3 files changed, 423 insertions, 49 deletions

diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 1c37ccd5d402..62b39149b8c8 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -63,3 +63,6 @@ config HAVE_KVM_NO_POLL
 
 config KVM_XFER_TO_GUEST_WORK
        bool
+
+config HAVE_KVM_PM_NOTIFIER
+       bool
diff --git a/virt/kvm/binary_stats.c b/virt/kvm/binary_stats.c
new file mode 100644
index 000000000000..e609d428811a
--- /dev/null
+++ b/virt/kvm/binary_stats.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KVM binary statistics interface implementation
+ *
+ * Copyright 2021 Google LLC
+ */
+
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+#include <linux/errno.h>
+#include <linux/uaccess.h>
+
+/**
+ * kvm_stats_read() - Common function to read from the binary statistics
+ * file descriptor.
+ *
+ * @id: identification string of the stats
+ * @header: stats header for a vm or a vcpu
+ * @desc: start address of an array of stats descriptors for a vm or a vcpu
+ * @stats: start address of stats data block for a vm or a vcpu
+ * @size_stats: the size of stats data block pointed by @stats
+ * @user_buffer: start address of userspace buffer
+ * @size: requested read size from userspace
+ * @offset: the start position from which the content will be read for the
+ *          corresponding vm or vcp file descriptor
+ *
+ * The file content of a vm/vcpu file descriptor is now defined as below:
+ * +-------------+
+ * |   Header    |
+ * +-------------+
+ * |  id string  |
+ * +-------------+
+ * | Descriptors |
+ * +-------------+
+ * | Stats Data  |
+ * +-------------+
+ * Although this function allows userspace to read any amount of data (as long
+ * as in the limit) from any position, the typical usage would follow below
+ * steps:
+ * 1. Read header from offset 0. Get the offset of descriptors and stats data
+ *    and some other necessary information. This is a one-time work for the
+ *    lifecycle of the corresponding vm/vcpu stats fd.
+ * 2. Read id string from its offset. This is a one-time work for the lifecycle
+ *    of the corresponding vm/vcpu stats fd.
+ * 3. Read descriptors from its offset and discover all the stats by parsing
+ *    descriptors. This is a one-time work for the lifecycle of the
+ *    corresponding vm/vcpu stats fd.
+ * 4. Periodically read stats data from its offset using pread.
+ *
+ * Return: the number of bytes that has been successfully read
+ */
+ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header,
+		       const struct _kvm_stats_desc *desc,
+		       void *stats, size_t size_stats,
+		       char __user *user_buffer, size_t size, loff_t *offset)
+{
+	ssize_t len;
+	ssize_t copylen;
+	ssize_t remain = size;
+	size_t size_desc;
+	size_t size_header;
+	void *src;
+	loff_t pos = *offset;
+	char __user *dest = user_buffer;
+
+	size_header = sizeof(*header);
+	size_desc = header->num_desc * sizeof(*desc);
+
+	len = KVM_STATS_NAME_SIZE + size_header + size_desc + size_stats - pos;
+	len = min(len, remain);
+	if (len <= 0)
+		return 0;
+	remain = len;
+
+	/*
+	 * Copy kvm stats header.
+	 * The header is the first block of content userspace usually read out.
+	 * The pos is 0 and the copylen and remain would be the size of header.
+	 * The copy of the header would be skipped if offset is larger than the
+	 * size of header. That usually happens when userspace reads stats
+	 * descriptors and stats data.
+	 */
+	copylen = size_header - pos;
+	copylen = min(copylen, remain);
+	if (copylen > 0) {
+		src = (void *)header + pos;
+		if (copy_to_user(dest, src, copylen))
+			return -EFAULT;
+		remain -= copylen;
+		pos += copylen;
+		dest += copylen;
+	}
+
+	/*
+	 * Copy kvm stats header id string.
+	 * The id string is unique for every vm/vcpu, which is stored in kvm
+	 * and kvm_vcpu structure.
+	 * The id string is part of the stat header from the perspective of
+	 * userspace, it is usually read out together with previous constant
+	 * header part and could be skipped for later descriptors and stats
+	 * data readings.
+	 */
+	copylen = header->id_offset + KVM_STATS_NAME_SIZE - pos;
+	copylen = min(copylen, remain);
+	if (copylen > 0) {
+		src = id + pos - header->id_offset;
+		if (copy_to_user(dest, src, copylen))
+			return -EFAULT;
+		remain -= copylen;
+		pos += copylen;
+		dest += copylen;
+	}
+
+	/*
+	 * Copy kvm stats descriptors.
+	 * The descriptors copy would be skipped in the typical case that
+	 * userspace periodically read stats data, since the pos would be
+	 * greater than the end address of descriptors
+	 * (header->header.desc_offset + size_desc) causing copylen <= 0.
+	 */
+	copylen = header->desc_offset + size_desc - pos;
+	copylen = min(copylen, remain);
+	if (copylen > 0) {
+		src = (void *)desc + pos - header->desc_offset;
+		if (copy_to_user(dest, src, copylen))
+			return -EFAULT;
+		remain -= copylen;
+		pos += copylen;
+		dest += copylen;
+	}
+
+	/* Copy kvm stats values */
+	copylen = header->data_offset + size_stats - pos;
+	copylen = min(copylen, remain);
+	if (copylen > 0) {
+		src = stats + pos - header->data_offset;
+		if (copy_to_user(dest, src, copylen))
+			return -EFAULT;
+		remain -= copylen;
+		pos += copylen;
+		dest += copylen;
+	}
+
+	*offset = pos;
+	return len;
+}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 46fb042837d2..f7445c3bcd90 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -51,6 +51,7 @@
 #include <linux/io.h>
 #include <linux/lockdep.h>
 #include <linux/kthread.h>
+#include <linux/suspend.h>
 
