE_R_PP);
+	key = (vcpu->arch.shregs.msr & MSR_PR) ? SLB_VSID_KP : SLB_VSID_KS;
+	key &= slb_v;
+
+	/* Calculate permissions */
+	gpte->may_read = hpte_read_permission(pp, key);
+	gpte->may_write = hpte_write_permission(pp, key);
+	gpte->may_execute = gpte->may_read && !(gr & (HPTE_R_N | HPTE_R_G));
+
+	/* Storage key permission check for POWER7 */
+	if (data && virtmode) {
+		int amrfield = hpte_get_skey_perm(gr, vcpu->arch.amr);
+		if (amrfield & 1)
+			gpte->may_read = 0;
+		if (amrfield & 2)
+			gpte->may_write = 0;
+	}
+
+	/* Get the guest physical address */
+	gpte->raddr = kvmppc_mmu_get_real_addr(v, gr, eaddr);
+	return 0;
+}
+
+/*
+ * Quick test for whether an instruction is a load or a store.
+ * If the instruction is a load or a store, then this will indicate
+ * which it is, at least on server processors.  (Embedded processors
+ * have some external PID instructions that don't follow the rule
+ * embodied here.)  If the instruction isn't a load or store, then
+ * this doesn't return anything useful.
+ */
+static int instruction_is_store(unsigned int instr)
+{
+	unsigned int mask;
+
+	mask = 0x10000000;
+	if ((instr & 0xfc000000) == 0x7c000000)
+		mask = 0x100;		/* major opcode 31 */
+	return (instr & mask) != 0;
+}
+
+static int kvmppc_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu,
+				  unsigned long gpa, gva_t ea, int is_store)
+{
+	u32 last_inst;
+
+	/*
+	 * If we fail, we just return to the guest and try executing it again.
+	 */
+	if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
+		EMULATE_DONE)
+		return RESUME_GUEST;
+
+	/*
+	 * WARNING: We do not know for sure whether the instruction we just
+	 * read from memory is the same that caused the fault in the first
+	 * place.  If the instruction we read is neither an load or a store,
+	 * then it can't access memory, so we don't need to worry about
+	 * enforcing access permissions.  So, assuming it is a load or
+	 * store, we just check that its direction (load or store) is
+	 * consistent with the original fault, since that's what we
+	 * checked the access permissions against.  If there is a mismatch
+	 * we just return and retry the instruction.
+	 */
+
+	if (instruction_is_store(last_inst) != !!is_store)
+		return RESUME_GUEST;
+
+	/*
+	 * Emulated accesses are emulated by looking at the hash for
+	 * translation once, then performing the access later. The
+	 * translation could be invalidated in the meantime in which
+	 * point performing the subsequent memory access on the old
+	 * physical address could possibly be a security hole for the
+	 * guest (but not the host).
+	 *
+	 * This is less of an issue for MMIO stores since they aren't
+	 * globally visible. It could be an issue for MMIO loads to
+	 * a certain extent but we'll ignore it for now.
+	 */
+
+	vcpu->arch.paddr_accessed = gpa;
+	vcpu->arch.vaddr_accessed = ea;
+	return kvmppc_emulate_mmio(run, vcpu);
+}
+
+int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
+				unsigned long ea, unsigned long dsisr)
+{
+	struct kvm *kvm = vcpu->kvm;
+	unsigned long hpte[3], r;
+	__be64 *hptep;
+	unsigned long mmu_seq, psize, pte_size;
+	unsigned long gpa_base, gfn_base;
+	unsigned long gpa, gfn, hva, pfn;
+	struct kvm_memory_slot *memslot;
+	unsigned long *rmap;
+	struct revmap_entry *rev;
+	struct page *page, *pages[1];
+	long index, ret, npages;
+	unsigned long is_io;
+	unsigned int writing, write_ok;
+	struct vm_area_struct *vma;
+	unsigned long rcbits;
+
+	/*
+	 * Real-mode code has already searched the HPT and found the
+	 * entry we're interested in.  Lock the entry and check that
+	 * it hasn't changed.  If it has, just return and re-execute the
+	 * instruction.
+	 */
+	if (ea != vcpu->arch.pgfault_addr)
+		return RESUME_GUEST;
+	index = vcpu->arch.pgfault_index;
+	hptep = (__be64 *)(kvm->arch.hpt_virt + (index << 4));
+	rev = &kvm->arch.revmap[index];
+	preempt_disable();
+	while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
+		cpu_relax();
+	hpte[0] = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
+	hpte[1] = be64_to_cpu(hptep[1]);
+	hpte[2] = r = rev->guest_rpte;
+	unlock_hpte(hptep, hpte[0]);
+	preempt_enable();
+
+	if (hpte[0] != vcpu->arch.pgfault_hpte[0] ||
+	    hpte[1] != vcpu->arch.pgfault_hpte[1])
+		return RESUME_GUEST;
+
+	/* Translate the logical address and get the page */
+	psize = hpte_page_size(hpte[0], r);
+	gpa_base = r & HPTE_R_RPN & ~(psize - 1);
+	gfn_base = gpa_base >> PAGE_SHIFT;
+	gpa = gpa_base | (ea & (psize - 1));
+	gfn = gpa >> PAGE_SHIFT;
+	memslot = gfn_to_memslot(kvm, gfn);
+
+	trace_kvm_page_fault_enter(vcpu, hpte, memslot, ea, dsisr);
+
+	/* No memslot means it's an emulated MMIO region */
+	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
+		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
+					      dsisr & DSISR_ISSTORE);
+
+	/*
+	 * This should never happen, because of the slot_is_aligned()
+	 * check in kvmppc_do_h_enter().
