16 files changed, 235 insertions, 105 deletions

diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 27a1f6341d41..ae95fc0e3214 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -425,6 +425,11 @@ int kvm_timer_hyp_init(void)
 	info = arch_timer_get_kvm_info();
 	timecounter = &info->timecounter;
 
+	if (!timecounter->cc) {
+		kvm_err("kvm_arch_timer: uninitialized timecounter\n");
+		return -ENODEV;
+	}
+
 	if (info->virtual_irq <= 0) {
 		kvm_err("kvm_arch_timer: invalid virtual timer IRQ: %d\n",
 			info->virtual_irq);
@@ -498,17 +503,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 	if (ret)
 		return ret;
 
-
-	/*
-	 * There is a potential race here between VCPUs starting for the first
-	 * time, which may be enabling the timer multiple times.  That doesn't
-	 * hurt though, because we're just setting a variable to the same
-	 * variable that it already was.  The important thing is that all
-	 * VCPUs have the enabled variable set, before entering the guest, if
-	 * the arch timers are enabled.
-	 */
-	if (timecounter)
-		timer->enabled = 1;
+	timer->enabled = 1;
 
 	return 0;
 }
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 6e9c40eea208..69ccce308458 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -305,7 +305,7 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
 			continue;
 		type = vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i)
 		       & ARMV8_PMU_EVTYPE_EVENT;
-		if ((type == ARMV8_PMU_EVTYPE_EVENT_SW_INCR)
+		if ((type == ARMV8_PMUV3_PERFCTR_SW_INCR)
 		    && (enable & BIT(i))) {
 			reg = vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
 			reg = lower_32_bits(reg);
@@ -379,7 +379,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 	eventsel = data & ARMV8_PMU_EVTYPE_EVENT;
 
 	/* Software increment event does't need to be backed by a perf event */
-	if (eventsel == ARMV8_PMU_EVTYPE_EVENT_SW_INCR)
+	if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR &&
+	    select_idx != ARMV8_PMU_CYCLE_IDX)
 		return;
 
 	memset(&attr, 0, sizeof(struct perf_event_attr));
@@ -391,7 +392,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 	attr.exclude_kernel = data & ARMV8_PMU_EXCLUDE_EL1 ? 1 : 0;
 	attr.exclude_hv = 1; /* Don't count EL2 events */
 	attr.exclude_host = 1; /* Don't count host events */
-	attr.config = eventsel;
+	attr.config = (select_idx == ARMV8_PMU_CYCLE_IDX) ?
+		ARMV8_PMUV3_PERFCTR_CPU_CYCLES : eventsel;
 
 	counter = kvm_pmu_get_counter_value(vcpu, select_idx);
 	/* The initial sample period (overflow count) of an event. */
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 4660a7d04eea..8c2b3cdcb2c5 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -632,21 +632,22 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
 	int index;
 	u64 indirect_ptr;
 	gfn_t gfn;
+	int esz = GITS_BASER_ENTRY_SIZE(baser);
 
 	if (!(baser & GITS_BASER_INDIRECT)) {
 		phys_addr_t addr;
 
-		if (id >= (l1_tbl_size / GITS_BASER_ENTRY_SIZE(baser)))
+		if (id >= (l1_tbl_size / esz))
 			return false;
 
-		addr = BASER_ADDRESS(baser) + id * GITS_BASER_ENTRY_SIZE(baser);
+		addr = BASER_ADDRESS(baser) + id * esz;
 		gfn = addr >> PAGE_SHIFT;
 
 		return kvm_is_visible_gfn(its->dev->kvm, gfn);
 	}
 
 	/* calculate and check the index into the 1st level */
-	index = id / (SZ_64K / GITS_BASER_ENTRY_SIZE(baser));
+	index = id / (SZ_64K / esz);
 	if (index >= (l1_tbl_size / sizeof(u64)))
 		return false;
 
