xref: /freebsd/sys/x86/xen/pv.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
1 /*
2  * Copyright (c) 2004 Christian Limpach.
3  * Copyright (c) 2004-2006,2008 Kip Macy
4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
5  * Copyright (c) 2013 Roger Pau Monné <roger.pau@citrix.com>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include "opt_ddb.h"
34 #include "opt_kstack_pages.h"
35 
36 #include <sys/param.h>
37 #include <sys/bus.h>
38 #include <sys/kernel.h>
39 #include <sys/reboot.h>
40 #include <sys/systm.h>
41 #include <sys/malloc.h>
42 #include <sys/linker.h>
43 #include <sys/lock.h>
44 #include <sys/rwlock.h>
45 #include <sys/boot.h>
46 #include <sys/ctype.h>
47 #include <sys/mutex.h>
48 #include <sys/smp.h>
49 
50 #include <vm/vm.h>
51 #include <vm/vm_extern.h>
52 #include <vm/vm_kern.h>
53 #include <vm/vm_page.h>
54 #include <vm/vm_map.h>
55 #include <vm/vm_object.h>
56 #include <vm/vm_pager.h>
57 #include <vm/vm_param.h>
58 
59 #include <machine/intr_machdep.h>
60 #include <x86/apicvar.h>
61 #include <x86/init.h>
62 #include <machine/pc/bios.h>
63 #include <machine/smp.h>
64 #include <machine/intr_machdep.h>
65 #include <machine/metadata.h>
66 
67 #include <xen/xen-os.h>
68 #include <xen/hypervisor.h>
69 #include <xen/xenstore/xenstorevar.h>
70 #include <xen/xen_pv.h>
71 #include <xen/xen_msi.h>
72 
73 #include <xen/interface/vcpu.h>
74 
75 #include <dev/xen/timer/timer.h>
76 
77 #ifdef DDB
78 #include <ddb/ddb.h>
79 #endif
80 
81 /* Native initial function */
82 extern u_int64_t hammer_time(u_int64_t, u_int64_t);
83 /* Xen initial function */
84 uint64_t hammer_time_xen(start_info_t *, uint64_t);
85 
86 #define MAX_E820_ENTRIES	128
87 
88 /*--------------------------- Forward Declarations ---------------------------*/
89 static caddr_t xen_pv_parse_preload_data(u_int64_t);
90 static void xen_pv_parse_memmap(caddr_t, vm_paddr_t *, int *);
91 
92 #ifdef SMP
93 static int xen_pv_start_all_aps(void);
94 #endif
95 
96 /*---------------------------- Extern Declarations ---------------------------*/
97 #ifdef SMP
98 /* Variables used by amd64 mp_machdep to start APs */
99 extern struct mtx ap_boot_mtx;
100 extern void *bootstacks[];
101 extern char *doublefault_stack;
102 extern char *nmi_stack;
103 extern void *dpcpu;
104 extern int bootAP;
105 extern char *bootSTK;
106 #endif
107 
108 /*
109  * Placed by the linker at the end of the bss section, which is the last
110  * section loaded by Xen before loading the symtab and strtab.
111  */
112 extern uint32_t end;
113 
114 /*-------------------------------- Global Data -------------------------------*/
115 /* Xen init_ops implementation. */
116 struct init_ops xen_init_ops = {
117 	.parse_preload_data		= xen_pv_parse_preload_data,
118 	.early_clock_source_init	= xen_clock_init,
119 	.early_delay			= xen_delay,
120 	.parse_memmap			= xen_pv_parse_memmap,
121 #ifdef SMP
122 	.start_all_aps			= xen_pv_start_all_aps,
123 #endif
124 	.msi_init =			xen_msi_init,
125 };
126 
127 static struct bios_smap xen_smap[MAX_E820_ENTRIES];
128 
129 /*-------------------------------- Xen PV init -------------------------------*/
130 /*
131  * First function called by the Xen PVH boot sequence.
132  *
133  * Set some Xen global variables and prepare the environment so it is
134  * as similar as possible to what native FreeBSD init function expects.
135  */
136 uint64_t
137 hammer_time_xen(start_info_t *si, uint64_t xenstack)
138 {
139 	uint64_t physfree;
140 	uint64_t *PT4 = (u_int64_t *)xenstack;
141 	uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
142 	uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
143 	int i;
144 
145 	xen_domain_type = XEN_PV_DOMAIN;
146 	vm_guest = VM_GUEST_XEN;
147 
148 	if ((si == NULL) || (xenstack == 0)) {
149 		xc_printf("ERROR: invalid start_info or xen stack, halting\n");
150 		HYPERVISOR_shutdown(SHUTDOWN_crash);
151 	}
152 
153 	xc_printf("FreeBSD PVH running on %s\n", si->magic);
154 
155 	/* We use 3 pages of xen stack for the boot pagetables */
156 	physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
157 
158 	/* Setup Xen global variables */
159 	HYPERVISOR_start_info = si;
160 	HYPERVISOR_shared_info =
161 	    (shared_info_t *)(si->shared_info + KERNBASE);
162 
163 	/*
164 	 * Setup some misc global variables for Xen devices
165 	 *
166 	 * XXX: Devices that need these specific variables should
167 	 *      be rewritten to fetch this info by themselves from the
168 	 *      start_info page.