+	 */
+	if (gfn_base < memslot->base_gfn)
+		return -EFAULT;
+
+	/* used to check for invalidations in progress */
+	mmu_seq = kvm->mmu_notifier_seq;
+	smp_rmb();
+
+	ret = -EFAULT;
+	is_io = 0;
+	pfn = 0;
+	page = NULL;
+	pte_size = PAGE_SIZE;
+	writing = (dsisr & DSISR_ISSTORE) != 0;
+	/* If writing != 0, then the HPTE must allow writing, if we get here */
+	write_ok = writing;
+	hva = gfn_to_hva_memslot(memslot, gfn);
+	npages = get_user_pages_fast(hva, 1, writing, pages);
+	if (npages < 1) {
+		/* Check if it's an I/O mapping */
+		down_read(&current->mm->mmap_sem);
+		vma = find_vma(current->mm, hva);
+		if (vma && vma->vm_start <= hva && hva + psize <= vma->vm_end &&
+		    (vma->vm_flags & VM_PFNMAP)) {
+			pfn = vma->vm_pgoff +
+				((hva - vma->vm_start) >> PAGE_SHIFT);
+			pte_size = psize;
+			is_io = hpte_cache_bits(pgprot_val(vma->vm_page_prot));
+			write_ok = vma->vm_flags & VM_WRITE;
+		}
+		up_read(&current->mm->mmap_sem);
+		if (!pfn)
+			goto out_put;
+	} else {
+		page = pages[0];
+		pfn = page_to_pfn(page);
+		if (PageHuge(page)) {
+			page = compound_head(page);
+			pte_size <<= compound_order(page);
+		}
+		/* if the guest wants write access, see if that is OK */
+		if (!writing && hpte_is_writable(r)) {
+			pte_t *ptep, pte;
+			unsigned long flags;
+			/*
+			 * We need to protect against page table destruction
+			 * hugepage split and collapse.
+			 */
+			local_irq_save(flags);
+			ptep = find_linux_pte_or_hugepte(current->mm->pgd,
+							 hva, NULL);
+			if (ptep) {
+				pte = kvmppc_read_update_linux_pte(ptep, 1);
+				if (pte_write(pte))
+					write_ok = 1;
+			}
+			local_irq_restore(flags);
+		}
+	}
+
+	if (psize > pte_size)
+		goto out_put;
+
+	/* Check WIMG vs. the actual page we're accessing */
+	if (!hpte_cache_flags_ok(r, is_io)) {
+		if (is_io)
+			goto out_put;
+
+		/*
+		 * Allow guest to map emulated device memory as
+		 * uncacheable, but actually make it cacheable.
+		 */
+		r = (r & ~(HPTE_R_W|HPTE_R_I|HPTE_R_G)) | HPTE_R_M;
+	}
+
+	/*
+	 * Set the HPTE to point to pfn.
+	 * Since the pfn is at PAGE_SIZE granularity, make sure we
+	 * don't mask out lower-order bits if psize < PAGE_SIZE.
+	 */
+	if (psize < PAGE_SIZE)
+		psize = PAGE_SIZE;
+	r = (r & ~(HPTE_R_PP0 - psize)) | ((pfn << PAGE_SHIFT) & ~(psize - 1));
+	if (hpte_is_writable(r) && !write_ok)
+		r = hpte_make_readonly(r);
+	ret = RESUME_GUEST;
+	preempt_disable();
+	while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
+		cpu_relax();
+	if ((be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK) != hpte[0] ||
+		be64_to_cpu(hptep[1]) != hpte[1] ||
+		rev->guest_rpte != hpte[2])
+		/* HPTE has been changed under us; let the guest retry */
+		goto out_unlock;
+	hpte[0] = (hpte[0] & ~HPTE_V_ABSENT) | HPTE_V_VALID;
+
+	/* Always put the HPTE in the rmap chain for the page base address */
+	rmap = &memslot->arch.rmap[gfn_base - memslot->base_gfn];
+	lock_rmap(rmap);
+
+	/* Check if we might have been invalidated; let the guest retry if so */
+	ret = RESUME_GUEST;
+	if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
+		unlock_rmap(rmap);
+		goto out_unlock;
+	}
+
+	/* Only set R/C in real HPTE if set in both *rmap and guest_rpte */
+	rcbits = *rmap >> KVMPPC_RMAP_RC_SHIFT;
+	r &= rcbits | ~(HPTE_R_R | HPTE_R_C);
+
+	if (be64_to_cpu(hptep[0]) & HPTE_V_VALID) {
+		/* HPTE was previously valid, so we need to invalidate it */
+		unlock_rmap(rmap);
+		hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
+		kvmppc_invalidate_hpte(kvm, hptep, index);
+		/* don't lose previous R and C bits */
+		r |= be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
+	} else {
+		kvmppc_add_revmap_chain(kvm, rev, rmap, index, 0);
+	}
+
+	hptep[1] = cpu_to_be64(r);
+	eieio();
+	__unlock_hpte(hptep, hpte[0]);
+	asm volatile("ptesync" : : : "memory");
+	preempt_enable();
+	if (page && hpte_is_writable(r))
+		SetPageDirty(page);
+
+ out_put:
+	trace_kvm_page_fault_exit(vcpu, hpte, ret);
+
+	if (page) {
+		/*
+		 * We drop pages[0] here, not page because page might
+		 * have been set to the head page of a compound, but
+		 * we have to drop the reference on the correct tail
+		 * page to match the get inside gup()
+		 */
+		put_page(pages[0]);
+	}
+	return ret;
+
+ out_unlock:
+	__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
+	preempt_enable();
+	goto out_put;
+}
+
+static void kvmppc_rmap_reset(struct kvm *kvm)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *memslot;
+	int srcu_idx;
+
+	srcu_idx = srcu_read_lock(&kvm->srcu);
+	slots = kvm->memslots;
+	kvm_for_each_memslot(memslot, slots) {
+		/*
+		 * This assumes it is acceptable to lose reference and
+		 * change bits across a reset.
