1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
4 * Architecture neutral utility routines for interacting with
5 * Hyper-V. This file is specifically for code that must be
6 * built-in to the kernel image when CONFIG_HYPERV is set
7 * (vs. being in a module) because it is called from architecture
8 * specific code under arch/.
9 *
10 * Copyright (C) 2021, Microsoft, Inc.
11 *
12 * Author : Michael Kelley <mikelley@microsoft.com>
13 */
14
15 #include <linux/types.h>
16 #include <linux/acpi.h>
17 #include <linux/export.h>
18 #include <linux/bitfield.h>
19 #include <linux/cpumask.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/panic_notifier.h>
22 #include <linux/ptrace.h>
23 #include <linux/random.h>
24 #include <linux/efi.h>
25 #include <linux/kdebug.h>
26 #include <linux/kmsg_dump.h>
27 #include <linux/sizes.h>
28 #include <linux/slab.h>
29 #include <linux/dma-map-ops.h>
30 #include <linux/set_memory.h>
31 #include <hyperv/hvhdk.h>
32 #include <asm/mshyperv.h>
33
34 u64 hv_current_partition_id = HV_PARTITION_ID_SELF;
35 EXPORT_SYMBOL_GPL(hv_current_partition_id);
36
37 enum hv_partition_type hv_curr_partition_type;
38 EXPORT_SYMBOL_GPL(hv_curr_partition_type);
39
40 /*
41 * ms_hyperv and hv_nested are defined here with other
42 * Hyper-V specific globals so they are shared across all architectures and are
43 * built only when CONFIG_HYPERV is defined. But on x86,
44 * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not
45 * defined, and it uses these three variables. So mark them as __weak
46 * here, allowing for an overriding definition in the module containing
47 * ms_hyperv_init_platform().
48 */
49 bool __weak hv_nested;
50 EXPORT_SYMBOL_GPL(hv_nested);
51
52 struct ms_hyperv_info __weak ms_hyperv;
53 EXPORT_SYMBOL_GPL(ms_hyperv);
54
55 u32 *hv_vp_index;
56 EXPORT_SYMBOL_GPL(hv_vp_index);
57
58 u32 hv_max_vp_index;
59 EXPORT_SYMBOL_GPL(hv_max_vp_index);
60
61 void * __percpu *hyperv_pcpu_input_arg;
62 EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
63
64 void * __percpu *hyperv_pcpu_output_arg;
65 EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
66
67 static void hv_kmsg_dump_unregister(void);
68
69 static struct ctl_table_header *hv_ctl_table_hdr;
70
71 /*
72 * Per-cpu array holding the tail pointer for the SynIC event ring buffer
73 * for each SINT.
74 *
75 * We cannot maintain this in mshv driver because the tail pointer should
76 * persist even if the mshv driver is unloaded.
77 */
78 u8 * __percpu *hv_synic_eventring_tail;
79 EXPORT_SYMBOL_GPL(hv_synic_eventring_tail);
80
81 /*
82 * Hyper-V specific initialization and shutdown code that is
83 * common across all architectures. Called from architecture
84 * specific initialization functions.
85 */
86
hv_common_free(void)87 void __init hv_common_free(void)
88 {
89 unregister_sysctl_table(hv_ctl_table_hdr);
90 hv_ctl_table_hdr = NULL;
91
92 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
93 hv_kmsg_dump_unregister();
94
95 kfree(hv_vp_index);
96 hv_vp_index = NULL;
97
98 free_percpu(hyperv_pcpu_output_arg);
99 hyperv_pcpu_output_arg = NULL;
100
101 free_percpu(hyperv_pcpu_input_arg);
102 hyperv_pcpu_input_arg = NULL;
103
104 free_percpu(hv_synic_eventring_tail);
105 hv_synic_eventring_tail = NULL;
106 }
107
108 static void *hv_panic_page;
109
110 /*
111 * Boolean to control whether to report panic messages over Hyper-V.