 #include <asm/processor.h>
 #include <asm/ioctl.h>
@@ -114,7 +115,6 @@ static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
 struct dentry *kvm_debugfs_dir;
 EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
 
-static int kvm_debugfs_num_entries;
 static const struct file_operations stat_fops_per_vm;
 
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
@@ -331,7 +331,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
 	 */
 	if (!kvm_arch_flush_remote_tlb(kvm)
 	    || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
-		++kvm->stat.remote_tlb_flush;
+		++kvm->stat.generic.remote_tlb_flush;
 	cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
@@ -780,6 +780,38 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
 
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
+#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
+static int kvm_pm_notifier_call(struct notifier_block *bl,
+				unsigned long state,
+				void *unused)
+{
+	struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
+
+	return kvm_arch_pm_notifier(kvm, state);
+}
+
+static void kvm_init_pm_notifier(struct kvm *kvm)
+{
+	kvm->pm_notifier.notifier_call = kvm_pm_notifier_call;
+	/* Suspend KVM before we suspend ftrace, RCU, etc. */
+	kvm->pm_notifier.priority = INT_MAX;
+	register_pm_notifier(&kvm->pm_notifier);
+}
+
+static void kvm_destroy_pm_notifier(struct kvm *kvm)
+{
+	unregister_pm_notifier(&kvm->pm_notifier);
+}
+#else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */
+static void kvm_init_pm_notifier(struct kvm *kvm)
+{
+}
+
+static void kvm_destroy_pm_notifier(struct kvm *kvm)
+{
+}
+#endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
+
 static struct kvm_memslots *kvm_alloc_memslots(void)
 {
 	int i;
@@ -827,9 +859,24 @@ static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
 	kvfree(slots);
 }
 
+static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc)
+{
+	switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) {
+	case KVM_STATS_TYPE_INSTANT:
+		return 0444;
+	case KVM_STATS_TYPE_CUMULATIVE:
+	case KVM_STATS_TYPE_PEAK:
+	default:
+		return 0644;
+	}
+}
+
+
 static void kvm_destroy_vm_debugfs(struct kvm *kvm)
 {
 	int i;
+	int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
+				      kvm_vcpu_stats_header.num_desc;
 
 	if (!kvm->debugfs_dentry)
 		return;
@@ -847,7 +894,10 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 {
 	char dir_name[ITOA_MAX_LEN * 2];
 	struct kvm_stat_data *stat_data;
-	struct kvm_stats_debugfs_item *p;
+	const struct _kvm_stats_desc *pdesc;
+	int i;
+	int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
+				      kvm_vcpu_stats_header.num_desc;
 
 	if (!debugfs_initialized())
 		return 0;
@@ -861,15 +911,32 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 	if (!kvm->debugfs_stat_data)
 		return -ENOMEM;
 