+		 */
+		memset(memslot->arch.rmap, 0,
+		       memslot->npages * sizeof(*memslot->arch.rmap));
+	}
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+}
+
+static int kvm_handle_hva_range(struct kvm *kvm,
+				unsigned long start,
+				unsigned long end,
+				int (*handler)(struct kvm *kvm,
+					       unsigned long *rmapp,
+					       unsigned long gfn))
+{
+	int ret;
+	int retval = 0;
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *memslot;
+
+	slots = kvm_memslots(kvm);
+	kvm_for_each_memslot(memslot, slots) {
+		unsigned long hva_start, hva_end;
+		gfn_t gfn, gfn_end;
+
+		hva_start = max(start, memslot->userspace_addr);
+		hva_end = min(end, memslot->userspace_addr +
+					(memslot->npages << PAGE_SHIFT));
+		if (hva_start >= hva_end)
+			continue;
+		/*
+		 * {gfn(page) | page intersects with [hva_start, hva_end)} =
+		 * {gfn, gfn+1, ..., gfn_end-1}.
+		 */
+		gfn = hva_to_gfn_memslot(hva_start, memslot);
+		gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
+
+		for (; gfn < gfn_end; ++gfn) {
+			gfn_t gfn_offset = gfn - memslot->base_gfn;
+
+			ret = handler(kvm, &memslot->arch.rmap[gfn_offset], gfn);
+			retval |= ret;
+		}
+	}
+
+	return retval;
+}
+
+static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
+			  int (*handler)(struct kvm *kvm, unsigned long *rmapp,
+					 unsigned long gfn))
+{
+	return kvm_handle_hva_range(kvm, hva, hva + 1, handler);
+}
+
+static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
+			   unsigned long gfn)
+{
+	struct revmap_entry *rev = kvm->arch.revmap;
+	unsigned long h, i, j;
+	__be64 *hptep;
+	unsigned long ptel, psize, rcbits;
+
+	for (;;) {
+		lock_rmap(rmapp);
+		if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
+			unlock_rmap(rmapp);
+			break;
+		}
+
+		/*
+		 * To avoid an ABBA deadlock with the HPTE lock bit,
+		 * we can't spin on the HPTE lock while holding the
+		 * rmap chain lock.
+		 */
+		i = *rmapp & KVMPPC_RMAP_INDEX;
+		hptep = (__be64 *) (kvm->arch.hpt_virt + (i << 4));
+		if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
+			/* unlock rmap before spinning on the HPTE lock */
+			unlock_rmap(rmapp);
+			while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)
+				cpu_relax();
+			continue;
+		}
+		j = rev[i].forw;
+		if (j == i) {
+			/* chain is now empty */
+			*rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
+		} else {
+			/* remove i from chain */
+			h = rev[i].back;
+			rev[h].forw = j;
+			rev[j].back = h;
+			rev[i].forw = rev[i].back = i;
+			*rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
+		}
+
+		/* Now check and modify the HPTE */
+		ptel = rev[i].guest_rpte;
+		psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
+		if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
+		    hpte_rpn(ptel, psize) == gfn) {
+			hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
+			kvmppc_invalidate_hpte(kvm, hptep, i);
+			/* Harvest R and C */
+			rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
+			*rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
+			if (rcbits & ~rev[i].guest_rpte) {
+				rev[i].guest_rpte = ptel | rcbits;
+				note_hpte_modification(kvm, &rev[i]);
+			}
+		}
+		unlock_rmap(rmapp);
+		__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
+	}
+	return 0;
+}
+
+int kvm_unmap_hva_hv(struct kvm *kvm, unsigned long hva)
+{
+	kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
+	return 0;
+}
+
+int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+	kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
+	return 0;
+}
+
+void kvmppc_core_flush_memslot_hv(struct kvm *kvm,
+				  struct kvm_memory_slot *memslot)
+{
+	unsigned long *rmapp;
+	unsigned long gfn;
+	unsigned long n;
+
+	rmapp = memslot->arch.rmap;
+	gfn = memslot->base_gfn;
+	for (n = memslot->npages; n; --n) {
+		/*
+		 * Testing the present bit without locking is OK because
+		 * the memslot has been marked invalid already, and hence
+		 * no new HPTEs referencing this page can be created,
+		 * thus the present bit can't go from 0 to 1.
