1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright © 2019 Oracle and/or its affiliates. All rights reserved.
   4 * Copyright © 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   5 *
   6 * KVM Xen emulation
   7 */
 
   8
   9#include "x86.h"
  10#include "xen.h"
  11#include "hyperv.h"
  12#include "lapic.h"
  13
  14#include <linux/eventfd.h>
  15#include <linux/kvm_host.h>
  16#include <linux/sched/stat.h>
  17
  18#include <trace/events/kvm.h>
  19#include <xen/interface/xen.h>
  20#include <xen/interface/vcpu.h>
  21#include <xen/interface/version.h>
  22#include <xen/interface/event_channel.h>
  23#include <xen/interface/sched.h>
  24
 
 
 
  25#include "trace.h"
  26
  27static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm);
  28static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
  29static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r);
  30
  31DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
  32
  33static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
  34{
  35	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
  36	struct pvclock_wall_clock *wc;
  37	gpa_t gpa = gfn_to_gpa(gfn);
  38	u32 *wc_sec_hi;
  39	u32 wc_version;
  40	u64 wall_nsec;
  41	int ret = 0;
  42	int idx = srcu_read_lock(&kvm->srcu);
  43
  44	if (gfn == KVM_XEN_INVALID_GFN) {
  45		kvm_gpc_deactivate(gpc);
  46		goto out;
  47	}
  48
  49	do {
  50		ret = kvm_gpc_activate(gpc, gpa, PAGE_SIZE);
  51		if (ret)
  52			goto out;
  53
  54		/*
  55		 * This code mirrors kvm_write_wall_clock() except that it writes
  56		 * directly through the pfn cache and doesn't mark the page dirty.
  57		 */
  58		wall_nsec = ktime_get_real_ns() - get_kvmclock_ns(kvm);
  59
  60		/* It could be invalid again already, so we need to check */
  61		read_lock_irq(&gpc->lock);
  62
  63		if (gpc->valid)
  64			break;
  65
  66		read_unlock_irq(&gpc->lock);
  67	} while (1);
  68
  69	/* Paranoia checks on the 32-bit struct layout */
  70	BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900);
  71	BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924);
  72	BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);
  73
  74#ifdef CONFIG_X86_64
  75	/* Paranoia checks on the 64-bit struct layout */
  76	BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00);
  77	BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c);
  78
  79	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
  80		struct shared_info *shinfo = gpc->khva;
  81
  82		wc_sec_hi = &shinfo->wc_sec_hi;
  83		wc = &shinfo->wc;
  84	} else
  85#endif
  86	{
  87		struct compat_shared_info *shinfo = gpc->khva;
  88
  89		wc_sec_hi = &shinfo->arch.wc_sec_hi;
  90		wc = &shinfo->wc;
  91	}
  92
  93	/* Increment and ensure an odd value */
  94	wc_version = wc->version = (wc->version + 1) | 1;
  95	smp_wmb();
  96
  97	wc->nsec = do_div(wall_nsec,  1000000000);
  98	wc->sec = (u32)wall_nsec;
  99	*wc_sec_hi = wall_nsec >> 32;
 100	smp_wmb();
 101
 102	wc->version = wc_version + 1;
 103	read_unlock_irq(&gpc->lock);
 104
 105	kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);
 106
 107out:
 108	srcu_read_unlock(&kvm->srcu, idx);
 109	return ret;
 110}
 111
 112void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu)
 113{
 114	if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) {
 115		struct kvm_xen_evtchn e;
 116
 117		e.vcpu_id = vcpu->vcpu_id;
 118		e.vcpu_idx = vcpu->vcpu_idx;
 119		e.port = vcpu->arch.xen.timer_virq;
 120		e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
 121
 122		kvm_xen_set_evtchn(&e, vcpu->kvm);
 123
 124		vcpu->arch.xen.timer_expires = 0;
 125		atomic_set(&vcpu->arch.xen.timer_pending, 0);
 126	}
 127}
 128
 129static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
 130{
 131	struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu,
 132					     arch.xen.timer);
 
 
 
 133	if (atomic_read(&vcpu->arch.xen.timer_pending))
 134		return HRTIMER_NORESTART;
 135
 
 
 
 
 
 
 
 
 
 
 
 136	atomic_inc(&vcpu->arch.xen.timer_pending);
 137	kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
 138	kvm_vcpu_kick(vcpu);
 139
 140	return HRTIMER_NORESTART;
 141}
 142
 143static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_ns)
 144{
 
 
 
 
 
 
 