@@ -670,8 +671,8 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
 	indirect_ptr &= GENMASK_ULL(51, 16);
 
 	/* Find the address of the actual entry */
-	index = id % (SZ_64K / GITS_BASER_ENTRY_SIZE(baser));
-	indirect_ptr += index * GITS_BASER_ENTRY_SIZE(baser);
+	index = id % (SZ_64K / esz);
+	indirect_ptr += index * esz;
 	gfn = indirect_ptr >> PAGE_SHIFT;
 
 	return kvm_is_visible_gfn(its->dev->kvm, gfn);
diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index ce1f4ed9daf4..fbe87a63d250 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -221,11 +221,9 @@ int kvm_register_vgic_device(unsigned long type)
 		ret = kvm_register_device_ops(&kvm_arm_vgic_v3_ops,
 					      KVM_DEV_TYPE_ARM_VGIC_V3);
 
-#ifdef CONFIG_KVM_ARM_VGIC_V3_ITS
 		if (ret)
 			break;
 		ret = kvm_vgic_register_its_device();
-#endif
 		break;
 	}
 
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index b44b359cbbad..78e34bc4d89b 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -129,6 +129,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
 				   unsigned long val)
 {
 	u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
+	u8 cpu_mask = GENMASK(atomic_read(&vcpu->kvm->online_vcpus) - 1, 0);
 	int i;
 
 	/* GICD_ITARGETSR[0-7] are read-only */
@@ -141,7 +142,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
 
 		spin_lock(&irq->irq_lock);
 
-		irq->targets = (val >> (i * 8)) & 0xff;
+		irq->targets = (val >> (i * 8)) & cpu_mask;
 		target = irq->targets ? __ffs(irq->targets) : 0;
 		irq->target_vcpu = kvm_get_vcpu(vcpu->kvm, target);
 
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index 0d3c76a4208b..50f42f0f8c4f 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -42,7 +42,6 @@ u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
 	return reg | ((u64)val << lower);
 }
 
-#ifdef CONFIG_KVM_ARM_VGIC_V3_ITS
 bool vgic_has_its(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
@@ -52,7 +51,6 @@ bool vgic_has_its(struct kvm *kvm)
 
 	return dist->has_its;
 }
-#endif
 
 static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 					    gpa_t addr, unsigned int len)
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index e18b30ddcdce..ebe1b9fa3c4d 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -453,17 +453,33 @@ struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev)
 	return container_of(dev, struct vgic_io_device, dev);
 }
 
-static bool check_region(const struct vgic_register_region *region,
+static bool check_region(const struct kvm *kvm,
+			 const struct vgic_register_region *region,
 			 gpa_t addr, int len)
 {
-	if ((region->access_flags & VGIC_ACCESS_8bit) && len == 1)
-		return true;
-	if ((region->access_flags & VGIC_ACCESS_32bit) &&
-	    len == sizeof(u32) && !(addr & 3))
-		return true;
-	if ((region->access_flags & VGIC_ACCESS_64bit) &&
-	    len == sizeof(u64) && !(addr & 7))
-		return true;
+	int flags, nr_irqs = kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
+
+	switch (len) {
+	case sizeof(u8):
+		flags = VGIC_ACCESS_8bit;
+		break;
+	case sizeof(u32):
+		flags = VGIC_ACCESS_32bit;
+		break;
+	case sizeof(u64):
+		flags = VGIC_ACCESS_64bit;
+		break;
+	default:
+		return false;
+	}
+
+	if ((region->access_flags & flags) && IS_ALIGNED(addr, len)) {
+		if (!region->bits_per_irq)
+			return true;
+
+		/* Do we access a non-allocated IRQ? */
+		return VGIC_ADDR_TO_INTID(addr, region->bits_per_irq) < nr_irqs;
+	}
 