+		 */
+		if (*rmapp & KVMPPC_RMAP_PRESENT)
+			kvm_unmap_rmapp(kvm, rmapp, gfn);
+		++rmapp;
+		++gfn;
+	}
+}
+
+static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
+			 unsigned long gfn)
+{
+	struct revmap_entry *rev = kvm->arch.revmap;
+	unsigned long head, i, j;
+	__be64 *hptep;
+	int ret = 0;
+
+ retry:
+	lock_rmap(rmapp);
+	if (*rmapp & KVMPPC_RMAP_REFERENCED) {
+		*rmapp &= ~KVMPPC_RMAP_REFERENCED;
+		ret = 1;
+	}
+	if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
+		unlock_rmap(rmapp);
+		return ret;
+	}
+
+	i = head = *rmapp & KVMPPC_RMAP_INDEX;
+	do {
+		hptep = (__be64 *) (kvm->arch.hpt_virt + (i << 4));
+		j = rev[i].forw;
+
+		/* If this HPTE isn't referenced, ignore it */
+		if (!(be64_to_cpu(hptep[1]) & HPTE_R_R))
+			continue;
+
+		if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
+			/* unlock rmap before spinning on the HPTE lock */
+			unlock_rmap(rmapp);
+			while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)
+				cpu_relax();
+			goto retry;
+		}
+
+		/* Now check and modify the HPTE */
+		if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
+		    (be64_to_cpu(hptep[1]) & HPTE_R_R)) {
+			kvmppc_clear_ref_hpte(kvm, hptep, i);
+			if (!(rev[i].guest_rpte & HPTE_R_R)) {
+				rev[i].guest_rpte |= HPTE_R_R;
+				note_hpte_modification(kvm, &rev[i]);
+			}
+			ret = 1;
+		}
+		__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
+	} while ((i = j) != head);
+
+	unlock_rmap(rmapp);
+	return ret;
+}
+
+int kvm_age_hva_hv(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+	return kvm_handle_hva_range(kvm, start, end, kvm_age_rmapp);
+}
+
+static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
+			      unsigned long gfn)
+{
+	struct revmap_entry *rev = kvm->arch.revmap;
+	unsigned long head, i, j;
+	unsigned long *hp;
+	int ret = 1;
+
+	if (*rmapp & KVMPPC_RMAP_REFERENCED)
+		return 1;
+
+	lock_rmap(rmapp);
+	if (*rmapp & KVMPPC_RMAP_REFERENCED)
+		goto out;
+
+	if (*rmapp & KVMPPC_RMAP_PRESENT) {
+		i = head = *rmapp & KVMPPC_RMAP_INDEX;
+		do {
+			hp = (unsigned long *)(kvm->arch.hpt_virt + (i << 4));
+			j = rev[i].forw;
+			if (be64_to_cpu(hp[1]) & HPTE_R_R)
+				goto out;
+		} while ((i = j) != head);
+	}
+	ret = 0;
+
+ out:
+	unlock_rmap(rmapp);
+	return ret;
+}
+
+int kvm_test_age_hva_hv(struct kvm *kvm, unsigned long hva)
+{
+	return kvm_handle_hva(kvm, hva, kvm_test_age_rmapp);
+}
+
+void kvm_set_spte_hva_hv(struct kvm *kvm, unsigned long hva, pte_t pte)
+{
+	kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
+}
+
+static int vcpus_running(struct kvm *kvm)
+{
+	return atomic_read(&kvm->arch.vcpus_running) != 0;
+}
+
+/*
+ * Returns the number of system pages that are dirty.
+ * This can be more than 1 if we find a huge-page HPTE.
+ */
+static int kvm_test_clear_dirty_npages(struct kvm *kvm, unsigned long *rmapp)
+{
+	struct revmap_entry *rev = kvm->arch.revmap;
+	unsigned long head, i, j;
+	unsigned long n;
+	unsigned long v, r;
+	__be64 *hptep;
+	int npages_dirty = 0;
+
+ retry:
+	lock_rmap(rmapp);
+	if (*rmapp & KVMPPC_RMAP_CHANGED) {
+		*rmapp &= ~KVMPPC_RMAP_CHANGED;
+		npages_dirty = 1;
+	}
+	if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
+		unlock_rmap(rmapp);
+		return npages_dirty;
+	}
+
+	i = head = *rmapp & KVMPPC_RMAP_INDEX;
+	do {
+		unsigned long hptep1;
+		hptep = (__be64 *) (kvm->arch.hpt_virt + (i << 4));
+		j = rev[i].forw;
+
+		/*
+		 * Checking the C (changed) bit here is racy since there
+		 * is no guarantee about when the hardware writes it back.
+		 * If the HPTE is not writable then it is stable since the
+		 * page can't be written to, and we would have done a tlbie
+		 * (which forces the hardware to complete any writeback)
+		 * when making the HPTE read-only.
+		 * If vcpus are running then this call is racy anyway
+		 * since the page could get dirtied subsequently, so we
+		 * expect there to be a further call which would pick up
+		 * any delayed C bit writeback.
+		 * Otherwise we need to do the tlbie even if C==0 in
+		 * order to pick up any delayed writeback of C.
