xref: /freebsd/sys/x86/xen/pv.c (revision be930504becc794c808b529bd65fa09d2d85f846)
1 /*
2  * Copyright (c) 2004 Christian Limpach.
3  * Copyright (c) 2004-2006,2008 Kip Macy
4  * Copyright (c) 2013 Roger Pau Monné <roger.pau@citrix.com>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_ddb.h"
33 
34 #include <sys/param.h>
35 #include <sys/bus.h>
36 #include <sys/kernel.h>
37 #include <sys/reboot.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/linker.h>
41 #include <sys/lock.h>
42 #include <sys/rwlock.h>
43 #include <sys/boot.h>
44 #include <sys/ctype.h>
45 #include <sys/mutex.h>
46 #include <sys/smp.h>
47 
48 #include <vm/vm.h>
49 #include <vm/vm_extern.h>
50 #include <vm/vm_kern.h>
51 #include <vm/vm_page.h>
52 #include <vm/vm_map.h>
53 #include <vm/vm_object.h>
54 #include <vm/vm_pager.h>
55 #include <vm/vm_param.h>
56 
57 #include <machine/intr_machdep.h>
58 #include <x86/apicvar.h>
59 #include <x86/init.h>
60 #include <machine/pc/bios.h>
61 #include <machine/smp.h>
62 
63 #include <xen/xen-os.h>
64 #include <xen/hypervisor.h>
65 #include <xen/xenstore/xenstorevar.h>
66 #include <xen/xen_pv.h>
67 
68 #include <xen/interface/vcpu.h>
69 
70 #include <dev/xen/timer/timer.h>
71 
72 #ifdef DDB
73 #include <ddb/ddb.h>
74 #endif
75 
76 /* Native initial function */
77 extern u_int64_t hammer_time(u_int64_t, u_int64_t);
78 /* Xen initial function */
79 uint64_t hammer_time_xen(start_info_t *, uint64_t);
80 
81 #define MAX_E820_ENTRIES	128
82 
83 /*--------------------------- Forward Declarations ---------------------------*/
84 static caddr_t xen_pv_parse_preload_data(u_int64_t);
85 static void xen_pv_parse_memmap(caddr_t, vm_paddr_t *, int *);
86 
87 #ifdef SMP
88 static int xen_pv_start_all_aps(void);
89 #endif
90 
91 /*---------------------------- Extern Declarations ---------------------------*/
92 #ifdef SMP
93 /* Variables used by amd64 mp_machdep to start APs */
94 extern struct mtx ap_boot_mtx;
95 extern void *bootstacks[];
96 extern char *doublefault_stack;
97 extern char *nmi_stack;
98 extern void *dpcpu;
99 extern int bootAP;
100 extern char *bootSTK;
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 };
120 
121 static struct bios_smap xen_smap[MAX_E820_ENTRIES];
122 
123 /*-------------------------------- Xen PV init -------------------------------*/
124 /*
125  * First function called by the Xen PVH boot sequence.
126  *
127  * Set some Xen global variables and prepare the environment so it is
128  * as similar as possible to what native FreeBSD init function expects.
129  */
130 uint64_t
131 hammer_time_xen(start_info_t *si, uint64_t xenstack)
132 {
133 	uint64_t physfree;
134 	uint64_t *PT4 = (u_int64_t *)xenstack;
135 	uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
136 	uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
137 	int i;
138 
139 	xen_domain_type = XEN_PV_DOMAIN;
140 	vm_guest = VM_GUEST_XEN;
141 
142 	if ((si == NULL) || (xenstack == 0)) {
143 		xc_printf("ERROR: invalid start_info or xen stack, halting\n");
144 		HYPERVISOR_shutdown(SHUTDOWN_crash);
145 	}
146 
147 	xc_printf("FreeBSD PVH running on %s\n", si->magic);
148 
149 	/* We use 3 pages of xen stack for the boot pagetables */
150 	physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
151 
152 	/* Setup Xen global variables */
153 	HYPERVISOR_start_info = si;
154 	HYPERVISOR_shared_info =
155 	    (shared_info_t *)(si->shared_info + KERNBASE);
156 
157 	/*
158 	 * Setup some misc global variables for Xen devices
159 	 *
160 	 * XXX: Devices that need these specific variables should
161 	 *      be rewritten to fetch this info by themselves from the
162 	 *      start_info page.
163 	 */
164 	xen_store = (struct xenstore_domain_interface *)
165 	    (ptoa(si->store_mfn) + KERNBASE);
166 	console_page = (char *)(ptoa(si->console.domU.mfn) + KERNBASE);
167 
168 	/*
169 	 * Use the stack Xen gives us to build the page tables
170 	 * as native FreeBSD expects to find them (created
171 	 * by the boot trampoline).
172 	 */
173 	for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
174 		/*
175 		 * Each slot of the level 4 pages points
176 		 * to the same level 3 page
177 		 */
178 		PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
179 		PT4[i] |= PG_V | PG_RW | PG_U;
180 
181 		/*
182 		 * Each slot of the level 3 pages points
183 		 * to the same level 2 page
184 		 */
185 		PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
186 		PT3[i] |= PG_V | PG_RW | PG_U;
187 
188 		/*
189 		 * The level 2 page slots are mapped with
190 		 * 2MB pages for 1GB.
