xref: /freebsd/sys/x86/xen/pv.c (revision 7cc42f6d25ef2e19059d088fa7d4853fe9afefb5)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-NetBSD
3  *
4  * Copyright (c) 2004 Christian Limpach.
5  * Copyright (c) 2004-2006,2008 Kip Macy
6  * Copyright (c) 2008 The NetBSD Foundation, Inc.
7  * Copyright (c) 2013 Roger Pau Monné <roger.pau@citrix.com>
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_ddb.h"
36 #include "opt_kstack_pages.h"
37 
38 #include <sys/param.h>
39 #include <sys/bus.h>
40 #include <sys/kernel.h>
41 #include <sys/reboot.h>
42 #include <sys/systm.h>
43 #include <sys/malloc.h>
44 #include <sys/linker.h>
45 #include <sys/lock.h>
46 #include <sys/rwlock.h>
47 #include <sys/boot.h>
48 #include <sys/ctype.h>
49 #include <sys/mutex.h>
50 #include <sys/smp.h>
51 
52 #include <vm/vm.h>
53 #include <vm/vm_extern.h>
54 #include <vm/vm_kern.h>
55 #include <vm/vm_page.h>
56 #include <vm/vm_map.h>
57 #include <vm/vm_object.h>
58 #include <vm/vm_pager.h>
59 #include <vm/vm_param.h>
60 
61 #include <machine/_inttypes.h>
62 #include <machine/intr_machdep.h>
63 #include <x86/apicvar.h>
64 #include <x86/init.h>
65 #include <machine/pc/bios.h>
66 #include <machine/smp.h>
67 #include <machine/intr_machdep.h>
68 #include <machine/metadata.h>
69 
70 #include <xen/xen-os.h>
71 #include <xen/hvm.h>
72 #include <xen/hypervisor.h>
73 #include <xen/xenstore/xenstorevar.h>
74 #include <xen/xen_pv.h>
75 #include <xen/xen_msi.h>
76 
77 #include <xen/interface/arch-x86/hvm/start_info.h>
78 #include <xen/interface/vcpu.h>
79 
80 #include <dev/xen/timer/timer.h>
81 
82 #ifdef DDB
83 #include <ddb/ddb.h>
84 #endif
85 
86 /* Native initial function */
87 extern u_int64_t hammer_time(u_int64_t, u_int64_t);
88 /* Xen initial function */
89 uint64_t hammer_time_xen_legacy(start_info_t *, uint64_t);
90 uint64_t hammer_time_xen(vm_paddr_t);
91 
92 #define MAX_E820_ENTRIES	128
93 
94 /*--------------------------- Forward Declarations ---------------------------*/
95 static caddr_t xen_legacy_pvh_parse_preload_data(uint64_t);
96 static caddr_t xen_pvh_parse_preload_data(uint64_t);
97 static void xen_pvh_parse_memmap(caddr_t, vm_paddr_t *, int *);
98 
99 #ifdef SMP
100 static int xen_pv_start_all_aps(void);
101 #endif
102 
103 /*---------------------------- Extern Declarations ---------------------------*/
104 #ifdef SMP
105 /* Variables used by amd64 mp_machdep to start APs */
106 extern char *doublefault_stack;
107 extern char *mce_stack;
108 extern char *nmi_stack;
109 extern char *dbg_stack;
110 #endif
111 
112 /*
113  * Placed by the linker at the end of the bss section, which is the last
114  * section loaded by Xen before loading the symtab and strtab.