 
 145	atomic_set(&vcpu->arch.xen.timer_pending, 0);
 146	vcpu->arch.xen.timer_expires = guest_abs;
 147
 148	if (delta_ns <= 0) {
 149		xen_timer_callback(&vcpu->arch.xen.timer);
 150	} else {
 151		ktime_t ktime_now = ktime_get();
 152		hrtimer_start(&vcpu->arch.xen.timer,
 153			      ktime_add_ns(ktime_now, delta_ns),
 154			      HRTIMER_MODE_ABS_HARD);
 155	}
 156}
 157
 158static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
 159{
 160	hrtimer_cancel(&vcpu->arch.xen.timer);
 161	vcpu->arch.xen.timer_expires = 0;
 162	atomic_set(&vcpu->arch.xen.timer_pending, 0);
 163}
 164
 165static void kvm_xen_init_timer(struct kvm_vcpu *vcpu)
 166{
 167	hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC,
 168		     HRTIMER_MODE_ABS_HARD);
 169	vcpu->arch.xen.timer.function = xen_timer_callback;
 170}
 171
 172static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic)
 173{
 174	struct kvm_vcpu_xen *vx = &v->arch.xen;
 175	struct gfn_to_pfn_cache *gpc1 = &vx->runstate_cache;
 176	struct gfn_to_pfn_cache *gpc2 = &vx->runstate2_cache;
 177	size_t user_len, user_len1, user_len2;
 178	struct vcpu_runstate_info rs;
 179	unsigned long flags;
 180	size_t times_ofs;
 181	uint8_t *update_bit = NULL;
 182	uint64_t entry_time;
 183	uint64_t *rs_times;
 184	int *rs_state;
 185
 186	/*
 187	 * The only difference between 32-bit and 64-bit versions of the
 188	 * runstate struct is the alignment of uint64_t in 32-bit, which
 189	 * means that the 64-bit version has an additional 4 bytes of
 190	 * padding after the first field 'state'. Let's be really really
 191	 * paranoid about that, and matching it with our internal data
 192	 * structures that we memcpy into it...
 193	 */
 194	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0);
 195	BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0);
 196	BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);
 197#ifdef CONFIG_X86_64
 198	/*
 199	 * The 64-bit structure has 4 bytes of padding before 'state_entry_time'
 200	 * so each subsequent field is shifted by 4, and it's 4 bytes longer.
 201	 */
 202	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 203		     offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
 204	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
 205		     offsetof(struct compat_vcpu_runstate_info, time) + 4);
 206	BUILD_BUG_ON(sizeof(struct vcpu_runstate_info) != 0x2c + 4);
 207#endif
 208	/*
 209	 * The state field is in the same place at the start of both structs,
 210	 * and is the same size (int) as vx->current_runstate.
 211	 */
 212	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
 213		     offsetof(struct compat_vcpu_runstate_info, state));
 214	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) !=
 215		     sizeof(vx->current_runstate));
 216	BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
 217		     sizeof(vx->current_runstate));
 218
 219	/*
 220	 * The state_entry_time field is 64 bits in both versions, and the
 221	 * XEN_RUNSTATE_UPDATE flag is in the top bit, which given that x86
 222	 * is little-endian means that it's in the last *byte* of the word.
 223	 * That detail is important later.
 224	 */
 225	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
 226		     sizeof(uint64_t));
 227	BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
 228		     sizeof(uint64_t));
 229	BUILD_BUG_ON((XEN_RUNSTATE_UPDATE >> 56) != 0x80);
 230
 231	/*
 232	 * The time array is four 64-bit quantities in both versions, matching
 233	 * the vx->runstate_times and immediately following state_entry_time.
 234	 */
 235	BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 236		     offsetof(struct vcpu_runstate_info, time) - sizeof(uint64_t));
 237	BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
 238		     offsetof(struct compat_vcpu_runstate_info, time) - sizeof(uint64_t));
 239	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 240		     sizeof_field(struct compat_vcpu_runstate_info, time));
 241	BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 242		     sizeof(vx->runstate_times));
 243
 244	if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
 245		user_len = sizeof(struct vcpu_runstate_info);
 246		times_ofs = offsetof(struct vcpu_runstate_info,
 247				     state_entry_time);
 248	} else {
 249		user_len = sizeof(struct compat_vcpu_runstate_info);
 250		times_ofs = offsetof(struct compat_vcpu_runstate_info,
 251				     state_entry_time);
 252	}
 253
 254	/*
 255	 * There are basically no alignment constraints. The guest can set it
 256	 * up so it crosses from one page to the next, and at arbitrary byte
 257	 * alignment (and the 32-bit ABI doesn't align the 64-bit integers
 258	 * anyway, even if the overall struct had been 64-bit aligned).
 259	 */
 260	if ((gpc1->gpa & ~PAGE_MASK) + user_len >= PAGE_SIZE) {
 261		user_len1 = PAGE_SIZE - (gpc1->gpa & ~PAGE_MASK);
 262		user_len2 = user_len - user_len1;
 263	} else {
 264		user_len1 = user_len;
 265		user_len2 = 0;
 266	}
 267	BUG_ON(user_len1 + user_len2 != user_len);
 268
 269 retry:
 270	/*
 271	 * Attempt to obtain the GPC lock on *both* (if there are two)
 272	 * gfn_to_pfn caches that cover the region.
 273	 */
 274	if (atomic) {
 275		local_irq_save(flags);
 276		if (!read_trylock(&gpc1->lock)) {
 277			local_irq_restore(flags);
 278			return;
 279		}
 280	} else {
 281		read_lock_irqsave(&gpc1->lock, flags);
 282	}
 283	while (!kvm_gpc_check(gpc1, user_len1)) {
 284		read_unlock_irqrestore(&gpc1->lock, flags);
 285
 286		/* When invoked from kvm_sched_out() we cannot sleep */
 287		if (atomic)
 288			return;
 289
 290		if (kvm_gpc_refresh(gpc1, user_len1))
 291			return;
 292
 293		read_lock_irqsave(&gpc1->lock, flags);
 294	}
 295
 296	if (likely(!user_len2)) {
 297		/*
 298		 * Set up three pointers directly to the runstate_info
 299		 * struct in the guest (via the GPC).
 300		 *
 301		 *  • @rs_state   → state field
 302		 *  • @rs_times   → state_entry_time field.
 303		 *  • @update_bit → last byte of state_entry_time, which
 304		 *                  contains the XEN_RUNSTATE_UPDATE bit.
 305		 */
 306		rs_state = gpc1->khva;
 307		rs_times = gpc1->khva + times_ofs;
 308		if (v->kvm->arch.xen.runstate_update_flag)
 309			update_bit = ((void *)(&rs_times[1])) - 1;
 310	} else {
 311		/*
 312		 * The guest's runstate_info is split across two pages and we
 313		 * need to hold and validate both GPCs simultaneously. We can
 314		 * declare a lock ordering GPC1 > GPC2 because nothing else
 315		 * takes them more than one at a time. Set a subclass on the
 316		 * gpc1 lock to make lockdep shut up about it.
 317		 */
 318		lock_set_subclass(&gpc1->lock.dep_map, 1, _THIS_IP_);
 319		if (atomic) {
 320			if (!read_trylock(&gpc2->lock)) {
 321				read_unlock_irqrestore(&gpc1->lock, flags);
 322				return;
 323			}
 324		} else {
 325			read_lock(&gpc2->lock);
 326		}
 327
 328		if (!kvm_gpc_check(gpc2, user_len2)) {
 329			read_unlock(&gpc2->lock);
 330			read_unlock_irqrestore(&gpc1->lock, flags);
 331
 332			/* When invoked from kvm_sched_out() we cannot sleep */
 333			if (atomic)
 334				return;
 335
 336			/*
 337			 * Use kvm_gpc_activate() here because if the runstate
 338			 * area was configured in 32-bit mode and only extends
 339			 * to the second page now because the guest changed to
 340			 * 64-bit mode, the second GPC won't have been set up.
 341			 */
 342			if (kvm_gpc_activate(gpc2, gpc1->gpa + user_len1,
 343					     user_len2))
 344				return;
 345
 346			/*
 347			 * We dropped the lock on GPC1 so we have to go all the
 348			 * way back and revalidate that too.
 349			 */
 350			goto retry;
 351		}
 352
 353		/*
 354		 * In this case, the runstate_info struct will be assembled on
 355		 * the kernel stack (compat or not as appropriate) and will
 356		 * be copied to GPC1/GPC2 with a dual memcpy. Set up the three
 357		 * rs pointers accordingly.
 358		 */
 359		rs_times = &rs.state_entry_time;
 360
 361		/*
 362		 * The rs_state pointer points to the start of what we'll
 363		 * copy to the guest, which in the case of a compat guest
 364		 * is the 32-bit field that the compiler thinks is padding.
 365		 */
 366		rs_state = ((void *)rs_times) - times_ofs;
 367
 368		/*
 369		 * The update_bit is still directly in the guest memory,
 370		 * via one GPC or the other.
 371		 */
 372		if (v->kvm->arch.xen.runstate_update_flag) {
 373			if (user_len1 >= times_ofs + sizeof(uint64_t))
 374				update_bit = gpc1->khva + times_ofs +
 375					sizeof(uint64_t) - 1;
 376			else
 377				update_bit = gpc2->khva + times_ofs +
 378					sizeof(uint64_t) - 1 - user_len1;
 379		}
 380
 381#ifdef CONFIG_X86_64
 382		/*
 383		 * Don't leak kernel memory through the padding in the 64-bit
 384		 * version of the struct.
 385		 */
 386		memset(&rs, 0, offsetof(struct vcpu_runstate_info, state_entry_time));
 387#endif
 388	}
 389
 390	/*
 391	 * First, set the XEN_RUNSTATE_UPDATE bit in the top bit of the
 392	 * state_entry_time field, directly in the guest. We need to set
 393	 * that (and write-barrier) before writing to the rest of the
 394	 * structure, and clear it last. Just as Xen does, we address the
 395	 * single *byte* in which it resides because it might be in a
 396	 * different cache line to the rest of the 64-bit word, due to
 397	 * the (lack of) alignment constraints.
 398	 */
 399	entry_time = vx->runstate_entry_time;
 400	if (update_bit) {
 401		entry_time |= XEN_RUNSTATE_UPDATE;
 402		*update_bit = (vx->runstate_entry_time | XEN_RUNSTATE_UPDATE) >> 56;
 403		smp_wmb();
 404	}
 405
 406	/*
 407	 * Now assemble the actual structure, either on our kernel stack
