xref: /linux/arch/x86/hyperv/ivm.c (revision d53b8e36925256097a08d7cb749198d85cbf9b2b)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Hyper-V Isolation VM interface with paravisor and hypervisor
4  *
5  * Author:
6  *  Tianyu Lan <Tianyu.Lan@microsoft.com>
7  */
8 
9 #include <linux/bitfield.h>
10 #include <linux/hyperv.h>
11 #include <linux/types.h>
12 #include <linux/slab.h>
13 #include <asm/svm.h>
14 #include <asm/sev.h>
15 #include <asm/io.h>
16 #include <asm/coco.h>
17 #include <asm/mem_encrypt.h>
18 #include <asm/set_memory.h>
19 #include <asm/mshyperv.h>
20 #include <asm/hypervisor.h>
21 #include <asm/mtrr.h>
22 #include <asm/io_apic.h>
23 #include <asm/realmode.h>
24 #include <asm/e820/api.h>
25 #include <asm/desc.h>
26 #include <uapi/asm/vmx.h>
27 
28 #ifdef CONFIG_AMD_MEM_ENCRYPT
29 
30 #define GHCB_USAGE_HYPERV_CALL	1
31 
32 union hv_ghcb {
33 	struct ghcb ghcb;
34 	struct {
35 		u64 hypercalldata[509];
36 		u64 outputgpa;
37 		union {
38 			union {
39 				struct {
40 					u32 callcode        : 16;
41 					u32 isfast          : 1;
42 					u32 reserved1       : 14;
43 					u32 isnested        : 1;
44 					u32 countofelements : 12;
45 					u32 reserved2       : 4;
46 					u32 repstartindex   : 12;
47 					u32 reserved3       : 4;
48 				};
49 				u64 asuint64;
50 			} hypercallinput;
51 			union {
52 				struct {
53 					u16 callstatus;
54 					u16 reserved1;
55 					u32 elementsprocessed : 12;
56 					u32 reserved2         : 20;
57 				};
58 				u64 asunit64;
59 			} hypercalloutput;
60 		};
61 		u64 reserved2;
62 	} hypercall;
63 } __packed __aligned(HV_HYP_PAGE_SIZE);
64 
65 /* Only used in an SNP VM with the paravisor */
66 static u16 hv_ghcb_version __ro_after_init;
67 
68 /* Functions only used in an SNP VM with the paravisor go here. */
69 u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
70 {
71 	union hv_ghcb *hv_ghcb;
72 	void **ghcb_base;
73 	unsigned long flags;
74 	u64 status;
75 
76 	if (!hv_ghcb_pg)
77 		return -EFAULT;
78 
79 	WARN_ON(in_nmi());
80 
81 	local_irq_save(flags);
82 	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
83 	hv_ghcb = (union hv_ghcb *)*ghcb_base;
84 	if (!hv_ghcb) {
85 		local_irq_restore(flags);
86 		return -EFAULT;
87 	}
88 
89 	hv_ghcb->ghcb.protocol_version = GHCB_PROTOCOL_MAX;
90 	hv_ghcb->ghcb.ghcb_usage = GHCB_USAGE_HYPERV_CALL;
91 
92 	hv_ghcb->hypercall.outputgpa = (u64)output;
93 	hv_ghcb->hypercall.hypercallinput.asuint64 = 0;
94 	hv_ghcb->hypercall.hypercallinput.callcode = control;
95 
96 	if (input_size)
97 		memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size);
98 
99 	VMGEXIT();
100 
101 	hv_ghcb->ghcb.ghcb_usage = 0xffffffff;
102 	memset(hv_ghcb->ghcb.save.valid_bitmap, 0,
103 	       sizeof(hv_ghcb->ghcb.save.valid_bitmap));
104 
105 	status = hv_ghcb->hypercall.hypercalloutput.callstatus;
106 
107 	local_irq_restore(flags);
108 
109 	return status;
110 }
111 
112 static inline u64 rd_ghcb_msr(void)
113 {
114 	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
115 }
116 
117 static inline void wr_ghcb_msr(u64 val)
118 {
119 	native_wrmsrl(MSR_AMD64_SEV_ES_GHCB, val);
120 }
121 
122 static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code,
123 				   u64 exit_info_1, u64 exit_info_2)
124 {
125 	/* Fill in protocol and format specifiers */
126 	ghcb->protocol_version = hv_ghcb_version;
127 	ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
128 
129 	ghcb_set_sw_exit_code(ghcb, exit_code);
130 	ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
131 	ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
132 
133 	VMGEXIT();
134 
135 	if (ghcb->save.sw_exit_info_1 & GENMASK_ULL(31, 0))
136 		return ES_VMM_ERROR;
137 	else
138 		return ES_OK;
139 }
140 
141 void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason)
142 {
143 	u64 val = GHCB_MSR_TERM_REQ;
