xref: /freebsd/sys/x86/xen/pv.c (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
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/intr_machdep.h>
62 #include <x86/apicvar.h>
63 #include <x86/init.h>
64 #include <machine/pc/bios.h>
65 #include <machine/smp.h>
66 #include <machine/intr_machdep.h>
67 #include <machine/metadata.h>
68 
69 #include <xen/xen-os.h>
70 #include <xen/hypervisor.h>
71 #include <xen/xenstore/xenstorevar.h>
72 #include <xen/xen_pv.h>
73 #include <xen/xen_msi.h>
74 
75 #include <xen/interface/vcpu.h>
76 
77 #include <dev/xen/timer/timer.h>
78 
79 #ifdef DDB
80 #include <ddb/ddb.h>
81 #endif
82 
83 /* Native initial function */
84 extern u_int64_t hammer_time(u_int64_t, u_int64_t);
85 /* Xen initial function */
86 uint64_t hammer_time_xen(start_info_t *, uint64_t);
87 
88 #define MAX_E820_ENTRIES	128
89 
90 /*--------------------------- Forward Declarations ---------------------------*/
91 static caddr_t xen_pv_parse_preload_data(u_int64_t);
92 static void xen_pv_parse_memmap(caddr_t, vm_paddr_t *, int *);
93 
94 #ifdef SMP
95 static int xen_pv_start_all_aps(void);
96 #endif
97 
98 /*---------------------------- Extern Declarations ---------------------------*/
99 #ifdef SMP
100 /* Variables used by amd64 mp_machdep to start APs */
101 extern char *doublefault_stack;
102 extern char *mce_stack;
103 extern char *nmi_stack;
104 extern char *dbg_stack;
105 #endif
106 
107 /*
108  * Placed by the linker at the end of the bss section, which is the last
109  * section loaded by Xen before loading the symtab and strtab.
110  */
111 extern uint32_t end;
112 
113 /*-------------------------------- Global Data -------------------------------*/
114 /* Xen init_ops implementation. */
115 struct init_ops xen_init_ops = {
116 	.parse_preload_data		= xen_pv_parse_preload_data,
117 	.early_clock_source_init	= xen_clock_init,
118 	.early_delay			= xen_delay,
119 	.parse_memmap			= xen_pv_parse_memmap,
120 #ifdef SMP
121 	.start_all_aps			= xen_pv_start_all_aps,
122 #endif
123 	.msi_init			= xen_msi_init,
124 };
125 
126 static struct bios_smap xen_smap[MAX_E820_ENTRIES];
127 
128 /*-------------------------------- Xen PV init -------------------------------*/
129 /*
130  * First function called by the Xen PVH boot sequence.
131  *
132  * Set some Xen global variables and prepare the environment so it is
133  * as similar as possible to what native FreeBSD init function expects.
134  */
135 uint64_t
136 hammer_time_xen(start_info_t *si, uint64_t xenstack)
137 {
138 	uint64_t physfree;
139 	uint64_t *PT4 = (u_int64_t *)xenstack;
140 	uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
141 	uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
142 	int i;
143 
144 	xen_domain_type = XEN_PV_DOMAIN;
145 	vm_guest = VM_GUEST_XEN;
146 
147 	if ((si == NULL) || (xenstack == 0)) {
148 		xc_printf("ERROR: invalid start_info or xen stack, halting\n");
149 		HYPERVISOR_shutdown(SHUTDOWN_crash);
150 	}
151 
152 	xc_printf("FreeBSD PVH running on %s\n", si->magic);
153 
154 	/* We use 3 pages of xen stack for the boot pagetables */
155 	physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
156 
157 	/* Setup Xen global variables */
158 	HYPERVISOR_start_info = si;
159 	HYPERVISOR_shared_info =
160 	    (shared_info_t *)(si->shared_info + KERNBASE);
161 
162 	/*
163 	 * Setup some misc global variables for Xen devices
164 	 *
165 	 * XXX: Devices that need these specific variables should
166 	 *      be rewritten to fetch this info by themselves from the
167 	 *      start_info page.
168 	 */
169 	xen_store = (struct xenstore_domain_interface *)
170 	    (ptoa(si->store_mfn) + KERNBASE);
171 	console_page = (char *)(ptoa(si->console.domU.mfn) + KERNBASE);
172 
173 	/*
174 	 * Use the stack Xen gives us to build the page tables
175 	 * as native FreeBSD expects to find them (created
176 	 * by the boot trampoline).