 	return false;
 }
@@ -477,7 +493,7 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 
 	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
 				       addr - iodev->base_addr);
-	if (!region || !check_region(region, addr, len)) {
+	if (!region || !check_region(vcpu->kvm, region, addr, len)) {
 		memset(val, 0, len);
 		return 0;
 	}
@@ -510,10 +526,7 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 
 	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
 				       addr - iodev->base_addr);
-	if (!region)
-		return 0;
-
-	if (!check_region(region, addr, len))
+	if (!region || !check_region(vcpu->kvm, region, addr, len))
 		return 0;
 
 	switch (iodev->iodev_type) {
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 4c34d39d44a0..84961b4e4422 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -50,15 +50,15 @@ extern struct kvm_io_device_ops kvm_io_gic_ops;
 #define VGIC_ADDR_IRQ_MASK(bits) (((bits) * 1024 / 8) - 1)
 
 /*
- * (addr & mask) gives us the byte offset for the INT ID, so we want to
- * divide this with 'bytes per irq' to get the INT ID, which is given
- * by '(bits) / 8'.  But we do this with fixed-point-arithmetic and
- * take advantage of the fact that division by a fraction equals
- * multiplication with the inverted fraction, and scale up both the
- * numerator and denominator with 8 to support at most 64 bits per IRQ:
+ * (addr & mask) gives us the _byte_ offset for the INT ID.
+ * We multiply this by 8 the get the _bit_ offset, then divide this by
+ * the number of bits to learn the actual INT ID.
+ * But instead of a division (which requires a "long long div" implementation),
+ * we shift by the binary logarithm of <bits>.
+ * This assumes that <bits> is a power of two.
  */
 #define VGIC_ADDR_TO_INTID(addr, bits)  (((addr) & VGIC_ADDR_IRQ_MASK(bits)) * \
-					64 / (bits) / 8)
+					8 >> ilog2(bits))
 
 /*
  * Some VGIC registers store per-IRQ information, with a different number
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 0a063af40565..9bab86757fa4 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -50,8 +50,10 @@ void vgic_v2_process_maintenance(struct kvm_vcpu *vcpu)
 
 			WARN_ON(cpuif->vgic_lr[lr] & GICH_LR_STATE);
 
-			kvm_notify_acked_irq(vcpu->kvm, 0,
-					     intid - VGIC_NR_PRIVATE_IRQS);
+			/* Only SPIs require notification */
+			if (vgic_valid_spi(vcpu->kvm, intid))
+				kvm_notify_acked_irq(vcpu->kvm, 0,
+						     intid - VGIC_NR_PRIVATE_IRQS);
 		}
 	}
 
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 9f0dae397d9c..5c9f9745e6ca 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -41,8 +41,10 @@ void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
 
 			WARN_ON(cpuif->vgic_lr[lr] & ICH_LR_STATE);
 
-			kvm_notify_acked_irq(vcpu->kvm, 0,
-					     intid - VGIC_NR_PRIVATE_IRQS);
+			/* Only SPIs require notification */
+			if (vgic_valid_spi(vcpu->kvm, intid))
+				kvm_notify_acked_irq(vcpu->kvm, 0,
+						     intid - VGIC_NR_PRIVATE_IRQS);
 		}
 
 		/*
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 2893d5ba523a..6440b56ec90e 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -273,6 +273,18 @@ retry:
 		 * no more work for us to do.
 		 */
 		spin_unlock(&irq->irq_lock);
+
+		/*
+		 * We have to kick the VCPU here, because we could be
+		 * queueing an edge-triggered interrupt for which we
+		 * get no EOI maintenance interrupt. In that case,
+		 * while the IRQ is already on the VCPU's AP list, the
+		 * VCPU could have EOI'ed the original interrupt and
+		 * won't see this one until it exits for some other
+		 * reason.
+		 */
+		if (vcpu)
+			kvm_vcpu_kick(vcpu);
 		return false;
 	}
 