 408	 * or directly in the guest according to how the rs_state and
 409	 * rs_times pointers were set up above.
 410	 */
 411	*rs_state = vx->current_runstate;
 412	rs_times[0] = entry_time;
 413	memcpy(rs_times + 1, vx->runstate_times, sizeof(vx->runstate_times));
 414
 415	/* For the split case, we have to then copy it to the guest. */
 416	if (user_len2) {
 417		memcpy(gpc1->khva, rs_state, user_len1);
 418		memcpy(gpc2->khva, ((void *)rs_state) + user_len1, user_len2);
 419	}
 420	smp_wmb();
 421
 422	/* Finally, clear the XEN_RUNSTATE_UPDATE bit. */
 423	if (update_bit) {
 424		entry_time &= ~XEN_RUNSTATE_UPDATE;
 425		*update_bit = entry_time >> 56;
 426		smp_wmb();
 427	}
 428
 429	if (user_len2)
 430		read_unlock(&gpc2->lock);
 431
 432	read_unlock_irqrestore(&gpc1->lock, flags);
 433
 434	mark_page_dirty_in_slot(v->kvm, gpc1->memslot, gpc1->gpa >> PAGE_SHIFT);
 435	if (user_len2)
 436		mark_page_dirty_in_slot(v->kvm, gpc2->memslot, gpc2->gpa >> PAGE_SHIFT);
 437}
 438
 439void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
 440{
 441	struct kvm_vcpu_xen *vx = &v->arch.xen;
 442	u64 now = get_kvmclock_ns(v->kvm);
 443	u64 delta_ns = now - vx->runstate_entry_time;
 444	u64 run_delay = current->sched_info.run_delay;
 445
 446	if (unlikely(!vx->runstate_entry_time))
 447		vx->current_runstate = RUNSTATE_offline;
 448
 449	/*
 450	 * Time waiting for the scheduler isn't "stolen" if the
 451	 * vCPU wasn't running anyway.
 452	 */
 453	if (vx->current_runstate == RUNSTATE_running) {
 454		u64 steal_ns = run_delay - vx->last_steal;
 455
 456		delta_ns -= steal_ns;
 457
 458		vx->runstate_times[RUNSTATE_runnable] += steal_ns;
 459	}
 460	vx->last_steal = run_delay;
 461
 462	vx->runstate_times[vx->current_runstate] += delta_ns;
 463	vx->current_runstate = state;
 464	vx->runstate_entry_time = now;
 465
 466	if (vx->runstate_cache.active)
 467		kvm_xen_update_runstate_guest(v, state == RUNSTATE_runnable);
 468}
 469
 470static void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
 471{
 472	struct kvm_lapic_irq irq = { };
 473	int r;
 474
 475	irq.dest_id = v->vcpu_id;
 476	irq.vector = v->arch.xen.upcall_vector;
 477	irq.dest_mode = APIC_DEST_PHYSICAL;
 478	irq.shorthand = APIC_DEST_NOSHORT;
 479	irq.delivery_mode = APIC_DM_FIXED;
 480	irq.level = 1;
 481
 482	/* The fast version will always work for physical unicast */
 483	WARN_ON_ONCE(!kvm_irq_delivery_to_apic_fast(v->kvm, NULL, &irq, &r, NULL));
 484}
 485
 486/*
 487 * On event channel delivery, the vcpu_info may not have been accessible.
 488 * In that case, there are bits in vcpu->arch.xen.evtchn_pending_sel which
 489 * need to be marked into the vcpu_info (and evtchn_upcall_pending set).
 490 * Do so now that we can sleep in the context of the vCPU to bring the
 491 * page in, and refresh the pfn cache for it.
 492 */
 493void kvm_xen_inject_pending_events(struct kvm_vcpu *v)
 494{
 495	unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel);
 496	struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
 497	unsigned long flags;
 498
 499	if (!evtchn_pending_sel)
 500		return;
 501
 502	/*
 503	 * Yes, this is an open-coded loop. But that's just what put_user()
 504	 * does anyway. Page it in and retry the instruction. We're just a
 505	 * little more honest about it.
 506	 */
 507	read_lock_irqsave(&gpc->lock, flags);
 508	while (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
 509		read_unlock_irqrestore(&gpc->lock, flags);
 510
 511		if (kvm_gpc_refresh(gpc, sizeof(struct vcpu_info)))
 512			return;
 513
 514		read_lock_irqsave(&gpc->lock, flags);
 515	}
 516
 517	/* Now gpc->khva is a valid kernel address for the vcpu_info */
 518	if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
 519		struct vcpu_info *vi = gpc->khva;
 520
 521		asm volatile(LOCK_PREFIX "orq %0, %1\n"
 522			     "notq %0\n"
 523			     LOCK_PREFIX "andq %0, %2\n"
 524			     : "=r" (evtchn_pending_sel),
 525			       "+m" (vi->evtchn_pending_sel),
 526			       "+m" (v->arch.xen.evtchn_pending_sel)
 527			     : "0" (evtchn_pending_sel));
 528		WRITE_ONCE(vi->evtchn_upcall_pending, 1);
 529	} else {
 530		u32 evtchn_pending_sel32 = evtchn_pending_sel;
 531		struct compat_vcpu_info *vi = gpc->khva;
 532
 533		asm volatile(LOCK_PREFIX "orl %0, %1\n"
 534			     "notl %0\n"
 535			     LOCK_PREFIX "andl %0, %2\n"
 536			     : "=r" (evtchn_pending_sel32),
 537			       "+m" (vi->evtchn_pending_sel),
 538			       "+m" (v->arch.xen.evtchn_pending_sel)
 539			     : "0" (evtchn_pending_sel32));
 540		WRITE_ONCE(vi->evtchn_upcall_pending, 1);
 541	}
 542	read_unlock_irqrestore(&gpc->lock, flags);
 543
 544	/* For the per-vCPU lapic vector, deliver it as MSI. */
 545	if (v->arch.xen.upcall_vector)
 546		kvm_xen_inject_vcpu_vector(v);
 547
 548	mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
 549}
 550
 551int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
 552{
 553	struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
 554	unsigned long flags;
 555	u8 rc = 0;
 556
 557	/*
 558	 * If the global upcall vector (HVMIRQ_callback_vector) is set and
 559	 * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
 560	 */
 561
 562	/* No need for compat handling here */
 563	BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
 564		     offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
 565	BUILD_BUG_ON(sizeof(rc) !=
 566		     sizeof_field(struct vcpu_info, evtchn_upcall_pending));
 567	BUILD_BUG_ON(sizeof(rc) !=
 568		     sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));
 569
 570	read_lock_irqsave(&gpc->lock, flags);
 571	while (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
 572		read_unlock_irqrestore(&gpc->lock, flags);
 573
 574		/*
 575		 * This function gets called from kvm_vcpu_block() after setting the
 576		 * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
 577		 * from a HLT. So we really mustn't sleep. If the page ended up absent
 578		 * at that point, just return 1 in order to trigger an immediate wake,
 579		 * and we'll end up getting called again from a context where we *can*
 580		 * fault in the page and wait for it.
 581		 */
 582		if (in_atomic() || !task_is_running(current))
 583			return 1;
 584
 585		if (kvm_gpc_refresh(gpc, sizeof(struct vcpu_info))) {
 586			/*
 587			 * If this failed, userspace has screwed up the
 588			 * vcpu_info mapping. No interrupts for you.
 589			 */
 590			return 0;
 591		}
 592		read_lock_irqsave(&gpc->lock, flags);
 593	}
 594
 595	rc = ((struct vcpu_info *)gpc->khva)->evtchn_upcall_pending;
 596	read_unlock_irqrestore(&gpc->lock, flags);
 597	return rc;
 598}
 599
 600int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 601{
 602	int r = -ENOENT;
 603
 604
 605	switch (data->type) {
 606	case KVM_XEN_ATTR_TYPE_LONG_MODE:
 607		if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
 608			r = -EINVAL;
 609		} else {
 610			mutex_lock(&kvm->arch.xen.xen_lock);
 611			kvm->arch.xen.long_mode = !!data->u.long_mode;
 612			mutex_unlock(&kvm->arch.xen.xen_lock);
 613			r = 0;
 614		}
 615		break;
 616
 617	case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 618		mutex_lock(&kvm->arch.xen.xen_lock);
 619		r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
 620		mutex_unlock(&kvm->arch.xen.xen_lock);
 621		break;
 622
 623	case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 624		if (data->u.vector && data->u.vector < 0x10)
 625			r = -EINVAL;
 626		else {
 627			mutex_lock(&kvm->arch.xen.xen_lock);
 628			kvm->arch.xen.upcall_vector = data->u.vector;
 629			mutex_unlock(&kvm->arch.xen.xen_lock);
 630			r = 0;
 631		}
 632		break;
 633
 634	case KVM_XEN_ATTR_TYPE_EVTCHN:
 635		r = kvm_xen_setattr_evtchn(kvm, data);
 636		break;
 637
 638	case KVM_XEN_ATTR_TYPE_XEN_VERSION:
 639		mutex_lock(&kvm->arch.xen.xen_lock);
 640		kvm->arch.xen.xen_version = data->u.xen_version;
 641		mutex_unlock(&kvm->arch.xen.xen_lock);
 642		r = 0;
 643		break;
 644
 645	case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
 646		if (!sched_info_on()) {
 647			r = -EOPNOTSUPP;
 648			break;
 649		}
 650		mutex_lock(&kvm->arch.xen.xen_lock);
 651		kvm->arch.xen.runstate_update_flag = !!data->u.runstate_update_flag;
 652		mutex_unlock(&kvm->arch.xen.xen_lock);
 653		r = 0;
 654		break;
 655
 656	default:
 657		break;
 658	}
 659
 660	return r;
 661}
 662
 663int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 664{
 665	int r = -ENOENT;
 666
 667	mutex_lock(&kvm->arch.xen.xen_lock);
 668
 669	switch (data->type) {
 670	case KVM_XEN_ATTR_TYPE_LONG_MODE:
 671		data->u.long_mode = kvm->arch.xen.long_mode;
 672		r = 0;
 673		break;
 674
 675	case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 676		if (kvm->arch.xen.shinfo_cache.active)
 677			data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
 678		else
 679			data->u.shared_info.gfn = KVM_XEN_INVALID_GFN;
 680		r = 0;
 681		break;
 682
 683	case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 684		data->u.vector = kvm->arch.xen.upcall_vector;
 685		r = 0;
 686		break;
 687
 688	case KVM_XEN_ATTR_TYPE_XEN_VERSION:
 689		data->u.xen_version = kvm->arch.xen.xen_version;
 690		r = 0;
 691		break;
 692
 693	case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
 694		if (!sched_info_on()) {
 695			r = -EOPNOTSUPP;
 696			break;
 697		}
 698		data->u.runstate_update_flag = kvm->arch.xen.runstate_update_flag;
 699		r = 0;
 700		break;
 701
 702	default:
 703		break;
 704	}
 705
 706	mutex_unlock(&kvm->arch.xen.xen_lock);
 707	return r;
 708}
 709
 710int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 711{
 712	int idx, r = -ENOENT;
