1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Kernel-based Virtual Machine driver for Linux
4 *
5 * AMD SVM support
6 *
7 * Copyright (C) 2006 Qumranet, Inc.
8 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
9 *
10 * Authors:
11 * Yaniv Kamay <yaniv@qumranet.com>
12 * Avi Kivity <avi@qumranet.com>
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/kvm_types.h>
18#include <linux/hashtable.h>
19#include <linux/amd-iommu.h>
20#include <linux/kvm_host.h>
21
22#include <asm/irq_remapping.h>
23
24#include "trace.h"
25#include "lapic.h"
26#include "x86.h"
27#include "irq.h"
28#include "svm.h"
29
30/*
31 * Encode the arbitrary VM ID and the vCPU's default APIC ID, i.e the vCPU ID,
32 * into the GATag so that KVM can retrieve the correct vCPU from a GALog entry
33 * if an interrupt can't be delivered, e.g. because the vCPU isn't running.
34 *
35 * For the vCPU ID, use however many bits are currently allowed for the max
36 * guest physical APIC ID (limited by the size of the physical ID table), and
37 * use whatever bits remain to assign arbitrary AVIC IDs to VMs. Note, the
38 * size of the GATag is defined by hardware (32 bits), but is an opaque value
39 * as far as hardware is concerned.
40 */
41#define AVIC_VCPU_ID_MASK AVIC_PHYSICAL_MAX_INDEX_MASK
42
43#define AVIC_VM_ID_SHIFT HWEIGHT32(AVIC_PHYSICAL_MAX_INDEX_MASK)
44#define AVIC_VM_ID_MASK (GENMASK(31, AVIC_VM_ID_SHIFT) >> AVIC_VM_ID_SHIFT)
45
46#define AVIC_GATAG_TO_VMID(x) ((x >> AVIC_VM_ID_SHIFT) & AVIC_VM_ID_MASK)
47#define AVIC_GATAG_TO_VCPUID(x) (x & AVIC_VCPU_ID_MASK)
48
49#define __AVIC_GATAG(vm_id, vcpu_id) ((((vm_id) & AVIC_VM_ID_MASK) << AVIC_VM_ID_SHIFT) | \
50 ((vcpu_id) & AVIC_VCPU_ID_MASK))
51#define AVIC_GATAG(vm_id, vcpu_id) \
52({ \
53 u32 ga_tag = __AVIC_GATAG(vm_id, vcpu_id); \
54 \
55 WARN_ON_ONCE(AVIC_GATAG_TO_VCPUID(ga_tag) != (vcpu_id)); \
56 WARN_ON_ONCE(AVIC_GATAG_TO_VMID(ga_tag) != (vm_id)); \
57 ga_tag; \
58})
59
60static_assert(__AVIC_GATAG(AVIC_VM_ID_MASK, AVIC_VCPU_ID_MASK) == -1u);
61
62static bool force_avic;
63module_param_unsafe(force_avic, bool, 0444);
64
65/* Note:
66 * This hash table is used to map VM_ID to a struct kvm_svm,
67 * when handling AMD IOMMU GALOG notification to schedule in
68 * a particular vCPU.
69 */
70#define SVM_VM_DATA_HASH_BITS 8
71static DEFINE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS);
72static u32 next_vm_id = 0;
73static bool next_vm_id_wrapped = 0;
74static DEFINE_SPINLOCK(svm_vm_data_hash_lock);
75bool x2avic_enabled;
76
77/*
78 * This is a wrapper of struct amd_iommu_ir_data.
79 */
80struct amd_svm_iommu_ir {
81 struct list_head node; /* Used by SVM for per-vcpu ir_list */
82 void *data; /* Storing pointer to struct amd_ir_data */
83};
84
85static void avic_activate_vmcb(struct vcpu_svm *svm)
86{
87 struct vmcb *vmcb = svm->vmcb01.ptr;
88
89 vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
90 vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
91
92 vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
93
94 /*
95 * Note: KVM supports hybrid-AVIC mode, where KVM emulates x2APIC MSR
96 * accesses, while interrupt injection to a running vCPU can be
97 * achieved using AVIC doorbell. KVM disables the APIC access page
98 * (deletes the memslot) if any vCPU has x2APIC enabled, thus enabling
99 * AVIC in hybrid mode activates only the doorbell mechanism.
100 */
101 if (x2avic_enabled && apic_x2apic_mode(svm->vcpu.arch.apic)) {
102 vmcb->control.int_ctl |= X2APIC_MODE_MASK;
103 vmcb->control.avic_physical_id |= X2AVIC_MAX_PHYSICAL_ID;
104 /* Disabling MSR intercept for x2APIC registers */
105 svm_set_x2apic_msr_interception(svm, disable: false);
106 } else {
107 /*
108 * Flush the TLB, the guest may have inserted a non-APIC
109 * mapping into the TLB while AVIC was disabled.
110 */
111 kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu: &svm->vcpu);
112
113 /* For xAVIC and hybrid-xAVIC modes */
114 vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID;
115 /* Enabling MSR intercept for x2APIC registers */
116 svm_set_x2apic_msr_interception(svm, disable: true);
117 }
118}
119
120static void avic_deactivate_vmcb(struct vcpu_svm *svm)
121{
122 struct vmcb *vmcb = svm->vmcb01.ptr;
123
124 vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
125 vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
126
127 /*
128 * If running nested and the guest uses its own MSR bitmap, there
129 * is no need to update L0's msr bitmap
130 */
131 if (is_guest_mode(&svm->vcpu) &&
132 vmcb12_is_intercept(control: &svm->nested.ctl, bit: INTERCEPT_MSR_PROT))
133 return;
134
135 /* Enabling MSR intercept for x2APIC registers */
136 svm_set_x2apic_msr_interception(svm, disable: true);
137}
138
139/* Note:
140 * This function is called from IOMMU driver to notify
141 * SVM to schedule in a particular vCPU of a particular VM.
