1 files changed, 138 insertions, 95 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 8f8daaeeb3b7..5f8c2321cfb5 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -20,6 +20,7 @@
 #include <asm/pte-walk.h>
 #include <asm/reg.h>
 #include <asm/plpar_wrappers.h>
+#include <asm/firmware.h>
 
 static struct patb_entry *pseries_partition_tb;
 
@@ -31,7 +32,7 @@ void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
 
 	hr->pcr = vc->pcr | PCR_MASK;
-	hr->dpdes = vc->dpdes;
+	hr->dpdes = vcpu->arch.doorbell_request;
 	hr->hfscr = vcpu->arch.hfscr;
 	hr->tb_offset = vc->tb_offset;
 	hr->dawr0 = vcpu->arch.dawr0;
@@ -54,7 +55,7 @@ void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
 	hr->dawrx1 = vcpu->arch.dawrx1;
 }
 
-/* Use noinline_for_stack due to https://bugs.llvm.org/show_bug.cgi?id=49610 */
+/* Use noinline_for_stack due to https://llvm.org/pr49610 */
 static noinline_for_stack void byteswap_pt_regs(struct pt_regs *regs)
 {
 	unsigned long *addr = (unsigned long *) regs;
@@ -104,7 +105,7 @@ static void save_hv_return_state(struct kvm_vcpu *vcpu,
 {
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
 
-	hr->dpdes = vc->dpdes;
+	hr->dpdes = vcpu->arch.doorbell_request;
 	hr->purr = vcpu->arch.purr;
 	hr->spurr = vcpu->arch.spurr;
 	hr->ic = vcpu->arch.ic;
@@ -142,7 +143,7 @@ static void restore_hv_regs(struct kvm_vcpu *vcpu, const struct hv_guest_state *
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
 
 	vc->pcr = hr->pcr | PCR_MASK;
-	vc->dpdes = hr->dpdes;
+	vcpu->arch.doorbell_request = hr->dpdes;
 	vcpu->arch.hfscr = hr->hfscr;
 	vcpu->arch.dawr0 = hr->dawr0;
 	vcpu->arch.dawrx0 = hr->dawrx0;
@@ -169,7 +170,13 @@ void kvmhv_restore_hv_return_state(struct kvm_vcpu *vcpu,
 {
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
 
-	vc->dpdes = hr->dpdes;
+	/*
+	 * This L2 vCPU might have received a doorbell while H_ENTER_NESTED was being handled.
+	 * Make sure we preserve the doorbell if it was either:
+	 *   a) Sent after H_ENTER_NESTED was called on this vCPU (arch.doorbell_request would be 1)
+	 *   b) Doorbell was not handled and L2 exited for some other reason (hr->dpdes would be 1)
+	 */
+	vcpu->arch.doorbell_request = vcpu->arch.doorbell_request | hr->dpdes;
 	vcpu->arch.hfscr = hr->hfscr;
 	vcpu->arch.purr = hr->purr;
 	vcpu->arch.spurr = hr->spurr;
@@ -261,8 +268,7 @@ static void load_l2_hv_regs(struct kvm_vcpu *vcpu,
 	/*
 	 * Don't let L1 change LPCR bits for the L2 except these:
 	 */
-	mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD |
-		LPCR_LPES | LPCR_MER;
+	mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD | LPCR_MER;
 
 	/*
 	 * Additional filtering is required depending on hardware
@@ -306,10 +312,10 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 	/* copy parameters in */
 	hv_ptr = kvmppc_get_gpr(vcpu, 4);
 	regs_ptr = kvmppc_get_gpr(vcpu, 5);
-	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+	kvm_vcpu_srcu_read_lock(vcpu);
 	err = kvmhv_read_guest_state_and_regs(vcpu, &l2_hv, &l2_regs,
 					      hv_ptr, regs_ptr);
-	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+	kvm_vcpu_srcu_read_unlock(vcpu);
 	if (err)
 		return H_PARAMETER;
 