 713
 714	mutex_lock(&vcpu->kvm->arch.xen.xen_lock);
 715	idx = srcu_read_lock(&vcpu->kvm->srcu);
 716
 717	switch (data->type) {
 718	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 719		/* No compat necessary here. */
 720		BUILD_BUG_ON(sizeof(struct vcpu_info) !=
 721			     sizeof(struct compat_vcpu_info));
 722		BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
 723			     offsetof(struct compat_vcpu_info, time));
 724
 725		if (data->u.gpa == KVM_XEN_INVALID_GPA) {
 726			kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
 727			r = 0;
 728			break;
 729		}
 730
 731		r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_info_cache,
 732				     data->u.gpa, sizeof(struct vcpu_info));
 733		if (!r)
 734			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 735
 736		break;
 737
 738	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 739		if (data->u.gpa == KVM_XEN_INVALID_GPA) {
 740			kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
 741			r = 0;
 742			break;
 743		}
 744
 745		r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_time_info_cache,
 746				     data->u.gpa,
 747				     sizeof(struct pvclock_vcpu_time_info));
 748		if (!r)
 749			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 750		break;
 751
 752	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: {
 753		size_t sz, sz1, sz2;
 754
 755		if (!sched_info_on()) {
 756			r = -EOPNOTSUPP;
 757			break;
 758		}
 759		if (data->u.gpa == KVM_XEN_INVALID_GPA) {
 760			r = 0;
 761		deactivate_out:
 762			kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
 763			kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
 764			break;
 765		}
 766
 767		/*
 768		 * If the guest switches to 64-bit mode after setting the runstate
 769		 * address, that's actually OK. kvm_xen_update_runstate_guest()
 770		 * will cope.
 771		 */
 772		if (IS_ENABLED(CONFIG_64BIT) && vcpu->kvm->arch.xen.long_mode)
 773			sz = sizeof(struct vcpu_runstate_info);
 774		else
 775			sz = sizeof(struct compat_vcpu_runstate_info);
 776
 777		/* How much fits in the (first) page? */
 778		sz1 = PAGE_SIZE - (data->u.gpa & ~PAGE_MASK);
 779		r = kvm_gpc_activate(&vcpu->arch.xen.runstate_cache,
 780				     data->u.gpa, sz1);
 781		if (r)
 782			goto deactivate_out;
 783
 784		/* Either map the second page, or deactivate the second GPC */
 785		if (sz1 >= sz) {
 786			kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
 787		} else {
 788			sz2 = sz - sz1;
 789			BUG_ON((data->u.gpa + sz1) & ~PAGE_MASK);
 790			r = kvm_gpc_activate(&vcpu->arch.xen.runstate2_cache,
 791					     data->u.gpa + sz1, sz2);
 792			if (r)
 793				goto deactivate_out;
 794		}
 795
 796		kvm_xen_update_runstate_guest(vcpu, false);
 797		break;
 798	}
 799	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 800		if (!sched_info_on()) {
 801			r = -EOPNOTSUPP;
 802			break;
 803		}
 804		if (data->u.runstate.state > RUNSTATE_offline) {
 805			r = -EINVAL;
 806			break;
 807		}
 808
 809		kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 810		r = 0;
 811		break;
 812
 813	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 814		if (!sched_info_on()) {
 815			r = -EOPNOTSUPP;
 816			break;
 817		}
 818		if (data->u.runstate.state > RUNSTATE_offline) {
 819			r = -EINVAL;
 820			break;
 821		}
 822		if (data->u.runstate.state_entry_time !=
 823		    (data->u.runstate.time_running +
 824		     data->u.runstate.time_runnable +
 825		     data->u.runstate.time_blocked +
 826		     data->u.runstate.time_offline)) {
 827			r = -EINVAL;
 828			break;
 829		}
 830		if (get_kvmclock_ns(vcpu->kvm) <
 831		    data->u.runstate.state_entry_time) {
 832			r = -EINVAL;
 833			break;
 834		}
 835
 836		vcpu->arch.xen.current_runstate = data->u.runstate.state;
 837		vcpu->arch.xen.runstate_entry_time =
 838			data->u.runstate.state_entry_time;
 839		vcpu->arch.xen.runstate_times[RUNSTATE_running] =
 840			data->u.runstate.time_running;
 841		vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
 842			data->u.runstate.time_runnable;
 843		vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
 844			data->u.runstate.time_blocked;
 845		vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
 846			data->u.runstate.time_offline;
 847		vcpu->arch.xen.last_steal = current->sched_info.run_delay;
 848		r = 0;
 849		break;
 850
 851	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 852		if (!sched_info_on()) {
 853			r = -EOPNOTSUPP;
 854			break;
 855		}
 856		if (data->u.runstate.state > RUNSTATE_offline &&
 857		    data->u.runstate.state != (u64)-1) {
 858			r = -EINVAL;
 859			break;
 860		}
 861		/* The adjustment must add up */
 862		if (data->u.runstate.state_entry_time !=
 863		    (data->u.runstate.time_running +
 864		     data->u.runstate.time_runnable +
 865		     data->u.runstate.time_blocked +
 866		     data->u.runstate.time_offline)) {
 867			r = -EINVAL;
 868			break;
 869		}
 870
 871		if (get_kvmclock_ns(vcpu->kvm) <
 872		    (vcpu->arch.xen.runstate_entry_time +
 873		     data->u.runstate.state_entry_time)) {
 874			r = -EINVAL;
 875			break;
 876		}
 877
 878		vcpu->arch.xen.runstate_entry_time +=
 879			data->u.runstate.state_entry_time;
 880		vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
 881			data->u.runstate.time_running;
 882		vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
 883			data->u.runstate.time_runnable;
 884		vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
 885			data->u.runstate.time_blocked;
 886		vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
 887			data->u.runstate.time_offline;
 888
 889		if (data->u.runstate.state <= RUNSTATE_offline)
 890			kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 891		else if (vcpu->arch.xen.runstate_cache.active)
 892			kvm_xen_update_runstate_guest(vcpu, false);
 893		r = 0;
 894		break;
 895
 896	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
 897		if (data->u.vcpu_id >= KVM_MAX_VCPUS)
 898			r = -EINVAL;
 899		else {
 900			vcpu->arch.xen.vcpu_id = data->u.vcpu_id;
 901			r = 0;
 902		}
 903		break;
 904
 905	case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
 906		if (data->u.timer.port &&
 907		    data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
 908			r = -EINVAL;
 909			break;
 910		}
 911
 912		if (!vcpu->arch.xen.timer.function)
 913			kvm_xen_init_timer(vcpu);
 914
 915		/* Stop the timer (if it's running) before changing the vector */
 916		kvm_xen_stop_timer(vcpu);
 917		vcpu->arch.xen.timer_virq = data->u.timer.port;
 918
 919		/* Start the timer if the new value has a valid vector+expiry. */
 920		if (data->u.timer.port && data->u.timer.expires_ns)
 921			kvm_xen_start_timer(vcpu, data->u.timer.expires_ns,
 922					    data->u.timer.expires_ns -
 923					    get_kvmclock_ns(vcpu->kvm));
 924
 925		r = 0;
 926		break;
 927
 928	case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
 929		if (data->u.vector && data->u.vector < 0x10)
 930			r = -EINVAL;
 931		else {
 932			vcpu->arch.xen.upcall_vector = data->u.vector;
 933			r = 0;
 934		}
 935		break;
 936
 937	default:
 938		break;
 939	}
 940
 941	srcu_read_unlock(&vcpu->kvm->srcu, idx);
 942	mutex_unlock(&vcpu->kvm->arch.xen.xen_lock);
 943	return r;
 944}
 945
 946int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 947{
 948	int r = -ENOENT;
 949
 950	mutex_lock(&vcpu->kvm->arch.xen.xen_lock);
 951
 952	switch (data->type) {
 953	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 954		if (vcpu->arch.xen.vcpu_info_cache.active)
 955			data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
 956		else
 957			data->u.gpa = KVM_XEN_INVALID_GPA;
 958		r = 0;
 959		break;
 960
 961	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 962		if (vcpu->arch.xen.vcpu_time_info_cache.active)
 963			data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
 964		else
 965			data->u.gpa = KVM_XEN_INVALID_GPA;
 966		r = 0;
 967		break;
 968
 969	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 970		if (!sched_info_on()) {
 971			r = -EOPNOTSUPP;
 972			break;
 973		}
 974		if (vcpu->arch.xen.runstate_cache.active) {
 975			data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
 976			r = 0;
 977		}
 978		break;
 979
 980	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 981		if (!sched_info_on()) {
 982			r = -EOPNOTSUPP;
 983			break;
 984		}
 985		data->u.runstate.state = vcpu->arch.xen.current_runstate;
 986		r = 0;
 987		break;
 988
 989	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 990		if (!sched_info_on()) {
 991			r = -EOPNOTSUPP;
 992			break;
 993		}
 994		data->u.runstate.state = vcpu->arch.xen.current_runstate;
 995		data->u.runstate.state_entry_time =
 996			vcpu->arch.xen.runstate_entry_time;
 997		data->u.runstate.time_running =
 998			vcpu->arch.xen.runstate_times[RUNSTATE_running];
 999		data->u.runstate.time_runnable =
1000			vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
1001		data->u.runstate.time_blocked =
1002			vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
1003		data->u.runstate.time_offline =
1004			vcpu->arch.xen.runstate_times[RUNSTATE_offline];
1005		r = 0;
1006		break;
1007
1008	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
1009		r = -EINVAL;
1010		break;
1011
1012	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
1013		data->u.vcpu_id = vcpu->arch.xen.vcpu_id;
1014		r = 0;
1015		break;
1016
1017	case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1018		data->u.timer.port = vcpu->arch.xen.timer_virq;
1019		data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
1020		data->u.timer.expires_ns = vcpu->arch.xen.timer_expires;
 
