diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 7576e0e..fb8e508 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -252,6 +252,8 @@ struct kvm_hpt_info {
 	int cma;
 };
 
+struct kvm_resize_hpt;
+
 struct kvm_arch {
 	unsigned int lpid;
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
@@ -272,6 +274,7 @@ struct kvm_arch {
 	cpumask_t need_tlb_flush;
 	struct dentry *debugfs_dir;
 	struct dentry *htab_dentry;
+	struct kvm_resize_hpt *resize_hpt; /* protected by kvm->lock */
 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
 	struct mutex hpt_mutex;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 3b837bc..f8eaed0 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -215,6 +215,10 @@ extern void kvmppc_bookehv_exit(void);
 extern int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu);
 
 extern int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *);
+extern long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm,
+					    struct kvm_ppc_resize_hpt *rhpt);
+extern long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm,
+					   struct kvm_ppc_resize_hpt *rhpt);
 
 int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq);
 
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 74e909a..86a1bcb 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -40,9 +40,34 @@
 
 #include "trace_hv.h"
 
+//#define DEBUG_RESIZE_HPT	1
+
+#ifdef DEBUG_RESIZE_HPT
+#define resize_hpt_debug(resize, ...)				\
+	do {							\
+		printk(KERN_DEBUG "RESIZE HPT %p: ", resize);	\
+		printk(__VA_ARGS__);				\
+	} while (0)
+#else
+#define resize_hpt_debug(resize, ...)				\
+	do { } while (0)
+#endif
+
 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);
+
+struct kvm_resize_hpt {
+	/* These fields read-only after init */
+	struct kvm *kvm;
+	struct work_struct work;
+	u32 order;
+
+	/* These fields protected by kvm->lock */
+	int error;
+	bool prepare_done;
+};
+
 static void kvmppc_rmap_reset(struct kvm *kvm);
 
 int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order)
@@ -1158,6 +1183,172 @@ void kvmppc_unpin_guest_page(struct kvm *kvm, void *va, unsigned long gpa,
 }
 