@@ -363,7 +369,7 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 	/* set L1 state to L2 state */
 	vcpu->arch.nested = l2;
 	vcpu->arch.nested_vcpu_id = l2_hv.vcpu_token;
-	l2->hfscr = l2_hv.hfscr;
+	vcpu->arch.nested_hfscr = l2_hv.hfscr;
 	vcpu->arch.regs = l2_regs;
 
 	/* Guest must always run with ME enabled, HV disabled. */
@@ -410,10 +416,10 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 		byteswap_hv_regs(&l2_hv);
 		byteswap_pt_regs(&l2_regs);
 	}
-	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+	kvm_vcpu_srcu_read_lock(vcpu);
 	err = kvmhv_write_guest_state_and_regs(vcpu, &l2_hv, &l2_regs,
 					       hv_ptr, regs_ptr);
-	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+	kvm_vcpu_srcu_read_unlock(vcpu);
 	if (err)
 		return H_AUTHORITY;
 
@@ -428,10 +434,12 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 	return vcpu->arch.trap;
 }
 
+unsigned long nested_capabilities;
+
 long kvmhv_nested_init(void)
 {
 	long int ptb_order;
-	unsigned long ptcr;
+	unsigned long ptcr, host_capabilities;
 	long rc;
 
 	if (!kvmhv_on_pseries())
@@ -439,10 +447,36 @@ long kvmhv_nested_init(void)
 	if (!radix_enabled())
 		return -ENODEV;
 
-	/* find log base 2 of KVMPPC_NR_LPIDS, rounding up */
-	ptb_order = __ilog2(KVMPPC_NR_LPIDS - 1) + 1;
-	if (ptb_order < 8)
-		ptb_order = 8;
+	rc = plpar_guest_get_capabilities(0, &host_capabilities);
+	if (rc == H_SUCCESS) {
+		unsigned long capabilities = 0;
+
+		if (cpu_has_feature(CPU_FTR_P11_PVR))
+			capabilities |= H_GUEST_CAP_POWER11;
+		if (cpu_has_feature(CPU_FTR_ARCH_31))
+			capabilities |= H_GUEST_CAP_POWER10;
+		if (cpu_has_feature(CPU_FTR_ARCH_300))
+			capabilities |= H_GUEST_CAP_POWER9;
+
+		nested_capabilities = capabilities & host_capabilities;
+		rc = plpar_guest_set_capabilities(0, nested_capabilities);
+		if (rc != H_SUCCESS) {
+			pr_err("kvm-hv: Could not configure parent hypervisor capabilities (rc=%ld)",
+			       rc);
+			return -ENODEV;
+		}
+
+		static_branch_enable(&__kvmhv_is_nestedv2);
+		return 0;
+	}
+
+	pr_info("kvm-hv: nestedv2 get capabilities hcall failed, falling back to nestedv1 (rc=%ld)\n",
+		rc);
+	/* Partition table entry is 1<<4 bytes in size, hence the 4. */
+	ptb_order = KVM_MAX_NESTED_GUESTS_SHIFT + 4;
+	/* Minimum partition table size is 1<<12 bytes */
+	if (ptb_order < 12)
+		ptb_order = 12;
 	pseries_partition_tb = kmalloc(sizeof(struct patb_entry) << ptb_order,
 				       GFP_KERNEL);
 	if (!pseries_partition_tb) {
@@ -450,7 +484,7 @@ long kvmhv_nested_init(void)
 		return -ENOMEM;
 	}
 
-	ptcr = __pa(pseries_partition_tb) | (ptb_order - 8);
+	ptcr = __pa(pseries_partition_tb) | (ptb_order - 12);
 	rc = plpar_hcall_norets(H_SET_PARTITION_TABLE, ptcr);
 	if (rc != H_SUCCESS) {
 		pr_err("kvm-hv: Parent hypervisor does not support nesting (rc=%ld)\n",
@@ -477,7 +511,7 @@ void kvmhv_nested_exit(void)
 	}
 }
 
