Merge branch 'kvm-older-features' into HEAD

Merge branch for features that did not make it into 5.18:

* New ioctls to get/set TSC frequency for a whole VM

* Allow userspace to opt out of hypercall patching

Nested virtualization improvements for AMD:

* Support for "nested nested" optimizations (nested vVMLOAD/VMSAVE,
  nested vGIF)

* Allow AVIC to co-exist with a nested guest running

* Fixes for LBR virtualizations when a nested guest is running,
  and nested LBR virtualization support

* PAUSE filtering for nested hypervisors

Guest support:

* Decoupling of vcpu_is_preempted from PV spinlocks

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1023 insertions, 223 deletions

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index bf6cc25eee76..7e7c8a5bff52 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -8,18 +8,27 @@
 
 #include "x86.h"
 #include "xen.h"
+#include "lapic.h"
 #include "hyperv.h"
+#include "lapic.h"
 
+#include <linux/eventfd.h>
 #include <linux/kvm_host.h>
 #include <linux/sched/stat.h>
 
 #include <trace/events/kvm.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/vcpu.h>
+#include <xen/interface/version.h>
 #include <xen/interface/event_channel.h>
+#include <xen/interface/sched.h>
 
 #include "trace.h"
 
+static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm);
+static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
+static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r);
+
 DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
 
 static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
@@ -102,6 +111,66 @@ out:
 	return ret;
 }
 
+void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu)
+{
+	if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) {
+		struct kvm_xen_evtchn e;
+
+		e.vcpu_id = vcpu->vcpu_id;
+		e.vcpu_idx = vcpu->vcpu_idx;
+		e.port = vcpu->arch.xen.timer_virq;
+		e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
+
+		kvm_xen_set_evtchn(&e, vcpu->kvm);
+
+		vcpu->arch.xen.timer_expires = 0;
+		atomic_set(&vcpu->arch.xen.timer_pending, 0);
+	}
+}
+
+static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
+{
+	struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu,
+					     arch.xen.timer);
+	if (atomic_read(&vcpu->arch.xen.timer_pending))
+		return HRTIMER_NORESTART;
+
+	atomic_inc(&vcpu->arch.xen.timer_pending);
+	kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
+	kvm_vcpu_kick(vcpu);
+
+	return HRTIMER_NORESTART;
+}
+
+static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_ns)
+{
+	atomic_set(&vcpu->arch.xen.timer_pending, 0);
+	vcpu->arch.xen.timer_expires = guest_abs;
+
+	if (delta_ns <= 0) {
+		xen_timer_callback(&vcpu->arch.xen.timer);
+	} else {
+		ktime_t ktime_now = ktime_get();
+		hrtimer_start(&vcpu->arch.xen.timer,
+			      ktime_add_ns(ktime_now, delta_ns),
+			      HRTIMER_MODE_ABS_HARD);
+	}
+}
+
+static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
+{
+	hrtimer_cancel(&vcpu->arch.xen.timer);
+	vcpu->arch.xen.timer_expires = 0;
+	atomic_set(&vcpu->arch.xen.timer_pending, 0);
+}
+
+static void kvm_xen_init_timer(struct kvm_vcpu *vcpu)
+{
+	hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_ABS_HARD);
+	vcpu->arch.xen.timer.function = xen_timer_callback;
+}
+
 static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
 {
 	struct kvm_vcpu_xen *vx = &v->arch.xen;
@@ -133,27 +202,36 @@ static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
 void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
 {
 	struct kvm_vcpu_xen *vx = &v->arch.xen;
-	struct gfn_to_hva_cache *ghc = &vx->runstate_cache;
-	struct kvm_memslots *slots = kvm_memslots(v->kvm);
-	bool atomic = (state == RUNSTATE_runnable);
-	uint64_t state_entry_time;
-	int __user *user_state;
-	uint64_t __user *user_times;
+	struct gfn_to_pfn_cache *gpc = &vx->runstate_cache;
+	uint64_t *user_times;
+	unsigned long flags;
+	size_t user_len;
+	int *user_state;
 
 	kvm_xen_update_runstate(v, state);
 
-	if (!vx->runstate_set)
+	if (!vx->runstate_cache.active)
 		return;
 
-	if (unlikely(slots->generation != ghc->generation || kvm_is_error_hva(ghc->hva)) &&
-	    kvm_gfn_to_hva_cache_init(v->kvm, ghc, ghc->gpa, ghc->len))
-		return;
+	if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode)
+		user_len = sizeof(struct vcpu_runstate_info);
+	else
+		user_len = sizeof(struct compat_vcpu_runstate_info);
 
-	/* We made sure it fits in a single page */
-	BUG_ON(!ghc->memslot);
+	read_lock_irqsave(&gpc->lock, flags);
+	while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa,
+					   user_len)) {
+		read_unlock_irqrestore(&gpc->lock, flags);
 
-	if (atomic)
-		pagefault_disable();
+		/* When invoked from kvm_sched_out() we cannot sleep */
+		if (state == RUNSTATE_runnable)
+			return;
+
+		if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa, user_len))
+			return;
+
+		read_lock_irqsave(&gpc->lock, flags);
+	}
 
 	/*
 	 * The only difference between 32-bit and 64-bit versions of the
@@ -167,38 +245,33 @@ void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
 	 */
 	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0);
 	BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0);
-	user_state = (int __user *)ghc->hva;
-
 	BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);
-
-	user_times = (uint64_t __user *)(ghc->hva +
-					 offsetof(struct compat_vcpu_runstate_info,
-						  state_entry_time));
 #ifdef CONFIG_X86_64
 	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 		     offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
 	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
 		     offsetof(struct compat_vcpu_runstate_info, time) + 4);
-
-	if (v->kvm->arch.xen.long_mode)
-		user_times = (uint64_t __user *)(ghc->hva +
-						 offsetof(struct vcpu_runstate_info,
-							  state_entry_time));
 #endif
+
+	user_state = gpc->khva;
+
+	if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode)
+		user_times = gpc->khva + offsetof(struct vcpu_runstate_info,
+						  state_entry_time);
+	else
+		user_times = gpc->khva + offsetof(struct compat_vcpu_runstate_info,
+						  state_entry_time);
+
 	/*
 	 * First write the updated state_entry_time at the appropriate
 	 * location determined by 'offset'.
 	 */
-	state_entry_time = vx->runstate_entry_time;
-	state_entry_time |= XEN_RUNSTATE_UPDATE;
-
 	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
-		     sizeof(state_entry_time));
+		     sizeof(user_times[0]));
 	BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
-		     sizeof(state_entry_time));
+		     sizeof(user_times[0]));
 
