/*
   * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   *
   * 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.
   */

  
  #include <linux/mman.h>
  #include <linux/kvm_host.h>
  #include <linux/io.h>

  #include <linux/hugetlb.h>

  #include <linux/sched/signal.h>

  #include <trace/events/kvm.h>

  #include <asm/pgalloc.h>

  #include <asm/cacheflush.h>

  #include <asm/kvm_arm.h>
  #include <asm/kvm_mmu.h>

  #include <asm/kvm_mmio.h>

  #include <asm/kvm_asm.h>

  #include <asm/kvm_emulate.h>

  #include <asm/virt.h>

  #include <asm/system_misc.h>

  
  #include "trace.h"

  static pgd_t *boot_hyp_pgd;

  static pgd_t *hyp_pgd;

  static pgd_t *merged_hyp_pgd;

  static DEFINE_MUTEX(kvm_hyp_pgd_mutex);

  static unsigned long hyp_idmap_start;
  static unsigned long hyp_idmap_end;
  static phys_addr_t hyp_idmap_vector;

  #define S2_PGD_SIZE	(PTRS_PER_S2_PGD * sizeof(pgd_t))

  #define hyp_pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))

  #define KVM_S2PTE_FLAG_IS_IOMAP		(1UL << 0)
  #define KVM_S2_FLAG_LOGGING_ACTIVE	(1UL << 1)
  
  static bool memslot_is_logging(struct kvm_memory_slot *memslot)
  {

  	return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);

  }
  
  /**
   * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
   * @kvm:	pointer to kvm structure.
   *
   * Interface to HYP function to flush all VM TLB entries
   */
  void kvm_flush_remote_tlbs(struct kvm *kvm)
  {
  	kvm_call_hyp(__kvm_tlb_flush_vmid, kvm);

  }

  static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)

  {

  	kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);

  }

  /*
   * D-Cache management functions. They take the page table entries by
   * value, as they are flushing the cache using the kernel mapping (or
   * kmap on 32bit).
   */
  static void kvm_flush_dcache_pte(pte_t pte)
  {
  	__kvm_flush_dcache_pte(pte);
  }
  
  static void kvm_flush_dcache_pmd(pmd_t pmd)
  {
  	__kvm_flush_dcache_pmd(pmd);
  }
  
  static void kvm_flush_dcache_pud(pud_t pud)
  {
  	__kvm_flush_dcache_pud(pud);
  }

  static bool kvm_is_device_pfn(unsigned long pfn)
  {
  	return !pfn_valid(pfn);
  }

  /**
   * stage2_dissolve_pmd() - clear and flush huge PMD entry
   * @kvm:	pointer to kvm structure.
   * @addr:	IPA
   * @pmd:	pmd pointer for IPA
   *
   * Function clears a PMD entry, flushes addr 1st and 2nd stage TLBs. Marks all
   * pages in the range dirty.
   */
  static void stage2_dissolve_pmd(struct kvm *kvm, phys_addr_t addr, pmd_t *pmd)
  {

  	if (!pmd_thp_or_huge(*pmd))

  		return;
  
  	pmd_clear(pmd);
  	kvm_tlb_flush_vmid_ipa(kvm, addr);
  	put_page(virt_to_page(pmd));
  }

  static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
  				  int min, int max)
  {
  	void *page;
  
  	BUG_ON(max > KVM_NR_MEM_OBJS);
  	if (cache->nobjs >= min)
  		return 0;
  	while (cache->nobjs < max) {
  		page = (void *)__get_free_page(PGALLOC_GFP);
  		if (!page)
  			return -ENOMEM;
  		cache->objects[cache->nobjs++] = page;
  	}
  	return 0;
  }
  
  static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
  {
  	while (mc->nobjs)
  		free_page((unsigned long)mc->objects[--mc->nobjs]);
  }
  
  static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
  {
  	void *p;
  
  	BUG_ON(!mc || !mc->nobjs);
  	p = mc->objects[--mc->nobjs];
  	return p;
  }

  static void clear_stage2_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr)

  {

  	pud_t *pud_table __maybe_unused = stage2_pud_offset(pgd, 0UL);
  	stage2_pgd_clear(pgd);

  	kvm_tlb_flush_vmid_ipa(kvm, addr);

  	stage2_pud_free(pud_table);

  	put_page(virt_to_page(pgd));

  }

  static void clear_stage2_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)

  {

  	pmd_t *pmd_table __maybe_unused = stage2_pmd_offset(pud, 0);
  	VM_BUG_ON(stage2_pud_huge(*pud));
  	stage2_pud_clear(pud);

  	kvm_tlb_flush_vmid_ipa(kvm, addr);

  	stage2_pmd_free(pmd_table);

  	put_page(virt_to_page(pud));
  }

  static void clear_stage2_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr)

  {

  	pte_t *pte_table = pte_offset_kernel(pmd, 0);

  	VM_BUG_ON(pmd_thp_or_huge(*pmd));

  	pmd_clear(pmd);
  	kvm_tlb_flush_vmid_ipa(kvm, addr);
  	pte_free_kernel(NULL, pte_table);

  	put_page(virt_to_page(pmd));
  }

  /*
   * Unmapping vs dcache management:
   *
   * If a guest maps certain memory pages as uncached, all writes will
   * bypass the data cache and go directly to RAM.  However, the CPUs
   * can still speculate reads (not writes) and fill cache lines with
   * data.
   *
   * Those cache lines will be *clean* cache lines though, so a
   * clean+invalidate operation is equivalent to an invalidate
   * operation, because no cache lines are marked dirty.
   *
   * Those clean cache lines could be filled prior to an uncached write
   * by the guest, and the cache coherent IO subsystem would therefore
   * end up writing old data to disk.
   *
   * This is why right after unmapping a page/section and invalidating
   * the corresponding TLBs, we call kvm_flush_dcache_p*() to make sure
   * the IO subsystem will never hit in the cache.
   */

  static void unmap_stage2_ptes(struct kvm *kvm, pmd_t *pmd,

  		       phys_addr_t addr, phys_addr_t end)

  {

  	phys_addr_t start_addr = addr;
  	pte_t *pte, *start_pte;
  
  	start_pte = pte = pte_offset_kernel(pmd, addr);
  	do {
  		if (!pte_none(*pte)) {

  			pte_t old_pte = *pte;

  			kvm_set_pte(pte, __pte(0));

  			kvm_tlb_flush_vmid_ipa(kvm, addr);

  
  			/* No need to invalidate the cache for device mappings */

  			if (!kvm_is_device_pfn(pte_pfn(old_pte)))

  				kvm_flush_dcache_pte(old_pte);
  
  			put_page(virt_to_page(pte));

  		}
  	} while (pte++, addr += PAGE_SIZE, addr != end);

  	if (stage2_pte_table_empty(start_pte))
  		clear_stage2_pmd_entry(kvm, pmd, start_addr);

  }

  static void unmap_stage2_pmds(struct kvm *kvm, pud_t *pud,

  		       phys_addr_t addr, phys_addr_t end)

  {

  	phys_addr_t next, start_addr = addr;
  	pmd_t *pmd, *start_pmd;

  	start_pmd = pmd = stage2_pmd_offset(pud, addr);

  	do {

  		next = stage2_pmd_addr_end(addr, end);

  		if (!pmd_none(*pmd)) {

  			if (pmd_thp_or_huge(*pmd)) {

  				pmd_t old_pmd = *pmd;

  				pmd_clear(pmd);
  				kvm_tlb_flush_vmid_ipa(kvm, addr);

  
  				kvm_flush_dcache_pmd(old_pmd);

  				put_page(virt_to_page(pmd));
  			} else {

  				unmap_stage2_ptes(kvm, pmd, addr, next);

  			}

  		}

  	} while (pmd++, addr = next, addr != end);

  	if (stage2_pmd_table_empty(start_pmd))
  		clear_stage2_pud_entry(kvm, pud, start_addr);