112 *
113 * It can be set via /proc/sys/kernel/hyperv_record_panic_msg
114 */
115 static int sysctl_record_panic_msg = 1;
116
117 /*
118 * sysctl option to allow the user to control whether kmsg data should be
119 * reported to Hyper-V on panic.
120 */
121 static const struct ctl_table hv_ctl_table[] = {
122 {
123 .procname = "hyperv_record_panic_msg",
124 .data = &sysctl_record_panic_msg,
125 .maxlen = sizeof(int),
126 .mode = 0644,
127 .proc_handler = proc_dointvec_minmax,
128 .extra1 = SYSCTL_ZERO,
129 .extra2 = SYSCTL_ONE
130 },
131 };
132
133 static int hv_die_panic_notify_crash(struct notifier_block *self,
134 unsigned long val, void *args);
135
136 static struct notifier_block hyperv_die_report_block = {
137 .notifier_call = hv_die_panic_notify_crash,
138 };
139
140 static struct notifier_block hyperv_panic_report_block = {
141 .notifier_call = hv_die_panic_notify_crash,
142 };
143
144 /*
145 * The following callback works both as die and panic notifier; its
146 * goal is to provide panic information to the hypervisor unless the
147 * kmsg dumper is used [see hv_kmsg_dump()], which provides more
148 * information but isn't always available.
149 *
150 * Notice that both the panic/die report notifiers are registered only
151 * if we have the capability HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE set.
152 */
hv_die_panic_notify_crash(struct notifier_block * self,unsigned long val,void * args)153 static int hv_die_panic_notify_crash(struct notifier_block *self,
154 unsigned long val, void *args)
155 {
156 struct pt_regs *regs;
157 bool is_die;
158
159 /* Don't notify Hyper-V unless we have a die oops event or panic. */
160 if (self == &hyperv_panic_report_block) {
161 is_die = false;
162 regs = current_pt_regs();
163 } else { /* die event */
164 if (val != DIE_OOPS)
165 return NOTIFY_DONE;
166
167 is_die = true;
168 regs = ((struct die_args *)args)->regs;
169 }
170
171 /*
172 * Hyper-V should be notified only once about a panic/die. If we will
173 * be calling hv_kmsg_dump() later with kmsg data, don't do the
174 * notification here.
175 */
176 if (!sysctl_record_panic_msg || !hv_panic_page)
177 hyperv_report_panic(regs, val, is_die);
178
179 return NOTIFY_DONE;
180 }
181
182 /*
183 * Callback from kmsg_dump. Grab as much as possible from the end of the kmsg
184 * buffer and call into Hyper-V to transfer the data.
185 */
hv_kmsg_dump(struct kmsg_dumper * dumper,struct kmsg_dump_detail * detail)186 static void hv_kmsg_dump(struct kmsg_dumper *dumper,
187 struct kmsg_dump_detail *detail)
188 {
189 struct kmsg_dump_iter iter;
190 size_t bytes_written;
191
192 /* We are only interested in panics. */
193 if (detail->reason != KMSG_DUMP_PANIC || !sysctl_record_panic_msg)
194 return;
195
196 /*
197 * Write dump contents to the page. No need to synchronize; panic should
198 * be single-threaded.
199 */
200 kmsg_dump_rewind(&iter);
201 kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE,
202 &bytes_written);
203 if (!bytes_written)
204 return;
205 /*
206 * P3 to contain the physical address of the panic page & P4 to
207 * contain the size of the panic data in that page. Rest of the
208 * registers are no-op when the NOTIFY_MSG flag is set.
209 */
210 hv_set_msr(HV_MSR_CRASH_P0, 0);
211 hv_set_msr(HV_MSR_CRASH_P1, 0);
212 hv_set_msr(HV_MSR_CRASH_P2, 0);
213 hv_set_msr(HV_MSR_CRASH_P3, virt_to_phys(hv_panic_page));
214 hv_set_msr(HV_MSR_CRASH_P4, bytes_written);
215
216 /*
217 * Let Hyper-V know there is crash data available along with
218 * the panic message.