-	if (__put_user(state_entry_time, user_times))
-		goto out;
+	user_times[0] = vx->runstate_entry_time | XEN_RUNSTATE_UPDATE;
 	smp_wmb();
 
 	/*
@@ -212,8 +285,7 @@ void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
 	BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
 		     sizeof(vx->current_runstate));
 
-	if (__put_user(vx->current_runstate, user_state))
-		goto out;
+	*user_state = vx->current_runstate;
 
 	/*
 	 * Write the actual runstate times immediately after the
@@ -228,42 +300,114 @@ void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
 	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 		     sizeof(vx->runstate_times));
 
-	if (__copy_to_user(user_times + 1, vx->runstate_times, sizeof(vx->runstate_times)))
-		goto out;
+	memcpy(user_times + 1, vx->runstate_times, sizeof(vx->runstate_times));
 	smp_wmb();
 
 	/*
 	 * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's
 	 * runstate_entry_time field.
 	 */
-	state_entry_time &= ~XEN_RUNSTATE_UPDATE;
-	__put_user(state_entry_time, user_times);
+	user_times[0] &= ~XEN_RUNSTATE_UPDATE;
 	smp_wmb();
 
- out:
-	mark_page_dirty_in_slot(v->kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT);
+	read_unlock_irqrestore(&gpc->lock, flags);
 
-	if (atomic)
-		pagefault_enable();
+	mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
 }
 
-int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
+static void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
+{
+	struct kvm_lapic_irq irq = { };
+	int r;
+
+	irq.dest_id = v->vcpu_id;
+	irq.vector = v->arch.xen.upcall_vector;
+	irq.dest_mode = APIC_DEST_PHYSICAL;
+	irq.shorthand = APIC_DEST_NOSHORT;
+	irq.delivery_mode = APIC_DM_FIXED;
+	irq.level = 1;
+
+	/* The fast version will always work for physical unicast */
+	WARN_ON_ONCE(!kvm_irq_delivery_to_apic_fast(v->kvm, NULL, &irq, &r, NULL));
+}
+
+/*
+ * On event channel delivery, the vcpu_info may not have been accessible.
+ * In that case, there are bits in vcpu->arch.xen.evtchn_pending_sel which
+ * need to be marked into the vcpu_info (and evtchn_upcall_pending set).
+ * Do so now that we can sleep in the context of the vCPU to bring the
+ * page in, and refresh the pfn cache for it.
+ */
+void kvm_xen_inject_pending_events(struct kvm_vcpu *v)
 {
 	unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel);
-	bool atomic = in_atomic() || !task_is_running(current);
-	int err;
+	struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
+	unsigned long flags;
+
+	if (!evtchn_pending_sel)
+		return;
+
+	/*
+	 * Yes, this is an open-coded loop. But that's just what put_user()
+	 * does anyway. Page it in and retry the instruction. We're just a
+	 * little more honest about it.
+	 */
+	read_lock_irqsave(&gpc->lock, flags);
+	while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa,
+					   sizeof(struct vcpu_info))) {
+		read_unlock_irqrestore(&gpc->lock, flags);
+
+		if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa,
+						 sizeof(struct vcpu_info)))
+			return;
+
+		read_lock_irqsave(&gpc->lock, flags);
+	}
+
+	/* Now gpc->khva is a valid kernel address for the vcpu_info */
+	if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
+		struct vcpu_info *vi = gpc->khva;
+
+		asm volatile(LOCK_PREFIX "orq %0, %1\n"
+			     "notq %0\n"
+			     LOCK_PREFIX "andq %0, %2\n"
+			     : "=r" (evtchn_pending_sel),
+			       "+m" (vi->evtchn_pending_sel),
+			       "+m" (v->arch.xen.evtchn_pending_sel)
+			     : "0" (evtchn_pending_sel));
+		WRITE_ONCE(vi->evtchn_upcall_pending, 1);
+	} else {
+		u32 evtchn_pending_sel32 = evtchn_pending_sel;
+		struct compat_vcpu_info *vi = gpc->khva;
+
+		asm volatile(LOCK_PREFIX "orl %0, %1\n"
+			     "notl %0\n"
+			     LOCK_PREFIX "andl %0, %2\n"
+			     : "=r" (evtchn_pending_sel32),
+			       "+m" (vi->evtchn_pending_sel),
+			       "+m" (v->arch.xen.evtchn_pending_sel)
+			     : "0" (evtchn_pending_sel32));
+		WRITE_ONCE(vi->evtchn_upcall_pending, 1);
+	}
+	read_unlock_irqrestore(&gpc->lock, flags);
+
+	/* For the per-vCPU lapic vector, deliver it as MSI. */
+	if (v->arch.xen.upcall_vector)
+		kvm_xen_inject_vcpu_vector(v);
+
+	mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
+}
+
+int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
+{
+	struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
+	unsigned long flags;
 	u8 rc = 0;
 
 	/*
 	 * If the global upcall vector (HVMIRQ_callback_vector) is set and
 	 * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
 	 */
-	struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache;
-	struct kvm_memslots *slots = kvm_memslots(v->kvm);
-	bool ghc_valid = slots->generation == ghc->generation &&
-		!kvm_is_error_hva(ghc->hva) && ghc->memslot;
-
-	unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_pending);
 
 	/* No need for compat handling here */
 	BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
@@ -273,101 +417,35 @@ int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
 	BUILD_BUG_ON(sizeof(rc) !=
 		     sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));
 
-	/*
-	 * For efficiency, this mirrors the checks for using the valid
-	 * cache in kvm_read_guest_offset_cached(), but just uses
-	 * __get_user() instead. And falls back to the slow path.
-	 */
-	if (!evtchn_pending_sel && ghc_valid) {
-		/* Fast path */
-		pagefault_disable();
-		err = __get_user(rc, (u8 __user *)ghc->hva + offset);
-		pagefault_enable();
-		if (!err)
-			return rc;
-	}
-
-	/* Slow path */
+	read_lock_irqsave(&gpc->lock, flags);
+	while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa,
+					   sizeof(struct vcpu_info))) {
+		read_unlock_irqrestore(&gpc->lock, flags);
 