144 
145 	/* Tell the hypervisor what went wrong. */
146 	val |= GHCB_SEV_TERM_REASON(set, reason);
147 
148 	/* Request Guest Termination from Hypervisor */
149 	wr_ghcb_msr(val);
150 	VMGEXIT();
151 
152 	while (true)
153 		asm volatile("hlt\n" : : : "memory");
154 }
155 
156 bool hv_ghcb_negotiate_protocol(void)
157 {
158 	u64 ghcb_gpa;
159 	u64 val;
160 
161 	/* Save ghcb page gpa. */
162 	ghcb_gpa = rd_ghcb_msr();
163 
164 	/* Do the GHCB protocol version negotiation */
165 	wr_ghcb_msr(GHCB_MSR_SEV_INFO_REQ);
166 	VMGEXIT();
167 	val = rd_ghcb_msr();
168 
169 	if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP)
170 		return false;
171 
172 	if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN ||
173 	    GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX)
174 		return false;
175 
176 	hv_ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val),
177 			     GHCB_PROTOCOL_MAX);
178 
179 	/* Write ghcb page back after negotiating protocol. */
180 	wr_ghcb_msr(ghcb_gpa);
181 	VMGEXIT();
182 
183 	return true;
184 }
185 
186 static void hv_ghcb_msr_write(u64 msr, u64 value)
187 {
188 	union hv_ghcb *hv_ghcb;
189 	void **ghcb_base;
190 	unsigned long flags;
191 
192 	if (!hv_ghcb_pg)
193 		return;
194 
195 	WARN_ON(in_nmi());
196 
197 	local_irq_save(flags);
198 	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
199 	hv_ghcb = (union hv_ghcb *)*ghcb_base;
200 	if (!hv_ghcb) {
201 		local_irq_restore(flags);
202 		return;
203 	}
204 
205 	ghcb_set_rcx(&hv_ghcb->ghcb, msr);
206 	ghcb_set_rax(&hv_ghcb->ghcb, lower_32_bits(value));
207 	ghcb_set_rdx(&hv_ghcb->ghcb, upper_32_bits(value));
208 
209 	if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 1, 0))
210 		pr_warn("Fail to write msr via ghcb %llx.\n", msr);
211 
212 	local_irq_restore(flags);
213 }
214 
215 static void hv_ghcb_msr_read(u64 msr, u64 *value)
216 {
217 	union hv_ghcb *hv_ghcb;
218 	void **ghcb_base;
219 	unsigned long flags;
220 
221 	/* Check size of union hv_ghcb here. */
222 	BUILD_BUG_ON(sizeof(union hv_ghcb) != HV_HYP_PAGE_SIZE);
223 
224 	if (!hv_ghcb_pg)
225 		return;
226 
227 	WARN_ON(in_nmi());
228 
229 	local_irq_save(flags);
230 	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
231 	hv_ghcb = (union hv_ghcb *)*ghcb_base;
232 	if (!hv_ghcb) {
233 		local_irq_restore(flags);
234 		return;
235 	}
236 
237 	ghcb_set_rcx(&hv_ghcb->ghcb, msr);
238 	if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 0, 0))
239 		pr_warn("Fail to read msr via ghcb %llx.\n", msr);
240 	else
241 		*value = (u64)lower_32_bits(hv_ghcb->ghcb.save.rax)
242 			| ((u64)lower_32_bits(hv_ghcb->ghcb.save.rdx) << 32);
243 	local_irq_restore(flags);
244 }
245 
246 /* Only used in a fully enlightened SNP VM, i.e. without the paravisor */
247 static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
248 static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE);
249 static DEFINE_PER_CPU(struct sev_es_save_area *, hv_sev_vmsa);
250 
251 /* Functions only used in an SNP VM without the paravisor go here. */
252 
253 #define hv_populate_vmcb_seg(seg, gdtr_base)			\
254 do {								\
255 	if (seg.selector) {					\
256 		seg.base = 0;					\
257 		seg.limit = HV_AP_SEGMENT_LIMIT;		\
258 		seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);	\
259 		seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \
260 	}							\
261 } while (0)							\
262 
263 static int snp_set_vmsa(void *va, bool vmsa)
264 {
265 	u64 attrs;
266 
267 	/*
268 	 * Running at VMPL0 allows the kernel to change the VMSA bit for a page
269 	 * using the RMPADJUST instruction. However, for the instruction to
270 	 * succeed it must target the permissions of a lesser privileged
271 	 * (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST
272 	 * instruction in the AMD64 APM Volume 3).