-static void kvmhv_flush_lpid(unsigned int lpid)
+void kvmhv_flush_lpid(u64 lpid)
 {
 	long rc;
 
@@ -499,17 +533,22 @@ static void kvmhv_flush_lpid(unsigned int lpid)
 		pr_err("KVM: TLB LPID invalidation hcall failed, rc=%ld\n", rc);
 }
 
-void kvmhv_set_ptbl_entry(unsigned int lpid, u64 dw0, u64 dw1)
+void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1)
 {
 	if (!kvmhv_on_pseries()) {
 		mmu_partition_table_set_entry(lpid, dw0, dw1, true);
 		return;
 	}
 
-	pseries_partition_tb[lpid].patb0 = cpu_to_be64(dw0);
-	pseries_partition_tb[lpid].patb1 = cpu_to_be64(dw1);
-	/* L0 will do the necessary barriers */
-	kvmhv_flush_lpid(lpid);
+	if (kvmhv_is_nestedv1()) {
+		pseries_partition_tb[lpid].patb0 = cpu_to_be64(dw0);
+		pseries_partition_tb[lpid].patb1 = cpu_to_be64(dw1);
+		/* L0 will do the necessary barriers */
+		kvmhv_flush_lpid(lpid);
+	}
+
+	if (kvmhv_is_nestedv2())
+		kvmhv_nestedv2_set_ptbl_entry(lpid, dw0, dw1);
 }
 
 static void kvmhv_set_nested_ptbl(struct kvm_nested_guest *gp)
@@ -521,11 +560,6 @@ static void kvmhv_set_nested_ptbl(struct kvm_nested_guest *gp)
 	kvmhv_set_ptbl_entry(gp->shadow_lpid, dw0, gp->process_table);
 }
 
-void kvmhv_vm_nested_init(struct kvm *kvm)
-{
-	kvm->arch.max_nested_lpid = -1;
-}
-
 /*
  * Handle the H_SET_PARTITION_TABLE hcall.
  * r4 = guest real address of partition table + log_2(size) - 12
@@ -539,16 +573,14 @@ long kvmhv_set_partition_table(struct kvm_vcpu *vcpu)
 	long ret = H_SUCCESS;
 
 	srcu_idx = srcu_read_lock(&kvm->srcu);
-	/*
-	 * Limit the partition table to 4096 entries (because that's what
-	 * hardware supports), and check the base address.
-	 */
-	if ((ptcr & PRTS_MASK) > 12 - 8 ||
+	/* Check partition size and base address. */
+	if ((ptcr & PRTS_MASK) + 12 - 4 > KVM_MAX_NESTED_GUESTS_SHIFT ||
 	    !kvm_is_visible_gfn(vcpu->kvm, (ptcr & PRTB_MASK) >> PAGE_SHIFT))
 		ret = H_PARAMETER;
 	srcu_read_unlock(&kvm->srcu, srcu_idx);
 	if (ret == H_SUCCESS)
 		kvm->arch.l1_ptcr = ptcr;
+
 	return ret;
 }
 
@@ -600,16 +632,16 @@ long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu)
 			goto not_found;
 
 		/* Write what was loaded into our buffer back to the L1 guest */
-		vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+		kvm_vcpu_srcu_read_lock(vcpu);
 		rc = kvm_vcpu_write_guest(vcpu, gp_to, buf, n);
-		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+		kvm_vcpu_srcu_read_unlock(vcpu);
 		if (rc)
 			goto not_found;
 	} else {
 		/* Load the data to be stored from the L1 guest into our buf */
-		vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+		kvm_vcpu_srcu_read_lock(vcpu);
 		rc = kvm_vcpu_read_guest(vcpu, gp_from, buf, n);
-		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+		kvm_vcpu_srcu_read_unlock(vcpu);
 		if (rc)
 			goto not_found;
 