-	for (p = debugfs_entries; p->name; p++) {
+	for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
+		pdesc = &kvm_vm_stats_desc[i];
+		stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
+		if (!stat_data)
+			return -ENOMEM;
+
+		stat_data->kvm = kvm;
+		stat_data->desc = pdesc;
+		stat_data->kind = KVM_STAT_VM;
+		kvm->debugfs_stat_data[i] = stat_data;
+		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
+				    kvm->debugfs_dentry, stat_data,
+				    &stat_fops_per_vm);
+	}
+
+	for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
+		pdesc = &kvm_vcpu_stats_desc[i];
 		stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
 		if (!stat_data)
 			return -ENOMEM;
 
 		stat_data->kvm = kvm;
-		stat_data->dbgfs_item = p;
-		kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
-		debugfs_create_file(p->name, KVM_DBGFS_GET_MODE(p),
+		stat_data->desc = pdesc;
+		stat_data->kind = KVM_STAT_VCPU;
+		kvm->debugfs_stat_data[i] = stat_data;
+		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
 				    kvm->debugfs_dentry, stat_data,
 				    &stat_fops_per_vm);
 	}
@@ -909,6 +976,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
 	mutex_init(&kvm->lock);
 	mutex_init(&kvm->irq_lock);
 	mutex_init(&kvm->slots_lock);
+	mutex_init(&kvm->slots_arch_lock);
 	INIT_LIST_HEAD(&kvm->devices);
 
 	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
@@ -963,6 +1031,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
 	mutex_unlock(&kvm_lock);
 
 	preempt_notifier_inc();
+	kvm_init_pm_notifier(kvm);
 
 	return kvm;
 
@@ -1010,6 +1079,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 	int i;
 	struct mm_struct *mm = kvm->mm;
 
+	kvm_destroy_pm_notifier(kvm);
 	kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
 	kvm_destroy_vm_debugfs(kvm);
 	kvm_arch_sync_events(kvm);
@@ -1281,6 +1351,14 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
 	slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
 
 	rcu_assign_pointer(kvm->memslots[as_id], slots);
+
+	/*
+	 * Acquired in kvm_set_memslot. Must be released before synchronize
+	 * SRCU below in order to avoid deadlock with another thread
+	 * acquiring the slots_arch_lock in an srcu critical section.
+	 */
+	mutex_unlock(&kvm->slots_arch_lock);
+
 	synchronize_srcu_expedited(&kvm->srcu);
 
 	/*
@@ -1307,6 +1385,18 @@ static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
 	return old_memslots;
 }
 
+static size_t kvm_memslots_size(int slots)
+{
+	return sizeof(struct kvm_memslots) +
+	       (sizeof(struct kvm_memory_slot) * slots);
+}
+
+static void kvm_copy_memslots(struct kvm_memslots *to,
+			      struct kvm_memslots *from)
+{
+	memcpy(to, from, kvm_memslots_size(from->used_slots));
+}
+
 /*
  * Note, at a minimum, the current number of used slots must be allocated, even
  * when deleting a memslot, as we need a complete duplicate of the memslots for
@@ -1316,19 +1406,16 @@ static struct kvm_memslots *kvm_dup_memslots(struct kvm_memslots *old,
 					     enum kvm_mr_change change)
 {
 	struct kvm_memslots *slots;
-	size_t old_size, new_size;
-
-	old_size = sizeof(struct kvm_memslots) +
-		   (sizeof(struct kvm_memory_slot) * old->used_slots);
+	size_t new_size;
 
 	if (change == KVM_MR_CREATE)
-		new_size = old_size + sizeof(struct kvm_memory_slot);
+		new_size = kvm_memslots_size(old->used_slots + 1);
 	else
-		new_size = old_size;
+		new_size = kvm_memslots_size(old->used_slots);
 
 	slots = kvzalloc(new_size, GFP_KERNEL_ACCOUNT);
 	if (likely(slots))
-		memcpy(slots, old, old_size);
+		kvm_copy_memslots(slots, old);
 
 	return slots;
 }
@@ -1343,9 +1430,27 @@ static int kvm_set_memslot(struct kvm *kvm,
 	struct kvm_memslots *slots;
 	int r;
 