+		 */
+		hptep1 = be64_to_cpu(hptep[1]);
+		if (!(hptep1 & HPTE_R_C) &&
+		    (!hpte_is_writable(hptep1) || vcpus_running(kvm)))
+			continue;
+
+		if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
+			/* unlock rmap before spinning on the HPTE lock */
+			unlock_rmap(rmapp);
+			while (hptep[0] & cpu_to_be64(HPTE_V_HVLOCK))
+				cpu_relax();
+			goto retry;
+		}
+
+		/* Now check and modify the HPTE */
+		if (!(hptep[0] & cpu_to_be64(HPTE_V_VALID))) {
+			__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
+			continue;
+		}
+
+		/* need to make it temporarily absent so C is stable */
+		hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
+		kvmppc_invalidate_hpte(kvm, hptep, i);
+		v = be64_to_cpu(hptep[0]);
+		r = be64_to_cpu(hptep[1]);
+		if (r & HPTE_R_C) {
+			hptep[1] = cpu_to_be64(r & ~HPTE_R_C);
+			if (!(rev[i].guest_rpte & HPTE_R_C)) {
+				rev[i].guest_rpte |= HPTE_R_C;
+				note_hpte_modification(kvm, &rev[i]);
+			}
+			n = hpte_page_size(v, r);
+			n = (n + PAGE_SIZE - 1) >> PAGE_SHIFT;
+			if (n > npages_dirty)
+				npages_dirty = n;
+			eieio();
+		}
+		v &= ~HPTE_V_ABSENT;
+		v |= HPTE_V_VALID;
+		__unlock_hpte(hptep, v);
+	} while ((i = j) != head);
+
+	unlock_rmap(rmapp);
+	return npages_dirty;
+}
+
+static void harvest_vpa_dirty(struct kvmppc_vpa *vpa,
+			      struct kvm_memory_slot *memslot,
+			      unsigned long *map)
+{
+	unsigned long gfn;
+
+	if (!vpa->dirty || !vpa->pinned_addr)
+		return;
+	gfn = vpa->gpa >> PAGE_SHIFT;
+	if (gfn < memslot->base_gfn ||
+	    gfn >= memslot->base_gfn + memslot->npages)
+		return;
+
+	vpa->dirty = false;
+	if (map)
+		__set_bit_le(gfn - memslot->base_gfn, map);
+}
+
+long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot,
+			     unsigned long *map)
+{
+	unsigned long i, j;
+	unsigned long *rmapp;
+	struct kvm_vcpu *vcpu;
+
+	preempt_disable();
+	rmapp = memslot->arch.rmap;
+	for (i = 0; i < memslot->npages; ++i) {
+		int npages = kvm_test_clear_dirty_npages(kvm, rmapp);
+		/*
+		 * Note that if npages > 0 then i must be a multiple of npages,
+		 * since we always put huge-page HPTEs in the rmap chain
+		 * corresponding to their page base address.
+		 */
+		if (npages && map)
+			for (j = i; npages; ++j, --npages)
+				__set_bit_le(j, map);
+		++rmapp;
+	}
+
+	/* Harvest dirty bits from VPA and DTL updates */
+	/* Note: we never modify the SLB shadow buffer areas */
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		spin_lock(&vcpu->arch.vpa_update_lock);
+		harvest_vpa_dirty(&vcpu->arch.vpa, memslot, map);
+		harvest_vpa_dirty(&vcpu->arch.dtl, memslot, map);
+		spin_unlock(&vcpu->arch.vpa_update_lock);
+	}
+	preempt_enable();
+	return 0;
+}
+
+void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa,
+			    unsigned long *nb_ret)
+{
+	struct kvm_memory_slot *memslot;
+	unsigned long gfn = gpa >> PAGE_SHIFT;
+	struct page *page, *pages[1];
+	int npages;
+	unsigned long hva, offset;
+	int srcu_idx;
+
+	srcu_idx = srcu_read_lock(&kvm->srcu);
+	memslot = gfn_to_memslot(kvm, gfn);
+	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
+		goto err;
+	hva = gfn_to_hva_memslot(memslot, gfn);
+	npages = get_user_pages_fast(hva, 1, 1, pages);
+	if (npages < 1)
+		goto err;
+	page = pages[0];
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+
+	offset = gpa & (PAGE_SIZE - 1);
+	if (nb_ret)
+		*nb_ret = PAGE_SIZE - offset;
+	return page_address(page) + offset;
+
+ err:
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+	return NULL;
+}
+
+void kvmppc_unpin_guest_page(struct kvm *kvm, void *va, unsigned long gpa,
+			     bool dirty)
+{
+	struct page *page = virt_to_page(va);
+	struct kvm_memory_slot *memslot;
+	unsigned long gfn;
+	unsigned long *rmap;
+	int srcu_idx;
+
+	put_page(page);
+
+	if (!dirty)
+		return;
+
+	/* We need to mark this page dirty in the rmap chain */
+	gfn = gpa >> PAGE_SHIFT;
+	srcu_idx = srcu_read_lock(&kvm->srcu);
+	memslot = gfn_to_memslot(kvm, gfn);
+	if (memslot) {
+		rmap = &memslot->arch.rmap[gfn - memslot->base_gfn];
+		lock_rmap(rmap);
+		*rmap |= KVMPPC_RMAP_CHANGED;
+		unlock_rmap(rmap);
+	}
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+}
+
+/*
+ * Functions for reading and writing the hash table via reads and
+ * writes on a file descriptor.
+ *
+ * Reads return the guest view of the hash table, which has to be
+ * pieced together from the real hash table and the guest_rpte
+ * values in the revmap array.
+ *
+ * On writes, each HPTE written is considered in turn, and if it
+ * is valid, it is written to the HPT as if an H_ENTER with the
+ * exact flag set was done.  When the invalid count is non-zero
+ * in the header written to the stream, the kernel will make
+ * sure that that many HPTEs are invalid, and invalidate them
+ * if not.
+ */
+
+struct kvm_htab_ctx {
+	unsigned long	index;
+	unsigned long	flags;
+	struct kvm	*kvm;
+	int		first_pass;
+};
+
+#define HPTE_SIZE	(2 * sizeof(unsigned long))
+
+/*
+ * Returns 1 if this HPT entry has been modified or has pending
+ * R/C bit changes.