@@ -644,7 +676,7 @@ static void kvmhv_update_ptbl_cache(struct kvm_nested_guest *gp)
 
 	ret = -EFAULT;
 	ptbl_addr = (kvm->arch.l1_ptcr & PRTB_MASK) + (gp->l1_lpid << 4);
-	if (gp->l1_lpid < (1ul << ((kvm->arch.l1_ptcr & PRTS_MASK) + 8))) {
+	if (gp->l1_lpid < (1ul << ((kvm->arch.l1_ptcr & PRTS_MASK) + 12 - 4))) {
 		int srcu_idx = srcu_read_lock(&kvm->srcu);
 		ret = kvm_read_guest(kvm, ptbl_addr,
 				     &ptbl_entry, sizeof(ptbl_entry));
@@ -660,6 +692,35 @@ static void kvmhv_update_ptbl_cache(struct kvm_nested_guest *gp)
 	kvmhv_set_nested_ptbl(gp);
 }
 
+void kvmhv_vm_nested_init(struct kvm *kvm)
+{
+	idr_init(&kvm->arch.kvm_nested_guest_idr);
+}
+
+static struct kvm_nested_guest *__find_nested(struct kvm *kvm, int lpid)
+{
+	return idr_find(&kvm->arch.kvm_nested_guest_idr, lpid);
+}
+
+static bool __prealloc_nested(struct kvm *kvm, int lpid)
+{
+	if (idr_alloc(&kvm->arch.kvm_nested_guest_idr,
+				NULL, lpid, lpid + 1, GFP_KERNEL) != lpid)
+		return false;
+	return true;
+}
+
+static void __add_nested(struct kvm *kvm, int lpid, struct kvm_nested_guest *gp)
+{
+	if (idr_replace(&kvm->arch.kvm_nested_guest_idr, gp, lpid))
+		WARN_ON(1);
+}
+
+static void __remove_nested(struct kvm *kvm, int lpid)
+{
+	idr_remove(&kvm->arch.kvm_nested_guest_idr, lpid);
+}
+
 static struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int lpid)
 {
 	struct kvm_nested_guest *gp;
@@ -720,13 +781,8 @@ static void kvmhv_remove_nested(struct kvm_nested_guest *gp)
 	long ref;
 
 	spin_lock(&kvm->mmu_lock);
-	if (gp == kvm->arch.nested_guests[lpid]) {
-		kvm->arch.nested_guests[lpid] = NULL;
-		if (lpid == kvm->arch.max_nested_lpid) {
-			while (--lpid >= 0 && !kvm->arch.nested_guests[lpid])
-				;
-			kvm->arch.max_nested_lpid = lpid;
-		}
+	if (gp == __find_nested(kvm, lpid)) {
+		__remove_nested(kvm, lpid);
 		--gp->refcnt;
 	}
 	ref = gp->refcnt;
@@ -743,24 +799,22 @@ static void kvmhv_remove_nested(struct kvm_nested_guest *gp)
  */
 void kvmhv_release_all_nested(struct kvm *kvm)
 {
-	int i;
+	int lpid;
 	struct kvm_nested_guest *gp;
 	struct kvm_nested_guest *freelist = NULL;
 	struct kvm_memory_slot *memslot;
 	int srcu_idx, bkt;
 
 	spin_lock(&kvm->mmu_lock);
-	for (i = 0; i <= kvm->arch.max_nested_lpid; i++) {
-		gp = kvm->arch.nested_guests[i];
-		if (!gp)
-			continue;
-		kvm->arch.nested_guests[i] = NULL;
+	idr_for_each_entry(&kvm->arch.kvm_nested_guest_idr, gp, lpid) {
+		__remove_nested(kvm, lpid);
 		if (--gp->refcnt == 0) {
 			gp->next = freelist;
 			freelist = gp;
 		}
 	}
-	kvm->arch.max_nested_lpid = -1;
+	idr_destroy(&kvm->arch.kvm_nested_guest_idr);
+	/* idr is empty and may be reused at this point */
 	spin_unlock(&kvm->mmu_lock);
 	while ((gp = freelist) != NULL) {
 		freelist = gp->next;
@@ -792,12 +846,11 @@ struct kvm_nested_guest *kvmhv_get_nested(struct kvm *kvm, int l1_lpid,
 {
 	struct kvm_nested_guest *gp, *newgp;
 