273 	 */
274 	attrs = 1;
275 	if (vmsa)
276 		attrs |= RMPADJUST_VMSA_PAGE_BIT;
277 
278 	return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
279 }
280 
281 static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
282 {
283 	int err;
284 
285 	err = snp_set_vmsa(vmsa, false);
286 	if (err)
287 		pr_err("clear VMSA page failed (%u), leaking page\n", err);
288 	else
289 		free_page((unsigned long)vmsa);
290 }
291 
292 int hv_snp_boot_ap(u32 cpu, unsigned long start_ip)
293 {
294 	struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
295 		__get_free_page(GFP_KERNEL | __GFP_ZERO);
296 	struct sev_es_save_area *cur_vmsa;
297 	struct desc_ptr gdtr;
298 	u64 ret, retry = 5;
299 	struct hv_enable_vp_vtl *start_vp_input;
300 	unsigned long flags;
301 
302 	if (!vmsa)
303 		return -ENOMEM;
304 
305 	native_store_gdt(&gdtr);
306 
307 	vmsa->gdtr.base = gdtr.address;
308 	vmsa->gdtr.limit = gdtr.size;
309 
310 	asm volatile("movl %%es, %%eax;" : "=a" (vmsa->es.selector));
311 	hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base);
312 
313 	asm volatile("movl %%cs, %%eax;" : "=a" (vmsa->cs.selector));
314 	hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base);
315 
316 	asm volatile("movl %%ss, %%eax;" : "=a" (vmsa->ss.selector));
317 	hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base);
318 
319 	asm volatile("movl %%ds, %%eax;" : "=a" (vmsa->ds.selector));
320 	hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base);
321 
322 	vmsa->efer = native_read_msr(MSR_EFER);
323 
324 	asm volatile("movq %%cr4, %%rax;" : "=a" (vmsa->cr4));
325 	asm volatile("movq %%cr3, %%rax;" : "=a" (vmsa->cr3));
326 	asm volatile("movq %%cr0, %%rax;" : "=a" (vmsa->cr0));
327 
328 	vmsa->xcr0 = 1;
329 	vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT;
330 	vmsa->rip = (u64)secondary_startup_64_no_verify;
331 	vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE];
332 
333 	/*
334 	 * Set the SNP-specific fields for this VMSA:
335 	 *   VMPL level
336 	 *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
337 	 */
338 	vmsa->vmpl = 0;
339 	vmsa->sev_features = sev_status >> 2;
340 
341 	ret = snp_set_vmsa(vmsa, true);
342 	if (!ret) {
343 		pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret);
344 		free_page((u64)vmsa);
345 		return ret;
346 	}
347 
348 	local_irq_save(flags);
349 	start_vp_input = (struct hv_enable_vp_vtl *)ap_start_input_arg;
350 	memset(start_vp_input, 0, sizeof(*start_vp_input));
351 	start_vp_input->partition_id = -1;
352 	start_vp_input->vp_index = cpu;
353 	start_vp_input->target_vtl.target_vtl = ms_hyperv.vtl;
354 	*(u64 *)&start_vp_input->vp_context = __pa(vmsa) | 1;
355 
356 	do {
357 		ret = hv_do_hypercall(HVCALL_START_VP,
358 				      start_vp_input, NULL);
