xref: /freebsd/sys/x86/xen/pv.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
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 char *doublefault_stack;
100 extern char *nmi_stack;
101 #endif
102 
103 /*
104  * Placed by the linker at the end of the bss section, which is the last
105  * section loaded by Xen before loading the symtab and strtab.
106  */
107 extern uint32_t end;
108 
109 /*-------------------------------- Global Data -------------------------------*/
110 /* Xen init_ops implementation. */
111 struct init_ops xen_init_ops = {
112 	.parse_preload_data		= xen_pv_parse_preload_data,
113 	.early_clock_source_init	= xen_clock_init,
114 	.early_delay			= xen_delay,
115 	.parse_memmap			= xen_pv_parse_memmap,
116 #ifdef SMP
117 	.start_all_aps			= xen_pv_start_all_aps,
118 #endif
119 	.msi_init =			xen_msi_init,
120 };
121 
122 static struct bios_smap xen_smap[MAX_E820_ENTRIES];
123 
124 /*-------------------------------- Xen PV init -------------------------------*/
125 /*
126  * First function called by the Xen PVH boot sequence.
127  *
128  * Set some Xen global variables and prepare the environment so it is
129  * as similar as possible to what native FreeBSD init function expects.
130  */
131 uint64_t
132 hammer_time_xen(start_info_t *si, uint64_t xenstack)
133 {
134 	uint64_t physfree;
135 	uint64_t *PT4 = (u_int64_t *)xenstack;
136 	uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
137 	uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
138 	int i;
139 
140 	xen_domain_type = XEN_PV_DOMAIN;
141 	vm_guest = VM_GUEST_XEN;
142 
143 	if ((si == NULL) || (xenstack == 0)) {
144 		xc_printf("ERROR: invalid start_info or xen stack, halting\n");
145 		HYPERVISOR_shutdown(SHUTDOWN_crash);
146 	}
147 
148 	xc_printf("FreeBSD PVH running on %s\n", si->magic);
149 
150 	/* We use 3 pages of xen stack for the boot pagetables */
151 	physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
152 
153 	/* Setup Xen global variables */
154 	HYPERVISOR_start_info = si;
155 	HYPERVISOR_shared_info =
156 	    (shared_info_t *)(si->shared_info + KERNBASE);
157 
158 	/*
159 	 * Setup some misc global variables for Xen devices
160 	 *
161 	 * XXX: Devices that need these specific variables should
162 	 *      be rewritten to fetch this info by themselves from the
163 	 *      start_info page.
164 	 */
165 	xen_store = (struct xenstore_domain_interface *)
166 	    (ptoa(si->store_mfn) + KERNBASE);
167 	console_page = (char *)(ptoa(si->console.domU.mfn) + KERNBASE);
168 
169 	/*
170 	 * Use the stack Xen gives us to build the page tables
171 	 * as native FreeBSD expects to find them (created
172 	 * by the boot trampoline).
173 	 */
174 	for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
175 		/*
176 		 * Each slot of the level 4 pages points
177 		 * to the same level 3 page
178 		 */
179 		PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
180 		PT4[i] |= PG_V | PG_RW | PG_U;
181 
182 		/*
183 		 * Each slot of the level 3 pages points
184 		 * to the same level 2 page
185 		 */
186 		PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
187 		PT3[i] |= PG_V | PG_RW | PG_U;
188 
189 		/*
190 		 * The level 2 page slots are mapped with
191 		 * 2MB pages for 1GB.
192 		 */
193 		PT2[i] = i * (2 * 1024 * 1024);
194 		PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
195 	}
196 	load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
197 
198 	/* Set the hooks for early functions that diverge from bare metal */
199 	init_ops = xen_init_ops;
200 	apic_ops = xen_apic_ops;
201 
202 	/* Now we can jump into the native init function */
203 	return (hammer_time(0, physfree));
204 }
205 
206 /*-------------------------------- PV specific -------------------------------*/
207 #ifdef SMP
208 static bool
209 start_xen_ap(int cpu)
210 {
211 	struct vcpu_guest_context *ctxt;
212 	int ms, cpus = mp_naps;
213 	const size_t stacksize = kstack_pages * PAGE_SIZE;
214 
215 	/* allocate and set up an idle stack data page */
216 	bootstacks[cpu] =
217 	    (void *)kmem_malloc(kernel_arena, stacksize, M_WAITOK | M_ZERO);
218 	doublefault_stack =
219 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
220 	nmi_stack =
221 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
222 	dpcpu =
223 	    (void *)kmem_malloc(kernel_arena, DPCPU_SIZE, M_WAITOK | M_ZERO);
224 
225 	bootSTK = (char *)bootstacks[cpu] + kstack_pages * PAGE_SIZE - 8;
226 	bootAP = cpu;
227 
228 	ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
229 	if (ctxt == NULL)
230 		panic("unable to allocate memory");
231 
232 	ctxt->flags = VGCF_IN_KERNEL;
233 	ctxt->user_regs.rip = (unsigned long) init_secondary;
234 	ctxt->user_regs.rsp = (unsigned long) bootSTK;
235 
236 	/* Set the AP to use the same page tables */
237 	ctxt->ctrlreg[3] = KPML4phys;
238 
239 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
240 		panic("unable to initialize AP#%d", cpu);
241 
242 	free(ctxt, M_TEMP);
243 
244 	/* Launch the vCPU */
245 	if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
246 		panic("unable to start AP#%d", cpu);
247 
248 	/* Wait up to 5 seconds for it to start. */
249 	for (ms = 0; ms < 5000; ms++) {
250 		if (mp_naps > cpus)
251 			return (true);
252 		DELAY(1000);
253 	}
254 
255 	return (false);
256 }
257 
258 static int
259 xen_pv_start_all_aps(void)
260 {
261 	int cpu;
262 
263 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
264 
265 	for (cpu = 1; cpu < mp_ncpus; cpu++) {
266 
267 		/* attempt to start the Application Processor */
268 		if (!start_xen_ap(cpu))
269 			panic("AP #%d failed to start!", cpu);
270 
271 		CPU_SET(cpu, &all_cpus);	/* record AP in CPU map */
272 	}
273 
274 	return (mp_naps);
275 }
276 #endif /* SMP */
277 
278 /*
279  * Functions to convert the "extra" parameters passed by Xen
280  * into FreeBSD boot options.