  }

  static void unmap_stage2_puds(struct kvm *kvm, pgd_t *pgd,

  		       phys_addr_t addr, phys_addr_t end)
  {
  	phys_addr_t next, start_addr = addr;
  	pud_t *pud, *start_pud;

  	start_pud = pud = stage2_pud_offset(pgd, addr);

  	do {

  		next = stage2_pud_addr_end(addr, end);
  		if (!stage2_pud_none(*pud)) {
  			if (stage2_pud_huge(*pud)) {

  				pud_t old_pud = *pud;

  				stage2_pud_clear(pud);

  				kvm_tlb_flush_vmid_ipa(kvm, addr);

  				kvm_flush_dcache_pud(old_pud);

  				put_page(virt_to_page(pud));
  			} else {

  				unmap_stage2_pmds(kvm, pud, addr, next);

  			}
  		}

  	} while (pud++, addr = next, addr != end);

  	if (stage2_pud_table_empty(start_pud))
  		clear_stage2_pgd_entry(kvm, pgd, start_addr);

  }

  /**
   * unmap_stage2_range -- Clear stage2 page table entries to unmap a range
   * @kvm:   The VM pointer
   * @start: The intermediate physical base address of the range to unmap
   * @size:  The size of the area to unmap
   *
   * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
   * be called while holding mmu_lock (unless for freeing the stage2 pgd before
   * destroying the VM), otherwise another faulting VCPU may come in and mess
   * with things behind our backs.
   */
  static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)

  {
  	pgd_t *pgd;
  	phys_addr_t addr = start, end = start + size;
  	phys_addr_t next;

  	assert_spin_locked(&kvm->mmu_lock);

  	pgd = kvm->arch.pgd + stage2_pgd_index(addr);

  	do {

  		/*
  		 * Make sure the page table is still active, as another thread
  		 * could have possibly freed the page table, while we released
  		 * the lock.
  		 */
  		if (!READ_ONCE(kvm->arch.pgd))
  			break;

  		next = stage2_pgd_addr_end(addr, end);
  		if (!stage2_pgd_none(*pgd))
  			unmap_stage2_puds(kvm, pgd, addr, next);

  		/*
  		 * If the range is too large, release the kvm->mmu_lock
  		 * to prevent starvation and lockup detector warnings.
  		 */
  		if (next != end)
  			cond_resched_lock(&kvm->mmu_lock);

  	} while (pgd++, addr = next, addr != end);

  }

  static void stage2_flush_ptes(struct kvm *kvm, pmd_t *pmd,
  			      phys_addr_t addr, phys_addr_t end)
  {
  	pte_t *pte;
  
  	pte = pte_offset_kernel(pmd, addr);
  	do {

  		if (!pte_none(*pte) && !kvm_is_device_pfn(pte_pfn(*pte)))

  			kvm_flush_dcache_pte(*pte);

  	} while (pte++, addr += PAGE_SIZE, addr != end);
  }
  
  static void stage2_flush_pmds(struct kvm *kvm, pud_t *pud,
  			      phys_addr_t addr, phys_addr_t end)
  {
  	pmd_t *pmd;
  	phys_addr_t next;

  	pmd = stage2_pmd_offset(pud, addr);

  	do {

  		next = stage2_pmd_addr_end(addr, end);

  		if (!pmd_none(*pmd)) {

  			if (pmd_thp_or_huge(*pmd))

  				kvm_flush_dcache_pmd(*pmd);
  			else

  				stage2_flush_ptes(kvm, pmd, addr, next);

  		}
  	} while (pmd++, addr = next, addr != end);
  }
  
  static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd,
  			      phys_addr_t addr, phys_addr_t end)
  {
  	pud_t *pud;
  	phys_addr_t next;

  	pud = stage2_pud_offset(pgd, addr);

  	do {

  		next = stage2_pud_addr_end(addr, end);
  		if (!stage2_pud_none(*pud)) {
  			if (stage2_pud_huge(*pud))

  				kvm_flush_dcache_pud(*pud);
  			else

  				stage2_flush_pmds(kvm, pud, addr, next);

  		}
  	} while (pud++, addr = next, addr != end);
  }
  
  static void stage2_flush_memslot(struct kvm *kvm,
  				 struct kvm_memory_slot *memslot)
  {
  	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
  	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
  	phys_addr_t next;
  	pgd_t *pgd;

  	pgd = kvm->arch.pgd + stage2_pgd_index(addr);

  	do {

  		next = stage2_pgd_addr_end(addr, end);

  		stage2_flush_puds(kvm, pgd, addr, next);
  	} while (pgd++, addr = next, addr != end);
  }
  
  /**
   * stage2_flush_vm - Invalidate cache for pages mapped in stage 2
   * @kvm: The struct kvm pointer
   *
   * Go through the stage 2 page tables and invalidate any cache lines
   * backing memory already mapped to the VM.
   */

  static void stage2_flush_vm(struct kvm *kvm)

  {
  	struct kvm_memslots *slots;
  	struct kvm_memory_slot *memslot;
  	int idx;
  
  	idx = srcu_read_lock(&kvm->srcu);
  	spin_lock(&kvm->mmu_lock);
  
  	slots = kvm_memslots(kvm);
  	kvm_for_each_memslot(memslot, slots)
  		stage2_flush_memslot(kvm, memslot);
  
  	spin_unlock(&kvm->mmu_lock);
  	srcu_read_unlock(&kvm->srcu, idx);
  }

  static void clear_hyp_pgd_entry(pgd_t *pgd)
  {
  	pud_t *pud_table __maybe_unused = pud_offset(pgd, 0UL);
  	pgd_clear(pgd);
  	pud_free(NULL, pud_table);
  	put_page(virt_to_page(pgd));
  }
  
  static void clear_hyp_pud_entry(pud_t *pud)
  {
  	pmd_t *pmd_table __maybe_unused = pmd_offset(pud, 0);
  	VM_BUG_ON(pud_huge(*pud));
  	pud_clear(pud);
  	pmd_free(NULL, pmd_table);
  	put_page(virt_to_page(pud));
  }
  
  static void clear_hyp_pmd_entry(pmd_t *pmd)
  {
  	pte_t *pte_table = pte_offset_kernel(pmd, 0);
  	VM_BUG_ON(pmd_thp_or_huge(*pmd));
  	pmd_clear(pmd);
  	pte_free_kernel(NULL, pte_table);
  	put_page(virt_to_page(pmd));
  }
  
  static void unmap_hyp_ptes(pmd_t *pmd, phys_addr_t addr, phys_addr_t end)
  {
  	pte_t *pte, *start_pte;
  
  	start_pte = pte = pte_offset_kernel(pmd, addr);
  	do {
  		if (!pte_none(*pte)) {
  			kvm_set_pte(pte, __pte(0));
  			put_page(virt_to_page(pte));
  		}
  	} while (pte++, addr += PAGE_SIZE, addr != end);
  
  	if (hyp_pte_table_empty(start_pte))
  		clear_hyp_pmd_entry(pmd);
  }
  
  static void unmap_hyp_pmds(pud_t *pud, phys_addr_t addr, phys_addr_t end)
  {
  	phys_addr_t next;
  	pmd_t *pmd, *start_pmd;
  
  	start_pmd = pmd = pmd_offset(pud, addr);
  	do {
  		next = pmd_addr_end(addr, end);
  		/* Hyp doesn't use huge pmds */
  		if (!pmd_none(*pmd))
  			unmap_hyp_ptes(pmd, addr, next);
  	} while (pmd++, addr = next, addr != end);
  
  	if (hyp_pmd_table_empty(start_pmd))
  		clear_hyp_pud_entry(pud);
  }
  
  static void unmap_hyp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
  {
  	phys_addr_t next;
  	pud_t *pud, *start_pud;
  
  	start_pud = pud = pud_offset(pgd, addr);
  	do {
  		next = pud_addr_end(addr, end);
  		/* Hyp doesn't use huge puds */
  		if (!pud_none(*pud))
  			unmap_hyp_pmds(pud, addr, next);
  	} while (pud++, addr = next, addr != end);
  
  	if (hyp_pud_table_empty(start_pud))
  		clear_hyp_pgd_entry(pgd);
  }
  
  static void unmap_hyp_range(pgd_t *pgdp, phys_addr_t start, u64 size)
  {
  	pgd_t *pgd;
  	phys_addr_t addr = start, end = start + size;
  	phys_addr_t next;
  
  	/*
  	 * We don't unmap anything from HYP, except at the hyp tear down.
  	 * Hence, we don't have to invalidate the TLBs here.
  	 */
  	pgd = pgdp + pgd_index(addr);
  	do {
  		next = pgd_addr_end(addr, end);
  		if (!pgd_none(*pgd))
  			unmap_hyp_puds(pgd, addr, next);
  	} while (pgd++, addr = next, addr != end);
  }

  /**

   * free_hyp_pgds - free Hyp-mode page tables

   *

   * Assumes hyp_pgd is a page table used strictly in Hyp-mode and
   * therefore contains either mappings in the kernel memory area (above
   * PAGE_OFFSET), or device mappings in the vmalloc range (from
   * VMALLOC_START to VMALLOC_END).
   *
   * boot_hyp_pgd should only map two pages for the init code.