+ */
+static int hpte_dirty(struct revmap_entry *revp, __be64 *hptp)
+{
+	unsigned long rcbits_unset;
+
+	if (revp->guest_rpte & HPTE_GR_MODIFIED)
+		return 1;
+
+	/* Also need to consider changes in reference and changed bits */
+	rcbits_unset = ~revp->guest_rpte & (HPTE_R_R | HPTE_R_C);
+	if ((be64_to_cpu(hptp[0]) & HPTE_V_VALID) &&
+	    (be64_to_cpu(hptp[1]) & rcbits_unset))
+		return 1;
+
+	return 0;
+}
+
+static long record_hpte(unsigned long flags, __be64 *hptp,
+			unsigned long *hpte, struct revmap_entry *revp,
+			int want_valid, int first_pass)
+{
+	unsigned long v, r;
+	unsigned long rcbits_unset;
+	int ok = 1;
+	int valid, dirty;
+
+	/* Unmodified entries are uninteresting except on the first pass */
+	dirty = hpte_dirty(revp, hptp);
+	if (!first_pass && !dirty)
+		return 0;
+
+	valid = 0;
+	if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT)) {
+		valid = 1;
+		if ((flags & KVM_GET_HTAB_BOLTED_ONLY) &&
+		    !(be64_to_cpu(hptp[0]) & HPTE_V_BOLTED))
+			valid = 0;
+	}
+	if (valid != want_valid)
+		return 0;
+
+	v = r = 0;
+	if (valid || dirty) {
+		/* lock the HPTE so it's stable and read it */
+		preempt_disable();
+		while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
+			cpu_relax();
+		v = be64_to_cpu(hptp[0]);
+
+		/* re-evaluate valid and dirty from synchronized HPTE value */
+		valid = !!(v & HPTE_V_VALID);
+		dirty = !!(revp->guest_rpte & HPTE_GR_MODIFIED);
+
+		/* Harvest R and C into guest view if necessary */
+		rcbits_unset = ~revp->guest_rpte & (HPTE_R_R | HPTE_R_C);
+		if (valid && (rcbits_unset & be64_to_cpu(hptp[1]))) {
+			revp->guest_rpte |= (be64_to_cpu(hptp[1]) &
+				(HPTE_R_R | HPTE_R_C)) | HPTE_GR_MODIFIED;
+			dirty = 1;
+		}
+
+		if (v & HPTE_V_ABSENT) {
+			v &= ~HPTE_V_ABSENT;
+			v |= HPTE_V_VALID;
+			valid = 1;
+		}
+		if ((flags & KVM_GET_HTAB_BOLTED_ONLY) && !(v & HPTE_V_BOLTED))
+			valid = 0;
+
+		r = revp->guest_rpte;
+		/* only clear modified if this is the right sort of entry */
+		if (valid == want_valid && dirty) {
+			r &= ~HPTE_GR_MODIFIED;
+			revp->guest_rpte = r;
+		}
+		unlock_hpte(hptp, be64_to_cpu(hptp[0]));
+		preempt_enable();
+		if (!(valid == want_valid && (first_pass || dirty)))
+			ok = 0;
+	}
+	hpte[0] = cpu_to_be64(v);
+	hpte[1] = cpu_to_be64(r);
+	return ok;
+}
+
+static ssize_t kvm_htab_read(struct file *file, char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+	struct kvm_htab_ctx *ctx = file->private_data;
+	struct kvm *kvm = ctx->kvm;
+	struct kvm_get_htab_header hdr;
+	__be64 *hptp;
+	struct revmap_entry *revp;
+	unsigned long i, nb, nw;
+	unsigned long __user *lbuf;
+	struct kvm_get_htab_header __user *hptr;
+	unsigned long flags;
+	int first_pass;
+	unsigned long hpte[2];
+
+	if (!access_ok(VERIFY_WRITE, buf, count))
+		return -EFAULT;
+
+	first_pass = ctx->first_pass;
+	flags = ctx->flags;
+
+	i = ctx->index;
+	hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
+	revp = kvm->arch.revmap + i;
+	lbuf = (unsigned long __user *)buf;
+
+	nb = 0;
+	while (nb + sizeof(hdr) + HPTE_SIZE < count) {
+		/* Initialize header */
+		hptr = (struct kvm_get_htab_header __user *)buf;
+		hdr.n_valid = 0;
+		hdr.n_invalid = 0;
+		nw = nb;
+		nb += sizeof(hdr);
+		lbuf = (unsigned long __user *)(buf + sizeof(hdr));
+
+		/* Skip uninteresting entries, i.e. clean on not-first pass */
+		if (!first_pass) {
+			while (i < kvm->arch.hpt_npte &&
+			       !hpte_dirty(revp, hptp)) {
+				++i;
+				hptp += 2;
+				++revp;
+			}
+		}
+		hdr.index = i;
+
+		/* Grab a series of valid entries */
+		while (i < kvm->arch.hpt_npte &&
+		       hdr.n_valid < 0xffff &&
+		       nb + HPTE_SIZE < count &&
+		       record_hpte(flags, hptp, hpte, revp, 1, first_pass)) {
+			/* valid entry, write it out */
+			++hdr.n_valid;
+			if (__put_user(hpte[0], lbuf) ||
+			    __put_user(hpte[1], lbuf + 1))
+				return -EFAULT;
+			nb += HPTE_SIZE;
+			lbuf += 2;
+			++i;
+			hptp += 2;
+			++revp;
+		}
+		/* Now skip invalid entries while we can */
+		while (i < kvm->arch.hpt_npte &&