115  */
116 extern uint32_t end;
117 
118 /*-------------------------------- Global Data -------------------------------*/
119 /* Xen init_ops implementation. */
120 struct init_ops xen_legacy_init_ops = {
121 	.parse_preload_data		= xen_legacy_pvh_parse_preload_data,
122 	.early_clock_source_init	= xen_clock_init,
123 	.early_delay			= xen_delay,
124 	.parse_memmap			= xen_pvh_parse_memmap,
125 #ifdef SMP
126 	.start_all_aps			= xen_pv_start_all_aps,
127 #endif
128 	.msi_init			= xen_msi_init,
129 };
130 
131 struct init_ops xen_pvh_init_ops = {
132 	.parse_preload_data		= xen_pvh_parse_preload_data,
133 	.early_clock_source_init	= xen_clock_init,
134 	.early_delay			= xen_delay,
135 	.parse_memmap			= xen_pvh_parse_memmap,
136 #ifdef SMP
137 	.mp_bootaddress			= mp_bootaddress,
138 	.start_all_aps			= native_start_all_aps,
139 #endif
140 	.msi_init			= msi_init,
141 };
142 
143 static struct bios_smap xen_smap[MAX_E820_ENTRIES];
144 
145 static start_info_t *legacy_start_info;
146 static struct hvm_start_info *start_info;
147 
148 /*----------------------- Legacy PVH start_info accessors --------------------*/
149 static vm_paddr_t
150 legacy_get_xenstore_mfn(void)
151 {
152 
153 	return (legacy_start_info->store_mfn);
154 }
155 
156 static evtchn_port_t
157 legacy_get_xenstore_evtchn(void)
158 {
159 
160 	return (legacy_start_info->store_evtchn);
161 }
162 
163 static vm_paddr_t
164 legacy_get_console_mfn(void)
165 {
166 
167 	return (legacy_start_info->console.domU.mfn);
168 }
169 
170 static evtchn_port_t
171 legacy_get_console_evtchn(void)
172 {
173 
174 	return (legacy_start_info->console.domU.evtchn);
175 }
176 
177 static uint32_t
178 legacy_get_start_flags(void)
179 {
180 
181 	return (legacy_start_info->flags);
182 }
183 
184 struct hypervisor_info legacy_info = {
185 	.get_xenstore_mfn		= legacy_get_xenstore_mfn,
186 	.get_xenstore_evtchn		= legacy_get_xenstore_evtchn,
187 	.get_console_mfn		= legacy_get_console_mfn,
188 	.get_console_evtchn		= legacy_get_console_evtchn,
189 	.get_start_flags		= legacy_get_start_flags,
190 };
191 
192 /*-------------------------------- Xen PV init -------------------------------*/
193 /*
194  * First function called by the Xen legacy PVH boot sequence.
195  *
196  * Set some Xen global variables and prepare the environment so it is
197  * as similar as possible to what native FreeBSD init function expects.
198  */
199 uint64_t
200 hammer_time_xen_legacy(start_info_t *si, uint64_t xenstack)
201 {
202 	uint64_t physfree;
203 	uint64_t *PT4 = (u_int64_t *)xenstack;
204 	uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
205 	uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
206 	int i;
207 	char *kenv;
208 
209 	xen_domain_type = XEN_PV_DOMAIN;
210 	vm_guest = VM_GUEST_XEN;
211 
212 	if ((si == NULL) || (xenstack == 0)) {
213 		xc_printf("ERROR: invalid start_info or xen stack, halting\n");
214 		HYPERVISOR_shutdown(SHUTDOWN_crash);
215 	}
216 
217 	xc_printf("FreeBSD PVH running on %s\n", si->magic);
218 
219 	/* We use 3 pages of xen stack for the boot pagetables */
220 	physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
221 
222 	/* Setup Xen global variables */
223 	legacy_start_info = si;
224 	HYPERVISOR_shared_info =
225 	    (shared_info_t *)(si->shared_info + KERNBASE);
226 
227 	/*
228 	 * Use the stack Xen gives us to build the page tables
229 	 * as native FreeBSD expects to find them (created
230 	 * by the boot trampoline).
231 	 */
232 	for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
233 		/*
234 		 * Each slot of the level 4 pages points
235 		 * to the same level 3 page
236 		 */
237 		PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
238 		PT4[i] |= PG_V | PG_RW | PG_U;
239 
240 		/*
241 		 * Each slot of the level 3 pages points
242 		 * to the same level 2 page
243 		 */
244 		PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
245 		PT3[i] |= PG_V | PG_RW | PG_U;
246 
247 		/*
248 		 * The level 2 page slots are mapped with
249 		 * 2MB pages for 1GB.
250 		 */
251 		PT2[i] = i * (2 * 1024 * 1024);
252 		PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
253 	}
254 	load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
255 
256 	/*
257 	 * Init an empty static kenv using a free page. The contents will be
258 	 * filled from the parse_preload_data hook.