+	/*
+	 * Released in install_new_memslots.
+	 *
+	 * Must be held from before the current memslots are copied until
+	 * after the new memslots are installed with rcu_assign_pointer,
+	 * then released before the synchronize srcu in install_new_memslots.
+	 *
+	 * When modifying memslots outside of the slots_lock, must be held
+	 * before reading the pointer to the current memslots until after all
+	 * changes to those memslots are complete.
+	 *
+	 * These rules ensure that installing new memslots does not lose
+	 * changes made to the previous memslots.
+	 */
+	mutex_lock(&kvm->slots_arch_lock);
+
 	slots = kvm_dup_memslots(__kvm_memslots(kvm, as_id), change);
-	if (!slots)
+	if (!slots) {
+		mutex_unlock(&kvm->slots_arch_lock);
 		return -ENOMEM;
+	}
 
 	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
 		/*
@@ -1356,10 +1461,9 @@ static int kvm_set_memslot(struct kvm *kvm,
 		slot->flags |= KVM_MEMSLOT_INVALID;
 
 		/*
-		 * We can re-use the old memslots, the only difference from the
-		 * newly installed memslots is the invalid flag, which will get
-		 * dropped by update_memslots anyway.  We'll also revert to the
-		 * old memslots if preparing the new memory region fails.
+		 * We can re-use the memory from the old memslots.
+		 * It will be overwritten with a copy of the new memslots
+		 * after reacquiring the slots_arch_lock below.
 		 */
 		slots = install_new_memslots(kvm, as_id, slots);
 
@@ -1371,6 +1475,17 @@ static int kvm_set_memslot(struct kvm *kvm,
 		 *	- kvm_is_visible_gfn (mmu_check_root)
 		 */
 		kvm_arch_flush_shadow_memslot(kvm, slot);
+
+		/* Released in install_new_memslots. */
+		mutex_lock(&kvm->slots_arch_lock);
+
+		/*
+		 * The arch-specific fields of the memslots could have changed
+		 * between releasing the slots_arch_lock in
+		 * install_new_memslots and here, so get a fresh copy of the
+		 * slots.
+		 */
+		kvm_copy_memslots(slots, __kvm_memslots(kvm, as_id));
 	}
 
 	r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
@@ -1386,8 +1501,13 @@ static int kvm_set_memslot(struct kvm *kvm,
 	return 0;
 
 out_slots:
-	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
+	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
+		slot = id_to_memslot(slots, old->id);
+		slot->flags &= ~KVM_MEMSLOT_INVALID;
 		slots = install_new_memslots(kvm, as_id, slots);
+	} else {
+		mutex_unlock(&kvm->slots_arch_lock);
+	}
 	kvfree(slots);
 	return r;
 }
@@ -2958,9 +3078,9 @@ static inline void
 update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited)
 {
 	if (waited)
-		vcpu->stat.halt_poll_fail_ns += poll_ns;
+		vcpu->stat.generic.halt_poll_fail_ns += poll_ns;
 	else
-		vcpu->stat.halt_poll_success_ns += poll_ns;
+		vcpu->stat.generic.halt_poll_success_ns += poll_ns;
 }
 
 /*
@@ -2978,16 +3098,16 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 	if (vcpu->halt_poll_ns && !kvm_arch_no_poll(vcpu)) {
 		ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns);
 
-		++vcpu->stat.halt_attempted_poll;
+		++vcpu->stat.generic.halt_attempted_poll;
 		do {
 			/*
 			 * This sets KVM_REQ_UNHALT if an interrupt
 			 * arrives.
 			 */
 			if (kvm_vcpu_check_block(vcpu) < 0) {
-				++vcpu->stat.halt_successful_poll;
+				++vcpu->stat.generic.halt_successful_poll;
 				if (!vcpu_valid_wakeup(vcpu))
-					++vcpu->stat.halt_poll_invalid;
+					++vcpu->stat.generic.halt_poll_invalid;
 				goto out;
 			}
 			poll_end = cur = ktime_get();
@@ -3044,7 +3164,7 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 	waitp = kvm_arch_vcpu_get_wait(vcpu);
 	if (rcuwait_wake_up(waitp)) {
 		WRITE_ONCE(vcpu->ready, true);
-		++vcpu->stat.halt_wakeup;
+		++vcpu->stat.generic.halt_wakeup;
 		return true;
 	}
 
@@ -3377,6 +3497,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 	vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
 	BUG_ON(kvm->vcpus[vcpu->vcpu_idx]);
 
+	/* Fill the stats id string for the vcpu */
+	snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d",
+		 task_pid_nr(current), id);
+
 	/* Now it's all set up, let userspace reach it */
 	kvm_get_kvm(kvm);
 	r = create_vcpu_fd(vcpu);
@@ -3426,6 +3550,44 @@ static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
 	return 0;
 }
 