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 9d9e014765a2..859f65c6e056 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -84,37 +84,11 @@ int vgic_v3_probe(const struct gic_kvm_info *info);
 int vgic_v3_map_resources(struct kvm *kvm);
 int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
 
-#ifdef CONFIG_KVM_ARM_VGIC_V3_ITS
 int vgic_register_its_iodevs(struct kvm *kvm);
 bool vgic_has_its(struct kvm *kvm);
 int kvm_vgic_register_its_device(void);
 void vgic_enable_lpis(struct kvm_vcpu *vcpu);
 int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi);
-#else
-static inline int vgic_register_its_iodevs(struct kvm *kvm)
-{
-	return -ENODEV;
-}
-
-static inline bool vgic_has_its(struct kvm *kvm)
-{
-	return false;
-}
-
-static inline int kvm_vgic_register_its_device(void)
-{
-	return -ENODEV;
-}
-
-static inline void vgic_enable_lpis(struct kvm_vcpu *vcpu)
-{
-}
-
-static inline int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
-{
-	return -ENODEV;
-}
-#endif
 
 int kvm_register_vgic_device(unsigned long type);
 int vgic_lazy_init(struct kvm *kvm);
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index db9668869f6f..efeceb0a222d 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -84,12 +84,14 @@ static void async_pf_execute(struct work_struct *work)
 	 * mm and might be done in another context, so we must
 	 * use FOLL_REMOTE.
 	 */
-	__get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL, FOLL_REMOTE);
+	__get_user_pages_unlocked(NULL, mm, addr, 1, NULL,
+			FOLL_WRITE | FOLL_REMOTE);
 
 	kvm_async_page_present_sync(vcpu, apf);
 
 	spin_lock(&vcpu->async_pf.lock);
 	list_add_tail(&apf->link, &vcpu->async_pf.done);
+	apf->vcpu = NULL;
 	spin_unlock(&vcpu->async_pf.lock);
 
 	/*
@@ -112,6 +114,8 @@ static void async_pf_execute(struct work_struct *work)
 
 void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 {
+	spin_lock(&vcpu->async_pf.lock);
+
 	/* cancel outstanding work queue item */
 	while (!list_empty(&vcpu->async_pf.queue)) {
 		struct kvm_async_pf *work =
@@ -119,6 +123,14 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 					 typeof(*work), queue);
 		list_del(&work->queue);
 
+		/*
+		 * We know it's present in vcpu->async_pf.done, do
+		 * nothing here.
+		 */
+		if (!work->vcpu)
+			continue;
+
+		spin_unlock(&vcpu->async_pf.lock);
 #ifdef CONFIG_KVM_ASYNC_PF_SYNC
 		flush_work(&work->work);
 #else
@@ -128,9 +140,9 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 			kmem_cache_free(async_pf_cache, work);
 		}
 #endif
+		spin_lock(&vcpu->async_pf.lock);
 	}
 
-	spin_lock(&vcpu->async_pf.lock);
 	while (!list_empty(&vcpu->async_pf.done)) {
 		struct kvm_async_pf *work =
 			list_first_entry(&vcpu->async_pf.done,
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index f397e9b20370..a29786dd9522 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -42,6 +42,7 @@
 
 #ifdef CONFIG_HAVE_KVM_IRQFD
 
+static struct workqueue_struct *irqfd_cleanup_wq;
 
 static void
 irqfd_inject(struct work_struct *work)
@@ -167,7 +168,7 @@ irqfd_deactivate(struct kvm_kernel_irqfd *irqfd)
 
 	list_del_init(&irqfd->list);
 
-	schedule_work(&irqfd->shutdown);
+	queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
 }
 
 int __attribute__((weak)) kvm_arch_set_irq_inatomic(
@@ -554,7 +555,7 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
 	 * so that we guarantee there will not be any more interrupts on this
 	 * gsi once this deassign function returns.
 	 */
-	flush_work(&irqfd->shutdown);
+	flush_workqueue(irqfd_cleanup_wq);
 
 	return 0;
 }
@@ -591,7 +592,7 @@ kvm_irqfd_release(struct kvm *kvm)
 	 * Block until we know all outstanding shutdown jobs have completed
 	 * since we do not take a kvm* reference.
 	 */
-	flush_work(&irqfd->shutdown);
+	flush_workqueue(irqfd_cleanup_wq);
 