219 */
220 hv_set_msr(HV_MSR_CRASH_CTL,
221 (HV_CRASH_CTL_CRASH_NOTIFY |
222 HV_CRASH_CTL_CRASH_NOTIFY_MSG));
223 }
224
225 static struct kmsg_dumper hv_kmsg_dumper = {
226 .dump = hv_kmsg_dump,
227 };
228
hv_kmsg_dump_unregister(void)229 static void hv_kmsg_dump_unregister(void)
230 {
231 kmsg_dump_unregister(&hv_kmsg_dumper);
232 unregister_die_notifier(&hyperv_die_report_block);
233 atomic_notifier_chain_unregister(&panic_notifier_list,
234 &hyperv_panic_report_block);
235
236 kfree(hv_panic_page);
237 hv_panic_page = NULL;
238 }
239
hv_kmsg_dump_register(void)240 static void hv_kmsg_dump_register(void)
241 {
242 int ret;
243
244 hv_panic_page = kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
245 if (!hv_panic_page) {
246 pr_err("Hyper-V: panic message page memory allocation failed\n");
247 return;
248 }
249
250 ret = kmsg_dump_register(&hv_kmsg_dumper);
251 if (ret) {
252 pr_err("Hyper-V: kmsg dump register error 0x%x\n", ret);
253 kfree(hv_panic_page);
254 hv_panic_page = NULL;
255 }
256 }
257
hv_output_page_exists(void)258 static inline bool hv_output_page_exists(void)
259 {
260 return hv_root_partition() || IS_ENABLED(CONFIG_HYPERV_VTL_MODE);
261 }
262
hv_get_partition_id(void)263 void __init hv_get_partition_id(void)
264 {
265 struct hv_output_get_partition_id *output;
266 unsigned long flags;
267 u64 status, pt_id;
268
269 local_irq_save(flags);
270 output = *this_cpu_ptr(hyperv_pcpu_input_arg);
271 status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output);
272 pt_id = output->partition_id;
273 local_irq_restore(flags);
274
275 if (hv_result_success(status))
276 hv_current_partition_id = pt_id;
277 else
278 pr_err("Hyper-V: failed to get partition ID: %#x\n",
279 hv_result(status));
280 }
281 #if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
get_vtl(void)282 u8 __init get_vtl(void)
283 {
284 u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
285 struct hv_input_get_vp_registers *input;
286 struct hv_output_get_vp_registers *output;
287 unsigned long flags;
288 u64 ret;
289
290 local_irq_save(flags);
291 input = *this_cpu_ptr(hyperv_pcpu_input_arg);
292 output = *this_cpu_ptr(hyperv_pcpu_output_arg);
293
294 memset(input, 0, struct_size(input, names, 1));
295 input->partition_id = HV_PARTITION_ID_SELF;
296 input->vp_index = HV_VP_INDEX_SELF;
297 input->input_vtl.as_uint8 = 0;
298 input->names[0] = HV_REGISTER_VSM_VP_STATUS;
299
300 ret = hv_do_hypercall(control, input, output);
301 if (hv_result_success(ret)) {
302 ret = output->values[0].reg8 & HV_VTL_MASK;
303 } else {
304 pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
305 BUG();
306 }
307
308 local_irq_restore(flags);
309 return ret;
310 }
311 #endif
312
hv_common_init(void)313 int __init hv_common_init(void)
314 {
315 int i;
316 union hv_hypervisor_version_info version;
317
318 /* Get information about the Hyper-V host version */
319 if (!hv_get_hypervisor_version(&version))
320 pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
321 version.major_version, version.minor_version,
322 version.build_number, version.service_number,
323 version.service_pack, version.service_branch);
324
325 if (hv_is_isolation_supported())
326 sysctl_record_panic_msg = 0;
327
328 /*
329 * Hyper-V expects to get crash register data or kmsg when
330 * crash enlightment is available and system crashes. Set
331 * crash_kexec_post_notifiers to be true to make sure that
332 * calling crash enlightment interface before running kdump
333 * kernel.