+static ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer,
+			      size_t size, loff_t *offset)
+{
+	struct kvm_vcpu *vcpu = file->private_data;
+
+	return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header,
+			&kvm_vcpu_stats_desc[0], &vcpu->stat,
+			sizeof(vcpu->stat), user_buffer, size, offset);
+}
+
+static const struct file_operations kvm_vcpu_stats_fops = {
+	.read = kvm_vcpu_stats_read,
+	.llseek = noop_llseek,
+};
+
+static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu)
+{
+	int fd;
+	struct file *file;
+	char name[15 + ITOA_MAX_LEN + 1];
+
+	snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id);
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+
+	file = anon_inode_getfile(name, &kvm_vcpu_stats_fops, vcpu, O_RDONLY);
+	if (IS_ERR(file)) {
+		put_unused_fd(fd);
+		return PTR_ERR(file);
+	}
+	file->f_mode |= FMODE_PREAD;
+	fd_install(fd, file);
+
+	return fd;
+}
+
 static long kvm_vcpu_ioctl(struct file *filp,
 			   unsigned int ioctl, unsigned long arg)
 {
@@ -3623,6 +3785,10 @@ out_free1:
 		r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
 		break;
 	}
+	case KVM_GET_STATS_FD: {
+		r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
+		break;
+	}
 	default:
 		r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
 	}
@@ -3881,6 +4047,8 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 #else
 		return 0;
 #endif
+	case KVM_CAP_BINARY_STATS_FD:
+		return 1;
 	default:
 		break;
 	}
@@ -3984,6 +4152,42 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
 	}
 }
 
+static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer,
+			      size_t size, loff_t *offset)
+{
+	struct kvm *kvm = file->private_data;
+
+	return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header,
+				&kvm_vm_stats_desc[0], &kvm->stat,
+				sizeof(kvm->stat), user_buffer, size, offset);
+}
+
+static const struct file_operations kvm_vm_stats_fops = {
+	.read = kvm_vm_stats_read,
+	.llseek = noop_llseek,
+};
+
+static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm)
+{
+	int fd;
+	struct file *file;
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+
+	file = anon_inode_getfile("kvm-vm-stats",
+			&kvm_vm_stats_fops, kvm, O_RDONLY);
+	if (IS_ERR(file)) {
+		put_unused_fd(fd);
+		return PTR_ERR(file);
+	}
+	file->f_mode |= FMODE_PREAD;
+	fd_install(fd, file);
+
+	return fd;
+}
+
 static long kvm_vm_ioctl(struct file *filp,
 			   unsigned int ioctl, unsigned long arg)
 {
@@ -4166,6 +4370,9 @@ static long kvm_vm_ioctl(struct file *filp,
 	case KVM_RESET_DIRTY_RINGS:
 		r = kvm_vm_ioctl_reset_dirty_pages(kvm);
 		break;
+	case KVM_GET_STATS_FD:
+		r = kvm_vm_ioctl_get_stats_fd(kvm);
+		break;
 	default:
 		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
 	}
@@ -4245,6 +4452,9 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
 	if (r < 0)
 		goto put_kvm;
 
+	snprintf(kvm->stats_id, sizeof(kvm->stats_id),
+			"kvm-%d", task_pid_nr(current));
+
 	file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
 	if (IS_ERR(file)) {
 		put_unused_fd(r);
@@ -4739,7 +4949,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file,
 		return -ENOENT;
 
 	if (simple_attr_open(inode, file, get,
-		    KVM_DBGFS_GET_MODE(stat_data->dbgfs_item) & 0222
+		    kvm_stats_debugfs_mode(stat_data->desc) & 0222
 		    ? set : NULL,
 		    fmt)) {
 		kvm_put_kvm(stat_data->kvm);
@@ -4762,14 +4972,14 @@ static int kvm_debugfs_release(struct inode *inode, struct file *file)
 
 static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
 {
-	*val = *(ulong *)((void *)kvm + offset);
+	*val = *(u64 *)((void *)(&kvm->stat) + offset);
 
 	return 0;
 }
 
 static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
 {
-	*(ulong *)((void *)kvm + offset) = 0;
+	*(u64 *)((void *)(&kvm->stat) + offset) = 0;
 
 	return 0;
 }
@@ -4782,7 +4992,7 @@ static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
 	*val = 0;
 
 	kvm_for_each_vcpu(i, vcpu, kvm)
-		*val += *(u64 *)((void *)vcpu + offset);
+		*val += *(u64 *)((void *)(&vcpu->stat) + offset);
 
 	return 0;
 }
@@ -4793,7 +5003,7 @@ static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
 	struct kvm_vcpu *vcpu;
 
 	kvm_for_each_vcpu(i, vcpu, kvm)
-		*(u64 *)((void *)vcpu + offset) = 0;
+		*(u64 *)((void *)(&vcpu->stat) + offset) = 0;
 
 	return 0;
 }
@@ -4803,14 +5013,14 @@ static int kvm_stat_data_get(void *data, u64 *val)
 	int r = -EFAULT;
 	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
 