   */

  void free_hyp_pgds(void)

  {

  	mutex_lock(&kvm_hyp_pgd_mutex);

  	if (boot_hyp_pgd) {
  		unmap_hyp_range(boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE);
  		free_pages((unsigned long)boot_hyp_pgd, hyp_pgd_order);
  		boot_hyp_pgd = NULL;
  	}

  	if (hyp_pgd) {

  		unmap_hyp_range(hyp_pgd, hyp_idmap_start, PAGE_SIZE);

  		unmap_hyp_range(hyp_pgd, kern_hyp_va(PAGE_OFFSET),
  				(uintptr_t)high_memory - PAGE_OFFSET);
  		unmap_hyp_range(hyp_pgd, kern_hyp_va(VMALLOC_START),
  				VMALLOC_END - VMALLOC_START);

  		free_pages((unsigned long)hyp_pgd, hyp_pgd_order);

  		hyp_pgd = NULL;

  	}

  	if (merged_hyp_pgd) {
  		clear_page(merged_hyp_pgd);
  		free_page((unsigned long)merged_hyp_pgd);
  		merged_hyp_pgd = NULL;
  	}

  	mutex_unlock(&kvm_hyp_pgd_mutex);
  }
  
  static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,

  				    unsigned long end, unsigned long pfn,
  				    pgprot_t prot)

  {
  	pte_t *pte;
  	unsigned long addr;

  	addr = start;
  	do {

  		pte = pte_offset_kernel(pmd, addr);
  		kvm_set_pte(pte, pfn_pte(pfn, prot));

  		get_page(virt_to_page(pte));

  		kvm_flush_dcache_to_poc(pte, sizeof(*pte));

  		pfn++;

  	} while (addr += PAGE_SIZE, addr != end);

  }
  
  static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,

  				   unsigned long end, unsigned long pfn,
  				   pgprot_t prot)

  {
  	pmd_t *pmd;
  	pte_t *pte;
  	unsigned long addr, next;

  	addr = start;
  	do {

  		pmd = pmd_offset(pud, addr);

  
  		BUG_ON(pmd_sect(*pmd));
  
  		if (pmd_none(*pmd)) {

  			pte = pte_alloc_one_kernel(NULL, addr);

  			if (!pte) {
  				kvm_err("Cannot allocate Hyp pte
  ");
  				return -ENOMEM;
  			}
  			pmd_populate_kernel(NULL, pmd, pte);

  			get_page(virt_to_page(pmd));

  			kvm_flush_dcache_to_poc(pmd, sizeof(*pmd));

  		}
  
  		next = pmd_addr_end(addr, end);

  		create_hyp_pte_mappings(pmd, addr, next, pfn, prot);
  		pfn += (next - addr) >> PAGE_SHIFT;

  	} while (addr = next, addr != end);

  
  	return 0;
  }

  static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
  				   unsigned long end, unsigned long pfn,
  				   pgprot_t prot)
  {
  	pud_t *pud;
  	pmd_t *pmd;
  	unsigned long addr, next;
  	int ret;
  
  	addr = start;
  	do {
  		pud = pud_offset(pgd, addr);
  
  		if (pud_none_or_clear_bad(pud)) {
  			pmd = pmd_alloc_one(NULL, addr);
  			if (!pmd) {
  				kvm_err("Cannot allocate Hyp pmd
  ");
  				return -ENOMEM;
  			}
  			pud_populate(NULL, pud, pmd);
  			get_page(virt_to_page(pud));
  			kvm_flush_dcache_to_poc(pud, sizeof(*pud));
  		}
  
  		next = pud_addr_end(addr, end);
  		ret = create_hyp_pmd_mappings(pud, addr, next, pfn, prot);
  		if (ret)
  			return ret;
  		pfn += (next - addr) >> PAGE_SHIFT;
  	} while (addr = next, addr != end);
  
  	return 0;
  }

  static int __create_hyp_mappings(pgd_t *pgdp,
  				 unsigned long start, unsigned long end,
  				 unsigned long pfn, pgprot_t prot)

  {

  	pgd_t *pgd;
  	pud_t *pud;

  	unsigned long addr, next;
  	int err = 0;

  	mutex_lock(&kvm_hyp_pgd_mutex);

  	addr = start & PAGE_MASK;
  	end = PAGE_ALIGN(end);
  	do {

  		pgd = pgdp + pgd_index(addr);

  		if (pgd_none(*pgd)) {
  			pud = pud_alloc_one(NULL, addr);
  			if (!pud) {
  				kvm_err("Cannot allocate Hyp pud
  ");

  				err = -ENOMEM;
  				goto out;
  			}

  			pgd_populate(NULL, pgd, pud);
  			get_page(virt_to_page(pgd));
  			kvm_flush_dcache_to_poc(pgd, sizeof(*pgd));

  		}
  
  		next = pgd_addr_end(addr, end);

  		err = create_hyp_pud_mappings(pgd, addr, next, pfn, prot);

  		if (err)
  			goto out;

  		pfn += (next - addr) >> PAGE_SHIFT;

  	} while (addr = next, addr != end);

  out:
  	mutex_unlock(&kvm_hyp_pgd_mutex);
  	return err;
  }

  static phys_addr_t kvm_kaddr_to_phys(void *kaddr)
  {
  	if (!is_vmalloc_addr(kaddr)) {
  		BUG_ON(!virt_addr_valid(kaddr));
  		return __pa(kaddr);
  	} else {
  		return page_to_phys(vmalloc_to_page(kaddr)) +
  		       offset_in_page(kaddr);
  	}
  }

  /**

   * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode

   * @from:	The virtual kernel start address of the range
   * @to:		The virtual kernel end address of the range (exclusive)

   * @prot:	The protection to be applied to this range

   *

   * The same virtual address as the kernel virtual address is also used
   * in Hyp-mode mapping (modulo HYP_PAGE_OFFSET) to the same underlying
   * physical pages.

   */

  int create_hyp_mappings(void *from, void *to, pgprot_t prot)

  {

  	phys_addr_t phys_addr;
  	unsigned long virt_addr;

  	unsigned long start = kern_hyp_va((unsigned long)from);
  	unsigned long end = kern_hyp_va((unsigned long)to);

  	if (is_kernel_in_hyp_mode())
  		return 0;

  	start = start & PAGE_MASK;
  	end = PAGE_ALIGN(end);

  	for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) {
  		int err;

  		phys_addr = kvm_kaddr_to_phys(from + virt_addr - start);
  		err = __create_hyp_mappings(hyp_pgd, virt_addr,
  					    virt_addr + PAGE_SIZE,
  					    __phys_to_pfn(phys_addr),

  					    prot);

  		if (err)
  			return err;
  	}
  
  	return 0;

  }
  
  /**

   * create_hyp_io_mappings - duplicate a kernel IO mapping into Hyp mode
   * @from:	The kernel start VA of the range
   * @to:		The kernel end VA of the range (exclusive)

   * @phys_addr:	The physical start address which gets mapped

   *
   * The resulting HYP VA is the same as the kernel VA, modulo
   * HYP_PAGE_OFFSET.

   */

  int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)

  {

  	unsigned long start = kern_hyp_va((unsigned long)from);
  	unsigned long end = kern_hyp_va((unsigned long)to);

  	if (is_kernel_in_hyp_mode())
  		return 0;

  	/* Check for a valid kernel IO mapping */
  	if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
  		return -EINVAL;
  
  	return __create_hyp_mappings(hyp_pgd, start, end,
  				     __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);

  }

  /**
   * kvm_alloc_stage2_pgd - allocate level-1 table for stage-2 translation.
   * @kvm:	The KVM struct pointer for the VM.
   *

   * Allocates only the stage-2 HW PGD level table(s) (can support either full
   * 40-bit input addresses or limited to 32-bit input addresses). Clears the
   * allocated pages.