259 	 */
260 	kenv = (void *)(physfree + KERNBASE);
261 	physfree += PAGE_SIZE;
262 	bzero_early(kenv, PAGE_SIZE);
263 	init_static_kenv(kenv, PAGE_SIZE);
264 
265 	/* Set the hooks for early functions that diverge from bare metal */
266 	init_ops = xen_legacy_init_ops;
267 	apic_ops = xen_apic_ops;
268 	hypervisor_info = legacy_info;
269 
270 	/* Now we can jump into the native init function */
271 	return (hammer_time(0, physfree));
272 }
273 
274 uint64_t
275 hammer_time_xen(vm_paddr_t start_info_paddr)
276 {
277 	struct hvm_modlist_entry *mod;
278 	struct xen_add_to_physmap xatp;
279 	uint64_t physfree;
280 	char *kenv;
281 	int rc;
282 
283 	xen_domain_type = XEN_HVM_DOMAIN;
284 	vm_guest = VM_GUEST_XEN;
285 
286 	rc = xen_hvm_init_hypercall_stubs(XEN_HVM_INIT_EARLY);
287 	if (rc) {
288 		xc_printf("ERROR: failed to initialize hypercall page: %d\n",
289 		    rc);
290 		HYPERVISOR_shutdown(SHUTDOWN_crash);
291 	}
292 
293 	start_info = (struct hvm_start_info *)(start_info_paddr + KERNBASE);
294 	if (start_info->magic != XEN_HVM_START_MAGIC_VALUE) {
295 		xc_printf("Unknown magic value in start_info struct: %#x\n",
296 		    start_info->magic);
297 		HYPERVISOR_shutdown(SHUTDOWN_crash);
298 	}
299 
300 	/*
301 	 * The hvm_start_into structure is always appended after loading
302 	 * the kernel and modules.
303 	 */
304 	physfree = roundup2(start_info_paddr + PAGE_SIZE, PAGE_SIZE);
305 
306 	xatp.domid = DOMID_SELF;
307 	xatp.idx = 0;
308 	xatp.space = XENMAPSPACE_shared_info;
309 	xatp.gpfn = atop(physfree);
310 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) {
311 		xc_printf("ERROR: failed to setup shared_info page\n");
312 		HYPERVISOR_shutdown(SHUTDOWN_crash);
313 	}
314 	HYPERVISOR_shared_info = (shared_info_t *)(physfree + KERNBASE);
315 	physfree += PAGE_SIZE;
316 
317 	/*
318 	 * Init a static kenv using a free page. The contents will be filled
319 	 * from the parse_preload_data hook.
320 	 */
321 	kenv = (void *)(physfree + KERNBASE);
322 	physfree += PAGE_SIZE;
323 	bzero_early(kenv, PAGE_SIZE);
324 	init_static_kenv(kenv, PAGE_SIZE);
325 
326 	if (start_info->modlist_paddr != 0) {
327 		if (start_info->modlist_paddr >= physfree) {
328 			xc_printf(
329 			    "ERROR: unexpected module list memory address\n");
330 			HYPERVISOR_shutdown(SHUTDOWN_crash);
331 		}
332 		if (start_info->nr_modules == 0) {
333 			xc_printf(
334 			    "ERROR: modlist_paddr != 0 but nr_modules == 0\n");
335 			HYPERVISOR_shutdown(SHUTDOWN_crash);
336 		}
337 		mod = (struct hvm_modlist_entry *)
338 		    (vm_paddr_t)start_info->modlist_paddr + KERNBASE;
339 		if (mod[0].paddr >= physfree) {
340 			xc_printf("ERROR: unexpected module memory address\n");
341 			HYPERVISOR_shutdown(SHUTDOWN_crash);
342 		}
343 	}
344 
345 	/* Set the hooks for early functions that diverge from bare metal */
346 	init_ops = xen_pvh_init_ops;
347 	hvm_start_flags = start_info->flags;
348 
349 	/* Now we can jump into the native init function */
350 	return (hammer_time(0, physfree));
351 }
352 
353 /*-------------------------------- PV specific -------------------------------*/
354 #ifdef SMP
355 static bool
356 start_xen_ap(int cpu)
357 {
358 	struct vcpu_guest_context *ctxt;
359 	int ms, cpus = mp_naps;
360 	const size_t stacksize = kstack_pages * PAGE_SIZE;
361 
362 	/* allocate and set up an idle stack data page */
363 	bootstacks[cpu] = (void *)kmem_malloc(stacksize, M_WAITOK | M_ZERO);
364 	doublefault_stack = (char *)kmem_malloc(PAGE_SIZE, M_WAITOK | M_ZERO);
365 	mce_stack = (char *)kmem_malloc(PAGE_SIZE, M_WAITOK | M_ZERO);
366 	nmi_stack = (char *)kmem_malloc(PAGE_SIZE, M_WAITOK | M_ZERO);
367 	dbg_stack = (void *)kmem_malloc(PAGE_SIZE, M_WAITOK | M_ZERO);
368 	dpcpu = (void *)kmem_malloc(DPCPU_SIZE, M_WAITOK | M_ZERO);
369 
370 	bootSTK = (char *)bootstacks[cpu] + kstack_pages * PAGE_SIZE - 8;
371 	bootAP = cpu;
372 
373 	ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
374 
375 	ctxt->flags = VGCF_IN_KERNEL;
376 	ctxt->user_regs.rip = (unsigned long) init_secondary;
377 	ctxt->user_regs.rsp = (unsigned long) bootSTK;
378 
379 	/* Set the AP to use the same page tables */
380 	ctxt->ctrlreg[3] = KPML4phys;
381 
382 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
383 		panic("unable to initialize AP#%d", cpu);
384 