-	switch (stat_data->dbgfs_item->kind) {
+	switch (stat_data->kind) {
 	case KVM_STAT_VM:
 		r = kvm_get_stat_per_vm(stat_data->kvm,
-					stat_data->dbgfs_item->offset, val);
+					stat_data->desc->desc.offset, val);
 		break;
 	case KVM_STAT_VCPU:
 		r = kvm_get_stat_per_vcpu(stat_data->kvm,
-					  stat_data->dbgfs_item->offset, val);
+					  stat_data->desc->desc.offset, val);
 		break;
 	}
 
@@ -4825,14 +5035,14 @@ static int kvm_stat_data_clear(void *data, u64 val)
 	if (val)
 		return -EINVAL;
 
-	switch (stat_data->dbgfs_item->kind) {
+	switch (stat_data->kind) {
 	case KVM_STAT_VM:
 		r = kvm_clear_stat_per_vm(stat_data->kvm,
-					  stat_data->dbgfs_item->offset);
+					  stat_data->desc->desc.offset);
 		break;
 	case KVM_STAT_VCPU:
 		r = kvm_clear_stat_per_vcpu(stat_data->kvm,
-					    stat_data->dbgfs_item->offset);
+					    stat_data->desc->desc.offset);
 		break;
 	}
 
@@ -4889,6 +5099,7 @@ static int vm_stat_clear(void *_offset, u64 val)
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(vm_stat_readonly_fops, vm_stat_get, NULL, "%llu\n");
 
 static int vcpu_stat_get(void *_offset, u64 *val)
 {
@@ -4925,11 +5136,7 @@ static int vcpu_stat_clear(void *_offset, u64 val)
 
 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear,
 			"%llu\n");
-
-static const struct file_operations *stat_fops[] = {
-	[KVM_STAT_VCPU] = &vcpu_stat_fops,
-	[KVM_STAT_VM]   = &vm_stat_fops,
-};
+DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_readonly_fops, vcpu_stat_get, NULL, "%llu\n");
 
 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
 {
@@ -4983,15 +5190,32 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
 
 static void kvm_init_debug(void)
 {
-	struct kvm_stats_debugfs_item *p;
+	const struct file_operations *fops;
+	const struct _kvm_stats_desc *pdesc;
+	int i;
 
 	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
 
-	kvm_debugfs_num_entries = 0;
-	for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {
-		debugfs_create_file(p->name, KVM_DBGFS_GET_MODE(p),
-				    kvm_debugfs_dir, (void *)(long)p->offset,
-				    stat_fops[p->kind]);
+	for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
+		pdesc = &kvm_vm_stats_desc[i];
+		if (kvm_stats_debugfs_mode(pdesc) & 0222)
+			fops = &vm_stat_fops;
+		else
+			fops = &vm_stat_readonly_fops;
+		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
+				kvm_debugfs_dir,
+				(void *)(long)pdesc->desc.offset, fops);
+	}
+
+	for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
+		pdesc = &kvm_vcpu_stats_desc[i];
+		if (kvm_stats_debugfs_mode(pdesc) & 0222)
+			fops = &vcpu_stat_fops;
+		else
+			fops = &vcpu_stat_readonly_fops;
+		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
+				kvm_debugfs_dir,
+				(void *)(long)pdesc->desc.offset, fops);
 	}
 }
 
@@ -5141,7 +5365,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 		kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
 					   SLAB_ACCOUNT,
 					   offsetof(struct kvm_vcpu, arch),
-					   sizeof_field(struct kvm_vcpu, arch),
+					   offsetofend(struct kvm_vcpu, stats_id)
+					   - offsetof(struct kvm_vcpu, arch),
 					   NULL);
 	if (!kvm_vcpu_cache) {
 		r = -ENOMEM;