   *
   * Note we don't need locking here as this is only called when the VM is
   * created, which can only be done once.
   */
  int kvm_alloc_stage2_pgd(struct kvm *kvm)
  {
  	pgd_t *pgd;
  
  	if (kvm->arch.pgd != NULL) {
  		kvm_err("kvm_arch already initialized?
  ");
  		return -EINVAL;
  	}

  	/* Allocate the HW PGD, making sure that each page gets its own refcount */
  	pgd = alloc_pages_exact(S2_PGD_SIZE, GFP_KERNEL | __GFP_ZERO);
  	if (!pgd)

  		return -ENOMEM;

  	kvm->arch.pgd = pgd;

  	return 0;
  }

  static void stage2_unmap_memslot(struct kvm *kvm,
  				 struct kvm_memory_slot *memslot)
  {
  	hva_t hva = memslot->userspace_addr;
  	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
  	phys_addr_t size = PAGE_SIZE * memslot->npages;
  	hva_t reg_end = hva + size;
  
  	/*
  	 * A memory region could potentially cover multiple VMAs, and any holes
  	 * between them, so iterate over all of them to find out if we should
  	 * unmap any of them.
  	 *
  	 *     +--------------------------------------------+
  	 * +---------------+----------------+   +----------------+
  	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
  	 * +---------------+----------------+   +----------------+
  	 *     |               memory region                |
  	 *     +--------------------------------------------+
  	 */
  	do {
  		struct vm_area_struct *vma = find_vma(current->mm, hva);
  		hva_t vm_start, vm_end;
  
  		if (!vma || vma->vm_start >= reg_end)
  			break;
  
  		/*
  		 * Take the intersection of this VMA with the memory region
  		 */
  		vm_start = max(hva, vma->vm_start);
  		vm_end = min(reg_end, vma->vm_end);
  
  		if (!(vma->vm_flags & VM_PFNMAP)) {
  			gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
  			unmap_stage2_range(kvm, gpa, vm_end - vm_start);
  		}
  		hva = vm_end;
  	} while (hva < reg_end);
  }
  
  /**
   * stage2_unmap_vm - Unmap Stage-2 RAM mappings
   * @kvm: The struct kvm pointer
   *
   * Go through the memregions and unmap any reguler RAM
   * backing memory already mapped to the VM.
   */
  void stage2_unmap_vm(struct kvm *kvm)
  {
  	struct kvm_memslots *slots;
  	struct kvm_memory_slot *memslot;
  	int idx;
  
  	idx = srcu_read_lock(&kvm->srcu);

  	down_read(&current->mm->mmap_sem);

  	spin_lock(&kvm->mmu_lock);
  
  	slots = kvm_memslots(kvm);
  	kvm_for_each_memslot(memslot, slots)
  		stage2_unmap_memslot(kvm, memslot);
  
  	spin_unlock(&kvm->mmu_lock);

  	up_read(&current->mm->mmap_sem);

  	srcu_read_unlock(&kvm->srcu, idx);
  }

  /**
   * kvm_free_stage2_pgd - free all stage-2 tables
   * @kvm:	The KVM struct pointer for the VM.
   *
   * Walks the level-1 page table pointed to by kvm->arch.pgd and frees all
   * underlying level-2 and level-3 tables before freeing the actual level-1 table
   * and setting the struct pointer to NULL.

   */
  void kvm_free_stage2_pgd(struct kvm *kvm)
  {

  	void *pgd = NULL;

  	spin_lock(&kvm->mmu_lock);

  	if (kvm->arch.pgd) {
  		unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);

  		pgd = READ_ONCE(kvm->arch.pgd);

  		kvm->arch.pgd = NULL;
  	}

  	spin_unlock(&kvm->mmu_lock);

  	/* Free the HW pgd, one page at a time */

  	if (pgd)
  		free_pages_exact(pgd, S2_PGD_SIZE);

  }

  static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,

  			     phys_addr_t addr)

  {
  	pgd_t *pgd;
  	pud_t *pud;

  	pgd = kvm->arch.pgd + stage2_pgd_index(addr);
  	if (WARN_ON(stage2_pgd_none(*pgd))) {

  		if (!cache)
  			return NULL;
  		pud = mmu_memory_cache_alloc(cache);

  		stage2_pgd_populate(pgd, pud);

  		get_page(virt_to_page(pgd));
  	}

  	return stage2_pud_offset(pgd, addr);

  }
  
  static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
  			     phys_addr_t addr)
  {
  	pud_t *pud;
  	pmd_t *pmd;
  
  	pud = stage2_get_pud(kvm, cache, addr);

  	if (!pud)
  		return NULL;

  	if (stage2_pud_none(*pud)) {

  		if (!cache)

  			return NULL;

  		pmd = mmu_memory_cache_alloc(cache);

  		stage2_pud_populate(pud, pmd);

  		get_page(virt_to_page(pud));

  	}

  	return stage2_pmd_offset(pud, addr);

  }
  
  static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache
  			       *cache, phys_addr_t addr, const pmd_t *new_pmd)
  {
  	pmd_t *pmd, old_pmd;
  
  	pmd = stage2_get_pmd(kvm, cache, addr);
  	VM_BUG_ON(!pmd);

  	old_pmd = *pmd;

  	if (pmd_present(old_pmd)) {

  		/*
  		 * Multiple vcpus faulting on the same PMD entry, can
  		 * lead to them sequentially updating the PMD with the
  		 * same value. Following the break-before-make
  		 * (pmd_clear() followed by tlb_flush()) process can
  		 * hinder forward progress due to refaults generated
  		 * on missing translations.
  		 *
  		 * Skip updating the page table if the entry is
  		 * unchanged.
  		 */
  		if (pmd_val(old_pmd) == pmd_val(*new_pmd))
  			return 0;
  
  		/*
  		 * Mapping in huge pages should only happen through a
  		 * fault.  If a page is merged into a transparent huge
  		 * page, the individual subpages of that huge page
  		 * should be unmapped through MMU notifiers before we
  		 * get here.
  		 *
  		 * Merging of CompoundPages is not supported; they
  		 * should become splitting first, unmapped, merged,
  		 * and mapped back in on-demand.
  		 */
  		VM_BUG_ON(pmd_pfn(old_pmd) != pmd_pfn(*new_pmd));

  		pmd_clear(pmd);

  		kvm_tlb_flush_vmid_ipa(kvm, addr);

  	} else {

  		get_page(virt_to_page(pmd));

  	}
  
  	kvm_set_pmd(pmd, *new_pmd);

  	return 0;
  }
  
  static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,

  			  phys_addr_t addr, const pte_t *new_pte,
  			  unsigned long flags)

  {
  	pmd_t *pmd;
  	pte_t *pte, old_pte;

  	bool iomap = flags & KVM_S2PTE_FLAG_IS_IOMAP;
  	bool logging_active = flags & KVM_S2_FLAG_LOGGING_ACTIVE;
  
  	VM_BUG_ON(logging_active && !cache);

  	/* Create stage-2 page table mapping - Levels 0 and 1 */

  	pmd = stage2_get_pmd(kvm, cache, addr);
  	if (!pmd) {
  		/*
  		 * Ignore calls from kvm_set_spte_hva for unallocated
  		 * address ranges.
  		 */
  		return 0;
  	}

  	/*
  	 * While dirty page logging - dissolve huge PMD, then continue on to
  	 * allocate page.
  	 */
  	if (logging_active)
  		stage2_dissolve_pmd(kvm, addr, pmd);

  	/* Create stage-2 page mappings - Level 2 */

  	if (pmd_none(*pmd)) {
  		if (!cache)
  			return 0; /* ignore calls from kvm_set_spte_hva */
  		pte = mmu_memory_cache_alloc(cache);

  		pmd_populate_kernel(NULL, pmd, pte);

  		get_page(virt_to_page(pmd));

  	}
  
  	pte = pte_offset_kernel(pmd, addr);

  
  	if (iomap && pte_present(*pte))
  		return -EFAULT;
  