142 */
143int avic_ga_log_notifier(u32 ga_tag)
144{
145 unsigned long flags;
146 struct kvm_svm *kvm_svm;
147 struct kvm_vcpu *vcpu = NULL;
148 u32 vm_id = AVIC_GATAG_TO_VMID(ga_tag);
149 u32 vcpu_id = AVIC_GATAG_TO_VCPUID(ga_tag);
150
151 pr_debug("SVM: %s: vm_id=%#x, vcpu_id=%#x\n", __func__, vm_id, vcpu_id);
152 trace_kvm_avic_ga_log(vm_id, vcpu_id);
153
154 spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
155 hash_for_each_possible(svm_vm_data_hash, kvm_svm, hnode, vm_id) {
156 if (kvm_svm->avic_vm_id != vm_id)
157 continue;
158 vcpu = kvm_get_vcpu_by_id(kvm: &kvm_svm->kvm, id: vcpu_id);
159 break;
160 }
161 spin_unlock_irqrestore(lock: &svm_vm_data_hash_lock, flags);
162
163 /* Note:
164 * At this point, the IOMMU should have already set the pending
165 * bit in the vAPIC backing page. So, we just need to schedule
166 * in the vcpu.
167 */
168 if (vcpu)
169 kvm_vcpu_wake_up(vcpu);
170
171 return 0;
172}
173
174void avic_vm_destroy(struct kvm *kvm)
175{
176 unsigned long flags;
177 struct kvm_svm *kvm_svm = to_kvm_svm(kvm);
178
179 if (!enable_apicv)
180 return;
181
182 if (kvm_svm->avic_logical_id_table_page)
183 __free_page(kvm_svm->avic_logical_id_table_page);
184 if (kvm_svm->avic_physical_id_table_page)
185 __free_page(kvm_svm->avic_physical_id_table_page);
186
187 spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
188 hash_del(node: &kvm_svm->hnode);
189 spin_unlock_irqrestore(lock: &svm_vm_data_hash_lock, flags);
190}
191
192int avic_vm_init(struct kvm *kvm)
193{
194 unsigned long flags;
195 int err = -ENOMEM;
196 struct kvm_svm *kvm_svm = to_kvm_svm(kvm);
197 struct kvm_svm *k2;
198 struct page *p_page;
199 struct page *l_page;
200 u32 vm_id;
201
202 if (!enable_apicv)
203 return 0;
204
205 /* Allocating physical APIC ID table (4KB) */
206 p_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
207 if (!p_page)
208 goto free_avic;
209
210 kvm_svm->avic_physical_id_table_page = p_page;
211
212 /* Allocating logical APIC ID table (4KB) */
213 l_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
214 if (!l_page)
215 goto free_avic;
216
217 kvm_svm->avic_logical_id_table_page = l_page;
218
219 spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
220 again:
221 vm_id = next_vm_id = (next_vm_id + 1) & AVIC_VM_ID_MASK;
222 if (vm_id == 0) { /* id is 1-based, zero is not okay */
223 next_vm_id_wrapped = 1;
224 goto again;
225 }
226 /* Is it still in use? Only possible if wrapped at least once */
227 if (next_vm_id_wrapped) {
228 hash_for_each_possible(svm_vm_data_hash, k2, hnode, vm_id) {
229 if (k2->avic_vm_id == vm_id)
230 goto again;
231 }
232 }
233 kvm_svm->avic_vm_id = vm_id;
234 hash_add(svm_vm_data_hash, &kvm_svm->hnode, kvm_svm->avic_vm_id);
235 spin_unlock_irqrestore(lock: &svm_vm_data_hash_lock, flags);
236
237 return 0;
238
239free_avic:
240 avic_vm_destroy(kvm);
241 return err;
242}
243
244void avic_init_vmcb(struct vcpu_svm *svm, struct vmcb *vmcb)
245{
246 struct kvm_svm *kvm_svm = to_kvm_svm(kvm: svm->vcpu.kvm);
247 phys_addr_t bpa = __sme_set(page_to_phys(svm->avic_backing_page));
248 phys_addr_t lpa = __sme_set(page_to_phys(kvm_svm->avic_logical_id_table_page));
249 phys_addr_t ppa = __sme_set(page_to_phys(kvm_svm->avic_physical_id_table_page));
250
251 vmcb->control.avic_backing_page = bpa & AVIC_HPA_MASK;
252 vmcb->control.avic_logical_id = lpa & AVIC_HPA_MASK;
253 vmcb->control.avic_physical_id = ppa & AVIC_HPA_MASK;
254 vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE & VMCB_AVIC_APIC_BAR_MASK;
255
256 if (kvm_apicv_activated(kvm: svm->vcpu.kvm))
257 avic_activate_vmcb(svm);
258 else
259 avic_deactivate_vmcb(svm);
260}
261
262static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu,
263 unsigned int index)
264{
265 u64 *avic_physical_id_table;
266 struct kvm_svm *kvm_svm = to_kvm_svm(kvm: vcpu->kvm);
267
268 if ((!x2avic_enabled && index > AVIC_MAX_PHYSICAL_ID) ||
269 (index > X2AVIC_MAX_PHYSICAL_ID))
270 return NULL;
271
272 avic_physical_id_table = page_address(kvm_svm->avic_physical_id_table_page);
273
274 return &avic_physical_id_table[index];
275}
276
277static int avic_init_backing_page(struct kvm_vcpu *vcpu)
278{
279 u64 *entry, new_entry;
280 int id = vcpu->vcpu_id;
281 struct vcpu_svm *svm = to_svm(vcpu);
282
283 if ((!x2avic_enabled && id > AVIC_MAX_PHYSICAL_ID) ||
284 (id > X2AVIC_MAX_PHYSICAL_ID))
285 return -EINVAL;
286
287 if (!vcpu->arch.apic->regs)
288 return -EINVAL;
289
290 if (kvm_apicv_activated(kvm: vcpu->kvm)) {
291 int ret;
292
293 /*
294 * Note, AVIC hardware walks the nested page table to check
295 * permissions, but does not use the SPA address specified in
296 * the leaf SPTE since it uses address in the AVIC_BACKING_PAGE
297 * pointer field of the VMCB.