 
 
 
 
 
 
 
 
 
 
 
 
1021		r = 0;
1022		break;
1023
1024	case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
1025		data->u.vector = vcpu->arch.xen.upcall_vector;
1026		r = 0;
1027		break;
1028
1029	default:
1030		break;
1031	}
1032
1033	mutex_unlock(&vcpu->kvm->arch.xen.xen_lock);
1034	return r;
1035}
1036
1037int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
1038{
1039	struct kvm *kvm = vcpu->kvm;
1040	u32 page_num = data & ~PAGE_MASK;
1041	u64 page_addr = data & PAGE_MASK;
1042	bool lm = is_long_mode(vcpu);
1043
1044	/* Latch long_mode for shared_info pages etc. */
1045	vcpu->kvm->arch.xen.long_mode = lm;
1046
1047	/*
1048	 * If Xen hypercall intercept is enabled, fill the hypercall
1049	 * page with VMCALL/VMMCALL instructions since that's what
1050	 * we catch. Else the VMM has provided the hypercall pages
1051	 * with instructions of its own choosing, so use those.
1052	 */
1053	if (kvm_xen_hypercall_enabled(kvm)) {
1054		u8 instructions[32];
1055		int i;
1056
1057		if (page_num)
1058			return 1;
1059
1060		/* mov imm32, %eax */
1061		instructions[0] = 0xb8;
1062
1063		/* vmcall / vmmcall */
1064		static_call(kvm_x86_patch_hypercall)(vcpu, instructions + 5);
1065
1066		/* ret */
1067		instructions[8] = 0xc3;
1068
1069		/* int3 to pad */
1070		memset(instructions + 9, 0xcc, sizeof(instructions) - 9);
1071
1072		for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
1073			*(u32 *)&instructions[1] = i;
1074			if (kvm_vcpu_write_guest(vcpu,
1075						 page_addr + (i * sizeof(instructions)),
1076						 instructions, sizeof(instructions)))
1077				return 1;
1078		}
1079	} else {
1080		/*
1081		 * Note, truncation is a non-issue as 'lm' is guaranteed to be
1082		 * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
1083		 */
1084		hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
1085				     : kvm->arch.xen_hvm_config.blob_addr_32;
1086		u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
1087				  : kvm->arch.xen_hvm_config.blob_size_32;
1088		u8 *page;
1089		int ret;
1090
1091		if (page_num >= blob_size)
1092			return 1;
1093
1094		blob_addr += page_num * PAGE_SIZE;
1095
1096		page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
1097		if (IS_ERR(page))
1098			return PTR_ERR(page);
1099
1100		ret = kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE);
1101		kfree(page);
1102		if (ret)
1103			return 1;
1104	}
1105	return 0;
1106}
1107
1108int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
1109{
1110	/* Only some feature flags need to be *enabled* by userspace */
1111	u32 permitted_flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL |
1112		KVM_XEN_HVM_CONFIG_EVTCHN_SEND;
 
 
1113
1114	if (xhc->flags & ~permitted_flags)
1115		return -EINVAL;
1116
1117	/*
1118	 * With hypercall interception the kernel generates its own
1119	 * hypercall page so it must not be provided.
1120	 */
1121	if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
1122	    (xhc->blob_addr_32 || xhc->blob_addr_64 ||
1123	     xhc->blob_size_32 || xhc->blob_size_64))
1124		return -EINVAL;
1125
1126	mutex_lock(&kvm->arch.xen.xen_lock);
1127
1128	if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
1129		static_branch_inc(&kvm_xen_enabled.key);
1130	else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
1131		static_branch_slow_dec_deferred(&kvm_xen_enabled);
1132
 
1133	memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
1134
1135	mutex_unlock(&kvm->arch.xen.xen_lock);
 
 
 
 
1136	return 0;
1137}
1138
1139static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
1140{
1141	kvm_rax_write(vcpu, result);
1142	return kvm_skip_emulated_instruction(vcpu);
1143}
1144
1145static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
1146{
1147	struct kvm_run *run = vcpu->run;
1148
1149	if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
1150		return 1;
1151
1152	return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
1153}
1154
1155static inline int max_evtchn_port(struct kvm *kvm)
1156{
1157	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode)
1158		return EVTCHN_2L_NR_CHANNELS;
1159	else
1160		return COMPAT_EVTCHN_2L_NR_CHANNELS;
1161}
1162
1163static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports,
1164			       evtchn_port_t *ports)
1165{
1166	struct kvm *kvm = vcpu->kvm;
1167	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1168	unsigned long *pending_bits;
1169	unsigned long flags;
1170	bool ret = true;
1171	int idx, i;
1172
1173	idx = srcu_read_lock(&kvm->srcu);
1174	read_lock_irqsave(&gpc->lock, flags);
1175	if (!kvm_gpc_check(gpc, PAGE_SIZE))
1176		goto out_rcu;
1177
1178	ret = false;
1179	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1180		struct shared_info *shinfo = gpc->khva;
1181		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1182	} else {
1183		struct compat_shared_info *shinfo = gpc->khva;
1184		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1185	}
1186
1187	for (i = 0; i < nr_ports; i++) {
1188		if (test_bit(ports[i], pending_bits)) {
1189			ret = true;
1190			break;
1191		}
1192	}
1193
1194 out_rcu:
1195	read_unlock_irqrestore(&gpc->lock, flags);
1196	srcu_read_unlock(&kvm->srcu, idx);
1197
1198	return ret;
1199}
1200
1201static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
1202				 u64 param, u64 *r)
1203{
1204	struct sched_poll sched_poll;
1205	evtchn_port_t port, *ports;
1206	struct x86_exception e;
1207	int i;
1208
1209	if (!lapic_in_kernel(vcpu) ||
1210	    !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
1211		return false;
1212
1213	if (IS_ENABLED(CONFIG_64BIT) && !longmode) {
1214		struct compat_sched_poll sp32;
1215
1216		/* Sanity check that the compat struct definition is correct */
1217		BUILD_BUG_ON(sizeof(sp32) != 16);
1218
1219		if (kvm_read_guest_virt(vcpu, param, &sp32, sizeof(sp32), &e)) {
1220			*r = -EFAULT;
1221			return true;
1222		}
1223
1224		/*
1225		 * This is a 32-bit pointer to an array of evtchn_port_t which
1226		 * are uint32_t, so once it's converted no further compat
1227		 * handling is needed.
1228		 */
1229		sched_poll.ports = (void *)(unsigned long)(sp32.ports);
1230		sched_poll.nr_ports = sp32.nr_ports;
1231		sched_poll.timeout = sp32.timeout;
1232	} else {
1233		if (kvm_read_guest_virt(vcpu, param, &sched_poll,
1234					sizeof(sched_poll), &e)) {
1235			*r = -EFAULT;
1236			return true;
1237		}
1238	}
1239
1240	if (unlikely(sched_poll.nr_ports > 1)) {
1241		/* Xen (unofficially) limits number of pollers to 128 */
1242		if (sched_poll.nr_ports > 128) {
1243			*r = -EINVAL;
1244			return true;
1245		}
1246
1247		ports = kmalloc_array(sched_poll.nr_ports,
1248				      sizeof(*ports), GFP_KERNEL);
1249		if (!ports) {
1250			*r = -ENOMEM;
1251			return true;
1252		}
1253	} else
1254		ports = &port;
1255
1256	if (kvm_read_guest_virt(vcpu, (gva_t)sched_poll.ports, ports,
1257				sched_poll.nr_ports * sizeof(*ports), &e)) {
1258		*r = -EFAULT;
1259		return true;
1260	}
1261
1262	for (i = 0; i < sched_poll.nr_ports; i++) {
1263		if (ports[i] >= max_evtchn_port(vcpu->kvm)) {
1264			*r = -EINVAL;
1265			goto out;
1266		}
1267	}
1268
1269	if (sched_poll.nr_ports == 1)
1270		vcpu->arch.xen.poll_evtchn = port;
1271	else
1272		vcpu->arch.xen.poll_evtchn = -1;
1273
1274	set_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
1275
1276	if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) {
1277		vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
1278
1279		if (sched_poll.timeout)
1280			mod_timer(&vcpu->arch.xen.poll_timer,
1281				  jiffies + nsecs_to_jiffies(sched_poll.timeout));
1282
1283		kvm_vcpu_halt(vcpu);
1284
1285		if (sched_poll.timeout)
1286			del_timer(&vcpu->arch.xen.poll_timer);
1287
1288		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
1289	}
1290
1291	vcpu->arch.xen.poll_evtchn = 0;
1292	*r = 0;
1293out:
1294	/* Really, this is only needed in case of timeout */
1295	clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
1296
1297	if (unlikely(sched_poll.nr_ports > 1))
1298		kfree(ports);
1299	return true;
1300}
1301
1302static void cancel_evtchn_poll(struct timer_list *t)
1303{
1304	struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer);
1305
1306	kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1307	kvm_vcpu_kick(vcpu);
1308}
1309
1310static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode,
1311				   int cmd, u64 param, u64 *r)
1312{
1313	switch (cmd) {
1314	case SCHEDOP_poll:
1315		if (kvm_xen_schedop_poll(vcpu, longmode, param, r))
1316			return true;
1317		fallthrough;
1318	case SCHEDOP_yield:
1319		kvm_vcpu_on_spin(vcpu, true);
1320		*r = 0;
1321		return true;
1322	default:
1323		break;
1324	}
1325
1326	return false;
1327}
1328
1329struct compat_vcpu_set_singleshot_timer {
1330    uint64_t timeout_abs_ns;
1331    uint32_t flags;
1332} __attribute__((packed));
1333
1334static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
1335				  int vcpu_id, u64 param, u64 *r)
1336{
1337	struct vcpu_set_singleshot_timer oneshot;
1338	struct x86_exception e;
1339	s64 delta;
1340
1341	if (!kvm_xen_timer_enabled(vcpu))
1342		return false;
1343
1344	switch (cmd) {
1345	case VCPUOP_set_singleshot_timer:
1346		if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1347			*r = -EINVAL;
1348			return true;
1349		}
1350
1351		/*
1352		 * The only difference for 32-bit compat is the 4 bytes of
1353		 * padding after the interesting part of the structure. So
1354		 * for a faithful emulation of Xen we have to *try* to copy
1355		 * the padding and return -EFAULT if we can't. Otherwise we
1356		 * might as well just have copied the 12-byte 32-bit struct.
1357		 */
1358		BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1359			     offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1360		BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1361			     sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1362		BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) !=
1363			     offsetof(struct vcpu_set_singleshot_timer, flags));
1364		BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) !=
1365			     sizeof_field(struct vcpu_set_singleshot_timer, flags));
1366
1367		if (kvm_read_guest_virt(vcpu, param, &oneshot, longmode ? sizeof(oneshot) :
1368					sizeof(struct compat_vcpu_set_singleshot_timer), &e)) {
1369			*r = -EFAULT;
1370			return true;
1371		}
1372
 