334 */
335 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
336 u64 hyperv_crash_ctl;
337
338 crash_kexec_post_notifiers = true;
339 pr_info("Hyper-V: enabling crash_kexec_post_notifiers\n");
340
341 /*
342 * Panic message recording (sysctl_record_panic_msg)
343 * is enabled by default in non-isolated guests and
344 * disabled by default in isolated guests; the panic
345 * message recording won't be available in isolated
346 * guests should the following registration fail.
347 */
348 hv_ctl_table_hdr = register_sysctl("kernel", hv_ctl_table);
349 if (!hv_ctl_table_hdr)
350 pr_err("Hyper-V: sysctl table register error");
351
352 /*
353 * Register for panic kmsg callback only if the right
354 * capability is supported by the hypervisor.
355 */
356 hyperv_crash_ctl = hv_get_msr(HV_MSR_CRASH_CTL);
357 if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG)
358 hv_kmsg_dump_register();
359
360 register_die_notifier(&hyperv_die_report_block);
361 atomic_notifier_chain_register(&panic_notifier_list,
362 &hyperv_panic_report_block);
363 }
364
365 /*
366 * Allocate the per-CPU state for the hypercall input arg.
367 * If this allocation fails, we will not be able to setup
368 * (per-CPU) hypercall input page and thus this failure is
369 * fatal on Hyper-V.
370 */
371 hyperv_pcpu_input_arg = alloc_percpu(void *);
372 BUG_ON(!hyperv_pcpu_input_arg);
373
374 /* Allocate the per-CPU state for output arg for root */
375 if (hv_output_page_exists()) {
376 hyperv_pcpu_output_arg = alloc_percpu(void *);
377 BUG_ON(!hyperv_pcpu_output_arg);
378 }
379
380 if (hv_root_partition()) {
381 hv_synic_eventring_tail = alloc_percpu(u8 *);
382 BUG_ON(!hv_synic_eventring_tail);
383 }
384
385 hv_vp_index = kmalloc_array(nr_cpu_ids, sizeof(*hv_vp_index),
386 GFP_KERNEL);
387 if (!hv_vp_index) {
388 hv_common_free();
389 return -ENOMEM;
390 }
391
392 for (i = 0; i < nr_cpu_ids; i++)
393 hv_vp_index[i] = VP_INVAL;
394
395 return 0;
396 }
397
ms_hyperv_late_init(void)398 void __init ms_hyperv_late_init(void)
399 {
400 struct acpi_table_header *header;
401 acpi_status status;
402 u8 *randomdata;
403 u32 length, i;
404
405 /*
406 * Seed the Linux random number generator with entropy provided by
407 * the Hyper-V host in ACPI table OEM0.
408 */
409 if (!IS_ENABLED(CONFIG_ACPI))
410 return;
411
412 status = acpi_get_table("OEM0", 0, &header);
413 if (ACPI_FAILURE(status) || !header)
414 return;
415
416 /*
417 * Since the "OEM0" table name is for OEM specific usage, verify
418 * that what we're seeing purports to be from Microsoft.
419 */
420 if (strncmp(header->oem_table_id, "MICROSFT", 8))
421 goto error;
422
423 /*
424 * Ensure the length is reasonable. Requiring at least 8 bytes and
425 * no more than 4K bytes is somewhat arbitrary and just protects
426 * against a malformed table. Hyper-V currently provides 64 bytes,
427 * but allow for a change in a later version.
428 */
429 if (header->length < sizeof(*header) + 8 ||
430 header->length > sizeof(*header) + SZ_4K)
431 goto error;
432
433 length = header->length - sizeof(*header);
434 randomdata = (u8 *)(header + 1);
435
436 pr_debug("Hyper-V: Seeding rng with %d random bytes from ACPI table OEM0\n",
437 length);
438
439 add_bootloader_randomness(randomdata, length);
440
441 /*
442 * To prevent the seed data from being visible in /sys/firmware/acpi,
443 * zero out the random data in the ACPI table and fixup the checksum.