  	/* Create 2nd stage page table mapping - Level 3 */
  	old_pte = *pte;

  	if (pte_present(old_pte)) {

  		/* Skip page table update if there is no change */
  		if (pte_val(old_pte) == pte_val(*new_pte))
  			return 0;

  		kvm_set_pte(pte, __pte(0));

  		kvm_tlb_flush_vmid_ipa(kvm, addr);

  	} else {

  		get_page(virt_to_page(pte));

  	}

  	kvm_set_pte(pte, *new_pte);

  	return 0;
  }

  #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  static int stage2_ptep_test_and_clear_young(pte_t *pte)
  {
  	if (pte_young(*pte)) {
  		*pte = pte_mkold(*pte);
  		return 1;
  	}

  	return 0;
  }

  #else
  static int stage2_ptep_test_and_clear_young(pte_t *pte)
  {
  	return __ptep_test_and_clear_young(pte);
  }
  #endif
  
  static int stage2_pmdp_test_and_clear_young(pmd_t *pmd)
  {
  	return stage2_ptep_test_and_clear_young((pte_t *)pmd);
  }

  
  /**
   * kvm_phys_addr_ioremap - map a device range to guest IPA
   *
   * @kvm:	The KVM pointer
   * @guest_ipa:	The IPA at which to insert the mapping
   * @pa:		The physical address of the device
   * @size:	The size of the mapping
   */
  int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,

  			  phys_addr_t pa, unsigned long size, bool writable)

  {
  	phys_addr_t addr, end;
  	int ret = 0;
  	unsigned long pfn;
  	struct kvm_mmu_memory_cache cache = { 0, };
  
  	end = (guest_ipa + size + PAGE_SIZE - 1) & PAGE_MASK;
  	pfn = __phys_to_pfn(pa);
  
  	for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) {

  		pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE);

  		if (writable)

  			pte = kvm_s2pte_mkwrite(pte);

  		ret = mmu_topup_memory_cache(&cache, KVM_MMU_CACHE_MIN_PAGES,
  						KVM_NR_MEM_OBJS);

  		if (ret)
  			goto out;
  		spin_lock(&kvm->mmu_lock);

  		ret = stage2_set_pte(kvm, &cache, addr, &pte,
  						KVM_S2PTE_FLAG_IS_IOMAP);

  		spin_unlock(&kvm->mmu_lock);
  		if (ret)
  			goto out;
  
  		pfn++;
  	}
  
  out:
  	mmu_free_memory_cache(&cache);
  	return ret;
  }

  static bool transparent_hugepage_adjust(kvm_pfn_t *pfnp, phys_addr_t *ipap)

  {

  	kvm_pfn_t pfn = *pfnp;

  	gfn_t gfn = *ipap >> PAGE_SHIFT;

  	if (PageTransCompoundMap(pfn_to_page(pfn))) {

  		unsigned long mask;
  		/*
  		 * The address we faulted on is backed by a transparent huge
  		 * page.  However, because we map the compound huge page and
  		 * not the individual tail page, we need to transfer the
  		 * refcount to the head page.  We have to be careful that the
  		 * THP doesn't start to split while we are adjusting the
  		 * refcounts.
  		 *
  		 * We are sure this doesn't happen, because mmu_notifier_retry
  		 * was successful and we are holding the mmu_lock, so if this
  		 * THP is trying to split, it will be blocked in the mmu
  		 * notifier before touching any of the pages, specifically
  		 * before being able to call __split_huge_page_refcount().
  		 *
  		 * We can therefore safely transfer the refcount from PG_tail
  		 * to PG_head and switch the pfn from a tail page to the head
  		 * page accordingly.
  		 */
  		mask = PTRS_PER_PMD - 1;
  		VM_BUG_ON((gfn & mask) != (pfn & mask));
  		if (pfn & mask) {
  			*ipap &= PMD_MASK;
  			kvm_release_pfn_clean(pfn);
  			pfn &= ~mask;
  			kvm_get_pfn(pfn);
  			*pfnp = pfn;
  		}
  
  		return true;
  	}
  
  	return false;
  }

  static bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
  {
  	if (kvm_vcpu_trap_is_iabt(vcpu))
  		return false;
  
  	return kvm_vcpu_dabt_iswrite(vcpu);
  }

  /**
   * stage2_wp_ptes - write protect PMD range
   * @pmd:	pointer to pmd entry
   * @addr:	range start address
   * @end:	range end address
   */
  static void stage2_wp_ptes(pmd_t *pmd, phys_addr_t addr, phys_addr_t end)
  {
  	pte_t *pte;
  
  	pte = pte_offset_kernel(pmd, addr);
  	do {
  		if (!pte_none(*pte)) {
  			if (!kvm_s2pte_readonly(pte))
  				kvm_set_s2pte_readonly(pte);
  		}
  	} while (pte++, addr += PAGE_SIZE, addr != end);
  }
  
  /**
   * stage2_wp_pmds - write protect PUD range
   * @pud:	pointer to pud entry
   * @addr:	range start address
   * @end:	range end address
   */
  static void stage2_wp_pmds(pud_t *pud, phys_addr_t addr, phys_addr_t end)
  {
  	pmd_t *pmd;
  	phys_addr_t next;

  	pmd = stage2_pmd_offset(pud, addr);

  
  	do {

  		next = stage2_pmd_addr_end(addr, end);

  		if (!pmd_none(*pmd)) {

  			if (pmd_thp_or_huge(*pmd)) {

  				if (!kvm_s2pmd_readonly(pmd))
  					kvm_set_s2pmd_readonly(pmd);
  			} else {
  				stage2_wp_ptes(pmd, addr, next);
  			}
  		}
  	} while (pmd++, addr = next, addr != end);
  }
  
  /**
    * stage2_wp_puds - write protect PGD range
    * @pgd:	pointer to pgd entry
    * @addr:	range start address
    * @end:	range end address
    *
    * Process PUD entries, for a huge PUD we cause a panic.
    */
  static void  stage2_wp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
  {
  	pud_t *pud;
  	phys_addr_t next;

  	pud = stage2_pud_offset(pgd, addr);

  	do {

  		next = stage2_pud_addr_end(addr, end);
  		if (!stage2_pud_none(*pud)) {

  			/* TODO:PUD not supported, revisit later if supported */

  			BUG_ON(stage2_pud_huge(*pud));

  			stage2_wp_pmds(pud, addr, next);
  		}
  	} while (pud++, addr = next, addr != end);
  }
  
  /**
   * stage2_wp_range() - write protect stage2 memory region range
   * @kvm:	The KVM pointer
   * @addr:	Start address of range
   * @end:	End address of range
   */
  static void stage2_wp_range(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
  {
  	pgd_t *pgd;
  	phys_addr_t next;

  	pgd = kvm->arch.pgd + stage2_pgd_index(addr);

  	do {
  		/*
  		 * Release kvm_mmu_lock periodically if the memory region is
  		 * large. Otherwise, we may see kernel panics with

  		 * CONFIG_DETECT_HUNG_TASK, CONFIG_LOCKUP_DETECTOR,
  		 * CONFIG_LOCKDEP. Additionally, holding the lock too long

  		 * will also starve other vCPUs. We have to also make sure
  		 * that the page tables are not freed while we released
  		 * the lock.