-	/*
-	 * This function gets called from kvm_vcpu_block() after setting the
-	 * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
-	 * from a HLT. So we really mustn't sleep. If the page ended up absent
-	 * at that point, just return 1 in order to trigger an immediate wake,
-	 * and we'll end up getting called again from a context where we *can*
-	 * fault in the page and wait for it.
-	 */
-	if (atomic)
-		return 1;
+		/*
+		 * This function gets called from kvm_vcpu_block() after setting the
+		 * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
+		 * from a HLT. So we really mustn't sleep. If the page ended up absent
+		 * at that point, just return 1 in order to trigger an immediate wake,
+		 * and we'll end up getting called again from a context where we *can*
+		 * fault in the page and wait for it.
+		 */
+		if (in_atomic() || !task_is_running(current))
+			return 1;
 
-	if (!ghc_valid) {
-		err = kvm_gfn_to_hva_cache_init(v->kvm, ghc, ghc->gpa, ghc->len);
-		if (err || !ghc->memslot) {
+		if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa,
+						 sizeof(struct vcpu_info))) {
 			/*
 			 * If this failed, userspace has screwed up the
 			 * vcpu_info mapping. No interrupts for you.
 			 */
 			return 0;
 		}
+		read_lock_irqsave(&gpc->lock, flags);
 	}
 
-	/*
-	 * Now we have a valid (protected by srcu) userspace HVA in
-	 * ghc->hva which points to the struct vcpu_info. If there
-	 * are any bits in the in-kernel evtchn_pending_sel then
-	 * we need to write those to the guest vcpu_info and set
-	 * its evtchn_upcall_pending flag. If there aren't any bits
-	 * to add, we only want to *check* evtchn_upcall_pending.
-	 */
-	if (evtchn_pending_sel) {
-		bool long_mode = v->kvm->arch.xen.long_mode;
-
-		if (!user_access_begin((void __user *)ghc->hva, sizeof(struct vcpu_info)))
-			return 0;
-
-		if (IS_ENABLED(CONFIG_64BIT) && long_mode) {
-			struct vcpu_info __user *vi = (void __user *)ghc->hva;
-
-			/* Attempt to set the evtchn_pending_sel bits in the
-			 * guest, and if that succeeds then clear the same
-			 * bits in the in-kernel version. */
-			asm volatile("1:\t" LOCK_PREFIX "orq %0, %1\n"
-				     "\tnotq %0\n"
-				     "\t" LOCK_PREFIX "andq %0, %2\n"
-				     "2:\n"
-				     _ASM_EXTABLE_UA(1b, 2b)
-				     : "=r" (evtchn_pending_sel),
-				       "+m" (vi->evtchn_pending_sel),
-				       "+m" (v->arch.xen.evtchn_pending_sel)
-				     : "0" (evtchn_pending_sel));
-		} else {
-			struct compat_vcpu_info __user *vi = (void __user *)ghc->hva;
-			u32 evtchn_pending_sel32 = evtchn_pending_sel;
-
-			/* Attempt to set the evtchn_pending_sel bits in the
-			 * guest, and if that succeeds then clear the same
-			 * bits in the in-kernel version. */
-			asm volatile("1:\t" LOCK_PREFIX "orl %0, %1\n"
-				     "\tnotl %0\n"
-				     "\t" LOCK_PREFIX "andl %0, %2\n"
-				     "2:\n"
-				     _ASM_EXTABLE_UA(1b, 2b)
-				     : "=r" (evtchn_pending_sel32),
-				       "+m" (vi->evtchn_pending_sel),
-				       "+m" (v->arch.xen.evtchn_pending_sel)
-				     : "0" (evtchn_pending_sel32));
-		}
-		rc = 1;
-		unsafe_put_user(rc, (u8 __user *)ghc->hva + offset, err);
-
-	err:
-		user_access_end();
-
-		mark_page_dirty_in_slot(v->kvm, ghc->memslot, ghc->gpa >> PAGE_SHIFT);
-	} else {
-		__get_user(rc, (u8 __user *)ghc->hva + offset);
-	}
-
+	rc = ((struct vcpu_info *)gpc->khva)->evtchn_upcall_pending;
+	read_unlock_irqrestore(&gpc->lock, flags);
 	return rc;
 }
 
@@ -375,36 +453,51 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 {
 	int r = -ENOENT;
 
-	mutex_lock(&kvm->lock);
 
 	switch (data->type) {
 	case KVM_XEN_ATTR_TYPE_LONG_MODE:
 		if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
 			r = -EINVAL;
 		} else {
+			mutex_lock(&kvm->lock);
 			kvm->arch.xen.long_mode = !!data->u.long_mode;
+			mutex_unlock(&kvm->lock);
 			r = 0;
 		}
 		break;
 
 	case KVM_XEN_ATTR_TYPE_SHARED_INFO:
+		mutex_lock(&kvm->lock);
 		r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
+		mutex_unlock(&kvm->lock);
 		break;
 
 	case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 		if (data->u.vector && data->u.vector < 0x10)
 			r = -EINVAL;
 		else {
+			mutex_lock(&kvm->lock);
 			kvm->arch.xen.upcall_vector = data->u.vector;
+			mutex_unlock(&kvm->lock);
 			r = 0;
 		}
 		break;
 
+	case KVM_XEN_ATTR_TYPE_EVTCHN:
+		r = kvm_xen_setattr_evtchn(kvm, data);
+		break;
+
+	case KVM_XEN_ATTR_TYPE_XEN_VERSION:
+		mutex_lock(&kvm->lock);
+		kvm->arch.xen.xen_version = data->u.xen_version;
+		mutex_unlock(&kvm->lock);
+		r = 0;
+		break;
+
 	default:
 		break;
 	}
 
-	mutex_unlock(&kvm->lock);
 	return r;
 }
 
@@ -433,6 +526,11 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 		r = 0;
 		break;
 
+	case KVM_XEN_ATTR_TYPE_XEN_VERSION:
+		data->u.xen_version = kvm->arch.xen.xen_version;
+		r = 0;
+		break;
+
 	default:
 		break;
 	}
@@ -457,48 +555,34 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 			     offsetof(struct compat_vcpu_info, time));
 
 		if (data->u.gpa == GPA_INVALID) {
-			vcpu->arch.xen.vcpu_info_set = false;
+			kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
 			r = 0;
 			break;
 		}
 