359 	} while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--);
360 
361 	local_irq_restore(flags);
362 
363 	if (!hv_result_success(ret)) {
364 		pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret);
365 		snp_cleanup_vmsa(vmsa);
366 		vmsa = NULL;
367 	}
368 
369 	cur_vmsa = per_cpu(hv_sev_vmsa, cpu);
370 	/* Free up any previous VMSA page */
371 	if (cur_vmsa)
372 		snp_cleanup_vmsa(cur_vmsa);
373 
374 	/* Record the current VMSA page */
375 	per_cpu(hv_sev_vmsa, cpu) = vmsa;
376 
377 	return ret;
378 }
379 
380 #else
381 static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
382 static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
383 #endif /* CONFIG_AMD_MEM_ENCRYPT */
384 
385 #ifdef CONFIG_INTEL_TDX_GUEST
386 static void hv_tdx_msr_write(u64 msr, u64 val)
387 {
388 	struct tdx_module_args args = {
389 		.r10 = TDX_HYPERCALL_STANDARD,
390 		.r11 = EXIT_REASON_MSR_WRITE,
391 		.r12 = msr,
392 		.r13 = val,
393 	};
394 
395 	u64 ret = __tdx_hypercall(&args);
396 
397 	WARN_ONCE(ret, "Failed to emulate MSR write: %lld\n", ret);
398 }
399 
400 static void hv_tdx_msr_read(u64 msr, u64 *val)
401 {
402 	struct tdx_module_args args = {
403 		.r10 = TDX_HYPERCALL_STANDARD,
404 		.r11 = EXIT_REASON_MSR_READ,
405 		.r12 = msr,
406 	};
407 
408 	u64 ret = __tdx_hypercall(&args);
409 
410 	if (WARN_ONCE(ret, "Failed to emulate MSR read: %lld\n", ret))
411 		*val = 0;
412 	else
413 		*val = args.r11;
414 }
415 
416 u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
417 {
418 	struct tdx_module_args args = { };
419 
420 	args.r10 = control;
421 	args.rdx = param1;
422 	args.r8  = param2;
423 
424 	(void)__tdx_hypercall(&args);
425 
426 	return args.r11;
427 }
428 
429 #else
430 static inline void hv_tdx_msr_write(u64 msr, u64 value) {}
431 static inline void hv_tdx_msr_read(u64 msr, u64 *value) {}
432 #endif /* CONFIG_INTEL_TDX_GUEST */
433 
434 #if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST)
435 void hv_ivm_msr_write(u64 msr, u64 value)
436 {
437 	if (!ms_hyperv.paravisor_present)
438 		return;
439 
440 	if (hv_isolation_type_tdx())
441 		hv_tdx_msr_write(msr, value);
442 	else if (hv_isolation_type_snp())
443 		hv_ghcb_msr_write(msr, value);
444 }
445 
446 void hv_ivm_msr_read(u64 msr, u64 *value)
447 {
448 	if (!ms_hyperv.paravisor_present)
449 		return;
450 
451 	if (hv_isolation_type_tdx())
452 		hv_tdx_msr_read(msr, value);
453 	else if (hv_isolation_type_snp())
454 		hv_ghcb_msr_read(msr, value);
455 }
456 
457 /*
458  * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
459  *
460  * In Isolation VM, all guest memory is encrypted from host and guest
461  * needs to set memory visible to host via hvcall before sharing memory
462  * with host.