 }
 
@@ -621,8 +622,23 @@ void kvm_irq_routing_update(struct kvm *kvm)
 	spin_unlock_irq(&kvm->irqfds.lock);
 }
 
+/*
+ * create a host-wide workqueue for issuing deferred shutdown requests
+ * aggregated from all vm* instances. We need our own isolated
+ * queue to ease flushing work items when a VM exits.
+ */
+int kvm_irqfd_init(void)
+{
+	irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", 0, 0);
+	if (!irqfd_cleanup_wq)
+		return -ENOMEM;
+
+	return 0;
+}
+
 void kvm_irqfd_exit(void)
 {
+	destroy_workqueue(irqfd_cleanup_wq);
 }
 #endif
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 81dfc73d3df3..823544c166be 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -70,16 +70,19 @@ MODULE_AUTHOR("Qumranet");
 MODULE_LICENSE("GPL");
 
 /* Architectures should define their poll value according to the halt latency */
-static unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
+unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
 module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
+EXPORT_SYMBOL_GPL(halt_poll_ns);
 
 /* Default doubles per-vcpu halt_poll_ns. */
-static unsigned int halt_poll_ns_grow = 2;
+unsigned int halt_poll_ns_grow = 2;
 module_param(halt_poll_ns_grow, uint, S_IRUGO | S_IWUSR);
+EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
 
 /* Default resets per-vcpu halt_poll_ns . */
-static unsigned int halt_poll_ns_shrink;
+unsigned int halt_poll_ns_shrink;
 module_param(halt_poll_ns_shrink, uint, S_IRUGO | S_IWUSR);
+EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
 
 /*
  * Ordering of locks:
@@ -595,7 +598,7 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 		stat_data->kvm = kvm;
 		stat_data->offset = p->offset;
 		kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
-		if (!debugfs_create_file(p->name, 0444,
+		if (!debugfs_create_file(p->name, 0644,
 					 kvm->debugfs_dentry,
 					 stat_data,
 					 stat_fops_per_vm[p->kind]))
@@ -1346,21 +1349,19 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w
 static int get_user_page_nowait(unsigned long start, int write,
 		struct page **page)
 {
-	int flags = FOLL_TOUCH | FOLL_NOWAIT | FOLL_HWPOISON | FOLL_GET;
+	int flags = FOLL_NOWAIT | FOLL_HWPOISON;
 
 	if (write)
 		flags |= FOLL_WRITE;
 
-	return __get_user_pages(current, current->mm, start, 1, flags, page,
-			NULL, NULL);
+	return get_user_pages(start, 1, flags, page, NULL);
 }
 
 static inline int check_user_page_hwpoison(unsigned long addr)
 {
-	int rc, flags = FOLL_TOUCH | FOLL_HWPOISON | FOLL_WRITE;
+	int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
 
-	rc = __get_user_pages(current, current->mm, addr, 1,
-			      flags, NULL, NULL, NULL);
+	rc = get_user_pages(addr, 1, flags, NULL, NULL);
 	return rc == -EHWPOISON;
 }
 
@@ -1416,10 +1417,15 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
 		down_read(&current->mm->mmap_sem);
 		npages = get_user_page_nowait(addr, write_fault, page);
 		up_read(&current->mm->mmap_sem);
-	} else
+	} else {
+		unsigned int flags = FOLL_TOUCH | FOLL_HWPOISON;
+
+		if (write_fault)
+			flags |= FOLL_WRITE;
+
 		npages = __get_user_pages_unlocked(current, current->mm, addr, 1,
-						   write_fault, 0, page,
-						   FOLL_TOUCH|FOLL_HWPOISON);
+						   page, flags);
+	}
 	if (npages != 1)
 		return npages;
 