1373		delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
1374		if ((oneshot.flags & VCPU_SSHOTTMR_future) && delta < 0) {
1375			*r = -ETIME;
1376			return true;
1377		}
1378
1379		kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta);
1380		*r = 0;
1381		return true;
1382
1383	case VCPUOP_stop_singleshot_timer:
1384		if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1385			*r = -EINVAL;
1386			return true;
1387		}
1388		kvm_xen_stop_timer(vcpu);
1389		*r = 0;
1390		return true;
1391	}
1392
1393	return false;
1394}
1395
1396static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
1397				       u64 *r)
1398{
1399	if (!kvm_xen_timer_enabled(vcpu))
1400		return false;
1401
1402	if (timeout) {
1403		uint64_t guest_now = get_kvmclock_ns(vcpu->kvm);
1404		int64_t delta = timeout - guest_now;
1405
1406		/* Xen has a 'Linux workaround' in do_set_timer_op() which
1407		 * checks for negative absolute timeout values (caused by
1408		 * integer overflow), and for values about 13 days in the
1409		 * future (2^50ns) which would be caused by jiffies
1410		 * overflow. For those cases, it sets the timeout 100ms in
1411		 * the future (not *too* soon, since if a guest really did
1412		 * set a long timeout on purpose we don't want to keep
1413		 * churning CPU time by waking it up).
1414		 */
1415		if (unlikely((int64_t)timeout < 0 ||
1416			     (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
1417			delta = 100 * NSEC_PER_MSEC;
1418			timeout = guest_now + delta;
1419		}
1420
1421		kvm_xen_start_timer(vcpu, timeout, delta);
1422	} else {
1423		kvm_xen_stop_timer(vcpu);
1424	}
1425
1426	*r = 0;
1427	return true;
1428}
1429
1430int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
1431{
1432	bool longmode;
1433	u64 input, params[6], r = -ENOSYS;
1434	bool handled = false;
1435	u8 cpl;
1436
1437	input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
1438
1439	/* Hyper-V hypercalls get bit 31 set in EAX */
1440	if ((input & 0x80000000) &&
1441	    kvm_hv_hypercall_enabled(vcpu))
1442		return kvm_hv_hypercall(vcpu);
1443
1444	longmode = is_64_bit_hypercall(vcpu);
1445	if (!longmode) {
1446		params[0] = (u32)kvm_rbx_read(vcpu);
1447		params[1] = (u32)kvm_rcx_read(vcpu);
1448		params[2] = (u32)kvm_rdx_read(vcpu);
1449		params[3] = (u32)kvm_rsi_read(vcpu);
1450		params[4] = (u32)kvm_rdi_read(vcpu);
1451		params[5] = (u32)kvm_rbp_read(vcpu);
1452	}
1453#ifdef CONFIG_X86_64
1454	else {
1455		params[0] = (u64)kvm_rdi_read(vcpu);
1456		params[1] = (u64)kvm_rsi_read(vcpu);
1457		params[2] = (u64)kvm_rdx_read(vcpu);
1458		params[3] = (u64)kvm_r10_read(vcpu);
1459		params[4] = (u64)kvm_r8_read(vcpu);
1460		params[5] = (u64)kvm_r9_read(vcpu);
1461	}
1462#endif
1463	cpl = static_call(kvm_x86_get_cpl)(vcpu);
1464	trace_kvm_xen_hypercall(cpl, input, params[0], params[1], params[2],
1465				params[3], params[4], params[5]);
1466
1467	/*
1468	 * Only allow hypercall acceleration for CPL0. The rare hypercalls that
1469	 * are permitted in guest userspace can be handled by the VMM.
1470	 */
1471	if (unlikely(cpl > 0))
1472		goto handle_in_userspace;
1473
1474	switch (input) {
1475	case __HYPERVISOR_xen_version:
1476		if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) {
1477			r = vcpu->kvm->arch.xen.xen_version;
1478			handled = true;
1479		}
1480		break;
1481	case __HYPERVISOR_event_channel_op:
1482		if (params[0] == EVTCHNOP_send)
1483			handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r);
1484		break;
1485	case __HYPERVISOR_sched_op:
1486		handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0],
1487						 params[1], &r);
1488		break;
1489	case __HYPERVISOR_vcpu_op:
1490		handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1],
1491						params[2], &r);
1492		break;
1493	case __HYPERVISOR_set_timer_op: {
1494		u64 timeout = params[0];
1495		/* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */
1496		if (!longmode)
1497			timeout |= params[1] << 32;
1498		handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r);
1499		break;
1500	}
1501	default:
1502		break;
1503	}
1504
1505	if (handled)
1506		return kvm_xen_hypercall_set_result(vcpu, r);
1507
1508handle_in_userspace:
1509	vcpu->run->exit_reason = KVM_EXIT_XEN;
1510	vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
1511	vcpu->run->xen.u.hcall.longmode = longmode;
1512	vcpu->run->xen.u.hcall.cpl = cpl;
1513	vcpu->run->xen.u.hcall.input = input;
1514	vcpu->run->xen.u.hcall.params[0] = params[0];
1515	vcpu->run->xen.u.hcall.params[1] = params[1];
1516	vcpu->run->xen.u.hcall.params[2] = params[2];
1517	vcpu->run->xen.u.hcall.params[3] = params[3];
1518	vcpu->run->xen.u.hcall.params[4] = params[4];
1519	vcpu->run->xen.u.hcall.params[5] = params[5];
1520	vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
1521	vcpu->arch.complete_userspace_io =
1522		kvm_xen_hypercall_complete_userspace;
1523
1524	return 0;
1525}
1526
1527static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port)
1528{
1529	int poll_evtchn = vcpu->arch.xen.poll_evtchn;
1530
1531	if ((poll_evtchn == port || poll_evtchn == -1) &&
1532	    test_and_clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask)) {
1533		kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1534		kvm_vcpu_kick(vcpu);
1535	}
1536}
1537
1538/*
1539 * The return value from this function is propagated to kvm_set_irq() API,
1540 * so it returns:
1541 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
1542 *  = 0   Interrupt was coalesced (previous irq is still pending)
1543 *  > 0   Number of CPUs interrupt was delivered to
1544 *
1545 * It is also called directly from kvm_arch_set_irq_inatomic(), where the
1546 * only check on its return value is a comparison with -EWOULDBLOCK'.
1547 */
1548int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1549{
1550	struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1551	struct kvm_vcpu *vcpu;
1552	unsigned long *pending_bits, *mask_bits;
1553	unsigned long flags;
1554	int port_word_bit;
1555	bool kick_vcpu = false;
1556	int vcpu_idx, idx, rc;
1557
1558	vcpu_idx = READ_ONCE(xe->vcpu_idx);
1559	if (vcpu_idx >= 0)
1560		vcpu = kvm_get_vcpu(kvm, vcpu_idx);
1561	else {
1562		vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id);
1563		if (!vcpu)
1564			return -EINVAL;
1565		WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx);
1566	}
1567
1568	if (!vcpu->arch.xen.vcpu_info_cache.active)
1569		return -EINVAL;
1570
1571	if (xe->port >= max_evtchn_port(kvm))
1572		return -EINVAL;
1573
1574	rc = -EWOULDBLOCK;
1575
1576	idx = srcu_read_lock(&kvm->srcu);
1577
1578	read_lock_irqsave(&gpc->lock, flags);
1579	if (!kvm_gpc_check(gpc, PAGE_SIZE))
1580		goto out_rcu;
1581
1582	if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1583		struct shared_info *shinfo = gpc->khva;
1584		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1585		mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1586		port_word_bit = xe->port / 64;
1587	} else {
1588		struct compat_shared_info *shinfo = gpc->khva;
1589		pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1590		mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1591		port_word_bit = xe->port / 32;
1592	}
1593
1594	/*
1595	 * If this port wasn't already set, and if it isn't masked, then
1596	 * we try to set the corresponding bit in the in-kernel shadow of
1597	 * evtchn_pending_sel for the target vCPU. And if *that* wasn't
1598	 * already set, then we kick the vCPU in question to write to the
1599	 * *real* evtchn_pending_sel in its own guest vcpu_info struct.
1600	 */
1601	if (test_and_set_bit(xe->port, pending_bits)) {
1602		rc = 0; /* It was already raised */