298 */
299 ret = kvm_alloc_apic_access_page(vcpu->kvm);
300 if (ret)
301 return ret;
302 }
303
304 svm->avic_backing_page = virt_to_page(vcpu->arch.apic->regs);
305
306 /* Setting AVIC backing page address in the phy APIC ID table */
307 entry = avic_get_physical_id_entry(vcpu, index: id);
308 if (!entry)
309 return -EINVAL;
310
311 new_entry = __sme_set((page_to_phys(svm->avic_backing_page) &
312 AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK) |
313 AVIC_PHYSICAL_ID_ENTRY_VALID_MASK);
314 WRITE_ONCE(*entry, new_entry);
315
316 svm->avic_physical_id_cache = entry;
317
318 return 0;
319}
320
321void avic_ring_doorbell(struct kvm_vcpu *vcpu)
322{
323 /*
324 * Note, the vCPU could get migrated to a different pCPU at any point,
325 * which could result in signalling the wrong/previous pCPU. But if
326 * that happens the vCPU is guaranteed to do a VMRUN (after being
327 * migrated) and thus will process pending interrupts, i.e. a doorbell
328 * is not needed (and the spurious one is harmless).
329 */
330 int cpu = READ_ONCE(vcpu->cpu);
331
332 if (cpu != get_cpu()) {
333 wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, val: kvm_cpu_get_apicid(mps_cpu: cpu));
334 trace_kvm_avic_doorbell(vcpu->vcpu_id, kvm_cpu_get_apicid(mps_cpu: cpu));
335 }
336 put_cpu();
337}
338
339
340static void avic_kick_vcpu(struct kvm_vcpu *vcpu, u32 icrl)
341{
342 vcpu->arch.apic->irr_pending = true;
343 svm_complete_interrupt_delivery(vcpu,
344 delivery_mode: icrl & APIC_MODE_MASK,
345 trig_mode: icrl & APIC_INT_LEVELTRIG,
346 vec: icrl & APIC_VECTOR_MASK);
347}
348
349static void avic_kick_vcpu_by_physical_id(struct kvm *kvm, u32 physical_id,
350 u32 icrl)
351{
352 /*
353 * KVM inhibits AVIC if any vCPU ID diverges from the vCPUs APIC ID,
354 * i.e. APIC ID == vCPU ID.
355 */
356 struct kvm_vcpu *target_vcpu = kvm_get_vcpu_by_id(kvm, id: physical_id);
357
358 /* Once again, nothing to do if the target vCPU doesn't exist. */
359 if (unlikely(!target_vcpu))
360 return;
361
362 avic_kick_vcpu(vcpu: target_vcpu, icrl);
363}
364
365static void avic_kick_vcpu_by_logical_id(struct kvm *kvm, u32 *avic_logical_id_table,
366 u32 logid_index, u32 icrl)
367{
368 u32 physical_id;
369
370 if (avic_logical_id_table) {
371 u32 logid_entry = avic_logical_id_table[logid_index];
372
373 /* Nothing to do if the logical destination is invalid. */
374 if (unlikely(!(logid_entry & AVIC_LOGICAL_ID_ENTRY_VALID_MASK)))
375 return;
376
377 physical_id = logid_entry &
378 AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK;
379 } else {
380 /*
381 * For x2APIC, the logical APIC ID is a read-only value that is
382 * derived from the x2APIC ID, thus the x2APIC ID can be found
383 * by reversing the calculation (stored in logid_index). Note,
384 * bits 31:20 of the x2APIC ID aren't propagated to the logical
385 * ID, but KVM limits the x2APIC ID limited to KVM_MAX_VCPU_IDS.
386 */
387 physical_id = logid_index;
388 }
389
390 avic_kick_vcpu_by_physical_id(kvm, physical_id, icrl);
391}
392
393/*
394 * A fast-path version of avic_kick_target_vcpus(), which attempts to match
395 * destination APIC ID to vCPU without looping through all vCPUs.
396 */
397static int avic_kick_target_vcpus_fast(struct kvm *kvm, struct kvm_lapic *source,
398 u32 icrl, u32 icrh, u32 index)
399{
400 int dest_mode = icrl & APIC_DEST_MASK;
401 int shorthand = icrl & APIC_SHORT_MASK;
402 struct kvm_svm *kvm_svm = to_kvm_svm(kvm);
403 u32 dest;
404
405 if (shorthand != APIC_DEST_NOSHORT)
406 return -EINVAL;
407
408 if (apic_x2apic_mode(source))
409 dest = icrh;
410 else
411 dest = GET_XAPIC_DEST_FIELD(icrh);
412
413 if (dest_mode == APIC_DEST_PHYSICAL) {
414 /* broadcast destination, use slow path */
415 if (apic_x2apic_mode(source) && dest == X2APIC_BROADCAST)
416 return -EINVAL;
417 if (!apic_x2apic_mode(source) && dest == APIC_BROADCAST)
418 return -EINVAL;
419
420 if (WARN_ON_ONCE(dest != index))
421 return -EINVAL;
422
423 avic_kick_vcpu_by_physical_id(kvm, physical_id: dest, icrl);
424 } else {
425 u32 *avic_logical_id_table;
426 unsigned long bitmap, i;
427 u32 cluster;
428
429 if (apic_x2apic_mode(source)) {
430 /* 16 bit dest mask, 16 bit cluster id */
431 bitmap = dest & 0xFFFF;
432 cluster = (dest >> 16) << 4;
433 } else if (kvm_lapic_get_reg(source, APIC_DFR) == APIC_DFR_FLAT) {
434 /* 8 bit dest mask*/
435 bitmap = dest;
436 cluster = 0;
437 } else {
438 /* 4 bit desk mask, 4 bit cluster id */
439 bitmap = dest & 0xF;
440 cluster = (dest >> 4) << 2;
441 }
442
443 /* Nothing to do if there are no destinations in the cluster. */
444 if (unlikely(!bitmap))
445 return 0;
446
447 if (apic_x2apic_mode(source))
448 avic_logical_id_table = NULL;
449 else
450 avic_logical_id_table = page_address(kvm_svm->avic_logical_id_table_page);
451
452 /*
453 * AVIC is inhibited if vCPUs aren't mapped 1:1 with logical
454 * IDs, thus each bit in the destination is guaranteed to map
455 * to at most one vCPU.