@@ -1969,30 +1975,38 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 }
 EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
 
-int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
-			   void *data, unsigned long len)
+int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+			   void *data, int offset, unsigned long len)
 {
 	struct kvm_memslots *slots = kvm_memslots(kvm);
 	int r;
+	gpa_t gpa = ghc->gpa + offset;
 
-	BUG_ON(len > ghc->len);
+	BUG_ON(len + offset > ghc->len);
 
 	if (slots->generation != ghc->generation)
 		kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa, ghc->len);
 
 	if (unlikely(!ghc->memslot))
-		return kvm_write_guest(kvm, ghc->gpa, data, len);
+		return kvm_write_guest(kvm, gpa, data, len);
 
 	if (kvm_is_error_hva(ghc->hva))
 		return -EFAULT;
 
-	r = __copy_to_user((void __user *)ghc->hva, data, len);
+	r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
 	if (r)
 		return -EFAULT;
-	mark_page_dirty_in_slot(ghc->memslot, ghc->gpa >> PAGE_SHIFT);
+	mark_page_dirty_in_slot(ghc->memslot, gpa >> PAGE_SHIFT);
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached);
+
+int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+			   void *data, unsigned long len)
+{
+	return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len);
+}
 EXPORT_SYMBOL_GPL(kvm_write_guest_cached);
 
 int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
@@ -2886,10 +2900,10 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
 
 	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
 	if (ret < 0) {
-		ops->destroy(dev);
 		mutex_lock(&kvm->lock);
 		list_del(&dev->vm_node);
 		mutex_unlock(&kvm->lock);
+		ops->destroy(dev);
 		return ret;
 	}
 
@@ -3658,11 +3672,23 @@ static int vm_stat_get_per_vm(void *data, u64 *val)
 	return 0;
 }
 
+static int vm_stat_clear_per_vm(void *data, u64 val)
+{
+	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+
+	if (val)
+		return -EINVAL;
+
+	*(ulong *)((void *)stat_data->kvm + stat_data->offset) = 0;
+
+	return 0;
+}
+
 static int vm_stat_get_per_vm_open(struct inode *inode, struct file *file)
 {
 	__simple_attr_check_format("%llu\n", 0ull);
 	return kvm_debugfs_open(inode, file, vm_stat_get_per_vm,
-				NULL, "%llu\n");
+				vm_stat_clear_per_vm, "%llu\n");
 }
 
 static const struct file_operations vm_stat_get_per_vm_fops = {
@@ -3688,11 +3714,26 @@ static int vcpu_stat_get_per_vm(void *data, u64 *val)
 	return 0;
 }
 
+static int vcpu_stat_clear_per_vm(void *data, u64 val)
+{
+	int i;
+	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+	struct kvm_vcpu *vcpu;
+
+	if (val)
+		return -EINVAL;
+
+	kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
+		*(u64 *)((void *)vcpu + stat_data->offset) = 0;
+
+	return 0;
+}
+
 static int vcpu_stat_get_per_vm_open(struct inode *inode, struct file *file)
 {
 	__simple_attr_check_format("%llu\n", 0ull);
 	return kvm_debugfs_open(inode, file, vcpu_stat_get_per_vm,
-				 NULL, "%llu\n");
+				 vcpu_stat_clear_per_vm, "%llu\n");
 }
 