  		 */

  		cond_resched_lock(&kvm->mmu_lock);
  		if (!READ_ONCE(kvm->arch.pgd))
  			break;

  		next = stage2_pgd_addr_end(addr, end);
  		if (stage2_pgd_present(*pgd))

  			stage2_wp_puds(pgd, addr, next);
  	} while (pgd++, addr = next, addr != end);
  }
  
  /**
   * kvm_mmu_wp_memory_region() - write protect stage 2 entries for memory slot
   * @kvm:	The KVM pointer
   * @slot:	The memory slot to write protect
   *
   * Called to start logging dirty pages after memory region
   * KVM_MEM_LOG_DIRTY_PAGES operation is called. After this function returns
   * all present PMD and PTEs are write protected in the memory region.
   * Afterwards read of dirty page log can be called.
   *
   * Acquires kvm_mmu_lock. Called with kvm->slots_lock mutex acquired,
   * serializing operations for VM memory regions.
   */
  void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
  {

  	struct kvm_memslots *slots = kvm_memslots(kvm);
  	struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);

  	phys_addr_t start = memslot->base_gfn << PAGE_SHIFT;
  	phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
  
  	spin_lock(&kvm->mmu_lock);
  	stage2_wp_range(kvm, start, end);
  	spin_unlock(&kvm->mmu_lock);
  	kvm_flush_remote_tlbs(kvm);
  }

  
  /**

   * kvm_mmu_write_protect_pt_masked() - write protect dirty pages

   * @kvm:	The KVM pointer
   * @slot:	The memory slot associated with mask
   * @gfn_offset:	The gfn offset in memory slot
   * @mask:	The mask of dirty pages at offset 'gfn_offset' in this memory
   *		slot to be write protected
   *
   * Walks bits set in mask write protects the associated pte's. Caller must
   * acquire kvm_mmu_lock.
   */

  static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,

  		struct kvm_memory_slot *slot,
  		gfn_t gfn_offset, unsigned long mask)
  {
  	phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
  	phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
  	phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
  
  	stage2_wp_range(kvm, start, end);
  }

  /*
   * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
   * dirty pages.
   *
   * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
   * enable dirty logging for them.
   */
  void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
  		struct kvm_memory_slot *slot,
  		gfn_t gfn_offset, unsigned long mask)
  {
  	kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
  }

  static void coherent_cache_guest_page(struct kvm_vcpu *vcpu, kvm_pfn_t pfn,

  				      unsigned long size)

  {

  	__coherent_cache_guest_page(vcpu, pfn, size);

  }

  static void kvm_send_hwpoison_signal(unsigned long address,
  				     struct vm_area_struct *vma)
  {
  	siginfo_t info;
  
  	info.si_signo   = SIGBUS;
  	info.si_errno   = 0;
  	info.si_code    = BUS_MCEERR_AR;
  	info.si_addr    = (void __user *)address;
  
  	if (is_vm_hugetlb_page(vma))
  		info.si_addr_lsb = huge_page_shift(hstate_vma(vma));
  	else
  		info.si_addr_lsb = PAGE_SHIFT;
  
  	send_sig_info(SIGBUS, &info, current);
  }

  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,

  			  struct kvm_memory_slot *memslot, unsigned long hva,

  			  unsigned long fault_status)
  {

  	int ret;

  	bool write_fault, writable, hugetlb = false, force_pte = false;

  	unsigned long mmu_seq;

  	gfn_t gfn = fault_ipa >> PAGE_SHIFT;

  	struct kvm *kvm = vcpu->kvm;

  	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;

  	struct vm_area_struct *vma;

  	kvm_pfn_t pfn;

  	pgprot_t mem_type = PAGE_S2;

  	bool logging_active = memslot_is_logging(memslot);
  	unsigned long flags = 0;

  	write_fault = kvm_is_write_fault(vcpu);

  	if (fault_status == FSC_PERM && !write_fault) {
  		kvm_err("Unexpected L2 read permission error
  ");
  		return -EFAULT;
  	}

  	/* Let's check if we will get back a huge page backed by hugetlbfs */
  	down_read(&current->mm->mmap_sem);
  	vma = find_vma_intersection(current->mm, hva, hva + 1);

  	if (unlikely(!vma)) {
  		kvm_err("Failed to find VMA for hva 0x%lx
  ", hva);
  		up_read(&current->mm->mmap_sem);
  		return -EFAULT;
  	}

  	if (vma_kernel_pagesize(vma) == PMD_SIZE && !logging_active) {

  		hugetlb = true;
  		gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT;

  	} else {
  		/*

  		 * Pages belonging to memslots that don't have the same
  		 * alignment for userspace and IPA cannot be mapped using
  		 * block descriptors even if the pages belong to a THP for
  		 * the process, because the stage-2 block descriptor will
  		 * cover more than a single THP and we loose atomicity for
  		 * unmapping, updates, and splits of the THP or other pages
  		 * in the stage-2 block range.

  		 */

  		if ((memslot->userspace_addr & ~PMD_MASK) !=
  		    ((memslot->base_gfn << PAGE_SHIFT) & ~PMD_MASK))

  			force_pte = true;

  	}
  	up_read(&current->mm->mmap_sem);

  	/* We need minimum second+third level pages */

  	ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
  				     KVM_NR_MEM_OBJS);

  	if (ret)
  		return ret;
  
  	mmu_seq = vcpu->kvm->mmu_notifier_seq;
  	/*
  	 * Ensure the read of mmu_notifier_seq happens before we call
  	 * 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
  	 * from us again properly. This smp_rmb() interacts with the smp_wmb()
  	 * in kvm_mmu_notifier_invalidate_<page|range_end>.
  	 */
  	smp_rmb();

  	pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writable);

  	if (pfn == KVM_PFN_ERR_HWPOISON) {
  		kvm_send_hwpoison_signal(hva, vma);
  		return 0;
  	}

  	if (is_error_noslot_pfn(pfn))

  		return -EFAULT;

  	if (kvm_is_device_pfn(pfn)) {

  		mem_type = PAGE_S2_DEVICE;

  		flags |= KVM_S2PTE_FLAG_IS_IOMAP;
  	} else if (logging_active) {
  		/*
  		 * Faults on pages in a memslot with logging enabled
  		 * should not be mapped with huge pages (it introduces churn
  		 * and performance degradation), so force a pte mapping.
  		 */
  		force_pte = true;
  		flags |= KVM_S2_FLAG_LOGGING_ACTIVE;
  
  		/*
  		 * Only actually map the page as writable if this was a write
  		 * fault.
  		 */
  		if (!write_fault)
  			writable = false;
  	}

  	spin_lock(&kvm->mmu_lock);
  	if (mmu_notifier_retry(kvm, mmu_seq))

  		goto out_unlock;

  	if (!hugetlb && !force_pte)
  		hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa);

  
  	if (hugetlb) {

  		pmd_t new_pmd = pfn_pmd(pfn, mem_type);

  		new_pmd = pmd_mkhuge(new_pmd);
  		if (writable) {

  			new_pmd = kvm_s2pmd_mkwrite(new_pmd);

  			kvm_set_pfn_dirty(pfn);
  		}

  		coherent_cache_guest_page(vcpu, pfn, PMD_SIZE);

  		ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd);
  	} else {

  		pte_t new_pte = pfn_pte(pfn, mem_type);

  		if (writable) {

  			new_pte = kvm_s2pte_mkwrite(new_pte);

  			kvm_set_pfn_dirty(pfn);

  			mark_page_dirty(kvm, gfn);

  		}

  		coherent_cache_guest_page(vcpu, pfn, PAGE_SIZE);

  		ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags);

  	}

  out_unlock:

  	spin_unlock(&kvm->mmu_lock);

  	kvm_set_pfn_accessed(pfn);

  	kvm_release_pfn_clean(pfn);

  	return ret;

  }

  /*
   * Resolve the access fault by making the page young again.
   * Note that because the faulting entry is guaranteed not to be
   * cached in the TLB, we don't need to invalidate anything.

   * Only the HW Access Flag updates are supported for Stage 2 (no DBM),
   * so there is no need for atomic (pte|pmd)_mkyoung operations.

   */
  static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
  {
  	pmd_t *pmd;
  	pte_t *pte;

  	kvm_pfn_t pfn;

  	bool pfn_valid = false;
  
  	trace_kvm_access_fault(fault_ipa);
  
  	spin_lock(&vcpu->kvm->mmu_lock);
  
  	pmd = stage2_get_pmd(vcpu->kvm, NULL, fault_ipa);
  	if (!pmd || pmd_none(*pmd))	/* Nothing there */
  		goto out;

  	if (pmd_thp_or_huge(*pmd)) {	/* THP, HugeTLB */

  		*pmd = pmd_mkyoung(*pmd);
  		pfn = pmd_pfn(*pmd);
  		pfn_valid = true;
  		goto out;
  	}
  
  	pte = pte_offset_kernel(pmd, fault_ipa);
  	if (pte_none(*pte))		/* Nothing there either */
  		goto out;
  
  	*pte = pte_mkyoung(*pte);	/* Just a page... */
  	pfn = pte_pfn(*pte);
  	pfn_valid = true;
  out:
  	spin_unlock(&vcpu->kvm->mmu_lock);
  	if (pfn_valid)
  		kvm_set_pfn_accessed(pfn);
  }

