xref: /freebsd/sys/x86/xen/pv.c (revision 243e928310d073338c5ec089f0dce238a80b9866)
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 
230 	ctxt->flags = VGCF_IN_KERNEL;
231 	ctxt->user_regs.rip = (unsigned long) init_secondary;
232 	ctxt->user_regs.rsp = (unsigned long) bootSTK;
233 
234 	/* Set the AP to use the same page tables */
235 	ctxt->ctrlreg[3] = KPML4phys;
236 
237 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
238 		panic("unable to initialize AP#%d", cpu);
239 
240 	free(ctxt, M_TEMP);
241 
242 	/* Launch the vCPU */
243 	if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
244 		panic("unable to start AP#%d", cpu);
245 
246 	/* Wait up to 5 seconds for it to start. */
247 	for (ms = 0; ms < 5000; ms++) {
248 		if (mp_naps > cpus)
249 			return (true);
250 		DELAY(1000);
251 	}
252 
253 	return (false);
254 }
255 
256 static int
257 xen_pv_start_all_aps(void)
258 {
259 	int cpu;
260 
261 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
262 
263 	for (cpu = 1; cpu < mp_ncpus; cpu++) {
264 
265 		/* attempt to start the Application Processor */
266 		if (!start_xen_ap(cpu))
267 			panic("AP #%d failed to start!", cpu);
268 
269 		CPU_SET(cpu, &all_cpus);	/* record AP in CPU map */
270 	}
271 
272 	return (mp_naps);
273 }
274 #endif /* SMP */
275 
276 /*
277  * Functions to convert the "extra" parameters passed by Xen
278  * into FreeBSD boot options.
279  */
280 static void
281 xen_pv_set_env(void)
282 {
283 	char *cmd_line_next, *cmd_line;
284 	size_t env_size;
285 
286 	cmd_line = HYPERVISOR_start_info->cmd_line;
287 	env_size = sizeof(HYPERVISOR_start_info->cmd_line);
288 
289 	/* Skip leading spaces */
290 	for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
291 		env_size--;
292 
293 	/* Replace ',' with '\0' */
294 	for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
295 		;
296 
297 	init_static_kenv(cmd_line, 0);
298 }
299 
300 static void
301 xen_pv_set_boothowto(void)
302 {
303 	int i;
304 	char *env;
305 
306 	/* get equivalents from the environment */
307 	for (i = 0; howto_names[i].ev != NULL; i++) {
308 		if ((env = kern_getenv(howto_names[i].ev)) != NULL) {
309 			boothowto |= howto_names[i].mask;
310 			freeenv(env);
311 		}
312 	}
313 }
314 
315 #ifdef DDB
316 /*
317  * The way Xen loads the symtab is different from the native boot loader,
318  * because it's tailored for NetBSD. So we have to adapt and use the same
319  * method as NetBSD. Portions of the code below have been picked from NetBSD:
320  * sys/kern/kern_ksyms.c CVS Revision 1.71.
321  */
322 static void
323 xen_pv_parse_symtab(void)
324 {
325 	Elf_Ehdr *ehdr;
326 	Elf_Shdr *shdr;
327 	vm_offset_t sym_end;
328 	uint32_t size;
329 	int i, j;
330 
331 	size = end;
332 	sym_end = HYPERVISOR_start_info->mod_start != 0 ?
333 	    HYPERVISOR_start_info->mod_start :
334 	    HYPERVISOR_start_info->mfn_list;
335 
336 	/*
337 	 * Make sure the size is right headed, sym_end is just a
338 	 * high boundary, but at least allows us to fail earlier.
339 	 */
340 	if ((vm_offset_t)&end + size > sym_end) {
341 		xc_printf("Unable to load ELF symtab: size mismatch\n");
342 		return;
343 	}
344 
345 	ehdr = (Elf_Ehdr *)(&end + 1);
346 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
347 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
348 	    ehdr->e_version > 1) {
349 		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
350 		return;
351 	}
352 
353 	shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
354 	/* Find the symbol table and the corresponding string table. */
355 	for (i = 1; i < ehdr->e_shnum; i++) {
356 		if (shdr[i].sh_type != SHT_SYMTAB)
357 			continue;
358 		if (shdr[i].sh_offset == 0)
359 			continue;
360 		ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
361 		ksymtab_size = shdr[i].sh_size;
362 		j = shdr[i].sh_link;
363 		if (shdr[j].sh_offset == 0)
364 			continue; /* Can this happen? */
365 		kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
366 		break;
367 	}
368 
369 	if (ksymtab == 0 || kstrtab == 0) {
370 		xc_printf(
371     "Unable to load ELF symtab: could not find symtab or strtab\n");
372 		return;
373 	}
374 }
375 #endif
376 
377 static caddr_t
378 xen_pv_parse_preload_data(u_int64_t modulep)
379 {
380 	caddr_t		 kmdp;
381 	vm_ooffset_t	 off;
382 	vm_paddr_t	 metadata;
383 	char             *envp;
384 
385 	if (HYPERVISOR_start_info->mod_start != 0) {
386 		preload_metadata = (caddr_t)(HYPERVISOR_start_info->mod_start);
387 
388 		kmdp = preload_search_by_type("elf kernel");
389 		if (kmdp == NULL)
390 			kmdp = preload_search_by_type("elf64 kernel");
391 		KASSERT(kmdp != NULL, ("unable to find kernel"));
392 
393 		/*
394 		 * Xen has relocated the metadata and the modules,
395 		 * so we need to recalculate it's position. This is
396 		 * done by saving the original modulep address and
397 		 * then calculating the offset with mod_start,
398 		 * which contains the relocated modulep address.
399 		 */
400 		metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
401 		off = HYPERVISOR_start_info->mod_start - metadata;
402 
403 		preload_bootstrap_relocate(off);
404 
405 		boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
406 		envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
407 		if (envp != NULL)
408 			envp += off;
409 		init_static_kenv(envp, 0);
410 	} else {
411 		/* Parse the extra boot information given by Xen */
412 		xen_pv_set_env();
413 		xen_pv_set_boothowto();
414 		kmdp = NULL;
415 	}
416 
417 #ifdef DDB
418 	xen_pv_parse_symtab();
419 #endif
420 	return (kmdp);
421 }
422 
423 static void
424 xen_pv_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
425 {
426 	struct xen_memory_map memmap;
427 	u_int32_t size;
428 	int rc;
429 
430 	/* Fetch the E820 map from Xen */
431 	memmap.nr_entries = MAX_E820_ENTRIES;
432 	set_xen_guest_handle(memmap.buffer, xen_smap);
433 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
434 	if (rc)
435 		panic("unable to fetch Xen E820 memory map");
436 	size = memmap.nr_entries * sizeof(xen_smap[0]);
437 
438 	bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
439 }
440