463  */
464 static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
465 			   enum hv_mem_host_visibility visibility)
466 {
467 	struct hv_gpa_range_for_visibility *input;
468 	u16 pages_processed;
469 	u64 hv_status;
470 	unsigned long flags;
471 
472 	/* no-op if partition isolation is not enabled */
473 	if (!hv_is_isolation_supported())
474 		return 0;
475 
476 	if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
477 		pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
478 			HV_MAX_MODIFY_GPA_REP_COUNT);
479 		return -EINVAL;
480 	}
481 
482 	local_irq_save(flags);
483 	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
484 
485 	if (unlikely(!input)) {
486 		local_irq_restore(flags);
487 		return -EINVAL;
488 	}
489 
490 	input->partition_id = HV_PARTITION_ID_SELF;
491 	input->host_visibility = visibility;
492 	input->reserved0 = 0;
493 	input->reserved1 = 0;
494 	memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
495 	hv_status = hv_do_rep_hypercall(
496 			HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
497 			0, input, &pages_processed);
498 	local_irq_restore(flags);
499 
500 	if (hv_result_success(hv_status))
501 		return 0;
502 	else
503 		return -EFAULT;
504 }
505 
506 /*
507  * When transitioning memory between encrypted and decrypted, the caller
508  * of set_memory_encrypted() or set_memory_decrypted() is responsible for
509  * ensuring that the memory isn't in use and isn't referenced while the
510  * transition is in progress.  The transition has multiple steps, and the
511  * memory is in an inconsistent state until all steps are complete. A
512  * reference while the state is inconsistent could result in an exception
513  * that can't be cleanly fixed up.
514  *
515  * But the Linux kernel load_unaligned_zeropad() mechanism could cause a
516  * stray reference that can't be prevented by the caller, so Linux has
517  * specific code to handle this case. But when the #VC and #VE exceptions
518  * routed to a paravisor, the specific code doesn't work. To avoid this
519  * problem, mark the pages as "not present" while the transition is in
520  * progress. If load_unaligned_zeropad() causes a stray reference, a normal
521  * page fault is generated instead of #VC or #VE, and the page-fault-based
522  * handlers for load_unaligned_zeropad() resolve the reference.  When the
523  * transition is complete, hv_vtom_set_host_visibility() marks the pages
524  * as "present" again.
525  */
526 static int hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)
527 {
528 	return set_memory_np(kbuffer, pagecount);
529 }
530 
531 /*
532  * hv_vtom_set_host_visibility - Set specified memory visible to host.
533  *
534  * In Isolation VM, all guest memory is encrypted from host and guest
535  * needs to set memory visible to host via hvcall before sharing memory
536  * with host. This function works as wrap of hv_mark_gpa_visibility()
537  * with memory base and size.
538  */
539 static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
540 {
541 	enum hv_mem_host_visibility visibility = enc ?
542 			VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
543 	u64 *pfn_array;
544 	phys_addr_t paddr;
545 	int i, pfn, err;
546 	void *vaddr;
547 	int ret = 0;
548 
549 	pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
550 	if (!pfn_array) {
551 		ret = -ENOMEM;
552 		goto err_set_memory_p;
553 	}
554 
555 	for (i = 0, pfn = 0; i < pagecount; i++) {
556 		/*
557 		 * Use slow_virt_to_phys() because the PRESENT bit has been
558 		 * temporarily cleared in the PTEs.  slow_virt_to_phys() works
559 		 * without the PRESENT bit while virt_to_hvpfn() or similar
560 		 * does not.
561 		 */
562 		vaddr = (void *)kbuffer + (i * HV_HYP_PAGE_SIZE);
563 		paddr = slow_virt_to_phys(vaddr);
564 		pfn_array[pfn] = paddr >> HV_HYP_PAGE_SHIFT;
565 		pfn++;
566 
567 		if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
568 			ret = hv_mark_gpa_visibility(pfn, pfn_array,
569 						     visibility);
570 			if (ret)
571 				goto err_free_pfn_array;
572 			pfn = 0;
573 		}
574 	}
575 
576 err_free_pfn_array:
577 	kfree(pfn_array);
578 
579 err_set_memory_p:
580 	/*
581 	 * Set the PTE PRESENT bits again to revert what hv_vtom_clear_present()
582 	 * did. Do this even if there is an error earlier in this function in
583 	 * order to avoid leaving the memory range in a "broken" state. Setting
584 	 * the PRESENT bits shouldn't fail, but return an error if it does.
