KVM: MMU: Add rmap_next(), a helper for walking kvm rmaps

	}

}

static void rmap_write_protect(struct kvm *kvm, u64 gfn)

static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)

{

	struct kvm_rmap_desc *desc;

	struct kvm_rmap_desc *prev_desc;

	u64 *prev_spte;

	int i;

	if (!*rmapp)

		return NULL;

	else if (!(*rmapp & 1)) {

		if (!spte)

			return (u64 *)*rmapp;

		return NULL;

	}

	desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);

	prev_desc = NULL;

	prev_spte = NULL;

	while (desc) {

		for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {

			if (prev_spte == spte)

				return desc->shadow_ptes[i];

			prev_spte = desc->shadow_ptes[i];

		}

		desc = desc->more;

	}

	return NULL;

}

static void rmap_write_protect(struct kvm *kvm, u64 gfn)

{

	unsigned long *rmapp;

	u64 *spte;

	u64 *prev_spte;

	gfn = unalias_gfn(kvm, gfn);

	rmapp = gfn_to_rmap(kvm, gfn);

	while (*rmapp) {

		if (!(*rmapp & 1))

			spte = (u64 *)*rmapp;

		else {

			desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);

			spte = desc->shadow_ptes[0];

		}

	spte = rmap_next(kvm, rmapp, NULL);

	while (spte) {

		BUG_ON(!spte);

		BUG_ON(!(*spte & PT_PRESENT_MASK));

		BUG_ON(!(*spte & PT_WRITABLE_MASK));

		rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);

		rmap_remove(kvm, spte);

		set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);

		prev_spte = spte;

		spte = rmap_next(kvm, rmapp, spte);

		rmap_remove(kvm, prev_spte);

		set_shadow_pte(prev_spte, *prev_spte & ~PT_WRITABLE_MASK);

		kvm_flush_remote_tlbs(kvm);

	}

}