281  */
282 static void
283 xen_pv_set_env(void)
284 {
285 	char *cmd_line_next, *cmd_line;
286 	size_t env_size;
287 
288 	cmd_line = HYPERVISOR_start_info->cmd_line;
289 	env_size = sizeof(HYPERVISOR_start_info->cmd_line);
290 
291 	/* Skip leading spaces */
292 	for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
293 		env_size--;
294 
295 	/* Replace ',' with '\0' */
296 	for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
297 		;
298 
299 	init_static_kenv(cmd_line, 0);
300 }
301 
302 static void
303 xen_pv_set_boothowto(void)
304 {
305 	int i;
306 	char *env;
307 
308 	/* get equivalents from the environment */
309 	for (i = 0; howto_names[i].ev != NULL; i++) {
310 		if ((env = kern_getenv(howto_names[i].ev)) != NULL) {
311 			boothowto |= howto_names[i].mask;
312 			freeenv(env);
313 		}
314 	}
315 }
316 
317 #ifdef DDB
318 /*
319  * The way Xen loads the symtab is different from the native boot loader,
320  * because it's tailored for NetBSD. So we have to adapt and use the same
321  * method as NetBSD. Portions of the code below have been picked from NetBSD:
322  * sys/kern/kern_ksyms.c CVS Revision 1.71.
323  */
324 static void
325 xen_pv_parse_symtab(void)
326 {
327 	Elf_Ehdr *ehdr;
328 	Elf_Shdr *shdr;
329 	vm_offset_t sym_end;
330 	uint32_t size;
331 	int i, j;
332 
333 	size = end;
334 	sym_end = HYPERVISOR_start_info->mod_start != 0 ?
335 	    HYPERVISOR_start_info->mod_start :
336 	    HYPERVISOR_start_info->mfn_list;
337 
338 	/*
339 	 * Make sure the size is right headed, sym_end is just a
340 	 * high boundary, but at least allows us to fail earlier.
341 	 */
342 	if ((vm_offset_t)&end + size > sym_end) {
343 		xc_printf("Unable to load ELF symtab: size mismatch\n");
344 		return;
345 	}
346 
347 	ehdr = (Elf_Ehdr *)(&end + 1);
348 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
349 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
350 	    ehdr->e_version > 1) {
351 		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
352 		return;
353 	}
354 
355 	shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
356 	/* Find the symbol table and the corresponding string table. */
357 	for (i = 1; i < ehdr->e_shnum; i++) {
358 		if (shdr[i].sh_type != SHT_SYMTAB)
359 			continue;
360 		if (shdr[i].sh_offset == 0)
361 			continue;
362 		ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
363 		ksymtab_size = shdr[i].sh_size;
364 		j = shdr[i].sh_link;
365 		if (shdr[j].sh_offset == 0)
366 			continue; /* Can this happen? */
367 		kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
368 		break;
369 	}
370 
371 	if (ksymtab == 0 || kstrtab == 0) {
372 		xc_printf(
373     "Unable to load ELF symtab: could not find symtab or strtab\n");
374 		return;
375 	}
376 }
377 #endif
378 
379 static caddr_t
380 xen_pv_parse_preload_data(u_int64_t modulep)
381 {
382 	caddr_t		 kmdp;
383 	vm_ooffset_t	 off;
384 	vm_paddr_t	 metadata;
385 	char             *envp;
386 
387 	if (HYPERVISOR_start_info->mod_start != 0) {
388 		preload_metadata = (caddr_t)(HYPERVISOR_start_info->mod_start);
389 
390 		kmdp = preload_search_by_type("elf kernel");
391 		if (kmdp == NULL)
392 			kmdp = preload_search_by_type("elf64 kernel");
393 		KASSERT(kmdp != NULL, ("unable to find kernel"));
394 
395 		/*
396 		 * Xen has relocated the metadata and the modules,
397 		 * so we need to recalculate it's position. This is
398 		 * done by saving the original modulep address and
399 		 * then calculating the offset with mod_start,
400 		 * which contains the relocated modulep address.
401 		 */
402 		metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
403 		off = HYPERVISOR_start_info->mod_start - metadata;
404 
405 		preload_bootstrap_relocate(off);
406 
407 		boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
408 		envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
409 		if (envp != NULL)
410 			envp += off;
411 		init_static_kenv(envp, 0);
412 	} else {
413 		/* Parse the extra boot information given by Xen */
414 		xen_pv_set_env();
415 		xen_pv_set_boothowto();
416 		kmdp = NULL;
417 	}
418 
419 #ifdef DDB
420 	xen_pv_parse_symtab();
421 #endif
422 	return (kmdp);
423 }
424 
425 static void
426 xen_pv_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
427 {
428 	struct xen_memory_map memmap;
429 	u_int32_t size;
430 	int rc;
431 
432 	/* Fetch the E820 map from Xen */
433 	memmap.nr_entries = MAX_E820_ENTRIES;
434 	set_xen_guest_handle(memmap.buffer, xen_smap);
435 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
436 	if (rc)
437 		panic("unable to fetch Xen E820 memory map");
438 	size = memmap.nr_entries * sizeof(xen_smap[0]);
439 
440 	bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
441 }
442