585 	 */
586 	err = set_memory_p(kbuffer, pagecount);
587 	if (err && !ret)
588 		ret = err;
589 
590 	return ret;
591 }
592 
593 static bool hv_vtom_tlb_flush_required(bool private)
594 {
595 	/*
596 	 * Since hv_vtom_clear_present() marks the PTEs as "not present"
597 	 * and flushes the TLB, they can't be in the TLB. That makes the
598 	 * flush controlled by this function redundant, so return "false".
599 	 */
600 	return false;
601 }
602 
603 static bool hv_vtom_cache_flush_required(void)
604 {
605 	return false;
606 }
607 
608 static bool hv_is_private_mmio(u64 addr)
609 {
610 	/*
611 	 * Hyper-V always provides a single IO-APIC in a guest VM.
612 	 * When a paravisor is used, it is emulated by the paravisor
613 	 * in the guest context and must be mapped private.
614 	 */
615 	if (addr >= HV_IOAPIC_BASE_ADDRESS &&
616 	    addr < (HV_IOAPIC_BASE_ADDRESS + PAGE_SIZE))
617 		return true;
618 
619 	/* Same with a vTPM */
620 	if (addr >= VTPM_BASE_ADDRESS &&
621 	    addr < (VTPM_BASE_ADDRESS + PAGE_SIZE))
622 		return true;
623 
624 	return false;
625 }
626 
627 void __init hv_vtom_init(void)
628 {
629 	enum hv_isolation_type type = hv_get_isolation_type();
630 
631 	switch (type) {
632 	case HV_ISOLATION_TYPE_VBS:
633 		fallthrough;
634 	/*
635 	 * By design, a VM using vTOM doesn't see the SEV setting,
636 	 * so SEV initialization is bypassed and sev_status isn't set.
637 	 * Set it here to indicate a vTOM VM.
638 	 *
639 	 * Note: if CONFIG_AMD_MEM_ENCRYPT is not set, sev_status is
640 	 * defined as 0ULL, to which we can't assigned a value.
641 	 */
642 #ifdef CONFIG_AMD_MEM_ENCRYPT
643 	case HV_ISOLATION_TYPE_SNP:
644 		sev_status = MSR_AMD64_SNP_VTOM;
645 		cc_vendor = CC_VENDOR_AMD;
646 		break;
647 #endif
648 
649 	case HV_ISOLATION_TYPE_TDX:
650 		cc_vendor = CC_VENDOR_INTEL;
651 		break;
652 
653 	default:
654 		panic("hv_vtom_init: unsupported isolation type %d\n", type);
655 	}
656 
657 	cc_set_mask(ms_hyperv.shared_gpa_boundary);
658 	physical_mask &= ms_hyperv.shared_gpa_boundary - 1;
659 
660 	x86_platform.hyper.is_private_mmio = hv_is_private_mmio;
661 	x86_platform.guest.enc_cache_flush_required = hv_vtom_cache_flush_required;
662 	x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required;
663 	x86_platform.guest.enc_status_change_prepare = hv_vtom_clear_present;
664 	x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility;
665 
666 	/* Set WB as the default cache mode. */
667 	mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
668 }
669 
670 #endif /* defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST) */
671 
672 enum hv_isolation_type hv_get_isolation_type(void)
673 {
674 	if (!(ms_hyperv.priv_high & HV_ISOLATION))
675 		return HV_ISOLATION_TYPE_NONE;
676 	return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
677 }
678 EXPORT_SYMBOL_GPL(hv_get_isolation_type);
679 
680 /*
681  * hv_is_isolation_supported - Check system runs in the Hyper-V
682  * isolation VM.
683  */
684 bool hv_is_isolation_supported(void)
685 {
686 	if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
687 		return false;
688 
689 	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
690 		return false;
691 
692 	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
693 }
694 
695 DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
696 
697 /*
698  * hv_isolation_type_snp - Check if the system runs in an AMD SEV-SNP based
699  * isolation VM.
700  */
701 bool hv_isolation_type_snp(void)
702 {
703 	return static_branch_unlikely(&isolation_type_snp);
704 }
705 
706 DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
707 /*
708  * hv_isolation_type_tdx - Check if the system runs in an Intel TDX based
709  * isolated VM.
710  */
711 bool hv_isolation_type_tdx(void)
712 {
713 	return static_branch_unlikely(&isolation_type_tdx);
714 }
715