1603	} else if (test_bit(xe->port, mask_bits)) {
1604		rc = -ENOTCONN; /* Masked */
1605		kvm_xen_check_poller(vcpu, xe->port);
1606	} else {
1607		rc = 1; /* Delivered to the bitmap in shared_info. */
1608		/* Now switch to the vCPU's vcpu_info to set the index and pending_sel */
1609		read_unlock_irqrestore(&gpc->lock, flags);
1610		gpc = &vcpu->arch.xen.vcpu_info_cache;
1611
1612		read_lock_irqsave(&gpc->lock, flags);
1613		if (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
1614			/*
1615			 * Could not access the vcpu_info. Set the bit in-kernel
1616			 * and prod the vCPU to deliver it for itself.
1617			 */
1618			if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
1619				kick_vcpu = true;
1620			goto out_rcu;
1621		}
1622
1623		if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1624			struct vcpu_info *vcpu_info = gpc->khva;
1625			if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) {
1626				WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1627				kick_vcpu = true;
1628			}
1629		} else {
1630			struct compat_vcpu_info *vcpu_info = gpc->khva;
1631			if (!test_and_set_bit(port_word_bit,
1632					      (unsigned long *)&vcpu_info->evtchn_pending_sel)) {
1633				WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1634				kick_vcpu = true;
1635			}
1636		}
1637
1638		/* For the per-vCPU lapic vector, deliver it as MSI. */
1639		if (kick_vcpu && vcpu->arch.xen.upcall_vector) {
1640			kvm_xen_inject_vcpu_vector(vcpu);
1641			kick_vcpu = false;
1642		}
1643	}
1644
1645 out_rcu:
1646	read_unlock_irqrestore(&gpc->lock, flags);
1647	srcu_read_unlock(&kvm->srcu, idx);
1648
1649	if (kick_vcpu) {
1650		kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1651		kvm_vcpu_kick(vcpu);
1652	}
1653
1654	return rc;
1655}
1656
1657static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1658{
1659	bool mm_borrowed = false;
1660	int rc;
1661
1662	rc = kvm_xen_set_evtchn_fast(xe, kvm);
1663	if (rc != -EWOULDBLOCK)
1664		return rc;
1665
1666	if (current->mm != kvm->mm) {
1667		/*
1668		 * If not on a thread which already belongs to this KVM,
1669		 * we'd better be in the irqfd workqueue.
1670		 */
1671		if (WARN_ON_ONCE(current->mm))
1672			return -EINVAL;
1673
1674		kthread_use_mm(kvm->mm);
1675		mm_borrowed = true;
1676	}
1677
1678	mutex_lock(&kvm->arch.xen.xen_lock);
1679
1680	/*
1681	 * It is theoretically possible for the page to be unmapped
1682	 * and the MMU notifier to invalidate the shared_info before
1683	 * we even get to use it. In that case, this looks like an
1684	 * infinite loop. It was tempting to do it via the userspace
1685	 * HVA instead... but that just *hides* the fact that it's
1686	 * an infinite loop, because if a fault occurs and it waits
1687	 * for the page to come back, it can *still* immediately
1688	 * fault and have to wait again, repeatedly.
1689	 *
1690	 * Conversely, the page could also have been reinstated by
1691	 * another thread before we even obtain the mutex above, so
1692	 * check again *first* before remapping it.
1693	 */
1694	do {
1695		struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1696		int idx;
1697
1698		rc = kvm_xen_set_evtchn_fast(xe, kvm);
1699		if (rc != -EWOULDBLOCK)
1700			break;
1701
1702		idx = srcu_read_lock(&kvm->srcu);
1703		rc = kvm_gpc_refresh(gpc, PAGE_SIZE);
1704		srcu_read_unlock(&kvm->srcu, idx);
1705	} while(!rc);
1706
1707	mutex_unlock(&kvm->arch.xen.xen_lock);
1708
1709	if (mm_borrowed)
1710		kthread_unuse_mm(kvm->mm);
1711
1712	return rc;
1713}
1714
1715/* This is the version called from kvm_set_irq() as the .set function */
1716static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
1717			 int irq_source_id, int level, bool line_status)
1718{
1719	if (!level)
1720		return -EINVAL;
1721
1722	return kvm_xen_set_evtchn(&e->xen_evtchn, kvm);
1723}
1724
1725/*
1726 * Set up an event channel interrupt from the KVM IRQ routing table.
1727 * Used for e.g. PIRQ from passed through physical devices.
1728 */
1729int kvm_xen_setup_evtchn(struct kvm *kvm,
1730			 struct kvm_kernel_irq_routing_entry *e,
1731			 const struct kvm_irq_routing_entry *ue)
1732
1733{
1734	struct kvm_vcpu *vcpu;
1735
1736	if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
1737		return -EINVAL;
1738
1739	/* We only support 2 level event channels for now */
1740	if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1741		return -EINVAL;
1742
1743	/*
1744	 * Xen gives us interesting mappings from vCPU index to APIC ID,
1745	 * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs
1746	 * to find it. Do that once at setup time, instead of every time.
1747	 * But beware that on live update / live migration, the routing
1748	 * table might be reinstated before the vCPU threads have finished
1749	 * recreating their vCPUs.
1750	 */
1751	vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu);
1752	if (vcpu)
1753		e->xen_evtchn.vcpu_idx = vcpu->vcpu_idx;
1754	else
1755		e->xen_evtchn.vcpu_idx = -1;
1756
1757	e->xen_evtchn.port = ue->u.xen_evtchn.port;
1758	e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu;
1759	e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
1760	e->set = evtchn_set_fn;
1761
1762	return 0;
1763}
1764
1765/*
1766 * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
1767 */
1768int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
1769{
1770	struct kvm_xen_evtchn e;
1771	int ret;
1772
1773	if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
1774		return -EINVAL;
1775
1776	/* We only support 2 level event channels for now */
1777	if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1778		return -EINVAL;
1779
1780	e.port = uxe->port;
1781	e.vcpu_id = uxe->vcpu;
1782	e.vcpu_idx = -1;
1783	e.priority = uxe->priority;
1784
1785	ret = kvm_xen_set_evtchn(&e, kvm);
1786
1787	/*
1788	 * None of that 'return 1 if it actually got delivered' nonsense.
1789	 * We don't care if it was masked (-ENOTCONN) either.
1790	 */
1791	if (ret > 0 || ret == -ENOTCONN)
1792		ret = 0;
1793
1794	return ret;
1795}
1796
1797/*
1798 * Support for *outbound* event channel events via the EVTCHNOP_send hypercall.
1799 */
1800struct evtchnfd {
1801	u32 send_port;
1802	u32 type;
1803	union {
1804		struct kvm_xen_evtchn port;
1805		struct {
1806			u32 port; /* zero */
1807			struct eventfd_ctx *ctx;
1808		} eventfd;
1809	} deliver;
1810};
1811
1812/*
1813 * Update target vCPU or priority for a registered sending channel.
1814 */
1815static int kvm_xen_eventfd_update(struct kvm *kvm,
1816				  struct kvm_xen_hvm_attr *data)
1817{
1818	u32 port = data->u.evtchn.send_port;
1819	struct evtchnfd *evtchnfd;
1820	int ret;
1821
1822	/* Protect writes to evtchnfd as well as the idr lookup.  */
1823	mutex_lock(&kvm->arch.xen.xen_lock);
1824	evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
1825
1826	ret = -ENOENT;
1827	if (!evtchnfd)
1828		goto out_unlock;
1829
1830	/* For an UPDATE, nothing may change except the priority/vcpu */
1831	ret = -EINVAL;
1832	if (evtchnfd->type != data->u.evtchn.type)
1833		goto out_unlock;
1834
1835	/*
1836	 * Port cannot change, and if it's zero that was an eventfd
1837	 * which can't be changed either.
1838	 */
1839	if (!evtchnfd->deliver.port.port ||
1840	    evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port)
1841		goto out_unlock;
1842
1843	/* We only support 2 level event channels for now */
1844	if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1845		goto out_unlock;
1846
1847	evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
1848	if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) {
1849		evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