-		/* It must fit within a single page */
-		if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct vcpu_info) > PAGE_SIZE) {
-			r = -EINVAL;
-			break;
-		}
-
-		r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
+		r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
 					      &vcpu->arch.xen.vcpu_info_cache,
-					      data->u.gpa,
+					      NULL, KVM_HOST_USES_PFN, data->u.gpa,
 					      sizeof(struct vcpu_info));
-		if (!r) {
-			vcpu->arch.xen.vcpu_info_set = true;
+		if (!r)
 			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
-		}
+
 		break;
 
 	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 		if (data->u.gpa == GPA_INVALID) {
-			vcpu->arch.xen.vcpu_time_info_set = false;
+			kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
+						     &vcpu->arch.xen.vcpu_time_info_cache);
 			r = 0;
 			break;
 		}
 
-		/* It must fit within a single page */
-		if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct pvclock_vcpu_time_info) > PAGE_SIZE) {
-			r = -EINVAL;
-			break;
-		}
-
-		r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
+		r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
 					      &vcpu->arch.xen.vcpu_time_info_cache,
-					      data->u.gpa,
+					      NULL, KVM_HOST_USES_PFN, data->u.gpa,
 					      sizeof(struct pvclock_vcpu_time_info));
-		if (!r) {
-			vcpu->arch.xen.vcpu_time_info_set = true;
+		if (!r)
 			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
-		}
 		break;
 
 	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
@@ -507,24 +591,16 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 			break;
 		}
 		if (data->u.gpa == GPA_INVALID) {
-			vcpu->arch.xen.runstate_set = false;
+			kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
+						     &vcpu->arch.xen.runstate_cache);
 			r = 0;
 			break;
 		}
 
-		/* It must fit within a single page */
-		if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct vcpu_runstate_info) > PAGE_SIZE) {
-			r = -EINVAL;
-			break;
-		}
-
-		r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
+		r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
 					      &vcpu->arch.xen.runstate_cache,
-					      data->u.gpa,
+					      NULL, KVM_HOST_USES_PFN, data->u.gpa,
 					      sizeof(struct vcpu_runstate_info));
-		if (!r) {
-			vcpu->arch.xen.runstate_set = true;
-		}
 		break;
 
 	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
@@ -622,6 +698,46 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 		r = 0;
 		break;
 
+	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
+		if (data->u.vcpu_id >= KVM_MAX_VCPUS)
+			r = -EINVAL;
+		else {
+			vcpu->arch.xen.vcpu_id = data->u.vcpu_id;
+			r = 0;
+		}
+		break;
+
+	case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
+		if (data->u.timer.port) {
+			if (data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
+				r = -EINVAL;
+				break;
+			}
+			vcpu->arch.xen.timer_virq = data->u.timer.port;
+			kvm_xen_init_timer(vcpu);
+
+			/* Restart the timer if it's set */
+			if (data->u.timer.expires_ns)
+				kvm_xen_start_timer(vcpu, data->u.timer.expires_ns,
+						    data->u.timer.expires_ns -
+						    get_kvmclock_ns(vcpu->kvm));
+		} else if (kvm_xen_timer_enabled(vcpu)) {
+			kvm_xen_stop_timer(vcpu);
+			vcpu->arch.xen.timer_virq = 0;
+		}
+
+		r = 0;
+		break;
+
+	case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
+		if (data->u.vector && data->u.vector < 0x10)
+			r = -EINVAL;
+		else {
+			vcpu->arch.xen.upcall_vector = data->u.vector;
+			r = 0;
+		}
+		break;
+
 	default:
 		break;
 	}
@@ -639,7 +755,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 
 	switch (data->type) {
 	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
-		if (vcpu->arch.xen.vcpu_info_set)
+		if (vcpu->arch.xen.vcpu_info_cache.active)
 			data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
 		else
 			data->u.gpa = GPA_INVALID;
@@ -647,7 +763,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 		break;
 
 	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
-		if (vcpu->arch.xen.vcpu_time_info_set)
+		if (vcpu->arch.xen.vcpu_time_info_cache.active)
 			data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
 		else
 			data->u.gpa = GPA_INVALID;
@@ -659,7 +775,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 			r = -EOPNOTSUPP;
 			break;
 		}
-		if (vcpu->arch.xen.runstate_set) {
+		if (vcpu->arch.xen.runstate_cache.active) {
 			data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
 			r = 0;
 		}
@@ -697,6 +813,23 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 		r = -EINVAL;
 		break;
 
+	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
+		data->u.vcpu_id = vcpu->arch.xen.vcpu_id;
+		r = 0;
+		break;
+
+	case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
+		data->u.timer.port = vcpu->arch.xen.timer_virq;
+		data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
+		data->u.timer.expires_ns = vcpu->arch.xen.timer_expires;
+		r = 0;
+		break;
+
+	case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
+		data->u.vector = vcpu->arch.xen.upcall_vector;
+		r = 0;
+		break;
+
 	default:
 		break;
 	}
@@ -777,7 +910,11 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
 
 int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
 {
-	if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL)
+	/* Only some feature flags need to be *enabled* by userspace */
+	u32 permitted_flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL |
+		KVM_XEN_HVM_CONFIG_EVTCHN_SEND;
+
+	if (xhc->flags & ~permitted_flags)
 		return -EINVAL;
 
 	/*
@@ -802,18 +939,6 @@ int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
 	return 0;
 }
 
-void kvm_xen_init_vm(struct kvm *kvm)
-{
-}
-
-void kvm_xen_destroy_vm(struct kvm *kvm)
-{
-	kvm_gfn_to_pfn_cache_destroy(kvm, &kvm->arch.xen.shinfo_cache);
-
-	if (kvm->arch.xen_hvm_config.msr)
-		static_branch_slow_dec_deferred(&kvm_xen_enabled);
-}
-
 static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
 {
 	kvm_rax_write(vcpu, result);
@@ -830,10 +955,268 @@ static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
 	return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
 }
 