-	if (l1_lpid >= KVM_MAX_NESTED_GUESTS ||
-	    l1_lpid >= (1ul << ((kvm->arch.l1_ptcr & PRTS_MASK) + 12 - 4)))
+	if (l1_lpid >= (1ul << ((kvm->arch.l1_ptcr & PRTS_MASK) + 12 - 4)))
 		return NULL;
 
 	spin_lock(&kvm->mmu_lock);
-	gp = kvm->arch.nested_guests[l1_lpid];
+	gp = __find_nested(kvm, l1_lpid);
 	if (gp)
 		++gp->refcnt;
 	spin_unlock(&kvm->mmu_lock);
@@ -808,17 +861,19 @@ struct kvm_nested_guest *kvmhv_get_nested(struct kvm *kvm, int l1_lpid,
 	newgp = kvmhv_alloc_nested(kvm, l1_lpid);
 	if (!newgp)
 		return NULL;
+
+	if (!__prealloc_nested(kvm, l1_lpid)) {
+		kvmhv_release_nested(newgp);
+		return NULL;
+	}
+
 	spin_lock(&kvm->mmu_lock);
-	if (kvm->arch.nested_guests[l1_lpid]) {
-		/* someone else beat us to it */
-		gp = kvm->arch.nested_guests[l1_lpid];
-	} else {
-		kvm->arch.nested_guests[l1_lpid] = newgp;
+	gp = __find_nested(kvm, l1_lpid);
+	if (!gp) {
+		__add_nested(kvm, l1_lpid, newgp);
 		++newgp->refcnt;
 		gp = newgp;
 		newgp = NULL;
-		if (l1_lpid > kvm->arch.max_nested_lpid)
-			kvm->arch.max_nested_lpid = l1_lpid;
 	}
 	++gp->refcnt;
 	spin_unlock(&kvm->mmu_lock);
@@ -841,20 +896,13 @@ void kvmhv_put_nested(struct kvm_nested_guest *gp)
 		kvmhv_release_nested(gp);
 }
 
-static struct kvm_nested_guest *kvmhv_find_nested(struct kvm *kvm, int lpid)
-{
-	if (lpid > kvm->arch.max_nested_lpid)
-		return NULL;
-	return kvm->arch.nested_guests[lpid];
-}
-
 pte_t *find_kvm_nested_guest_pte(struct kvm *kvm, unsigned long lpid,
 				 unsigned long ea, unsigned *hshift)
 {
 	struct kvm_nested_guest *gp;
 	pte_t *pte;
 
-	gp = kvmhv_find_nested(kvm, lpid);
+	gp = __find_nested(kvm, lpid);
 	if (!gp)
 		return NULL;
 
@@ -960,7 +1008,7 @@ static void kvmhv_remove_nest_rmap(struct kvm *kvm, u64 n_rmap,
 
 	gpa = n_rmap & RMAP_NESTED_GPA_MASK;
 	lpid = (n_rmap & RMAP_NESTED_LPID_MASK) >> RMAP_NESTED_LPID_SHIFT;
-	gp = kvmhv_find_nested(kvm, lpid);
+	gp = __find_nested(kvm, lpid);
 	if (!gp)
 		return;
 