  /**
   * kvm_handle_guest_abort - handles all 2nd stage aborts
   * @vcpu:	the VCPU pointer
   * @run:	the kvm_run structure
   *
   * Any abort that gets to the host is almost guaranteed to be caused by a
   * missing second stage translation table entry, which can mean that either the
   * guest simply needs more memory and we must allocate an appropriate page or it
   * can mean that the guest tried to access I/O memory, which is emulated by user
   * space. The distinction is based on the IPA causing the fault and whether this
   * memory region has been registered as standard RAM by user space.
   */

  int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
  {

  	unsigned long fault_status;
  	phys_addr_t fault_ipa;
  	struct kvm_memory_slot *memslot;

  	unsigned long hva;
  	bool is_iabt, write_fault, writable;

  	gfn_t gfn;
  	int ret, idx;

  	fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
  
  	fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);

  	is_iabt = kvm_vcpu_trap_is_iabt(vcpu);

  	/* Synchronous External Abort? */
  	if (kvm_vcpu_dabt_isextabt(vcpu)) {
  		/*
  		 * For RAS the host kernel may handle this abort.
  		 * There is no need to pass the error into the guest.
  		 */

  		if (!handle_guest_sea(fault_ipa, kvm_vcpu_get_hsr(vcpu)))
  			return 1;

  		if (unlikely(!is_iabt)) {
  			kvm_inject_vabt(vcpu);
  			return 1;
  		}

  	}

  	trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_hsr(vcpu),
  			      kvm_vcpu_get_hfar(vcpu), fault_ipa);

  
  	/* Check the stage-2 fault is trans. fault or write fault */

  	if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
  	    fault_status != FSC_ACCESS) {

  		kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx
  ",
  			kvm_vcpu_trap_get_class(vcpu),
  			(unsigned long)kvm_vcpu_trap_get_fault(vcpu),
  			(unsigned long)kvm_vcpu_get_hsr(vcpu));

  		return -EFAULT;
  	}
  
  	idx = srcu_read_lock(&vcpu->kvm->srcu);
  
  	gfn = fault_ipa >> PAGE_SHIFT;

  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
  	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);

  	write_fault = kvm_is_write_fault(vcpu);

  	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {

  		if (is_iabt) {
  			/* Prefetch Abort on I/O address */

  			kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));

  			ret = 1;
  			goto out_unlock;
  		}

  		/*

  		 * Check for a cache maintenance operation. Since we
  		 * ended-up here, we know it is outside of any memory
  		 * slot. But we can't find out if that is for a device,
  		 * or if the guest is just being stupid. The only thing
  		 * we know for sure is that this range cannot be cached.
  		 *
  		 * So let's assume that the guest is just being
  		 * cautious, and skip the instruction.
  		 */
  		if (kvm_vcpu_dabt_is_cm(vcpu)) {
  			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  			ret = 1;
  			goto out_unlock;
  		}
  
  		/*

  		 * The IPA is reported as [MAX:12], so we need to
  		 * complement it with the bottom 12 bits from the
  		 * faulting VA. This is always 12 bits, irrespective
  		 * of the page size.
  		 */
  		fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1);

  		ret = io_mem_abort(vcpu, run, fault_ipa);

  		goto out_unlock;
  	}

  	/* Userspace should not be able to register out-of-bounds IPAs */
  	VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);

  	if (fault_status == FSC_ACCESS) {
  		handle_access_fault(vcpu, fault_ipa);
  		ret = 1;
  		goto out_unlock;
  	}

  	ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status);

  	if (ret == 0)
  		ret = 1;
  out_unlock:
  	srcu_read_unlock(&vcpu->kvm->srcu, idx);
  	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)

  {
  	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;

  }

  static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)

  {

  	unmap_stage2_range(kvm, gpa, size);

  	return 0;

  }
  
  int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
  {
  	unsigned long end = hva + PAGE_SIZE;
  
  	if (!kvm->arch.pgd)
  		return 0;
  
  	trace_kvm_unmap_hva(hva);
  	handle_hva_to_gpa(kvm, hva, end, &kvm_unmap_hva_handler, NULL);
  	return 0;
  }
  
  int kvm_unmap_hva_range(struct kvm *kvm,
  			unsigned long start, unsigned long end)
  {
  	if (!kvm->arch.pgd)
  		return 0;
  
  	trace_kvm_unmap_hva_range(start, end);
  	handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
  	return 0;
  }

  static int kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)

  {
  	pte_t *pte = (pte_t *)data;

  	WARN_ON(size != PAGE_SIZE);

  	/*
  	 * We can always call stage2_set_pte with KVM_S2PTE_FLAG_LOGGING_ACTIVE
  	 * flag clear because MMU notifiers will have unmapped a huge PMD before
  	 * calling ->change_pte() (which in turn calls kvm_set_spte_hva()) and
  	 * therefore stage2_set_pte() never needs to clear out a huge PMD
  	 * through this calling path.
  	 */
  	stage2_set_pte(kvm, NULL, gpa, pte, 0);

  	return 0;

  }
  
  
  void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
  {
  	unsigned long end = hva + PAGE_SIZE;
  	pte_t stage2_pte;
  
  	if (!kvm->arch.pgd)
  		return;
  
  	trace_kvm_set_spte_hva(hva);
  	stage2_pte = pfn_pte(pte_pfn(pte), PAGE_S2);
  	handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte);
  }

  static int kvm_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)

  {
  	pmd_t *pmd;
  	pte_t *pte;

  	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE);

  	pmd = stage2_get_pmd(kvm, NULL, gpa);
  	if (!pmd || pmd_none(*pmd))	/* Nothing there */
  		return 0;

  	if (pmd_thp_or_huge(*pmd))	/* THP, HugeTLB */
  		return stage2_pmdp_test_and_clear_young(pmd);

  
  	pte = pte_offset_kernel(pmd, gpa);
  	if (pte_none(*pte))
  		return 0;

  	return stage2_ptep_test_and_clear_young(pte);

  }

  static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)

  {
  	pmd_t *pmd;
  	pte_t *pte;

  	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE);

  	pmd = stage2_get_pmd(kvm, NULL, gpa);
  	if (!pmd || pmd_none(*pmd))	/* Nothing there */
  		return 0;

  	if (pmd_thp_or_huge(*pmd))		/* THP, HugeTLB */

  		return pmd_young(*pmd);
  
  	pte = pte_offset_kernel(pmd, gpa);
  	if (!pte_none(*pte))		/* Just a page... */
  		return pte_young(*pte);
  
  	return 0;
  }
  
  int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
  {

  	if (!kvm->arch.pgd)
  		return 0;

  	trace_kvm_age_hva(start, end);
  	return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
  }
  
  int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
  {

  	if (!kvm->arch.pgd)
  		return 0;

  	trace_kvm_test_age_hva(hva);
  	return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
  }

  void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
  {
  	mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
  }

  phys_addr_t kvm_mmu_get_httbr(void)
  {

  	if (__kvm_cpu_uses_extended_idmap())
  		return virt_to_phys(merged_hyp_pgd);
  	else
  		return virt_to_phys(hyp_pgd);

  }

  phys_addr_t kvm_get_idmap_vector(void)
  {
  	return hyp_idmap_vector;
  }

  static int kvm_map_idmap_text(pgd_t *pgd)
  {
  	int err;
  
  	/* Create the idmap in the boot page tables */
  	err = 	__create_hyp_mappings(pgd,
  				      hyp_idmap_start, hyp_idmap_end,
  				      __phys_to_pfn(hyp_idmap_start),
  				      PAGE_HYP_EXEC);
  	if (err)
  		kvm_err("Failed to idmap %lx-%lx
  ",
  			hyp_idmap_start, hyp_idmap_end);
  
  	return err;
  }

  int kvm_mmu_init(void)
  {

  	int err;

  	hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start);
  	hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end);
  	hyp_idmap_vector = kvm_virt_to_phys(__kvm_hyp_init);

  	/*
  	 * We rely on the linker script to ensure at build time that the HYP
  	 * init code does not cross a page boundary.
  	 */
  	BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);

  	kvm_debug("IDMAP page: %lx
  ", hyp_idmap_start);
  	kvm_debug("HYP VA range: %lx:%lx
  ",
  		  kern_hyp_va(PAGE_OFFSET), kern_hyp_va(~0UL));

  	if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) &&

  	    hyp_idmap_start <  kern_hyp_va(~0UL) &&
  	    hyp_idmap_start != (unsigned long)__hyp_idmap_text_start) {