+static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports,
+			       evtchn_port_t *ports)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
+	unsigned long *pending_bits;
+	unsigned long flags;
+	bool ret = true;
+	int idx, i;
+
+	read_lock_irqsave(&gpc->lock, flags);
+	idx = srcu_read_lock(&kvm->srcu);
+	if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
+		goto out_rcu;
+
+	ret = false;
+	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
+		struct shared_info *shinfo = gpc->khva;
+		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
+	} else {
+		struct compat_shared_info *shinfo = gpc->khva;
+		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
+	}
+
+	for (i = 0; i < nr_ports; i++) {
+		if (test_bit(ports[i], pending_bits)) {
+			ret = true;
+			break;
+		}
+	}
+
+ out_rcu:
+	srcu_read_unlock(&kvm->srcu, idx);
+	read_unlock_irqrestore(&gpc->lock, flags);
+
+	return ret;
+}
+
+static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
+				 u64 param, u64 *r)
+{
+	int idx, i;
+	struct sched_poll sched_poll;
+	evtchn_port_t port, *ports;
+	gpa_t gpa;
+
+	if (!longmode || !lapic_in_kernel(vcpu) ||
+	    !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
+		return false;
+
+	idx = srcu_read_lock(&vcpu->kvm->srcu);
+	gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
+	srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+	if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &sched_poll,
+					sizeof(sched_poll))) {
+		*r = -EFAULT;
+		return true;
+	}
+
+	if (unlikely(sched_poll.nr_ports > 1)) {
+		/* Xen (unofficially) limits number of pollers to 128 */
+		if (sched_poll.nr_ports > 128) {
+			*r = -EINVAL;
+			return true;
+		}
+
+		ports = kmalloc_array(sched_poll.nr_ports,
+				      sizeof(*ports), GFP_KERNEL);
+		if (!ports) {
+			*r = -ENOMEM;
+			return true;
+		}
+	} else
+		ports = &port;
+
+	for (i = 0; i < sched_poll.nr_ports; i++) {
+		idx = srcu_read_lock(&vcpu->kvm->srcu);
+		gpa = kvm_mmu_gva_to_gpa_system(vcpu,
+						(gva_t)(sched_poll.ports + i),
+						NULL);
+		srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+		if (!gpa || kvm_vcpu_read_guest(vcpu, gpa,
+						&ports[i], sizeof(port))) {
+			*r = -EFAULT;
+			goto out;
+		}
+	}
+
+	if (sched_poll.nr_ports == 1)
+		vcpu->arch.xen.poll_evtchn = port;
+	else
+		vcpu->arch.xen.poll_evtchn = -1;
+
+	set_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.xen.poll_mask);
+
+	if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) {
+		vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
+
+		if (sched_poll.timeout)
+			mod_timer(&vcpu->arch.xen.poll_timer,
+				  jiffies + nsecs_to_jiffies(sched_poll.timeout));
+
+		kvm_vcpu_halt(vcpu);
+
+		if (sched_poll.timeout)
+			del_timer(&vcpu->arch.xen.poll_timer);
+
+		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+		kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+	}
+
+	vcpu->arch.xen.poll_evtchn = 0;
+	*r = 0;
+out:
+	/* Really, this is only needed in case of timeout */
+	clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.xen.poll_mask);
+
+	if (unlikely(sched_poll.nr_ports > 1))
+		kfree(ports);
+	return true;
+}
+
+static void cancel_evtchn_poll(struct timer_list *t)
+{
+	struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer);
+
+	kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
+	kvm_vcpu_kick(vcpu);
+}
+
+static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode,
+				   int cmd, u64 param, u64 *r)
+{
+	switch (cmd) {
+	case SCHEDOP_poll:
+		if (kvm_xen_schedop_poll(vcpu, longmode, param, r))
+			return true;
+		fallthrough;
+	case SCHEDOP_yield:
+		kvm_vcpu_on_spin(vcpu, true);
+		*r = 0;
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+struct compat_vcpu_set_singleshot_timer {
+    uint64_t timeout_abs_ns;
+    uint32_t flags;
+} __attribute__((packed));
+
+static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
+				  int vcpu_id, u64 param, u64 *r)
+{
+	struct vcpu_set_singleshot_timer oneshot;
+	s64 delta;
+	gpa_t gpa;
+	int idx;
+
+	if (!kvm_xen_timer_enabled(vcpu))
+		return false;
+
+	switch (cmd) {
+	case VCPUOP_set_singleshot_timer:
+		if (vcpu->arch.xen.vcpu_id != vcpu_id) {
+			*r = -EINVAL;
+			return true;
+		}
+		idx = srcu_read_lock(&vcpu->kvm->srcu);
+		gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
+		srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+		/*
+		 * The only difference for 32-bit compat is the 4 bytes of
+		 * padding after the interesting part of the structure. So
+		 * for a faithful emulation of Xen we have to *try* to copy
+		 * the padding and return -EFAULT if we can't. Otherwise we
+		 * might as well just have copied the 12-byte 32-bit struct.
+		 */
+		BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
+			     offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns));
+		BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
+			     sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns));
+		BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) !=
+			     offsetof(struct vcpu_set_singleshot_timer, flags));
+		BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) !=
+			     sizeof_field(struct vcpu_set_singleshot_timer, flags));
+
+		if (!gpa ||
+		    kvm_vcpu_read_guest(vcpu, gpa, &oneshot, longmode ? sizeof(oneshot) :
+					sizeof(struct compat_vcpu_set_singleshot_timer))) {
+			*r = -EFAULT;
+			return true;
+		}
+
+		delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
+		if ((oneshot.flags & VCPU_SSHOTTMR_future) && delta < 0) {
+			*r = -ETIME;
+			return true;
+		}
+
+		kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta);
+		*r = 0;
+		return true;
+
+	case VCPUOP_stop_singleshot_timer:
+		if (vcpu->arch.xen.vcpu_id != vcpu_id) {
+			*r = -EINVAL;
+			return true;
+		}
+		kvm_xen_stop_timer(vcpu);
+		*r = 0;
+		return true;
+	}
+
+	return false;
+}
+
+static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
+				       u64 *r)
+{
+	if (!kvm_xen_timer_enabled(vcpu))
+		return false;
+
+	if (timeout) {
+		uint64_t guest_now = get_kvmclock_ns(vcpu->kvm);
+		int64_t delta = timeout - guest_now;
+
+		/* Xen has a 'Linux workaround' in do_set_timer_op() which
+		 * checks for negative absolute timeout values (caused by
+		 * integer overflow), and for values about 13 days in the
+		 * future (2^50ns) which would be caused by jiffies
+		 * overflow. For those cases, it sets the timeout 100ms in
+		 * the future (not *too* soon, since if a guest really did
+		 * set a long timeout on purpose we don't want to keep
+		 * churning CPU time by waking it up).
+		 */
+		if (unlikely((int64_t)timeout < 0 ||
+			     (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
+			delta = 100 * NSEC_PER_MSEC;
+			timeout = guest_now + delta;
+		}
+
+		kvm_xen_start_timer(vcpu, timeout, delta);
+	} else {
+		kvm_xen_stop_timer(vcpu);
+	}
+
+	*r = 0;
+	return true;
+}
+
 int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
 {
 	bool longmode;
-	u64 input, params[6];
+	u64 input, params[6], r = -ENOSYS;
+	bool handled = false;
 