385 	free(ctxt, M_TEMP);
386 
387 	/* Launch the vCPU */
388 	if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
389 		panic("unable to start AP#%d", cpu);
390 
391 	/* Wait up to 5 seconds for it to start. */
392 	for (ms = 0; ms < 5000; ms++) {
393 		if (mp_naps > cpus)
394 			return (true);
395 		DELAY(1000);
396 	}
397 
398 	return (false);
399 }
400 
401 static int
402 xen_pv_start_all_aps(void)
403 {
404 	int cpu;
405 
406 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
407 
408 	for (cpu = 1; cpu < mp_ncpus; cpu++) {
409 		/* attempt to start the Application Processor */
410 		if (!start_xen_ap(cpu))
411 			panic("AP #%d failed to start!", cpu);
412 
413 		CPU_SET(cpu, &all_cpus);	/* record AP in CPU map */
414 	}
415 
416 	return (mp_naps);
417 }
418 #endif /* SMP */
419 
420 /*
421  * When booted as a PVH guest FreeBSD needs to avoid using the RSDP address
422  * hint provided by the loader because it points to the native set of ACPI
423  * tables instead of the ones crafted by Xen. The acpi.rsdp env variable is
424  * removed from kenv if present, and a new acpi.rsdp is added to kenv that
425  * points to the address of the Xen crafted RSDP.
426  */
427 static bool reject_option(const char *option)
428 {
429 	static const char *reject[] = {
430 		"acpi.rsdp",
431 	};
432 	unsigned int i;
433 
434 	for (i = 0; i < nitems(reject); i++)
435 		if (strncmp(option, reject[i], strlen(reject[i])) == 0)
436 			return (true);
437 
438 	return (false);
439 }
440 
441 static void
442 xen_pvh_set_env(char *env, bool (*filter)(const char *))
443 {
444 	char *option;
445 
446 	if (env == NULL)
447 		return;
448 
449 	option = env;
450 	while (*option != 0) {
451 		char *value;
452 
453 		if (filter != NULL && filter(option)) {
454 			option += strlen(option) + 1;
455 			continue;
456 		}
457 
458 		value = option;
459 		option = strsep(&value, "=");
460 		if (kern_setenv(option, value) != 0)
461 			xc_printf("unable to add kenv %s=%s\n", option, value);
462 		option = value + strlen(value) + 1;
463 	}
464 }
465 
466 #ifdef DDB
467 /*
468  * The way Xen loads the symtab is different from the native boot loader,
469  * because it's tailored for NetBSD. So we have to adapt and use the same
470  * method as NetBSD. Portions of the code below have been picked from NetBSD:
471  * sys/kern/kern_ksyms.c CVS Revision 1.71.
472  */
473 static void
474 xen_pvh_parse_symtab(void)
475 {
476 	Elf_Ehdr *ehdr;
477 	Elf_Shdr *shdr;
478 	uint32_t size;
479 	int i, j;
480 
481 	size = end;
482 
483 	ehdr = (Elf_Ehdr *)(&end + 1);
484 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
485 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
486 	    ehdr->e_version > 1) {
487 		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
488 		return;
489 	}
490 
491 	shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
492 	/* Find the symbol table and the corresponding string table. */
493 	for (i = 1; i < ehdr->e_shnum; i++) {
494 		if (shdr[i].sh_type != SHT_SYMTAB)
495 			continue;
496 		if (shdr[i].sh_offset == 0)
497 			continue;
498 		ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
499 		ksymtab_size = shdr[i].sh_size;
500 		j = shdr[i].sh_link;
501 		if (shdr[j].sh_offset == 0)
502 			continue; /* Can this happen? */
503 		kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
504 		break;
505 	}
506 
507 	if (ksymtab == 0 || kstrtab == 0)
508 		xc_printf(
509     "Unable to load ELF symtab: could not find symtab or strtab\n");
510 }
511 #endif
512 
513 static caddr_t
514 xen_legacy_pvh_parse_preload_data(uint64_t modulep)
515 {
516 	caddr_t		 kmdp;
517 	vm_ooffset_t	 off;
518 	vm_paddr_t	 metadata;
519 	char             *envp;
520 
521 	if (legacy_start_info->mod_start != 0) {
522 		preload_metadata = (caddr_t)legacy_start_info->mod_start;
523 
524 		kmdp = preload_search_by_type("elf kernel");
525 		if (kmdp == NULL)
526 			kmdp = preload_search_by_type("elf64 kernel");
527 		KASSERT(kmdp != NULL, ("unable to find kernel"));
528 
529 		/*
530 		 * Xen has relocated the metadata and the modules,
531 		 * so we need to recalculate it's position. This is
532 		 * done by saving the original modulep address and
533 		 * then calculating the offset with mod_start,
534 		 * which contains the relocated modulep address.