456 */
457 for_each_set_bit(i, &bitmap, 16)
458 avic_kick_vcpu_by_logical_id(kvm, avic_logical_id_table,
459 logid_index: cluster + i, icrl);
460 }
461
462 return 0;
463}
464
465static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
466 u32 icrl, u32 icrh, u32 index)
467{
468 u32 dest = apic_x2apic_mode(source) ? icrh : GET_XAPIC_DEST_FIELD(icrh);
469 unsigned long i;
470 struct kvm_vcpu *vcpu;
471
472 if (!avic_kick_target_vcpus_fast(kvm, source, icrl, icrh, index))
473 return;
474
475 trace_kvm_avic_kick_vcpu_slowpath(icrh, icrl, index);
476
477 /*
478 * Wake any target vCPUs that are blocking, i.e. waiting for a wake
479 * event. There's no need to signal doorbells, as hardware has handled
480 * vCPUs that were in guest at the time of the IPI, and vCPUs that have
481 * since entered the guest will have processed pending IRQs at VMRUN.
482 */
483 kvm_for_each_vcpu(i, vcpu, kvm) {
484 if (kvm_apic_match_dest(vcpu, source, icrl & APIC_SHORT_MASK,
485 dest, icrl & APIC_DEST_MASK))
486 avic_kick_vcpu(vcpu, icrl);
487 }
488}
489
490int avic_incomplete_ipi_interception(struct kvm_vcpu *vcpu)
491{
492 struct vcpu_svm *svm = to_svm(vcpu);
493 u32 icrh = svm->vmcb->control.exit_info_1 >> 32;
494 u32 icrl = svm->vmcb->control.exit_info_1;
495 u32 id = svm->vmcb->control.exit_info_2 >> 32;
496 u32 index = svm->vmcb->control.exit_info_2 & 0x1FF;
497 struct kvm_lapic *apic = vcpu->arch.apic;
498
499 trace_kvm_avic_incomplete_ipi(vcpu->vcpu_id, icrh, icrl, id, index);
500
501 switch (id) {
502 case AVIC_IPI_FAILURE_INVALID_TARGET:
503 case AVIC_IPI_FAILURE_INVALID_INT_TYPE:
504 /*
505 * Emulate IPIs that are not handled by AVIC hardware, which
506 * only virtualizes Fixed, Edge-Triggered INTRs, and falls over
507 * if _any_ targets are invalid, e.g. if the logical mode mask
508 * is a superset of running vCPUs.
509 *
510 * The exit is a trap, e.g. ICR holds the correct value and RIP
511 * has been advanced, KVM is responsible only for emulating the
512 * IPI. Sadly, hardware may sometimes leave the BUSY flag set,
513 * in which case KVM needs to emulate the ICR write as well in
514 * order to clear the BUSY flag.
515 */
516 if (icrl & APIC_ICR_BUSY)
517 kvm_apic_write_nodecode(vcpu, APIC_ICR);
518 else
519 kvm_apic_send_ipi(apic, icrl, icrh);
520 break;
521 case AVIC_IPI_FAILURE_TARGET_NOT_RUNNING:
522 /*
523 * At this point, we expect that the AVIC HW has already
524 * set the appropriate IRR bits on the valid target
525 * vcpus. So, we just need to kick the appropriate vcpu.
526 */
527 avic_kick_target_vcpus(kvm: vcpu->kvm, source: apic, icrl, icrh, index);
528 break;
529 case AVIC_IPI_FAILURE_INVALID_BACKING_PAGE:
530 WARN_ONCE(1, "Invalid backing page\n");
531 break;
532 case AVIC_IPI_FAILURE_INVALID_IPI_VECTOR:
533 /* Invalid IPI with vector < 16 */
534 break;
535 default:
536 vcpu_unimpl(vcpu, "Unknown avic incomplete IPI interception\n");
537 }
538
539 return 1;
540}
541
542unsigned long avic_vcpu_get_apicv_inhibit_reasons(struct kvm_vcpu *vcpu)
543{
544 if (is_guest_mode(vcpu))
545 return APICV_INHIBIT_REASON_NESTED;
546 return 0;
547}
548
549static u32 *avic_get_logical_id_entry(struct kvm_vcpu *vcpu, u32 ldr, bool flat)
550{
551 struct kvm_svm *kvm_svm = to_kvm_svm(kvm: vcpu->kvm);
552 u32 *logical_apic_id_table;
553 u32 cluster, index;
554
555 ldr = GET_APIC_LOGICAL_ID(ldr);
556
557 if (flat) {
558 cluster = 0;
559 } else {
560 cluster = (ldr >> 4);
561 if (cluster >= 0xf)
562 return NULL;
563 ldr &= 0xf;
564 }
565 if (!ldr || !is_power_of_2(n: ldr))
566 return NULL;
567
568 index = __ffs(ldr);
569 if (WARN_ON_ONCE(index > 7))
570 return NULL;
571 index += (cluster << 2);
572
573 logical_apic_id_table = (u32 *) page_address(kvm_svm->avic_logical_id_table_page);
574
575 return &logical_apic_id_table[index];
576}
577
578static void avic_ldr_write(struct kvm_vcpu *vcpu, u8 g_physical_id, u32 ldr)
579{
580 bool flat;
581 u32 *entry, new_entry;
582
583 flat = kvm_lapic_get_reg(vcpu->arch.apic, APIC_DFR) == APIC_DFR_FLAT;
584 entry = avic_get_logical_id_entry(vcpu, ldr, flat);
585 if (!entry)
586 return;
587
588 new_entry = READ_ONCE(*entry);
589 new_entry &= ~AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK;