 	input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
 
@@ -864,6 +1247,40 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
 	trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
 				params[3], params[4], params[5]);
 
+	switch (input) {
+	case __HYPERVISOR_xen_version:
+		if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) {
+			r = vcpu->kvm->arch.xen.xen_version;
+			handled = true;
+		}
+		break;
+	case __HYPERVISOR_event_channel_op:
+		if (params[0] == EVTCHNOP_send)
+			handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r);
+		break;
+	case __HYPERVISOR_sched_op:
+		handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0],
+						 params[1], &r);
+		break;
+	case __HYPERVISOR_vcpu_op:
+		handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1],
+						params[2], &r);
+		break;
+	case __HYPERVISOR_set_timer_op: {
+		u64 timeout = params[0];
+		/* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */
+		if (!longmode)
+			timeout |= params[1] << 32;
+		handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r);
+		break;
+	}
+	default:
+		break;
+	}
+
+	if (handled)
+		return kvm_xen_hypercall_set_result(vcpu, r);
+
 	vcpu->run->exit_reason = KVM_EXIT_XEN;
 	vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
 	vcpu->run->xen.u.hcall.longmode = longmode;
@@ -890,14 +1307,28 @@ static inline int max_evtchn_port(struct kvm *kvm)
 		return COMPAT_EVTCHN_2L_NR_CHANNELS;
 }
 
+static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port)
+{
+	int poll_evtchn = vcpu->arch.xen.poll_evtchn;
+
+	if ((poll_evtchn == port || poll_evtchn == -1) &&
+	    test_and_clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.xen.poll_mask)) {
+		kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
+		kvm_vcpu_kick(vcpu);
+	}
+}
+
 /*
- * This follows the kvm_set_irq() API, so it returns:
+ * The return value from this function is propagated to kvm_set_irq() API,
+ * so it returns:
  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
  *  = 0   Interrupt was coalesced (previous irq is still pending)
  *  > 0   Number of CPUs interrupt was delivered to
+ *
+ * It is also called directly from kvm_arch_set_irq_inatomic(), where the
+ * only check on its return value is a comparison with -EWOULDBLOCK'.
  */
-int kvm_xen_set_evtchn_fast(struct kvm_kernel_irq_routing_entry *e,
-			    struct kvm *kvm)
+int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
 {
 	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
 	struct kvm_vcpu *vcpu;
@@ -905,23 +1336,29 @@ int kvm_xen_set_evtchn_fast(struct kvm_kernel_irq_routing_entry *e,
 	unsigned long flags;
 	int port_word_bit;
 	bool kick_vcpu = false;
-	int idx;
-	int rc;
+	int vcpu_idx, idx, rc;
 
-	vcpu = kvm_get_vcpu_by_id(kvm, e->xen_evtchn.vcpu);
-	if (!vcpu)
-		return -1;
+	vcpu_idx = READ_ONCE(xe->vcpu_idx);
+	if (vcpu_idx >= 0)
+		vcpu = kvm_get_vcpu(kvm, vcpu_idx);
+	else {
+		vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id);
+		if (!vcpu)
+			return -EINVAL;
+		WRITE_ONCE(xe->vcpu_idx, kvm_vcpu_get_idx(vcpu));
+	}
 
-	if (!vcpu->arch.xen.vcpu_info_set)
-		return -1;
+	if (!vcpu->arch.xen.vcpu_info_cache.active)
+		return -EINVAL;
 
-	if (e->xen_evtchn.port >= max_evtchn_port(kvm))
-		return -1;
+	if (xe->port >= max_evtchn_port(kvm))
+		return -EINVAL;
 
 	rc = -EWOULDBLOCK;
-	read_lock_irqsave(&gpc->lock, flags);
 
 	idx = srcu_read_lock(&kvm->srcu);
+
+	read_lock_irqsave(&gpc->lock, flags);
 	if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
 		goto out_rcu;
 
@@ -929,12 +1366,12 @@ int kvm_xen_set_evtchn_fast(struct kvm_kernel_irq_routing_entry *e,
 		struct shared_info *shinfo = gpc->khva;
 		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
 		mask_bits = (unsigned long *)&shinfo->evtchn_mask;
-		port_word_bit = e->xen_evtchn.port / 64;
+		port_word_bit = xe->port / 64;
 	} else {
 		struct compat_shared_info *shinfo = gpc->khva;
 		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
 		mask_bits = (unsigned long *)&shinfo->evtchn_mask;
-		port_word_bit = e->xen_evtchn.port / 32;
+		port_word_bit = xe->port / 32;
 	}
 