 /*
+ * HPT resizing
+ */
+static int resize_hpt_allocate(struct kvm_resize_hpt *resize)
+{
+	return 0;
+}
+
+static int resize_hpt_rehash(struct kvm_resize_hpt *resize)
+{
+	return -EIO;
+}
+
+static void resize_hpt_pivot(struct kvm_resize_hpt *resize)
+{
+}
+
+static void resize_hpt_release(struct kvm *kvm, struct kvm_resize_hpt *resize)
+{
+	BUG_ON(kvm->arch.resize_hpt != resize);
+	kvm->arch.resize_hpt = NULL;
+	kfree(resize);
+}
+
+static void resize_hpt_prepare_work(struct work_struct *work)
+{
+	struct kvm_resize_hpt *resize = container_of(work,
+						     struct kvm_resize_hpt,
+						     work);
+	struct kvm *kvm = resize->kvm;
+	int err;
+
+	resize_hpt_debug(resize, "resize_hpt_prepare_work(): order = %d\n",
+			 resize->order);
+
+	err = resize_hpt_allocate(resize);
+
+	mutex_lock(&kvm->lock);
+
+	resize->error = err;
+	resize->prepare_done = true;
+
+	mutex_unlock(&kvm->lock);
+}
+
+long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm,
+				     struct kvm_ppc_resize_hpt *rhpt)
+{
+	unsigned long flags = rhpt->flags;
+	unsigned long shift = rhpt->shift;
+	struct kvm_resize_hpt *resize;
+	int ret;
+
+	if (flags != 0)
+		return -EINVAL;
+
+	if (shift && ((shift < 18) || (shift > 46)))
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+
+	resize = kvm->arch.resize_hpt;
+
+	if (resize) {
+		if (resize->order == shift) {
+			/* Suitable resize in progress */
+			if (resize->prepare_done) {
+				ret = resize->error;
+				if (ret != 0)
+					resize_hpt_release(kvm, resize);
+			} else {
+				ret = 100; /* estimated time in ms */
+			}
+
+			goto out;
+		}
+
+		/* not suitable, cancel it */
+		resize_hpt_release(kvm, resize);
+	}
+
+	ret = 0;
+	if (!shift)
+		goto out; /* nothing to do */
+
+	/* start new resize */
+
+	resize = kzalloc(sizeof(*resize), GFP_KERNEL);
+	resize->order = shift;
+	resize->kvm = kvm;
+	INIT_WORK(&resize->work, resize_hpt_prepare_work);
+	kvm->arch.resize_hpt = resize;
+
+	schedule_work(&resize->work);
+
+	ret = 100; /* estimated time in ms */
+
+out:
+	mutex_unlock(&kvm->lock);
+	return ret;
+}
+
+static void resize_hpt_boot_vcpu(void *opaque)
+{
+	/* Nothing to do, just force a KVM exit */
+}
+
+long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm,
+				    struct kvm_ppc_resize_hpt *rhpt)
+{
+	unsigned long flags = rhpt->flags;
+	unsigned long shift = rhpt->shift;
+	struct kvm_resize_hpt *resize;
+	long ret;
+
+	if (flags != 0)
+		return -EINVAL;
+
+	if (shift && ((shift < 18) || (shift > 46)))
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+
+	resize = kvm->arch.resize_hpt;
+
+	/* This shouldn't be possible */
+	ret = -EIO;
+	if (WARN_ON(!kvm->arch.hpte_setup_done))
+		goto out_no_hpt;
+
+	/* Stop VCPUs from running while we mess with the HPT */
+	kvm->arch.hpte_setup_done = 0;
+	smp_mb();
+
+	/* Boot all CPUs out of the guest so they re-read
+	 * hpte_setup_done */
+	on_each_cpu(resize_hpt_boot_vcpu, NULL, 1);
+
+	ret = -ENXIO;
+	if (!resize || (resize->order != shift))
+		goto out;
+
+	ret = -EBUSY;
+	if (!resize->prepare_done)
+		goto out;
+
+	ret = resize->error;
+	if (ret != 0)
+		goto out;
+
+	ret = resize_hpt_rehash(resize);
+	if (ret != 0)
+		goto out;
+
+	resize_hpt_pivot(resize);
+
+out:
+	/* Let VCPUs run again */
+	kvm->arch.hpte_setup_done = 1;
+	smp_mb();
+out_no_hpt:
+	resize_hpt_release(kvm, resize);
+	mutex_unlock(&kvm->lock);
+	return ret;
+}
+
+/*
  * Functions for reading and writing the hash table via reads and
  * writes on a file descriptor.
  *
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 9ebb9e6..7fd1dba 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3323,6 +3323,9 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
 
 	kvm->arch.lpcr = lpcr;
 
+	/* Initialization for future HPT resizes */
+	kvm->arch.resize_hpt = NULL;
+
 	/*
 	 * Work out how many sets the TLB has, for the use of
 	 * the TLB invalidation loop in book3s_hv_rmhandlers.S.
@@ -3617,6 +3620,28 @@ static long kvm_arch_vm_ioctl_hv(struct file *filp,
 		break;
 	}
 
+	case KVM_PPC_RESIZE_HPT_PREPARE: {
+		struct kvm_ppc_resize_hpt rhpt;
+
+		r = -EFAULT;
+		if (copy_from_user(&rhpt, argp, sizeof(rhpt)))
+			break;
+
+		r = kvm_vm_ioctl_resize_hpt_prepare(kvm, &rhpt);
+		break;
+	}
+
+	case KVM_PPC_RESIZE_HPT_COMMIT: {
+		struct kvm_ppc_resize_hpt rhpt;
+
+		r = -EFAULT;
+		if (copy_from_user(&rhpt, argp, sizeof(rhpt)))
+			break;
+
+		r = kvm_vm_ioctl_resize_hpt_commit(kvm, &rhpt);
+		break;
+	}
+
 	default:
 		r = -ENOTTY;
 	}