590 new_entry |= (g_physical_id & AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK);
591 new_entry |= AVIC_LOGICAL_ID_ENTRY_VALID_MASK;
592 WRITE_ONCE(*entry, new_entry);
593}
594
595static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu)
596{
597 struct vcpu_svm *svm = to_svm(vcpu);
598 bool flat = svm->dfr_reg == APIC_DFR_FLAT;
599 u32 *entry;
600
601 /* Note: x2AVIC does not use logical APIC ID table */
602 if (apic_x2apic_mode(vcpu->arch.apic))
603 return;
604
605 entry = avic_get_logical_id_entry(vcpu, ldr: svm->ldr_reg, flat);
606 if (entry)
607 clear_bit(AVIC_LOGICAL_ID_ENTRY_VALID_BIT, addr: (unsigned long *)entry);
608}
609
610static void avic_handle_ldr_update(struct kvm_vcpu *vcpu)
611{
612 struct vcpu_svm *svm = to_svm(vcpu);
613 u32 ldr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_LDR);
614 u32 id = kvm_xapic_id(vcpu->arch.apic);
615
616 /* AVIC does not support LDR update for x2APIC */
617 if (apic_x2apic_mode(vcpu->arch.apic))
618 return;
619
620 if (ldr == svm->ldr_reg)
621 return;
622
623 avic_invalidate_logical_id_entry(vcpu);
624
625 svm->ldr_reg = ldr;
626 avic_ldr_write(vcpu, g_physical_id: id, ldr);
627}
628
629static void avic_handle_dfr_update(struct kvm_vcpu *vcpu)
630{
631 struct vcpu_svm *svm = to_svm(vcpu);
632 u32 dfr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_DFR);
633
634 if (svm->dfr_reg == dfr)
635 return;
636
637 avic_invalidate_logical_id_entry(vcpu);
638 svm->dfr_reg = dfr;
639}
640
641static int avic_unaccel_trap_write(struct kvm_vcpu *vcpu)
642{
643 u32 offset = to_svm(vcpu)->vmcb->control.exit_info_1 &
644 AVIC_UNACCEL_ACCESS_OFFSET_MASK;
645
646 switch (offset) {
647 case APIC_LDR:
648 avic_handle_ldr_update(vcpu);
649 break;
650 case APIC_DFR:
651 avic_handle_dfr_update(vcpu);
652 break;
653 case APIC_RRR:
654 /* Ignore writes to Read Remote Data, it's read-only. */
655 return 1;
656 default:
657 break;
658 }
659
660 kvm_apic_write_nodecode(vcpu, offset);
661 return 1;
662}
663
664static bool is_avic_unaccelerated_access_trap(u32 offset)
665{
666 bool ret = false;
667
668 switch (offset) {
669 case APIC_ID:
670 case APIC_EOI:
671 case APIC_RRR:
672 case APIC_LDR:
673 case APIC_DFR:
674 case APIC_SPIV:
675 case APIC_ESR:
676 case APIC_ICR:
677 case APIC_LVTT:
678 case APIC_LVTTHMR:
679 case APIC_LVTPC:
680 case APIC_LVT0:
681 case APIC_LVT1:
682 case APIC_LVTERR:
683 case APIC_TMICT:
684 case APIC_TDCR:
685 ret = true;
686 break;
687 default:
688 break;
689 }
690 return ret;
691}
692
693int avic_unaccelerated_access_interception(struct kvm_vcpu *vcpu)
694{
695 struct vcpu_svm *svm = to_svm(vcpu);
696 int ret = 0;
697 u32 offset = svm->vmcb->control.exit_info_1 &
698 AVIC_UNACCEL_ACCESS_OFFSET_MASK;
699 u32 vector = svm->vmcb->control.exit_info_2 &
700 AVIC_UNACCEL_ACCESS_VECTOR_MASK;
701 bool write = (svm->vmcb->control.exit_info_1 >> 32) &
702 AVIC_UNACCEL_ACCESS_WRITE_MASK;
703 bool trap = is_avic_unaccelerated_access_trap(offset);
704
705 trace_kvm_avic_unaccelerated_access(vcpu->vcpu_id, offset,
706 trap, write, vector);
707 if (trap) {
708 /* Handling Trap */
709 WARN_ONCE(!write, "svm: Handling trap read.\n");
710 ret = avic_unaccel_trap_write(vcpu);
711 } else {
712 /* Handling Fault */
713 ret = kvm_emulate_instruction(vcpu, emulation_type: 0);
714 }
715
716 return ret;
717}
718
719int avic_init_vcpu(struct vcpu_svm *svm)
720{
721 int ret;
722 struct kvm_vcpu *vcpu = &svm->vcpu;
723
724 if (!enable_apicv || !irqchip_in_kernel(vcpu->kvm))
725 return 0;
726
727 ret = avic_init_backing_page(vcpu);
728 if (ret)
729 return ret;
730
731 INIT_LIST_HEAD(list: &svm->ir_list);
732 spin_lock_init(&svm->ir_list_lock);
733 svm->dfr_reg = APIC_DFR_FLAT;
734
735 return ret;
736}
737
738void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu)
739{
740 avic_handle_dfr_update(vcpu);
741 avic_handle_ldr_update(vcpu);
742}
743
744static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
745{
746 int ret = 0;
747 unsigned long flags;
748 struct amd_svm_iommu_ir *ir;
749 struct vcpu_svm *svm = to_svm(vcpu);
750
751 if (!kvm_arch_has_assigned_device(kvm: vcpu->kvm))
752 return 0;
753
754 /*
755 * Here, we go through the per-vcpu ir_list to update all existing
756 * interrupt remapping table entry targeting this vcpu.