 	/*
@@ -944,39 +1381,68 @@ int kvm_xen_set_evtchn_fast(struct kvm_kernel_irq_routing_entry *e,
 	 * already set, then we kick the vCPU in question to write to the
 	 * *real* evtchn_pending_sel in its own guest vcpu_info struct.
 	 */
-	if (test_and_set_bit(e->xen_evtchn.port, pending_bits)) {
+	if (test_and_set_bit(xe->port, pending_bits)) {
 		rc = 0; /* It was already raised */
-	} else if (test_bit(e->xen_evtchn.port, mask_bits)) {
-		rc = -1; /* Masked */
+	} else if (test_bit(xe->port, mask_bits)) {
+		rc = -ENOTCONN; /* Masked */
+		kvm_xen_check_poller(vcpu, xe->port);
 	} else {
-		rc = 1; /* Delivered. But was the vCPU waking already? */
-		if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
-			kick_vcpu = true;
+		rc = 1; /* Delivered to the bitmap in shared_info. */
+		/* Now switch to the vCPU's vcpu_info to set the index and pending_sel */
+		read_unlock_irqrestore(&gpc->lock, flags);
+		gpc = &vcpu->arch.xen.vcpu_info_cache;
+
+		read_lock_irqsave(&gpc->lock, flags);
+		if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) {
+			/*
+			 * Could not access the vcpu_info. Set the bit in-kernel
+			 * and prod the vCPU to deliver it for itself.
+			 */
+			if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
+				kick_vcpu = true;
+			goto out_rcu;
+		}
+
+		if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
+			struct vcpu_info *vcpu_info = gpc->khva;
+			if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) {
+				WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
+				kick_vcpu = true;
+			}
+		} else {
+			struct compat_vcpu_info *vcpu_info = gpc->khva;
+			if (!test_and_set_bit(port_word_bit,
+					      (unsigned long *)&vcpu_info->evtchn_pending_sel)) {
+				WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
+				kick_vcpu = true;
+			}
+		}
+
+		/* For the per-vCPU lapic vector, deliver it as MSI. */
+		if (kick_vcpu && vcpu->arch.xen.upcall_vector) {
+			kvm_xen_inject_vcpu_vector(vcpu);
+			kick_vcpu = false;
+		}
 	}
 
  out_rcu:
-	srcu_read_unlock(&kvm->srcu, idx);
 	read_unlock_irqrestore(&gpc->lock, flags);
+	srcu_read_unlock(&kvm->srcu, idx);
 
 	if (kick_vcpu) {
-		kvm_make_request(KVM_REQ_EVENT, vcpu);
+		kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
 		kvm_vcpu_kick(vcpu);
 	}
 
 	return rc;
 }
 
-/* This is the version called from kvm_set_irq() as the .set function */
-static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
-			 int irq_source_id, int level, bool line_status)
+static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
 {
 	bool mm_borrowed = false;
 	int rc;
 
-	if (!level)
-		return -1;
-
-	rc = kvm_xen_set_evtchn_fast(e, kvm);
+	rc = kvm_xen_set_evtchn_fast(xe, kvm);
 	if (rc != -EWOULDBLOCK)
 		return rc;
 
@@ -1020,7 +1486,7 @@ static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm
 		struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
 		int idx;
 
-		rc = kvm_xen_set_evtchn_fast(e, kvm);
+		rc = kvm_xen_set_evtchn_fast(xe, kvm);
 		if (rc != -EWOULDBLOCK)
 			break;
 
@@ -1037,11 +1503,27 @@ static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm
 	return rc;
 }
 
+/* This is the version called from kvm_set_irq() as the .set function */
+static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
+			 int irq_source_id, int level, bool line_status)
+{
+	if (!level)
+		return -EINVAL;
+
+	return kvm_xen_set_evtchn(&e->xen_evtchn, kvm);
+}
+
+/*
+ * Set up an event channel interrupt from the KVM IRQ routing table.
+ * Used for e.g. PIRQ from passed through physical devices.
+ */
 int kvm_xen_setup_evtchn(struct kvm *kvm,
 			 struct kvm_kernel_irq_routing_entry *e,
 			 const struct kvm_irq_routing_entry *ue)
 
 {
+	struct kvm_vcpu *vcpu;
+
 	if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
 		return -EINVAL;
 
@@ -1049,10 +1531,328 @@ int kvm_xen_setup_evtchn(struct kvm *kvm,
 	if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
 		return -EINVAL;
 
+	/*
+	 * Xen gives us interesting mappings from vCPU index to APIC ID,
+	 * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs
+	 * to find it. Do that once at setup time, instead of every time.
+	 * But beware that on live update / live migration, the routing
+	 * table might be reinstated before the vCPU threads have finished
+	 * recreating their vCPUs.
+	 */
+	vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu);
+	if (vcpu)
+		e->xen_evtchn.vcpu_idx = kvm_vcpu_get_idx(vcpu);
+	else
+		e->xen_evtchn.vcpu_idx = -1;
+
 	e->xen_evtchn.port = ue->u.xen_evtchn.port;
-	e->xen_evtchn.vcpu = ue->u.xen_evtchn.vcpu;
+	e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu;
 	e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
 	e->set = evtchn_set_fn;
 