  		/*
  		 * The idmap page is intersecting with the VA space,
  		 * it is not safe to continue further.
  		 */
  		kvm_err("IDMAP intersecting with HYP VA, unable to continue
  ");
  		err = -EINVAL;
  		goto out;
  	}

  	hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, hyp_pgd_order);

  	if (!hyp_pgd) {

  		kvm_err("Hyp mode PGD not allocated
  ");

  		err = -ENOMEM;
  		goto out;
  	}

  	if (__kvm_cpu_uses_extended_idmap()) {
  		boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
  							 hyp_pgd_order);
  		if (!boot_hyp_pgd) {
  			kvm_err("Hyp boot PGD not allocated
  ");
  			err = -ENOMEM;
  			goto out;
  		}

  		err = kvm_map_idmap_text(boot_hyp_pgd);
  		if (err)
  			goto out;

  		merged_hyp_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
  		if (!merged_hyp_pgd) {
  			kvm_err("Failed to allocate extra HYP pgd
  ");
  			goto out;
  		}
  		__kvm_extend_hypmap(boot_hyp_pgd, hyp_pgd, merged_hyp_pgd,
  				    hyp_idmap_start);

  	} else {
  		err = kvm_map_idmap_text(hyp_pgd);
  		if (err)
  			goto out;

  	}

  	return 0;

  out:

  	free_hyp_pgds();

  	return err;

  }

  
  void kvm_arch_commit_memory_region(struct kvm *kvm,

  				   const struct kvm_userspace_memory_region *mem,

  				   const struct kvm_memory_slot *old,

  				   const struct kvm_memory_slot *new,

  				   enum kvm_mr_change change)
  {

  	/*
  	 * At this point memslot has been committed and there is an
  	 * allocated dirty_bitmap[], dirty pages will be be tracked while the
  	 * memory slot is write protected.
  	 */
  	if (change != KVM_MR_DELETE && mem->flags & KVM_MEM_LOG_DIRTY_PAGES)
  		kvm_mmu_wp_memory_region(kvm, mem->slot);

  }
  
  int kvm_arch_prepare_memory_region(struct kvm *kvm,
  				   struct kvm_memory_slot *memslot,

  				   const struct kvm_userspace_memory_region *mem,

  				   enum kvm_mr_change change)
  {

  	hva_t hva = mem->userspace_addr;
  	hva_t reg_end = hva + mem->memory_size;
  	bool writable = !(mem->flags & KVM_MEM_READONLY);
  	int ret = 0;

  	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
  			change != KVM_MR_FLAGS_ONLY)

  		return 0;
  
  	/*

  	 * Prevent userspace from creating a memory region outside of the IPA
  	 * space addressable by the KVM guest IPA space.
  	 */
  	if (memslot->base_gfn + memslot->npages >=
  	    (KVM_PHYS_SIZE >> PAGE_SHIFT))
  		return -EFAULT;

  	down_read(&current->mm->mmap_sem);

  	/*

  	 * A memory region could potentially cover multiple VMAs, and any holes
  	 * between them, so iterate over all of them to find out if we can map
  	 * any of them right now.
  	 *
  	 *     +--------------------------------------------+
  	 * +---------------+----------------+   +----------------+
  	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
  	 * +---------------+----------------+   +----------------+
  	 *     |               memory region                |
  	 *     +--------------------------------------------+
  	 */
  	do {
  		struct vm_area_struct *vma = find_vma(current->mm, hva);
  		hva_t vm_start, vm_end;
  
  		if (!vma || vma->vm_start >= reg_end)
  			break;
  
  		/*
  		 * Mapping a read-only VMA is only allowed if the
  		 * memory region is configured as read-only.
  		 */
  		if (writable && !(vma->vm_flags & VM_WRITE)) {
  			ret = -EPERM;
  			break;
  		}
  
  		/*
  		 * Take the intersection of this VMA with the memory region
  		 */
  		vm_start = max(hva, vma->vm_start);
  		vm_end = min(reg_end, vma->vm_end);
  
  		if (vma->vm_flags & VM_PFNMAP) {
  			gpa_t gpa = mem->guest_phys_addr +
  				    (vm_start - mem->userspace_addr);

  			phys_addr_t pa;
  
  			pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
  			pa += vm_start - vma->vm_start;

  			/* IO region dirty page logging not allowed */

  			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {
  				ret = -EINVAL;
  				goto out;
  			}

  			ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
  						    vm_end - vm_start,
  						    writable);
  			if (ret)
  				break;
  		}
  		hva = vm_end;
  	} while (hva < reg_end);

  	if (change == KVM_MR_FLAGS_ONLY)

  		goto out;

  	spin_lock(&kvm->mmu_lock);
  	if (ret)

  		unmap_stage2_range(kvm, mem->guest_phys_addr, mem->memory_size);

  	else
  		stage2_flush_memslot(kvm, memslot);
  	spin_unlock(&kvm->mmu_lock);

  out:
  	up_read(&current->mm->mmap_sem);

  	return ret;

  }
  
  void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
  			   struct kvm_memory_slot *dont)
  {
  }
  
  int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
  			    unsigned long npages)
  {
  	return 0;
  }

  void kvm_arch_memslots_updated(struct kvm *kvm, struct kvm_memslots *slots)

  {
  }
  
  void kvm_arch_flush_shadow_all(struct kvm *kvm)
  {

  	kvm_free_stage2_pgd(kvm);

  }
  
  void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
  				   struct kvm_memory_slot *slot)
  {

  	gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
  	phys_addr_t size = slot->npages << PAGE_SHIFT;
  
  	spin_lock(&kvm->mmu_lock);
  	unmap_stage2_range(kvm, gpa, size);
  	spin_unlock(&kvm->mmu_lock);

  }

  
  /*
   * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
   *
   * Main problems:
   * - S/W ops are local to a CPU (not broadcast)
   * - We have line migration behind our back (speculation)
   * - System caches don't support S/W at all (damn!)
   *
   * In the face of the above, the best we can do is to try and convert
   * S/W ops to VA ops. Because the guest is not allowed to infer the
   * S/W to PA mapping, it can only use S/W to nuke the whole cache,
   * which is a rather good thing for us.
   *
   * Also, it is only used when turning caches on/off ("The expected
   * usage of the cache maintenance instructions that operate by set/way
   * is associated with the cache maintenance instructions associated
   * with the powerdown and powerup of caches, if this is required by
   * the implementation.").
   *
   * We use the following policy:
   *
   * - If we trap a S/W operation, we enable VM trapping to detect
   *   caches being turned on/off, and do a full clean.
   *
   * - We flush the caches on both caches being turned on and off.
   *
   * - Once the caches are enabled, we stop trapping VM ops.
   */
  void kvm_set_way_flush(struct kvm_vcpu *vcpu)
  {
  	unsigned long hcr = vcpu_get_hcr(vcpu);
  
  	/*
  	 * If this is the first time we do a S/W operation
  	 * (i.e. HCR_TVM not set) flush the whole memory, and set the
  	 * VM trapping.
  	 *
  	 * Otherwise, rely on the VM trapping to wait for the MMU +
  	 * Caches to be turned off. At that point, we'll be able to
  	 * clean the caches again.
  	 */
  	if (!(hcr & HCR_TVM)) {
  		trace_kvm_set_way_flush(*vcpu_pc(vcpu),
  					vcpu_has_cache_enabled(vcpu));
  		stage2_flush_vm(vcpu->kvm);
  		vcpu_set_hcr(vcpu, hcr | HCR_TVM);
  	}
  }
  
  void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled)
  {
  	bool now_enabled = vcpu_has_cache_enabled(vcpu);
  
  	/*
  	 * If switching the MMU+caches on, need to invalidate the caches.
  	 * If switching it off, need to clean the caches.
  	 * Clean + invalidate does the trick always.
  	 */
  	if (now_enabled != was_enabled)
  		stage2_flush_vm(vcpu->kvm);
  
  	/* Caches are now on, stop trapping VM ops (until a S/W op) */
  	if (now_enabled)
  		vcpu_set_hcr(vcpu, vcpu_get_hcr(vcpu) & ~HCR_TVM);
  
  	trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled);
  }