444 * The zero'ing is done out of an abundance of caution in avoiding
445 * potential security risks to the rng. Similarly, reset the table
446 * length to just the header size so that a subsequent kexec doesn't
447 * try to use the zero'ed out random data.
448 */
449 for (i = 0; i < length; i++) {
450 header->checksum += randomdata[i];
451 randomdata[i] = 0;
452 }
453
454 for (i = 0; i < sizeof(header->length); i++)
455 header->checksum += ((u8 *)&header->length)[i];
456 header->length = sizeof(*header);
457 for (i = 0; i < sizeof(header->length); i++)
458 header->checksum -= ((u8 *)&header->length)[i];
459
460 error:
461 acpi_put_table(header);
462 }
463
464 /*
465 * Hyper-V specific initialization and die code for
466 * individual CPUs that is common across all architectures.
467 * Called by the CPU hotplug mechanism.
468 */
469
hv_common_cpu_init(unsigned int cpu)470 int hv_common_cpu_init(unsigned int cpu)
471 {
472 void **inputarg, **outputarg;
473 u8 **synic_eventring_tail;
474 u64 msr_vp_index;
475 gfp_t flags;
476 const int pgcount = hv_output_page_exists() ? 2 : 1;
477 void *mem;
478 int ret = 0;
479
480 /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
481 flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
482
483 inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
484
485 /*
486 * The per-cpu memory is already allocated if this CPU was previously
487 * online and then taken offline
488 */
489 if (!*inputarg) {
490 mem = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
491 if (!mem)
492 return -ENOMEM;
493
494 if (hv_output_page_exists()) {
495 outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
496 *outputarg = (char *)mem + HV_HYP_PAGE_SIZE;
497 }
498
499 if (!ms_hyperv.paravisor_present &&
500 (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
501 ret = set_memory_decrypted((unsigned long)mem, pgcount);
502 if (ret) {
503 /* It may be unsafe to free 'mem' */
504 return ret;
505 }
506
507 memset(mem, 0x00, pgcount * HV_HYP_PAGE_SIZE);
508 }
509
510 /*
511 * In a fully enlightened TDX/SNP VM with more than 64 VPs, if
512 * hyperv_pcpu_input_arg is not NULL, set_memory_decrypted() ->
513 * ... -> cpa_flush()-> ... -> __send_ipi_mask_ex() tries to
514 * use hyperv_pcpu_input_arg as the hypercall input page, which
515 * must be a decrypted page in such a VM, but the page is still
516 * encrypted before set_memory_decrypted() returns. Fix this by
517 * setting *inputarg after the above set_memory_decrypted(): if
518 * hyperv_pcpu_input_arg is NULL, __send_ipi_mask_ex() returns
519 * HV_STATUS_INVALID_PARAMETER immediately, and the function
520 * hv_send_ipi_mask() falls back to orig_apic.send_IPI_mask(),
521 * which may be slightly slower than the hypercall, but still
522 * works correctly in such a VM.
523 */
524 *inputarg = mem;
525 }
526
527 msr_vp_index = hv_get_msr(HV_MSR_VP_INDEX);
528
529 hv_vp_index[cpu] = msr_vp_index;
530
531 if (msr_vp_index > hv_max_vp_index)
532 hv_max_vp_index = msr_vp_index;
533
534 if (hv_root_partition()) {
535 synic_eventring_tail = (u8 **)this_cpu_ptr(hv_synic_eventring_tail);
536 *synic_eventring_tail = kcalloc(HV_SYNIC_SINT_COUNT,
537 sizeof(u8), flags);
538 /* No need to unwind any of the above on failure here */
539 if (unlikely(!*synic_eventring_tail))
540 ret = -ENOMEM;
541 }
542
543 return ret;
544 }
545
hv_common_cpu_die(unsigned int cpu)546 int hv_common_cpu_die(unsigned int cpu)
547 {
548 u8 **synic_eventring_tail;
549 /*
550 * The hyperv_pcpu_input_arg and hyperv_pcpu_output_arg memory
551 * is not freed when the CPU goes offline as the hyperv_pcpu_input_arg
552 * may be used by the Hyper-V vPCI driver in reassigning interrupts
553 * as part of the offlining process. The interrupt reassignment
554 * happens *after* the CPUHP_AP_HYPERV_ONLINE state has run and
555 * called this function.