177 	 */
178 	for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
179 		/*
180 		 * Each slot of the level 4 pages points
181 		 * to the same level 3 page
182 		 */
183 		PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
184 		PT4[i] |= PG_V | PG_RW | PG_U;
185 
186 		/*
187 		 * Each slot of the level 3 pages points
188 		 * to the same level 2 page
189 		 */
190 		PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
191 		PT3[i] |= PG_V | PG_RW | PG_U;
192 
193 		/*
194 		 * The level 2 page slots are mapped with
195 		 * 2MB pages for 1GB.
196 		 */
197 		PT2[i] = i * (2 * 1024 * 1024);
198 		PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
199 	}
200 	load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
201 
202 	/* Set the hooks for early functions that diverge from bare metal */
203 	init_ops = xen_init_ops;
204 	apic_ops = xen_apic_ops;
205 
206 	/* Now we can jump into the native init function */
207 	return (hammer_time(0, physfree));
208 }
209 
210 /*-------------------------------- PV specific -------------------------------*/
211 #ifdef SMP
212 static bool
213 start_xen_ap(int cpu)
214 {
215 	struct vcpu_guest_context *ctxt;
216 	int ms, cpus = mp_naps;
217 	const size_t stacksize = kstack_pages * PAGE_SIZE;
218 
219 	/* allocate and set up an idle stack data page */
220 	bootstacks[cpu] =
221 	    (void *)kmem_malloc(kernel_arena, stacksize, M_WAITOK | M_ZERO);
222 	doublefault_stack =
223 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
224 	mce_stack =
225 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
226 	nmi_stack =
227 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
228 	dbg_stack =
229 	    (void *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
230 	dpcpu =
231 	    (void *)kmem_malloc(kernel_arena, DPCPU_SIZE, M_WAITOK | M_ZERO);
232 
233 	bootSTK = (char *)bootstacks[cpu] + kstack_pages * PAGE_SIZE - 8;
234 	bootAP = cpu;
235 
236 	ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
237 
238 	ctxt->flags = VGCF_IN_KERNEL;
239 	ctxt->user_regs.rip = (unsigned long) init_secondary;
240 	ctxt->user_regs.rsp = (unsigned long) bootSTK;
241 
242 	/* Set the AP to use the same page tables */
243 	ctxt->ctrlreg[3] = KPML4phys;
244 
245 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
246 		panic("unable to initialize AP#%d", cpu);
247 
248 	free(ctxt, M_TEMP);
249 
250 	/* Launch the vCPU */
251 	if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
252 		panic("unable to start AP#%d", cpu);
253 
254 	/* Wait up to 5 seconds for it to start. */
255 	for (ms = 0; ms < 5000; ms++) {
256 		if (mp_naps > cpus)
257 			return (true);
258 		DELAY(1000);
259 	}
260 
261 	return (false);
262 }
263 
264 static int
265 xen_pv_start_all_aps(void)
266 {
267 	int cpu;
268 
269 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
270 
271 	for (cpu = 1; cpu < mp_ncpus; cpu++) {
272 
273 		/* attempt to start the Application Processor */
274 		if (!start_xen_ap(cpu))
275 			panic("AP #%d failed to start!", cpu);
276 
277 		CPU_SET(cpu, &all_cpus);	/* record AP in CPU map */
278 	}
279 
280 	return (mp_naps);
281 }
282 #endif /* SMP */
283 
284 /*
285  * Functions to convert the "extra" parameters passed by Xen
286  * into FreeBSD boot options.
287  */
288 static void
289 xen_pv_set_env(void)
290 {
291 	char *cmd_line_next, *cmd_line;
292 	size_t env_size;
293 
294 	cmd_line = HYPERVISOR_start_info->cmd_line;
295 	env_size = sizeof(HYPERVISOR_start_info->cmd_line);
296 
297 	/* Skip leading spaces */
298 	for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
299 		env_size--;
300 
301 	/* Replace ',' with '\0' */
302 	for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
303 		;
304 
305 	init_static_kenv(cmd_line, 0);
306 }
307 
308 static void
309 xen_pv_set_boothowto(void)
310 {
311 	int i;
312 	char *env;
313 
314 	/* get equivalents from the environment */
315 	for (i = 0; howto_names[i].ev != NULL; i++) {
316 		if ((env = kern_getenv(howto_names[i].ev)) != NULL) {
317 			boothowto |= howto_names[i].mask;
318 			freeenv(env);
319 		}
320 	}
321 }
322 
323 #ifdef DDB
324 /*
325  * The way Xen loads the symtab is different from the native boot loader,
326  * because it's tailored for NetBSD. So we have to adapt and use the same
327  * method as NetBSD. Portions of the code below have been picked from NetBSD:
328  * sys/kern/kern_ksyms.c CVS Revision 1.71.