 static const struct file_operations vcpu_stat_get_per_vm_fops = {
@@ -3727,7 +3768,26 @@ static int vm_stat_get(void *_offset, u64 *val)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, NULL, "%llu\n");
+static int vm_stat_clear(void *_offset, u64 val)
+{
+	unsigned offset = (long)_offset;
+	struct kvm *kvm;
+	struct kvm_stat_data stat_tmp = {.offset = offset};
+
+	if (val)
+		return -EINVAL;
+
+	spin_lock(&kvm_lock);
+	list_for_each_entry(kvm, &vm_list, vm_list) {
+		stat_tmp.kvm = kvm;
+		vm_stat_clear_per_vm((void *)&stat_tmp, 0);
+	}
+	spin_unlock(&kvm_lock);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n");
 
 static int vcpu_stat_get(void *_offset, u64 *val)
 {
@@ -3747,7 +3807,27 @@ static int vcpu_stat_get(void *_offset, u64 *val)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, NULL, "%llu\n");
+static int vcpu_stat_clear(void *_offset, u64 val)
+{
+	unsigned offset = (long)_offset;
+	struct kvm *kvm;
+	struct kvm_stat_data stat_tmp = {.offset = offset};
+
+	if (val)
+		return -EINVAL;
+
+	spin_lock(&kvm_lock);
+	list_for_each_entry(kvm, &vm_list, vm_list) {
+		stat_tmp.kvm = kvm;
+		vcpu_stat_clear_per_vm((void *)&stat_tmp, 0);
+	}
+	spin_unlock(&kvm_lock);
+
+	return 0;
+}
+
+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,
@@ -3765,7 +3845,7 @@ static int kvm_init_debug(void)
 
 	kvm_debugfs_num_entries = 0;
 	for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {
-		if (!debugfs_create_file(p->name, 0444, kvm_debugfs_dir,
+		if (!debugfs_create_file(p->name, 0644, kvm_debugfs_dir,
 					 (void *)(long)p->offset,
 					 stat_fops[p->kind]))
 			goto out_dir;
@@ -3841,7 +3921,12 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 	 * kvm_arch_init makes sure there's at most one caller
 	 * for architectures that support multiple implementations,
 	 * like intel and amd on x86.
+	 * kvm_arch_init must be called before kvm_irqfd_init to avoid creating
+	 * conflicts in case kvm is already setup for another implementation.
 	 */
+	r = kvm_irqfd_init();
+	if (r)
+		goto out_irqfd;
 
 	if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
 		r = -ENOMEM;
@@ -3923,6 +4008,7 @@ out_free_0a:
 	free_cpumask_var(cpus_hardware_enabled);
 out_free_0:
 	kvm_irqfd_exit();
+out_irqfd:
 	kvm_arch_exit();
 out_fail:
 	return r;
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 1dd087da6f31..d32f239eb471 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -60,6 +60,19 @@ static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
 	symbol_put(vfio_group_put_external_user);
 }
 
+static void kvm_vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
+{
+	void (*fn)(struct vfio_group *, struct kvm *);
+
+	fn = symbol_get(vfio_group_set_kvm);
+	if (!fn)
+		return;
+
+	fn(group, kvm);
+
+	symbol_put(vfio_group_set_kvm);
+}
+
 static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
 {
 	long (*fn)(struct vfio_group *, unsigned long);
@@ -159,6 +172,8 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 
 		mutex_unlock(&kv->lock);
 
+		kvm_vfio_group_set_kvm(vfio_group, dev->kvm);
+
 		kvm_vfio_update_coherency(dev);
 
 		return 0;
@@ -196,6 +211,8 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
 
 		mutex_unlock(&kv->lock);
 
+		kvm_vfio_group_set_kvm(vfio_group, NULL);
+
 		kvm_vfio_group_put_external_user(vfio_group);
 
 		kvm_vfio_update_coherency(dev);
@@ -240,6 +257,7 @@ static void kvm_vfio_destroy(struct kvm_device *dev)
 	struct kvm_vfio_group *kvg, *tmp;
 
 	list_for_each_entry_safe(kvg, tmp, &kv->group_list, node) {
+		kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
 		kvm_vfio_group_put_external_user(kvg->vfio_group);
 		list_del(&kvg->node);
 		kfree(kvg);