535 		 */
536 		metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
537 		off = legacy_start_info->mod_start - metadata;
538 
539 		preload_bootstrap_relocate(off);
540 
541 		boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
542 		envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
543 		if (envp != NULL)
544 			envp += off;
545 		xen_pvh_set_env(envp, NULL);
546 	} else {
547 		/* Parse the extra boot information given by Xen */
548 		boot_parse_cmdline_delim(legacy_start_info->cmd_line, ",");
549 		kmdp = NULL;
550 	}
551 
552 	boothowto |= boot_env_to_howto();
553 
554 #ifdef DDB
555 	xen_pvh_parse_symtab();
556 #endif
557 	return (kmdp);
558 }
559 
560 static caddr_t
561 xen_pvh_parse_preload_data(uint64_t modulep)
562 {
563 	caddr_t kmdp;
564 	vm_ooffset_t off;
565 	vm_paddr_t metadata;
566 	char *envp;
567 	char acpi_rsdp[19];
568 
569 	if (start_info->modlist_paddr != 0) {
570 		struct hvm_modlist_entry *mod;
571 
572 		mod = (struct hvm_modlist_entry *)
573 		    (start_info->modlist_paddr + KERNBASE);
574 		preload_metadata = (caddr_t)(mod[0].paddr + KERNBASE);
575 
576 		kmdp = preload_search_by_type("elf kernel");
577 		if (kmdp == NULL)
578 			kmdp = preload_search_by_type("elf64 kernel");
579 		KASSERT(kmdp != NULL, ("unable to find kernel"));
580 
581 		/*
582 		 * Xen has relocated the metadata and the modules,
583 		 * so we need to recalculate it's position. This is
584 		 * done by saving the original modulep address and
585 		 * then calculating the offset with mod_start,
586 		 * which contains the relocated modulep address.
587 		 */
588 		metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
589 		off = mod[0].paddr + KERNBASE - metadata;
590 
591 		preload_bootstrap_relocate(off);
592 
593 		boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
594 		envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
595 		if (envp != NULL)
596 			envp += off;
597 		xen_pvh_set_env(envp, reject_option);
598 	} else {
599 		/* Parse the extra boot information given by Xen */
600 		if (start_info->cmdline_paddr != 0)
601 			boot_parse_cmdline_delim(
602 			    (char *)(start_info->cmdline_paddr + KERNBASE),
603 			    ",");
604 		kmdp = NULL;
605 	}
606 
607 	boothowto |= boot_env_to_howto();
608 
609 	snprintf(acpi_rsdp, sizeof(acpi_rsdp), "%#" PRIx64,
610 	    start_info->rsdp_paddr);
611 	kern_setenv("acpi.rsdp", acpi_rsdp);
612 
613 #ifdef DDB
614 	xen_pvh_parse_symtab();
615 #endif
616 	return (kmdp);
617 }
618 
619 static void
620 xen_pvh_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
621 {
622 	struct xen_memory_map memmap;
623 	u_int32_t size;
624 	int rc;
625 
626 	/* Fetch the E820 map from Xen */
627 	memmap.nr_entries = MAX_E820_ENTRIES;
628 	set_xen_guest_handle(memmap.buffer, xen_smap);
629 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
630 	if (rc) {
631 		xc_printf("ERROR: unable to fetch Xen E820 memory map: %d\n",
632 		    rc);
633 		HYPERVISOR_shutdown(SHUTDOWN_crash);
634 	}
635 
636 	size = memmap.nr_entries * sizeof(xen_smap[0]);
637 
638 	bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
639 }
640