 	return 0;
 }
+
+/*
+ * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
+ */
+int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
+{
+	struct kvm_xen_evtchn e;
+	int ret;
+
+	if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
+		return -EINVAL;
+
+	/* We only support 2 level event channels for now */
+	if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
+		return -EINVAL;
+
+	e.port = uxe->port;
+	e.vcpu_id = uxe->vcpu;
+	e.vcpu_idx = -1;
+	e.priority = uxe->priority;
+
+	ret = kvm_xen_set_evtchn(&e, kvm);
+
+	/*
+	 * None of that 'return 1 if it actually got delivered' nonsense.
+	 * We don't care if it was masked (-ENOTCONN) either.
+	 */
+	if (ret > 0 || ret == -ENOTCONN)
+		ret = 0;
+
+	return ret;
+}
+
+/*
+ * Support for *outbound* event channel events via the EVTCHNOP_send hypercall.
+ */
+struct evtchnfd {
+	u32 send_port;
+	u32 type;
+	union {
+		struct kvm_xen_evtchn port;
+		struct {
+			u32 port; /* zero */
+			struct eventfd_ctx *ctx;
+		} eventfd;
+	} deliver;
+};
+
+/*
+ * Update target vCPU or priority for a registered sending channel.
+ */
+static int kvm_xen_eventfd_update(struct kvm *kvm,
+				  struct kvm_xen_hvm_attr *data)
+{
+	u32 port = data->u.evtchn.send_port;
+	struct evtchnfd *evtchnfd;
+
+	if (!port || port >= max_evtchn_port(kvm))
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+	evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
+	mutex_unlock(&kvm->lock);
+
+	if (!evtchnfd)
+		return -ENOENT;
+
+	/* For an UPDATE, nothing may change except the priority/vcpu */
+	if (evtchnfd->type != data->u.evtchn.type)
+		return -EINVAL;
+
+	/*
+	 * Port cannot change, and if it's zero that was an eventfd
+	 * which can't be changed either.
+	 */
+	if (!evtchnfd->deliver.port.port ||
+	    evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port)
+		return -EINVAL;
+
+	/* We only support 2 level event channels for now */
+	if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+	evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
+	if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) {
+		evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
+		evtchnfd->deliver.port.vcpu_idx = -1;
+	}
+	mutex_unlock(&kvm->lock);
+	return 0;
+}
+
+/*
+ * Configure the target (eventfd or local port delivery) for sending on
+ * a given event channel.
+ */
+static int kvm_xen_eventfd_assign(struct kvm *kvm,
+				  struct kvm_xen_hvm_attr *data)
+{
+	u32 port = data->u.evtchn.send_port;
+	struct eventfd_ctx *eventfd = NULL;
+	struct evtchnfd *evtchnfd = NULL;
+	int ret = -EINVAL;
+
+	if (!port || port >= max_evtchn_port(kvm))
+		return -EINVAL;
+
+	evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL);
+	if (!evtchnfd)
+		return -ENOMEM;
+
+	switch(data->u.evtchn.type) {
+	case EVTCHNSTAT_ipi:
+		/* IPI  must map back to the same port# */
+		if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port)
+			goto out; /* -EINVAL */
+		break;
+
+	case EVTCHNSTAT_interdomain:
+		if (data->u.evtchn.deliver.port.port) {
+			if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm))
+				goto out; /* -EINVAL */
+		} else {
+			eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd);
+			if (IS_ERR(eventfd)) {
+				ret = PTR_ERR(eventfd);
+				goto out;
+			}
+		}
+		break;
+
+	case EVTCHNSTAT_virq:
+	case EVTCHNSTAT_closed:
+	case EVTCHNSTAT_unbound:
+	case EVTCHNSTAT_pirq:
+	default: /* Unknown event channel type */
+		goto out; /* -EINVAL */
+	}
+
+	evtchnfd->send_port = data->u.evtchn.send_port;
+	evtchnfd->type = data->u.evtchn.type;
+	if (eventfd) {
+		evtchnfd->deliver.eventfd.ctx = eventfd;
+	} else {
+		/* We only support 2 level event channels for now */
+		if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
+			goto out; /* -EINVAL; */
+
+		evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port;
+		evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
+		evtchnfd->deliver.port.vcpu_idx = -1;
+		evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
+	}
+
+	mutex_lock(&kvm->lock);
+	ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
+			GFP_KERNEL);
+	mutex_unlock(&kvm->lock);
+	if (ret >= 0)
+		return 0;
+
+	if (ret == -ENOSPC)
+		ret = -EEXIST;
+out:
+	if (eventfd)
+		eventfd_ctx_put(eventfd);
+	kfree(evtchnfd);
+	return ret;
+}
+
+static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port)
+{
+	struct evtchnfd *evtchnfd;
+
+	mutex_lock(&kvm->lock);
+	evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
+	mutex_unlock(&kvm->lock);
+
+	if (!evtchnfd)
+		return -ENOENT;
+
+	if (kvm)
+		synchronize_srcu(&kvm->srcu);
+	if (!evtchnfd->deliver.port.port)
+		eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
+	kfree(evtchnfd);
+	return 0;
+}
+
+static int kvm_xen_eventfd_reset(struct kvm *kvm)
+{
+	struct evtchnfd *evtchnfd;
+	int i;
+
+	mutex_lock(&kvm->lock);
+	idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
+		idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
+		synchronize_srcu(&kvm->srcu);
+		if (!evtchnfd->deliver.port.port)
+			eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
+		kfree(evtchnfd);
+	}
+	mutex_unlock(&kvm->lock);
+
+	return 0;
+}
+
+static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
+{
+	u32 port = data->u.evtchn.send_port;
+
+	if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET)
+		return kvm_xen_eventfd_reset(kvm);
+
+	if (!port || port >= max_evtchn_port(kvm))
+		return -EINVAL;
+
+	if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN)
+		return kvm_xen_eventfd_deassign(kvm, port);
+	if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE)
+		return kvm_xen_eventfd_update(kvm, data);
+	if (data->u.evtchn.flags)
+		return -EINVAL;
+
+	return kvm_xen_eventfd_assign(kvm, data);
+}
+
+static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
+{
+	struct evtchnfd *evtchnfd;
+	struct evtchn_send send;
+	gpa_t gpa;
+	int idx;
+
+	idx = srcu_read_lock(&vcpu->kvm->srcu);
+	gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
+	srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+	if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &send, sizeof(send))) {
+		*r = -EFAULT;
+		return true;
+	}
+
+	/* The evtchn_ports idr is protected by vcpu->kvm->srcu */
+	evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
+	if (!evtchnfd)
+		return false;
+
+	if (evtchnfd->deliver.port.port) {
+		int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm);
+		if (ret < 0 && ret != -ENOTCONN)
+			return false;
+	} else {
+		eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
+	}
+
+	*r = 0;
+	return true;
+}
+
+void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
+	vcpu->arch.xen.poll_evtchn = 0;
+	timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
+}
+
+void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
+{
+	if (kvm_xen_timer_enabled(vcpu))
+		kvm_xen_stop_timer(vcpu);
+
+	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
+				     &vcpu->arch.xen.runstate_cache);
+	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
+				     &vcpu->arch.xen.vcpu_info_cache);
+	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
+				     &vcpu->arch.xen.vcpu_time_info_cache);
+	del_timer_sync(&vcpu->arch.xen.poll_timer);
+}
+
+void kvm_xen_init_vm(struct kvm *kvm)
+{
+	idr_init(&kvm->arch.xen.evtchn_ports);
+}
+
+void kvm_xen_destroy_vm(struct kvm *kvm)
+{
+	struct evtchnfd *evtchnfd;
+	int i;
+
+	kvm_gfn_to_pfn_cache_destroy(kvm, &kvm->arch.xen.shinfo_cache);
+
+	idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
+		if (!evtchnfd->deliver.port.port)
+			eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
+		kfree(evtchnfd);
+	}
+	idr_destroy(&kvm->arch.xen.evtchn_ports);
+
+	if (kvm->arch.xen_hvm_config.msr)
+		static_branch_slow_dec_deferred(&kvm_xen_enabled);
+}