556 *
557 * If a previously offlined CPU is brought back online again, the
558 * originally allocated memory is reused in hv_common_cpu_init().
559 */
560
561 if (hv_root_partition()) {
562 synic_eventring_tail = this_cpu_ptr(hv_synic_eventring_tail);
563 kfree(*synic_eventring_tail);
564 *synic_eventring_tail = NULL;
565 }
566
567 return 0;
568 }
569
570 /* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */
hv_query_ext_cap(u64 cap_query)571 bool hv_query_ext_cap(u64 cap_query)
572 {
573 /*
574 * The address of the 'hv_extended_cap' variable will be used as an
575 * output parameter to the hypercall below and so it should be
576 * compatible with 'virt_to_phys'. Which means, it's address should be
577 * directly mapped. Use 'static' to keep it compatible; stack variables
578 * can be virtually mapped, making them incompatible with
579 * 'virt_to_phys'.
580 * Hypercall input/output addresses should also be 8-byte aligned.
581 */
582 static u64 hv_extended_cap __aligned(8);
583 static bool hv_extended_cap_queried;
584 u64 status;
585
586 /*
587 * Querying extended capabilities is an extended hypercall. Check if the
588 * partition supports extended hypercall, first.
589 */
590 if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS))
591 return false;
592
593 /* Extended capabilities do not change at runtime. */
594 if (hv_extended_cap_queried)
595 return hv_extended_cap & cap_query;
596
597 status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL,
598 &hv_extended_cap);
599
600 /*
601 * The query extended capabilities hypercall should not fail under
602 * any normal circumstances. Avoid repeatedly making the hypercall, on
603 * error.
604 */
605 hv_extended_cap_queried = true;
606 if (!hv_result_success(status)) {
607 pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n",
608 status);
609 return false;
610 }
611
612 return hv_extended_cap & cap_query;
613 }
614 EXPORT_SYMBOL_GPL(hv_query_ext_cap);
615
hv_setup_dma_ops(struct device * dev,bool coherent)616 void hv_setup_dma_ops(struct device *dev, bool coherent)
617 {
618 arch_setup_dma_ops(dev, coherent);
619 }
620 EXPORT_SYMBOL_GPL(hv_setup_dma_ops);
621
hv_is_hibernation_supported(void)622 bool hv_is_hibernation_supported(void)
623 {
624 return !hv_root_partition() && acpi_sleep_state_supported(ACPI_STATE_S4);
625 }
626 EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
627
628 /*
629 * Default function to read the Hyper-V reference counter, independent
630 * of whether Hyper-V enlightened clocks/timers are being used. But on
631 * architectures where it is used, Hyper-V enlightenment code in
632 * hyperv_timer.c may override this function.
633 */
__hv_read_ref_counter(void)634 static u64 __hv_read_ref_counter(void)
635 {
636 return hv_get_msr(HV_MSR_TIME_REF_COUNT);
637 }
638
639 u64 (*hv_read_reference_counter)(void) = __hv_read_ref_counter;
640 EXPORT_SYMBOL_GPL(hv_read_reference_counter);
641
642 /* These __weak functions provide default "no-op" behavior and
643 * may be overridden by architecture specific versions. Architectures
644 * for which the default "no-op" behavior is sufficient can leave
645 * them unimplemented and not be cluttered with a bunch of stub
646 * functions in arch-specific code.