+		       hdr.n_invalid < 0xffff &&
+		       record_hpte(flags, hptp, hpte, revp, 0, first_pass)) {
+			/* found an invalid entry */
+			++hdr.n_invalid;
+			++i;
+			hptp += 2;
+			++revp;
+		}
+
+		if (hdr.n_valid || hdr.n_invalid) {
+			/* write back the header */
+			if (__copy_to_user(hptr, &hdr, sizeof(hdr)))
+				return -EFAULT;
+			nw = nb;
+			buf = (char __user *)lbuf;
+		} else {
+			nb = nw;
+		}
+
+		/* Check if we've wrapped around the hash table */
+		if (i >= kvm->arch.hpt_npte) {
+			i = 0;
+			ctx->first_pass = 0;
+			break;
+		}
+	}
+
+	ctx->index = i;
+
+	return nb;
+}
+
+static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
+			      size_t count, loff_t *ppos)
+{
+	struct kvm_htab_ctx *ctx = file->private_data;
+	struct kvm *kvm = ctx->kvm;
+	struct kvm_get_htab_header hdr;
+	unsigned long i, j;
+	unsigned long v, r;
+	unsigned long __user *lbuf;
+	__be64 *hptp;
+	unsigned long tmp[2];
+	ssize_t nb;
+	long int err, ret;
+	int hpte_setup;
+
+	if (!access_ok(VERIFY_READ, buf, count))
+		return -EFAULT;
+
+	/* lock out vcpus from running while we're doing this */
+	mutex_lock(&kvm->lock);
+	hpte_setup = kvm->arch.hpte_setup_done;
+	if (hpte_setup) {
+		kvm->arch.hpte_setup_done = 0;	/* temporarily */
+		/* order hpte_setup_done vs. vcpus_running */
+		smp_mb();
+		if (atomic_read(&kvm->arch.vcpus_running)) {
+			kvm->arch.hpte_setup_done = 1;
+			mutex_unlock(&kvm->lock);
+			return -EBUSY;
+		}
+	}
+
+	err = 0;
+	for (nb = 0; nb + sizeof(hdr) <= count; ) {
+		err = -EFAULT;
+		if (__copy_from_user(&hdr, buf, sizeof(hdr)))
+			break;
+
+		err = 0;
+		if (nb + hdr.n_valid * HPTE_SIZE > count)
+			break;
+
+		nb += sizeof(hdr);
+		buf += sizeof(hdr);
+
+		err = -EINVAL;
+		i = hdr.index;
+		if (i >= kvm->arch.hpt_npte ||
+		    i + hdr.n_valid + hdr.n_invalid > kvm->arch.hpt_npte)
+			break;
+
+		hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
+		lbuf = (unsigned long __user *)buf;
+		for (j = 0; j < hdr.n_valid; ++j) {
+			__be64 hpte_v;
+			__be64 hpte_r;
+
+			err = -EFAULT;
+			if (__get_user(hpte_v, lbuf) ||
+			    __get_user(hpte_r, lbuf + 1))
+				goto out;
+			v = be64_to_cpu(hpte_v);
+			r = be64_to_cpu(hpte_r);
+			err = -EINVAL;
+			if (!(v & HPTE_V_VALID))
+				goto out;
+			lbuf += 2;
+			nb += HPTE_SIZE;
+
+			if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT))
+				kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
+			err = -EIO;
+			ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, i, v, r,
+							 tmp);
+			if (ret != H_SUCCESS) {
+				pr_err("kvm_htab_write ret %ld i=%ld v=%lx "
+				       "r=%lx\n", ret, i, v, r);
+				goto out;
+			}
+			if (!hpte_setup && is_vrma_hpte(v)) {
+				unsigned long psize = hpte_base_page_size(v, r);
+				unsigned long senc = slb_pgsize_encoding(psize);
+				unsigned long lpcr;
+
+				kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T |
+					(VRMA_VSID << SLB_VSID_SHIFT_1T);
+				lpcr = senc << (LPCR_VRMASD_SH - 4);
+				kvmppc_update_lpcr(kvm, lpcr, LPCR_VRMASD);
+				hpte_setup = 1;
+			}
+			++i;
+			hptp += 2;
+		}
+
+		for (j = 0; j < hdr.n_invalid; ++j) {
+			if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT))
+				kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
+			++i;
+			hptp += 2;
+		}
+		err = 0;
+	}
+
+ out:
+	/* Order HPTE updates vs. hpte_setup_done */
+	smp_wmb();
+	kvm->arch.hpte_setup_done = hpte_setup;
+	mutex_unlock(&kvm->lock);
+
+	if (err)
+		return err;
+	return nb;
+}
+
+static int kvm_htab_release(struct inode *inode, struct file *filp)
+{
+	struct kvm_htab_ctx *ctx = filp->private_data;
+
+	filp->private_data = NULL;
+	if (!(ctx->flags & KVM_GET_HTAB_WRITE))
+		atomic_dec(&ctx->kvm->arch.hpte_mod_interest);
+	kvm_put_kvm(ctx->kvm);
+	kfree(ctx);
+	return 0;
+}
+
+static const struct file_operations kvm_htab_fops = {
+	.read		= kvm_htab_read,
+	.write		= kvm_htab_write,
+	.llseek		= default_llseek,
+	.release	= kvm_htab_release,
+};
+
+int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *ghf)
+{
+	int ret;
+	struct kvm_htab_ctx *ctx;