757 */
758 spin_lock_irqsave(&svm->ir_list_lock, flags);
759
760 if (list_empty(head: &svm->ir_list))
761 goto out;
762
763 list_for_each_entry(ir, &svm->ir_list, node) {
764 if (activate)
765 ret = amd_iommu_activate_guest_mode(data: ir->data);
766 else
767 ret = amd_iommu_deactivate_guest_mode(data: ir->data);
768 if (ret)
769 break;
770 }
771out:
772 spin_unlock_irqrestore(lock: &svm->ir_list_lock, flags);
773 return ret;
774}
775
776static void svm_ir_list_del(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
777{
778 unsigned long flags;
779 struct amd_svm_iommu_ir *cur;
780
781 spin_lock_irqsave(&svm->ir_list_lock, flags);
782 list_for_each_entry(cur, &svm->ir_list, node) {
783 if (cur->data != pi->ir_data)
784 continue;
785 list_del(entry: &cur->node);
786 kfree(objp: cur);
787 break;
788 }
789 spin_unlock_irqrestore(lock: &svm->ir_list_lock, flags);
790}
791
792static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
793{
794 int ret = 0;
795 unsigned long flags;
796 struct amd_svm_iommu_ir *ir;
797 u64 entry;
798
799 /**
800 * In some cases, the existing irte is updated and re-set,
801 * so we need to check here if it's already been * added
802 * to the ir_list.
803 */
804 if (pi->ir_data && (pi->prev_ga_tag != 0)) {
805 struct kvm *kvm = svm->vcpu.kvm;
806 u32 vcpu_id = AVIC_GATAG_TO_VCPUID(pi->prev_ga_tag);
807 struct kvm_vcpu *prev_vcpu = kvm_get_vcpu_by_id(kvm, id: vcpu_id);
808 struct vcpu_svm *prev_svm;
809
810 if (!prev_vcpu) {
811 ret = -EINVAL;
812 goto out;
813 }
814
815 prev_svm = to_svm(vcpu: prev_vcpu);
816 svm_ir_list_del(svm: prev_svm, pi);
817 }
818
819 /**
820 * Allocating new amd_iommu_pi_data, which will get
821 * add to the per-vcpu ir_list.
822 */
823 ir = kzalloc(size: sizeof(struct amd_svm_iommu_ir), GFP_KERNEL_ACCOUNT);
824 if (!ir) {
825 ret = -ENOMEM;
826 goto out;
827 }
828 ir->data = pi->ir_data;
829
830 spin_lock_irqsave(&svm->ir_list_lock, flags);
831
832 /*
833 * Update the target pCPU for IOMMU doorbells if the vCPU is running.
834 * If the vCPU is NOT running, i.e. is blocking or scheduled out, KVM
835 * will update the pCPU info when the vCPU awkened and/or scheduled in.
836 * See also avic_vcpu_load().
837 */
838 entry = READ_ONCE(*(svm->avic_physical_id_cache));
839 if (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK)
840 amd_iommu_update_ga(cpu: entry & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK,
841 is_run: true, data: pi->ir_data);
842
843 list_add(new: &ir->node, head: &svm->ir_list);
844 spin_unlock_irqrestore(lock: &svm->ir_list_lock, flags);
845out:
846 return ret;
847}
848
849/*
850 * Note:
851 * The HW cannot support posting multicast/broadcast
852 * interrupts to a vCPU. So, we still use legacy interrupt
853 * remapping for these kind of interrupts.
854 *
855 * For lowest-priority interrupts, we only support
856 * those with single CPU as the destination, e.g. user
857 * configures the interrupts via /proc/irq or uses
858 * irqbalance to make the interrupts single-CPU.
859 */
860static int
861get_pi_vcpu_info(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
862 struct vcpu_data *vcpu_info, struct vcpu_svm **svm)
863{
864 struct kvm_lapic_irq irq;
865 struct kvm_vcpu *vcpu = NULL;
866
867 kvm_set_msi_irq(kvm, e, irq: &irq);
868
869 if (!kvm_intr_is_single_vcpu(kvm, irq: &irq, dest_vcpu: &vcpu) ||
870 !kvm_irq_is_postable(irq: &irq)) {
871 pr_debug("SVM: %s: use legacy intr remap mode for irq %u\n",
872 __func__, irq.vector);
873 return -1;
874 }
875
876 pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
877 irq.vector);
878 *svm = to_svm(vcpu);
879 vcpu_info->pi_desc_addr = __sme_set(page_to_phys((*svm)->avic_backing_page));
880 vcpu_info->vector = irq.vector;
881
882 return 0;
883}
884
885/*
886 * avic_pi_update_irte - set IRTE for Posted-Interrupts
887 *
888 * @kvm: kvm
889 * @host_irq: host irq of the interrupt
890 * @guest_irq: gsi of the interrupt
891 * @set: set or unset PI
892 * returns 0 on success, < 0 on failure
893 */
894int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
895 uint32_t guest_irq, bool set)
896{
897 struct kvm_kernel_irq_routing_entry *e;
898 struct kvm_irq_routing_table *irq_rt;
899 int idx, ret = 0;
900
901 if (!kvm_arch_has_assigned_device(kvm) ||
902 !irq_remapping_cap(cap: IRQ_POSTING_CAP))
903 return 0;
904
905 pr_debug("SVM: %s: host_irq=%#x, guest_irq=%#x, set=%#x\n",
906 __func__, host_irq, guest_irq, set);
907
908 idx = srcu_read_lock(ssp: &kvm->irq_srcu);
909 irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
910
911 if (guest_irq >= irq_rt->nr_rt_entries ||
912 hlist_empty(h: &irq_rt->map[guest_irq])) {
913 pr_warn_once("no route for guest_irq %u/%u (broken user space?)\n",
914 guest_irq, irq_rt->nr_rt_entries);
915 goto out;
916 }
917
918 hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) {
919 struct vcpu_data vcpu_info;
920 struct vcpu_svm *svm = NULL;
921
922 if (e->type != KVM_IRQ_ROUTING_MSI)
923 continue;
924
925 /**
926 * Here, we setup with legacy mode in the following cases:
927 * 1. When cannot target interrupt to a specific vcpu.