647 */
648
hv_is_isolation_supported(void)649 bool __weak hv_is_isolation_supported(void)
650 {
651 return false;
652 }
653 EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
654
hv_isolation_type_snp(void)655 bool __weak hv_isolation_type_snp(void)
656 {
657 return false;
658 }
659 EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
660
hv_isolation_type_tdx(void)661 bool __weak hv_isolation_type_tdx(void)
662 {
663 return false;
664 }
665 EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
666
hv_setup_vmbus_handler(void (* handler)(void))667 void __weak hv_setup_vmbus_handler(void (*handler)(void))
668 {
669 }
670 EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
671
hv_remove_vmbus_handler(void)672 void __weak hv_remove_vmbus_handler(void)
673 {
674 }
675 EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
676
hv_setup_mshv_handler(void (* handler)(void))677 void __weak hv_setup_mshv_handler(void (*handler)(void))
678 {
679 }
680 EXPORT_SYMBOL_GPL(hv_setup_mshv_handler);
681
hv_setup_kexec_handler(void (* handler)(void))682 void __weak hv_setup_kexec_handler(void (*handler)(void))
683 {
684 }
685 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
686
hv_remove_kexec_handler(void)687 void __weak hv_remove_kexec_handler(void)
688 {
689 }
690 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
691
hv_setup_crash_handler(void (* handler)(struct pt_regs * regs))692 void __weak hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
693 {
694 }
695 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
696
hv_remove_crash_handler(void)697 void __weak hv_remove_crash_handler(void)
698 {
699 }
700 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
701
hyperv_cleanup(void)702 void __weak hyperv_cleanup(void)
703 {
704 }
705 EXPORT_SYMBOL_GPL(hyperv_cleanup);
706
hv_ghcb_hypercall(u64 control,void * input,void * output,u32 input_size)707 u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
708 {
709 return HV_STATUS_INVALID_PARAMETER;
710 }
711 EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
712
hv_tdx_hypercall(u64 control,u64 param1,u64 param2)713 u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
714 {
715 return HV_STATUS_INVALID_PARAMETER;
716 }
717 EXPORT_SYMBOL_GPL(hv_tdx_hypercall);
718
hv_identify_partition_type(void)719 void hv_identify_partition_type(void)
720 {
721 /* Assume guest role */
722 hv_curr_partition_type = HV_PARTITION_TYPE_GUEST;
723 /*
724 * Check partition creation and cpu management privileges
725 *
726 * Hyper-V should never specify running as root and as a Confidential
727 * VM. But to protect against a compromised/malicious Hyper-V trying
728 * to exploit root behavior to expose Confidential VM memory, ignore
729 * the root partition setting if also a Confidential VM.
730 */
731 if ((ms_hyperv.priv_high & HV_CREATE_PARTITIONS) &&
732 (ms_hyperv.priv_high & HV_CPU_MANAGEMENT) &&
733 !(ms_hyperv.priv_high & HV_ISOLATION)) {
734 pr_info("Hyper-V: running as root partition\n");
735 if (IS_ENABLED(CONFIG_MSHV_ROOT))
736 hv_curr_partition_type = HV_PARTITION_TYPE_ROOT;
737 else
738 pr_crit("Hyper-V: CONFIG_MSHV_ROOT not enabled!\n");
739 }
740 }
741
742 struct hv_status_info {
743 char *string;
744 int errno;
745 u16 code;
746 };
747
748 /*
749 * Note on the errno mappings:
750 * A failed hypercall is usually only recoverable (or loggable) near
751 * the call site where the HV_STATUS_* code is known. So the errno
752 * it gets converted to is not too useful further up the stack.
753 * Provide a few mappings that could be useful, and revert to -EIO
754 * as a fallback.