@@ -1152,16 +1200,13 @@ static void kvmhv_emulate_tlbie_all_lpid(struct kvm_vcpu *vcpu, int ric)
 {
 	struct kvm *kvm = vcpu->kvm;
 	struct kvm_nested_guest *gp;
-	int i;
+	int lpid;
 
 	spin_lock(&kvm->mmu_lock);
-	for (i = 0; i <= kvm->arch.max_nested_lpid; i++) {
-		gp = kvm->arch.nested_guests[i];
-		if (gp) {
-			spin_unlock(&kvm->mmu_lock);
-			kvmhv_emulate_tlbie_lpid(vcpu, gp, ric);
-			spin_lock(&kvm->mmu_lock);
-		}
+	idr_for_each_entry(&kvm->arch.kvm_nested_guest_idr, gp, lpid) {
+		spin_unlock(&kvm->mmu_lock);
+		kvmhv_emulate_tlbie_lpid(vcpu, gp, ric);
+		spin_lock(&kvm->mmu_lock);
 	}
 	spin_unlock(&kvm->mmu_lock);
 }
@@ -1313,7 +1358,7 @@ long do_h_rpt_invalidate_pat(struct kvm_vcpu *vcpu, unsigned long lpid,
 	 * H_ENTER_NESTED call. Since we can't differentiate this case from
 	 * the invalid case, we ignore such flush requests and return success.
 	 */
-	if (!kvmhv_find_nested(vcpu->kvm, lpid))
+	if (!__find_nested(vcpu->kvm, lpid))
 		return H_SUCCESS;
 
 	/*
@@ -1490,7 +1535,6 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu *vcpu,
 	unsigned long n_gpa, gpa, gfn, perm = 0UL;
 	unsigned int shift, l1_shift, level;
 	bool writing = !!(dsisr & DSISR_ISSTORE);
-	bool kvm_ro = false;
 	long int ret;
 
 	if (!gp->l1_gr_to_hr) {
@@ -1553,7 +1597,9 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu *vcpu,
 	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
 		if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS)) {
 			/* unusual error -> reflect to the guest as a DSI */
-			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
+			kvmppc_core_queue_data_storage(vcpu,
+					kvmppc_get_msr(vcpu) & SRR1_PREFIXED,
+					ea, dsisr);
 			return RESUME_GUEST;
 		}
 
@@ -1563,17 +1609,17 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu *vcpu,
 	if (memslot->flags & KVM_MEM_READONLY) {
 		if (writing) {
 			/* Give the guest a DSI */
-			kvmppc_core_queue_data_storage(vcpu, ea,
-					DSISR_ISSTORE | DSISR_PROTFAULT);
+			kvmppc_core_queue_data_storage(vcpu,
+					kvmppc_get_msr(vcpu) & SRR1_PREFIXED,
+					ea, DSISR_ISSTORE | DSISR_PROTFAULT);
 			return RESUME_GUEST;
 		}
-		kvm_ro = true;
 	}
 
 	/* 2. Find the host pte for this L1 guest real address */
 
 	/* Used to check for invalidations in progress */
-	mmu_seq = kvm->mmu_notifier_seq;
+	mmu_seq = kvm->mmu_invalidate_seq;
 	smp_rmb();
 
 	/* See if can find translation in our partition scoped tables for L1 */
@@ -1589,7 +1635,7 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu *vcpu,
 	if (!pte_present(pte) || (writing && !(pte_val(pte) & _PAGE_WRITE))) {
 		/* No suitable pte found -> try to insert a mapping */
 		ret = kvmppc_book3s_instantiate_page(vcpu, gpa, memslot,
-					writing, kvm_ro, &pte, &level);
+					writing, &pte, &level);
 		if (ret == -EAGAIN)
 			return RESUME_GUEST;
 		else if (ret)
@@ -1657,15 +1703,12 @@ long int kvmhv_nested_page_fault(struct kvm_vcpu *vcpu)
 
 int kvmhv_nested_next_lpid(struct kvm *kvm, int lpid)
 {
-	int ret = -1;
+	int ret = lpid + 1;
 
 	spin_lock(&kvm->mmu_lock);
-	while (++lpid <= kvm->arch.max_nested_lpid) {
-		if (kvm->arch.nested_guests[lpid]) {
-			ret = lpid;
-			break;
-		}
-	}
+	if (!idr_get_next(&kvm->arch.kvm_nested_guest_idr, &ret))
+		ret = -1;
 	spin_unlock(&kvm->mmu_lock);
+
 	return ret;
 }