169 	 */
170 	xen_store = (struct xenstore_domain_interface *)
171 	    (ptoa(si->store_mfn) + KERNBASE);
172 	console_page = (char *)(ptoa(si->console.domU.mfn) + KERNBASE);
173 
174 	/*
175 	 * Use the stack Xen gives us to build the page tables
176 	 * as native FreeBSD expects to find them (created
177 	 * by the boot trampoline).
178 	 */
179 	for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
180 		/*
181 		 * Each slot of the level 4 pages points
182 		 * to the same level 3 page
183 		 */
184 		PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
185 		PT4[i] |= PG_V | PG_RW | PG_U;
186 
187 		/*
188 		 * Each slot of the level 3 pages points
189 		 * to the same level 2 page
190 		 */
191 		PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
192 		PT3[i] |= PG_V | PG_RW | PG_U;
193 
194 		/*
195 		 * The level 2 page slots are mapped with
196 		 * 2MB pages for 1GB.
197 		 */
198 		PT2[i] = i * (2 * 1024 * 1024);
199 		PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
200 	}
201 	load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
202 
203 	/* Set the hooks for early functions that diverge from bare metal */
204 	init_ops = xen_init_ops;
205 	apic_ops = xen_apic_ops;
206 
207 	/* Now we can jump into the native init function */
208 	return (hammer_time(0, physfree));
209 }
210 
211 /*-------------------------------- PV specific -------------------------------*/
212 #ifdef SMP
213 static bool
214 start_xen_ap(int cpu)
215 {
216 	struct vcpu_guest_context *ctxt;
217 	int ms, cpus = mp_naps;
218 	const size_t stacksize = KSTACK_PAGES * PAGE_SIZE;
219 
220 	/* allocate and set up an idle stack data page */
221 	bootstacks[cpu] =
222 	    (void *)kmem_malloc(kernel_arena, stacksize, M_WAITOK | M_ZERO);
223 	doublefault_stack =
224 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
225 	nmi_stack =
226 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
227 	dpcpu =
228 	    (void *)kmem_malloc(kernel_arena, DPCPU_SIZE, M_WAITOK | M_ZERO);
229 
230 	bootSTK = (char *)bootstacks[cpu] + KSTACK_PAGES * PAGE_SIZE - 8;
231 	bootAP = cpu;
232 
233 	ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
234 	if (ctxt == NULL)
235 		panic("unable to allocate memory");
236 
237 	ctxt->flags = VGCF_IN_KERNEL;
238 	ctxt->user_regs.rip = (unsigned long) init_secondary;
239 	ctxt->user_regs.rsp = (unsigned long) bootSTK;
240 
241 	/* Set the AP to use the same page tables */
242 	ctxt->ctrlreg[3] = KPML4phys;
243 
244 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
245 		panic("unable to initialize AP#%d", cpu);
246 
247 	free(ctxt, M_TEMP);
248 
249 	/* Launch the vCPU */
250 	if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
251 		panic("unable to start AP#%d", cpu);
252 
253 	/* Wait up to 5 seconds for it to start. */
254 	for (ms = 0; ms < 5000; ms++) {
255 		if (mp_naps > cpus)
256 			return (true);
257 		DELAY(1000);
258 	}
259 
260 	return (false);
261 }
262 
263 static int
264 xen_pv_start_all_aps(void)
265 {
266 	int cpu;
267 
268 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
269 
270 	for (cpu = 1; cpu < mp_ncpus; cpu++) {
271 
272 		/* attempt to start the Application Processor */
273 		if (!start_xen_ap(cpu))
274 			panic("AP #%d failed to start!", cpu);
275 
276 		CPU_SET(cpu, &all_cpus);	/* record AP in CPU map */
277 	}
278 
279 	return (mp_naps);
280 }
281 #endif /* SMP */
282 
283 /*
284  * Functions to convert the "extra" parameters passed by Xen
285  * into FreeBSD boot options.