+	int rwflag;
+
+	/* reject flags we don't recognize */
+	if (ghf->flags & ~(KVM_GET_HTAB_BOLTED_ONLY | KVM_GET_HTAB_WRITE))
+		return -EINVAL;
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	kvm_get_kvm(kvm);
+	ctx->kvm = kvm;
+	ctx->index = ghf->start_index;
+	ctx->flags = ghf->flags;
+	ctx->first_pass = 1;
+
+	rwflag = (ghf->flags & KVM_GET_HTAB_WRITE) ? O_WRONLY : O_RDONLY;
+	ret = anon_inode_getfd("kvm-htab", &kvm_htab_fops, ctx, rwflag | O_CLOEXEC);
+	if (ret < 0) {
+		kvm_put_kvm(kvm);
+		return ret;
+	}
+
+	if (rwflag == O_RDONLY) {
+		mutex_lock(&kvm->slots_lock);
+		atomic_inc(&kvm->arch.hpte_mod_interest);
+		/* make sure kvmppc_do_h_enter etc. see the increment */
+		synchronize_srcu_expedited(&kvm->srcu);
+		mutex_unlock(&kvm->slots_lock);
+	}
+
+	return ret;
+}
+
+struct debugfs_htab_state {
+	struct kvm	*kvm;
+	struct mutex	mutex;
+	unsigned long	hpt_index;
+	int		chars_left;
+	int		buf_index;
+	char		buf[64];
+};
+
+static int debugfs_htab_open(struct inode *inode, struct file *file)
+{
+	struct kvm *kvm = inode->i_private;
+	struct debugfs_htab_state *p;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	kvm_get_kvm(kvm);
+	p->kvm = kvm;
+	mutex_init(&p->mutex);
+	file->private_data = p;
+
+	return nonseekable_open(inode, file);
+}
+
+static int debugfs_htab_release(struct inode *inode, struct file *file)
+{
+	struct debugfs_htab_state *p = file->private_data;
+
+	kvm_put_kvm(p->kvm);
+	kfree(p);
+	return 0;
+}
+
+static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
+				 size_t len, loff_t *ppos)
+{
+	struct debugfs_htab_state *p = file->private_data;
+	ssize_t ret, r;
+	unsigned long i, n;
+	unsigned long v, hr, gr;
+	struct kvm *kvm;
+	__be64 *hptp;
+
+	ret = mutex_lock_interruptible(&p->mutex);
+	if (ret)
+		return ret;
+
+	if (p->chars_left) {
+		n = p->chars_left;
+		if (n > len)
+			n = len;
+		r = copy_to_user(buf, p->buf + p->buf_index, n);
+		n -= r;
+		p->chars_left -= n;
+		p->buf_index += n;
+		buf += n;
+		len -= n;
+		ret = n;
+		if (r) {
+			if (!n)
+				ret = -EFAULT;
+			goto out;
+		}
+	}
+
+	kvm = p->kvm;
+	i = p->hpt_index;
+	hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
+	for (; len != 0 && i < kvm->arch.hpt_npte; ++i, hptp += 2) {
+		if (!(be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT)))
+			continue;
+
+		/* lock the HPTE so it's stable and read it */
+		preempt_disable();
+		while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
+			cpu_relax();
+		v = be64_to_cpu(hptp[0]) & ~HPTE_V_HVLOCK;
+		hr = be64_to_cpu(hptp[1]);
+		gr = kvm->arch.revmap[i].guest_rpte;
+		unlock_hpte(hptp, v);
+		preempt_enable();
+
+		if (!(v & (HPTE_V_VALID | HPTE_V_ABSENT)))
+			continue;
+
+		n = scnprintf(p->buf, sizeof(p->buf),
+			      "%6lx %.16lx %.16lx %.16lx\n",
+			      i, v, hr, gr);
+		p->chars_left = n;
+		if (n > len)
+			n = len;
+		r = copy_to_user(buf, p->buf, n);
+		n -= r;
+		p->chars_left -= n;
+		p->buf_index = n;
+		buf += n;
+		len -= n;
+		ret += n;
+		if (r) {
+			if (!ret)
+				ret = -EFAULT;
+			goto out;
+		}
+	}
+	p->hpt_index = i;
+
+ out:
+	mutex_unlock(&p->mutex);
+	return ret;
+}
+
+ssize_t debugfs_htab_write(struct file *file, const char __user *buf,
+			   size_t len, loff_t *ppos)
+{
+	return -EACCES;
+}
+
+static const struct file_operations debugfs_htab_fops = {
+	.owner	 = THIS_MODULE,
+	.open	 = debugfs_htab_open,
+	.release = debugfs_htab_release,
+	.read	 = debugfs_htab_read,
+	.write	 = debugfs_htab_write,
+	.llseek	 = generic_file_llseek,
+};
+
+void kvmppc_mmu_debugfs_init(struct kvm *kvm)
+{
+	kvm->arch.htab_dentry = debugfs_create_file("htab", 0400,
+						    kvm->arch.debugfs_dir, kvm,
+						    &debugfs_htab_fops);
+}
+
+void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
+{
+	struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
+
+	vcpu->arch.slb_nr = 32;		/* POWER7/POWER8 */
+
+	mmu->xlate = kvmppc_mmu_book3s_64_hv_xlate;
+	mmu->reset_msr = kvmppc_mmu_book3s_64_hv_reset_msr;
+
+	vcpu->arch.hflags |= BOOK3S_HFLAG_SLB;
+}