755 */
756 static const struct hv_status_info hv_status_infos[] = {
757 #define _STATUS_INFO(status, errno) { #status, (errno), (status) }
758 _STATUS_INFO(HV_STATUS_SUCCESS, 0),
759 _STATUS_INFO(HV_STATUS_INVALID_HYPERCALL_CODE, -EINVAL),
760 _STATUS_INFO(HV_STATUS_INVALID_HYPERCALL_INPUT, -EINVAL),
761 _STATUS_INFO(HV_STATUS_INVALID_ALIGNMENT, -EIO),
762 _STATUS_INFO(HV_STATUS_INVALID_PARAMETER, -EINVAL),
763 _STATUS_INFO(HV_STATUS_ACCESS_DENIED, -EIO),
764 _STATUS_INFO(HV_STATUS_INVALID_PARTITION_STATE, -EIO),
765 _STATUS_INFO(HV_STATUS_OPERATION_DENIED, -EIO),
766 _STATUS_INFO(HV_STATUS_UNKNOWN_PROPERTY, -EIO),
767 _STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE, -EIO),
768 _STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY, -ENOMEM),
769 _STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID, -EINVAL),
770 _STATUS_INFO(HV_STATUS_INVALID_VP_INDEX, -EINVAL),
771 _STATUS_INFO(HV_STATUS_NOT_FOUND, -EIO),
772 _STATUS_INFO(HV_STATUS_INVALID_PORT_ID, -EINVAL),
773 _STATUS_INFO(HV_STATUS_INVALID_CONNECTION_ID, -EINVAL),
774 _STATUS_INFO(HV_STATUS_INSUFFICIENT_BUFFERS, -EIO),
775 _STATUS_INFO(HV_STATUS_NOT_ACKNOWLEDGED, -EIO),
776 _STATUS_INFO(HV_STATUS_INVALID_VP_STATE, -EIO),
777 _STATUS_INFO(HV_STATUS_NO_RESOURCES, -EIO),
778 _STATUS_INFO(HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED, -EIO),
779 _STATUS_INFO(HV_STATUS_INVALID_LP_INDEX, -EINVAL),
780 _STATUS_INFO(HV_STATUS_INVALID_REGISTER_VALUE, -EINVAL),
781 _STATUS_INFO(HV_STATUS_INVALID_LP_INDEX, -EIO),
782 _STATUS_INFO(HV_STATUS_INVALID_REGISTER_VALUE, -EIO),
783 _STATUS_INFO(HV_STATUS_OPERATION_FAILED, -EIO),
784 _STATUS_INFO(HV_STATUS_TIME_OUT, -EIO),
785 _STATUS_INFO(HV_STATUS_CALL_PENDING, -EIO),
786 _STATUS_INFO(HV_STATUS_VTL_ALREADY_ENABLED, -EIO),
787 #undef _STATUS_INFO
788 };
789
find_hv_status_info(u64 hv_status)790 static inline const struct hv_status_info *find_hv_status_info(u64 hv_status)
791 {
792 int i;
793 u16 code = hv_result(hv_status);
794
795 for (i = 0; i < ARRAY_SIZE(hv_status_infos); ++i) {
796 const struct hv_status_info *info = &hv_status_infos[i];
797
798 if (info->code == code)
799 return info;
800 }
801
802 return NULL;
803 }
804
805 /* Convert a hypercall result into a linux-friendly error code. */
hv_result_to_errno(u64 status)806 int hv_result_to_errno(u64 status)
807 {
808 const struct hv_status_info *info;
809
810 /* hv_do_hypercall() may return U64_MAX, hypercalls aren't possible */
811 if (unlikely(status == U64_MAX))
812 return -EOPNOTSUPP;
813
814 info = find_hv_status_info(status);
815 if (info)
816 return info->errno;
817
818 return -EIO;
819 }
820 EXPORT_SYMBOL_GPL(hv_result_to_errno);
821
hv_result_to_string(u64 status)822 const char *hv_result_to_string(u64 status)
823 {
824 const struct hv_status_info *info;
825
826 if (unlikely(status == U64_MAX))
827 return "Hypercall page missing!";
828
829 info = find_hv_status_info(status);
830 if (info)
831 return info->string;
832
833 return "Unknown";
834 }
835 EXPORT_SYMBOL_GPL(hv_result_to_string);
836