286  */
287 static void
288 xen_pv_set_env(void)
289 {
290 	char *cmd_line_next, *cmd_line;
291 	size_t env_size;
292 
293 	cmd_line = HYPERVISOR_start_info->cmd_line;
294 	env_size = sizeof(HYPERVISOR_start_info->cmd_line);
295 
296 	/* Skip leading spaces */
297 	for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
298 		env_size--;
299 
300 	/* Replace ',' with '\0' */
301 	for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
302 		;
303 
304 	init_static_kenv(cmd_line, env_size);
305 }
306 
307 static void
308 xen_pv_set_boothowto(void)
309 {
310 	int i;
311 	char *env;
312 
313 	/* get equivalents from the environment */
314 	for (i = 0; howto_names[i].ev != NULL; i++) {
315 		if ((env = kern_getenv(howto_names[i].ev)) != NULL) {
316 			boothowto |= howto_names[i].mask;
317 			freeenv(env);
318 		}
319 	}
320 }
321 
322 #ifdef DDB
323 /*
324  * The way Xen loads the symtab is different from the native boot loader,
325  * because it's tailored for NetBSD. So we have to adapt and use the same
326  * method as NetBSD. Portions of the code below have been picked from NetBSD:
327  * sys/kern/kern_ksyms.c CVS Revision 1.71.
328  */
329 static void
330 xen_pv_parse_symtab(void)
331 {
332 	Elf_Ehdr *ehdr;
333 	Elf_Shdr *shdr;
334 	vm_offset_t sym_end;
335 	uint32_t size;
336 	int i, j;
337 
338 	size = end;
339 	sym_end = HYPERVISOR_start_info->mod_start != 0 ?
340 	    HYPERVISOR_start_info->mod_start :
341 	    HYPERVISOR_start_info->mfn_list;
342 
343 	/*
344 	 * Make sure the size is right headed, sym_end is just a
345 	 * high boundary, but at least allows us to fail earlier.
346 	 */
347 	if ((vm_offset_t)&end + size > sym_end) {
348 		xc_printf("Unable to load ELF symtab: size mismatch\n");
349 		return;
350 	}
351 
352 	ehdr = (Elf_Ehdr *)(&end + 1);
353 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
354 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
355 	    ehdr->e_version > 1) {
356 		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
357 		return;
358 	}
359 
360 	shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
361 	/* Find the symbol table and the corresponding string table. */
362 	for (i = 1; i < ehdr->e_shnum; i++) {
363 		if (shdr[i].sh_type != SHT_SYMTAB)
364 			continue;
365 		if (shdr[i].sh_offset == 0)
366 			continue;
367 		ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
368 		ksymtab_size = shdr[i].sh_size;
369 		j = shdr[i].sh_link;
370 		if (shdr[j].sh_offset == 0)
371 			continue; /* Can this happen? */
372 		kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
373 		break;
374 	}
375 
376 	if (ksymtab == 0 || kstrtab == 0) {
377 		xc_printf(
378     "Unable to load ELF symtab: could not find symtab or strtab\n");
379 		return;
380 	}
381 }
382 #endif
383 
384 static caddr_t
385 xen_pv_parse_preload_data(u_int64_t modulep)
386 {
387 	caddr_t		 kmdp;
388 	vm_ooffset_t	 off;
389 	vm_paddr_t	 metadata;
390 
391 	if (HYPERVISOR_start_info->mod_start != 0) {
392 		preload_metadata = (caddr_t)(HYPERVISOR_start_info->mod_start);
393 
394 		kmdp = preload_search_by_type("elf kernel");
395 		if (kmdp == NULL)
396 			kmdp = preload_search_by_type("elf64 kernel");
397 		KASSERT(kmdp != NULL, ("unable to find kernel"));
398 
399 		/*
400 		 * Xen has relocated the metadata and the modules,
401 		 * so we need to recalculate it's position. This is
402 		 * done by saving the original modulep address and
403 		 * then calculating the offset with mod_start,
404 		 * which contains the relocated modulep address.
405 		 */
406 		metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
407 		off = HYPERVISOR_start_info->mod_start - metadata;
408 
409 		preload_bootstrap_relocate(off);
410 
411 		boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
412 		kern_envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
413 		kern_envp += off;
414 	} else {
415 		/* Parse the extra boot information given by Xen */
416 		xen_pv_set_env();
417 		xen_pv_set_boothowto();
418 		kmdp = NULL;
419 	}
420 
421 #ifdef DDB
422 	xen_pv_parse_symtab();
423 #endif
424 	return (kmdp);
425 }
426 
427 static void
428 xen_pv_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
429 {
430 	struct xen_memory_map memmap;
431 	u_int32_t size;
432 	int rc;
433 
434 	/* Fetch the E820 map from Xen */
435 	memmap.nr_entries = MAX_E820_ENTRIES;
436 	set_xen_guest_handle(memmap.buffer, xen_smap);
437 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
438 	if (rc)
439 		panic("unable to fetch Xen E820 memory map");
440 	size = memmap.nr_entries * sizeof(xen_smap[0]);
441 
442 	bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
443 }
444