1850		evtchnfd->deliver.port.vcpu_idx = -1;
1851	}
1852	ret = 0;
1853out_unlock:
1854	mutex_unlock(&kvm->arch.xen.xen_lock);
1855	return ret;
1856}
1857
1858/*
1859 * Configure the target (eventfd or local port delivery) for sending on
1860 * a given event channel.
1861 */
1862static int kvm_xen_eventfd_assign(struct kvm *kvm,
1863				  struct kvm_xen_hvm_attr *data)
1864{
1865	u32 port = data->u.evtchn.send_port;
1866	struct eventfd_ctx *eventfd = NULL;
1867	struct evtchnfd *evtchnfd;
1868	int ret = -EINVAL;
1869
1870	evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL);
1871	if (!evtchnfd)
1872		return -ENOMEM;
1873
1874	switch(data->u.evtchn.type) {
1875	case EVTCHNSTAT_ipi:
1876		/* IPI  must map back to the same port# */
1877		if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port)
1878			goto out_noeventfd; /* -EINVAL */
1879		break;
1880
1881	case EVTCHNSTAT_interdomain:
1882		if (data->u.evtchn.deliver.port.port) {
1883			if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm))
1884				goto out_noeventfd; /* -EINVAL */
1885		} else {
1886			eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd);
1887			if (IS_ERR(eventfd)) {
1888				ret = PTR_ERR(eventfd);
1889				goto out_noeventfd;
1890			}
1891		}
1892		break;
1893
1894	case EVTCHNSTAT_virq:
1895	case EVTCHNSTAT_closed:
1896	case EVTCHNSTAT_unbound:
1897	case EVTCHNSTAT_pirq:
1898	default: /* Unknown event channel type */
1899		goto out; /* -EINVAL */
1900	}
1901
1902	evtchnfd->send_port = data->u.evtchn.send_port;
1903	evtchnfd->type = data->u.evtchn.type;
1904	if (eventfd) {
1905		evtchnfd->deliver.eventfd.ctx = eventfd;
1906	} else {
1907		/* We only support 2 level event channels for now */
1908		if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1909			goto out; /* -EINVAL; */
1910
1911		evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port;
1912		evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
1913		evtchnfd->deliver.port.vcpu_idx = -1;
1914		evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
1915	}
1916
1917	mutex_lock(&kvm->arch.xen.xen_lock);
1918	ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
1919			GFP_KERNEL);
1920	mutex_unlock(&kvm->arch.xen.xen_lock);
1921	if (ret >= 0)
1922		return 0;
1923
1924	if (ret == -ENOSPC)
1925		ret = -EEXIST;
1926out:
1927	if (eventfd)
1928		eventfd_ctx_put(eventfd);
1929out_noeventfd:
1930	kfree(evtchnfd);
1931	return ret;
1932}
1933
1934static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port)
1935{
1936	struct evtchnfd *evtchnfd;
1937
1938	mutex_lock(&kvm->arch.xen.xen_lock);
1939	evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
1940	mutex_unlock(&kvm->arch.xen.xen_lock);
1941
1942	if (!evtchnfd)
1943		return -ENOENT;
1944
1945	synchronize_srcu(&kvm->srcu);
1946	if (!evtchnfd->deliver.port.port)
1947		eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1948	kfree(evtchnfd);
1949	return 0;
1950}
1951
1952static int kvm_xen_eventfd_reset(struct kvm *kvm)
1953{
1954	struct evtchnfd *evtchnfd, **all_evtchnfds;
1955	int i;
1956	int n = 0;
1957
1958	mutex_lock(&kvm->arch.xen.xen_lock);
1959
1960	/*
1961	 * Because synchronize_srcu() cannot be called inside the
1962	 * critical section, first collect all the evtchnfd objects
1963	 * in an array as they are removed from evtchn_ports.
1964	 */
1965	idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i)
1966		n++;
1967
1968	all_evtchnfds = kmalloc_array(n, sizeof(struct evtchnfd *), GFP_KERNEL);
1969	if (!all_evtchnfds) {
1970		mutex_unlock(&kvm->arch.xen.xen_lock);
1971		return -ENOMEM;
1972	}
1973
1974	n = 0;
1975	idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
1976		all_evtchnfds[n++] = evtchnfd;
1977		idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
1978	}
1979	mutex_unlock(&kvm->arch.xen.xen_lock);
1980
1981	synchronize_srcu(&kvm->srcu);
1982
1983	while (n--) {
1984		evtchnfd = all_evtchnfds[n];
1985		if (!evtchnfd->deliver.port.port)
1986			eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1987		kfree(evtchnfd);
1988	}
1989	kfree(all_evtchnfds);
1990
1991	return 0;
1992}
1993
1994static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
1995{
1996	u32 port = data->u.evtchn.send_port;
1997
1998	if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET)
1999		return kvm_xen_eventfd_reset(kvm);
2000
2001	if (!port || port >= max_evtchn_port(kvm))
2002		return -EINVAL;
2003
2004	if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN)
2005		return kvm_xen_eventfd_deassign(kvm, port);
2006	if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE)
2007		return kvm_xen_eventfd_update(kvm, data);
2008	if (data->u.evtchn.flags)
2009		return -EINVAL;
2010
2011	return kvm_xen_eventfd_assign(kvm, data);
2012}
2013
2014static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
2015{
2016	struct evtchnfd *evtchnfd;
2017	struct evtchn_send send;
2018	struct x86_exception e;
2019
2020	/* Sanity check: this structure is the same for 32-bit and 64-bit */
2021	BUILD_BUG_ON(sizeof(send) != 4);
2022	if (kvm_read_guest_virt(vcpu, param, &send, sizeof(send), &e)) {
2023		*r = -EFAULT;
2024		return true;
2025	}
2026
2027	/*
2028	 * evtchnfd is protected by kvm->srcu; the idr lookup instead
2029	 * is protected by RCU.
2030	 */
2031	rcu_read_lock();
2032	evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
2033	rcu_read_unlock();
2034	if (!evtchnfd)
2035		return false;
2036
2037	if (evtchnfd->deliver.port.port) {
2038		int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm);
2039		if (ret < 0 && ret != -ENOTCONN)
2040			return false;
2041	} else {
2042		eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
2043	}
2044
2045	*r = 0;
2046	return true;
2047}
2048
2049void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
2050{
2051	vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
2052	vcpu->arch.xen.poll_evtchn = 0;
2053
2054	timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
2055
2056	kvm_gpc_init(&vcpu->arch.xen.runstate_cache, vcpu->kvm, NULL,
2057		     KVM_HOST_USES_PFN);
2058	kvm_gpc_init(&vcpu->arch.xen.runstate2_cache, vcpu->kvm, NULL,
2059		     KVM_HOST_USES_PFN);
2060	kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache, vcpu->kvm, NULL,
2061		     KVM_HOST_USES_PFN);
2062	kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache, vcpu->kvm, NULL,
2063		     KVM_HOST_USES_PFN);
2064}
2065
2066void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
2067{
2068	if (kvm_xen_timer_enabled(vcpu))
2069		kvm_xen_stop_timer(vcpu);
2070
2071	kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
2072	kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
2073	kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
2074	kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
2075
2076	del_timer_sync(&vcpu->arch.xen.poll_timer);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2077}
2078
2079void kvm_xen_init_vm(struct kvm *kvm)
2080{
2081	mutex_init(&kvm->arch.xen.xen_lock);
2082	idr_init(&kvm->arch.xen.evtchn_ports);
2083	kvm_gpc_init(&kvm->arch.xen.shinfo_cache, kvm, NULL, KVM_HOST_USES_PFN);
2084}
2085
2086void kvm_xen_destroy_vm(struct kvm *kvm)
2087{
2088	struct evtchnfd *evtchnfd;
2089	int i;
2090
2091	kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
2092
2093	idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
2094		if (!evtchnfd->deliver.port.port)
2095			eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
2096		kfree(evtchnfd);
2097	}
2098	idr_destroy(&kvm->arch.xen.evtchn_ports);
2099
2100	if (kvm->arch.xen_hvm_config.msr)
2101		static_branch_slow_dec_deferred(&kvm_xen_enabled);
2102}