329  */
330 static void
331 xen_pv_parse_symtab(void)
332 {
333 	Elf_Ehdr *ehdr;
334 	Elf_Shdr *shdr;
335 	vm_offset_t sym_end;
336 	uint32_t size;
337 	int i, j;
338 
339 	size = end;
340 	sym_end = HYPERVISOR_start_info->mod_start != 0 ?
341 	    HYPERVISOR_start_info->mod_start :
342 	    HYPERVISOR_start_info->mfn_list;
343 
344 	/*
345 	 * Make sure the size is right headed, sym_end is just a
346 	 * high boundary, but at least allows us to fail earlier.
347 	 */
348 	if ((vm_offset_t)&end + size > sym_end) {
349 		xc_printf("Unable to load ELF symtab: size mismatch\n");
350 		return;
351 	}
352 
353 	ehdr = (Elf_Ehdr *)(&end + 1);
354 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
355 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
356 	    ehdr->e_version > 1) {
357 		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
358 		return;
359 	}
360 
361 	shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
362 	/* Find the symbol table and the corresponding string table. */
363 	for (i = 1; i < ehdr->e_shnum; i++) {
364 		if (shdr[i].sh_type != SHT_SYMTAB)
365 			continue;
366 		if (shdr[i].sh_offset == 0)
367 			continue;
368 		ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
369 		ksymtab_size = shdr[i].sh_size;
370 		j = shdr[i].sh_link;
371 		if (shdr[j].sh_offset == 0)
372 			continue; /* Can this happen? */
373 		kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
374 		break;
375 	}
376 
377 	if (ksymtab == 0 || kstrtab == 0) {
378 		xc_printf(
379     "Unable to load ELF symtab: could not find symtab or strtab\n");
380 		return;
381 	}
382 }
383 #endif
384 
385 static caddr_t
386 xen_pv_parse_preload_data(u_int64_t modulep)
387 {
388 	caddr_t		 kmdp;
389 	vm_ooffset_t	 off;
390 	vm_paddr_t	 metadata;
391 	char             *envp;
392 
393 	if (HYPERVISOR_start_info->mod_start != 0) {
394 		preload_metadata = (caddr_t)(HYPERVISOR_start_info->mod_start);
395 
396 		kmdp = preload_search_by_type("elf kernel");
397 		if (kmdp == NULL)
398 			kmdp = preload_search_by_type("elf64 kernel");
399 		KASSERT(kmdp != NULL, ("unable to find kernel"));
400 
401 		/*
402 		 * Xen has relocated the metadata and the modules,
403 		 * so we need to recalculate it's position. This is
404 		 * done by saving the original modulep address and
405 		 * then calculating the offset with mod_start,
406 		 * which contains the relocated modulep address.
407 		 */
408 		metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
409 		off = HYPERVISOR_start_info->mod_start - metadata;
410 
411 		preload_bootstrap_relocate(off);
412 
413 		boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
414 		envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
415 		if (envp != NULL)
416 			envp += off;
417 		init_static_kenv(envp, 0);
418 	} else {
419 		/* Parse the extra boot information given by Xen */
420 		xen_pv_set_env();
421 		xen_pv_set_boothowto();
422 		kmdp = NULL;
423 	}
424 
425 #ifdef DDB
426 	xen_pv_parse_symtab();
427 #endif
428 	return (kmdp);
429 }
430 
431 static void
432 xen_pv_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
433 {
434 	struct xen_memory_map memmap;
435 	u_int32_t size;
436 	int rc;
437 
438 	/* Fetch the E820 map from Xen */
439 	memmap.nr_entries = MAX_E820_ENTRIES;
440 	set_xen_guest_handle(memmap.buffer, xen_smap);
441 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
442 	if (rc)
443 		panic("unable to fetch Xen E820 memory map");
444 	size = memmap.nr_entries * sizeof(xen_smap[0]);
445 
446 	bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
447 }
448