928 * 2. Unsetting posted interrupt.
929 * 3. APIC virtualization is disabled for the vcpu.
930 * 4. IRQ has incompatible delivery mode (SMI, INIT, etc)
931 */
932 if (!get_pi_vcpu_info(kvm, e, vcpu_info: &vcpu_info, svm: &svm) && set &&
933 kvm_vcpu_apicv_active(&svm->vcpu)) {
934 struct amd_iommu_pi_data pi;
935
936 /* Try to enable guest_mode in IRTE */
937 pi.base = __sme_set(page_to_phys(svm->avic_backing_page) &
938 AVIC_HPA_MASK);
939 pi.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id,
940 svm->vcpu.vcpu_id);
941 pi.is_guest_mode = true;
942 pi.vcpu_data = &vcpu_info;
943 ret = irq_set_vcpu_affinity(irq: host_irq, vcpu_info: &pi);
944
945 /**
946 * Here, we successfully setting up vcpu affinity in
947 * IOMMU guest mode. Now, we need to store the posted
948 * interrupt information in a per-vcpu ir_list so that
949 * we can reference to them directly when we update vcpu
950 * scheduling information in IOMMU irte.
951 */
952 if (!ret && pi.is_guest_mode)
953 svm_ir_list_add(svm, pi: &pi);
954 } else {
955 /* Use legacy mode in IRTE */
956 struct amd_iommu_pi_data pi;
957
958 /**
959 * Here, pi is used to:
960 * - Tell IOMMU to use legacy mode for this interrupt.
961 * - Retrieve ga_tag of prior interrupt remapping data.
962 */
963 pi.prev_ga_tag = 0;
964 pi.is_guest_mode = false;
965 ret = irq_set_vcpu_affinity(irq: host_irq, vcpu_info: &pi);
966
967 /**
968 * Check if the posted interrupt was previously
969 * setup with the guest_mode by checking if the ga_tag
970 * was cached. If so, we need to clean up the per-vcpu
971 * ir_list.
972 */
973 if (!ret && pi.prev_ga_tag) {
974 int id = AVIC_GATAG_TO_VCPUID(pi.prev_ga_tag);
975 struct kvm_vcpu *vcpu;
976
977 vcpu = kvm_get_vcpu_by_id(kvm, id);
978 if (vcpu)
979 svm_ir_list_del(svm: to_svm(vcpu), pi: &pi);
980 }
981 }
982
983 if (!ret && svm) {
984 trace_kvm_pi_irte_update(host_irq, svm->vcpu.vcpu_id,
985 e->gsi, vcpu_info.vector,
986 vcpu_info.pi_desc_addr, set);
987 }
988
989 if (ret < 0) {
990 pr_err("%s: failed to update PI IRTE\n", __func__);
991 goto out;
992 }
993 }
994
995 ret = 0;
996out:
997 srcu_read_unlock(ssp: &kvm->irq_srcu, idx);
998 return ret;
999}
1000
1001static inline int
1002avic_update_iommu_vcpu_affinity(struct kvm_vcpu *vcpu, int cpu, bool r)
1003{
1004 int ret = 0;
1005 struct amd_svm_iommu_ir *ir;
1006 struct vcpu_svm *svm = to_svm(vcpu);
1007
1008 lockdep_assert_held(&svm->ir_list_lock);
1009
1010 if (!kvm_arch_has_assigned_device(kvm: vcpu->kvm))
1011 return 0;
1012
1013 /*
1014 * Here, we go through the per-vcpu ir_list to update all existing
1015 * interrupt remapping table entry targeting this vcpu.
1016 */
1017 if (list_empty(head: &svm->ir_list))
1018 return 0;
1019
1020 list_for_each_entry(ir, &svm->ir_list, node) {
1021 ret = amd_iommu_update_ga(cpu, is_run: r, data: ir->data);
1022 if (ret)
1023 return ret;
1024 }
1025 return 0;
1026}
1027
1028void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
1029{
1030 u64 entry;
1031 int h_physical_id = kvm_cpu_get_apicid(mps_cpu: cpu);
1032 struct vcpu_svm *svm = to_svm(vcpu);
1033 unsigned long flags;
1034
1035 lockdep_assert_preemption_disabled();
1036
1037 if (WARN_ON(h_physical_id & ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK))
1038 return;
1039
1040 /*
1041 * No need to update anything if the vCPU is blocking, i.e. if the vCPU
1042 * is being scheduled in after being preempted. The CPU entries in the
1043 * Physical APIC table and IRTE are consumed iff IsRun{ning} is '1'.
1044 * If the vCPU was migrated, its new CPU value will be stuffed when the
1045 * vCPU unblocks.
1046 */
1047 if (kvm_vcpu_is_blocking(vcpu))
1048 return;
1049
1050 /*
1051 * Grab the per-vCPU interrupt remapping lock even if the VM doesn't
1052 * _currently_ have assigned devices, as that can change. Holding
1053 * ir_list_lock ensures that either svm_ir_list_add() will consume
1054 * up-to-date entry information, or that this task will wait until
1055 * svm_ir_list_add() completes to set the new target pCPU.
1056 */
1057 spin_lock_irqsave(&svm->ir_list_lock, flags);
1058
1059 entry = READ_ONCE(*(svm->avic_physical_id_cache));
1060 WARN_ON_ONCE(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);
1061
1062 entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
1063 entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
1064 entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
1065
1066 WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
1067 avic_update_iommu_vcpu_affinity(vcpu, cpu: h_physical_id, r: true);
1068
1069 spin_unlock_irqrestore(lock: &svm->ir_list_lock, flags);
1070}
1071
1072void avic_vcpu_put(struct kvm_vcpu *vcpu)
1073{
1074 u64 entry;
1075 struct vcpu_svm *svm = to_svm(vcpu);
1076 unsigned long flags;
1077
1078 lockdep_assert_preemption_disabled();
1079
1080 /*
1081 * Note, reading the Physical ID entry outside of ir_list_lock is safe
1082 * as only the pCPU that has loaded (or is loading) the vCPU is allowed
1083 * to modify the entry, and preemption is disabled. I.e. the vCPU
1084 * can't be scheduled out and thus avic_vcpu_{put,load}() can't run
1085 * recursively.
1086 */
1087 entry = READ_ONCE(*(svm->avic_physical_id_cache));
1088
1089 /* Nothing to do if IsRunning == '0' due to vCPU blocking. */
1090 if (!(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK))
1091 return;
1092
1093 /*
1094 * Take and hold the per-vCPU interrupt remapping lock while updating
1095 * the Physical ID entry even though the lock doesn't protect against
1096 * multiple writers (see above). Holding ir_list_lock ensures that
1097 * either svm_ir_list_add() will consume up-to-date entry information,
1098 * or that this task will wait until svm_ir_list_add() completes to
1099 * mark the vCPU as not running.
1100 */
1101 spin_lock_irqsave(&svm->ir_list_lock, flags);
1102
1103 avic_update_iommu_vcpu_affinity(vcpu, cpu: -1, r: 0);
1104
1105 entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
1106 WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
1107
1108 spin_unlock_irqrestore(lock: &svm->ir_list_lock, flags);
1109
1110}
1111
1112void avic_refresh_virtual_apic_mode(struct kvm_vcpu *vcpu)
1113{
1114 struct vcpu_svm *svm = to_svm(vcpu);
1115 struct vmcb *vmcb = svm->vmcb01.ptr;
1116
1117 if (!lapic_in_kernel(vcpu) || !enable_apicv)
1118 return;
1119
1120 if (kvm_vcpu_apicv_active(vcpu)) {
1121 /**
1122 * During AVIC temporary deactivation, guest could update
1123 * APIC ID, DFR and LDR registers, which would not be trapped
1124 * by avic_unaccelerated_access_interception(). In this case,
1125 * we need to check and update the AVIC logical APIC ID table
1126 * accordingly before re-activating.
1127 */
1128 avic_apicv_post_state_restore(vcpu);
1129 avic_activate_vmcb(svm);
1130 } else {
1131 avic_deactivate_vmcb(svm);
1132 }
1133 vmcb_mark_dirty(vmcb, bit: VMCB_AVIC);
1134}
1135
1136void avic_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
1137{
1138 bool activated = kvm_vcpu_apicv_active(vcpu);
1139
1140 if (!enable_apicv)
1141 return;
1142
1143 avic_refresh_virtual_apic_mode(vcpu);
1144
1145 if (activated)
1146 avic_vcpu_load(vcpu, cpu: vcpu->cpu);
1147 else
1148 avic_vcpu_put(vcpu);
1149
1150 avic_set_pi_irte_mode(vcpu, activate: activated);
1151}
1152
1153void avic_vcpu_blocking(struct kvm_vcpu *vcpu)
1154{
1155 if (!kvm_vcpu_apicv_active(vcpu))
1156 return;
1157
1158 /*
1159 * Unload the AVIC when the vCPU is about to block, _before_
1160 * the vCPU actually blocks.
1161 *
1162 * Any IRQs that arrive before IsRunning=0 will not cause an
1163 * incomplete IPI vmexit on the source, therefore vIRR will also
1164 * be checked by kvm_vcpu_check_block() before blocking. The
1165 * memory barrier implicit in set_current_state orders writing
1166 * IsRunning=0 before reading the vIRR. The processor needs a
1167 * matching memory barrier on interrupt delivery between writing
1168 * IRR and reading IsRunning; the lack of this barrier might be
1169 * the cause of errata #1235).
1170 */
1171 avic_vcpu_put(vcpu);
1172}
1173
1174void avic_vcpu_unblocking(struct kvm_vcpu *vcpu)
1175{
1176 if (!kvm_vcpu_apicv_active(vcpu))
1177 return;
1178
1179 avic_vcpu_load(vcpu, cpu: vcpu->cpu);
1180}
1181
1182/*
1183 * Note:
1184 * - The module param avic enable both xAPIC and x2APIC mode.
1185 * - Hypervisor can support both xAVIC and x2AVIC in the same guest.
1186 * - The mode can be switched at run-time.
1187 */
1188bool avic_hardware_setup(void)
1189{
1190 if (!npt_enabled)
1191 return false;
1192
1193 /* AVIC is a prerequisite for x2AVIC. */
1194 if (!boot_cpu_has(X86_FEATURE_AVIC) && !force_avic) {
1195 if (boot_cpu_has(X86_FEATURE_X2AVIC)) {
1196 pr_warn(FW_BUG "Cannot support x2AVIC due to AVIC is disabled");
1197 pr_warn(FW_BUG "Try enable AVIC using force_avic option");
1198 }
1199 return false;
1200 }
1201
1202 if (boot_cpu_has(X86_FEATURE_AVIC)) {
1203 pr_info("AVIC enabled\n");
1204 } else if (force_avic) {
1205 /*
1206 * Some older systems does not advertise AVIC support.
1207 * See Revision Guide for specific AMD processor for more detail.
1208 */
1209 pr_warn("AVIC is not supported in CPUID but force enabled");
1210 pr_warn("Your system might crash and burn");
1211 }
1212
1213 /* AVIC is a prerequisite for x2AVIC. */
1214 x2avic_enabled = boot_cpu_has(X86_FEATURE_X2AVIC);
1215 if (x2avic_enabled)
1216 pr_info("x2AVIC enabled\n");
1217
1218 amd_iommu_register_ga_log_notifier(notifier: &avic_ga_log_notifier);
1219
1220 return true;
1221}
1222

source code of linux/arch/x86/kvm/svm/avic.c