191 		 */
192 		PT2[i] = i * (2 * 1024 * 1024);
193 		PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
194 	}
195 	load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
196 
197 	/* Set the hooks for early functions that diverge from bare metal */
198 	init_ops = xen_init_ops;
199 	apic_ops = xen_apic_ops;
200 
201 	/* Now we can jump into the native init function */
202 	return (hammer_time(0, physfree));
203 }
204 
205 /*-------------------------------- PV specific -------------------------------*/
206 #ifdef SMP
207 static bool
208 start_xen_ap(int cpu)
209 {
210 	struct vcpu_guest_context *ctxt;
211 	int ms, cpus = mp_naps;
212 	const size_t stacksize = KSTACK_PAGES * PAGE_SIZE;
213 
214 	/* allocate and set up an idle stack data page */
215 	bootstacks[cpu] =
216 	    (void *)kmem_malloc(kernel_arena, stacksize, M_WAITOK | M_ZERO);
217 	doublefault_stack =
218 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
219 	nmi_stack =
220 	    (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
221 	dpcpu =
222 	    (void *)kmem_malloc(kernel_arena, DPCPU_SIZE, M_WAITOK | M_ZERO);
223 
224 	bootSTK = (char *)bootstacks[cpu] + KSTACK_PAGES * PAGE_SIZE - 8;
225 	bootAP = cpu;
226 
227 	ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
228 	if (ctxt == NULL)
229 		panic("unable to allocate memory");
230 
231 	ctxt->flags = VGCF_IN_KERNEL;
232 	ctxt->user_regs.rip = (unsigned long) init_secondary;
233 	ctxt->user_regs.rsp = (unsigned long) bootSTK;
234 
235 	/* Set the AP to use the same page tables */
236 	ctxt->ctrlreg[3] = KPML4phys;
237 
238 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
239 		panic("unable to initialize AP#%d", cpu);
240 
241 	free(ctxt, M_TEMP);
242 
243 	/* Launch the vCPU */
244 	if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
245 		panic("unable to start AP#%d", cpu);
246 
247 	/* Wait up to 5 seconds for it to start. */
248 	for (ms = 0; ms < 5000; ms++) {
249 		if (mp_naps > cpus)
250 			return (true);
251 		DELAY(1000);
252 	}
253 
254 	return (false);
255 }
256 
257 static int
258 xen_pv_start_all_aps(void)
259 {
260 	int cpu;
261 
262 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
263 
264 	for (cpu = 1; cpu < mp_ncpus; cpu++) {
265 
266 		/* attempt to start the Application Processor */
267 		if (!start_xen_ap(cpu))
268 			panic("AP #%d failed to start!", cpu);
269 
270 		CPU_SET(cpu, &all_cpus);	/* record AP in CPU map */
271 	}
272 
273 	return (mp_naps);
274 }
275 #endif /* SMP */
276 
277 /*
278  * Functions to convert the "extra" parameters passed by Xen
279  * into FreeBSD boot options.
280  */
281 static void
282 xen_pv_set_env(void)
283 {
284 	char *cmd_line_next, *cmd_line;
285 	size_t env_size;
286 
287 	cmd_line = HYPERVISOR_start_info->cmd_line;
288 	env_size = sizeof(HYPERVISOR_start_info->cmd_line);
289 
290 	/* Skip leading spaces */
291 	for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
292 		env_size--;
293 
294 	/* Replace ',' with '\0' */
295 	for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
296 		;
297 
298 	init_static_kenv(cmd_line, env_size);
299 }
300 
301 static void
302 xen_pv_set_boothowto(void)
303 {
304 	int i;
305 
306 	/* get equivalents from the environment */
307 	for (i = 0; howto_names[i].ev != NULL; i++) {
308 		if (getenv(howto_names[i].ev) != NULL)
309 			boothowto |= howto_names[i].mask;
310 	}
311 }
312 
313 #ifdef DDB
314 /*
315  * The way Xen loads the symtab is different from the native boot loader,
316  * because it's tailored for NetBSD. So we have to adapt and use the same
317  * method as NetBSD. Portions of the code below have been picked from NetBSD:
318  * sys/kern/kern_ksyms.c CVS Revision 1.71.
319  */
320 static void
321 xen_pv_parse_symtab(void)
322 {
323 	Elf_Ehdr *ehdr;
324 	Elf_Shdr *shdr;
325 	vm_offset_t sym_end;
326 	uint32_t size;
327 	int i, j;
328 
329 	size = end;
330 	sym_end = HYPERVISOR_start_info->mod_start != 0 ?
331 	    HYPERVISOR_start_info->mod_start :
332 	    HYPERVISOR_start_info->mfn_list;
333 
334 	/*
335 	 * Make sure the size is right headed, sym_end is just a
336 	 * high boundary, but at least allows us to fail earlier.
337 	 */
338 	if ((vm_offset_t)&end + size > sym_end) {
339 		xc_printf("Unable to load ELF symtab: size mismatch\n");
340 		return;
341 	}
342 
343 	ehdr = (Elf_Ehdr *)(&end + 1);
344 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
345 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
346 	    ehdr->e_version > 1) {
347 		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
348 		return;
349 	}
350 
351 	shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
352 	/* Find the symbol table and the corresponding string table. */
353 	for (i = 1; i < ehdr->e_shnum; i++) {
354 		if (shdr[i].sh_type != SHT_SYMTAB)
355 			continue;
356 		if (shdr[i].sh_offset == 0)
357 			continue;
358 		ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
359 		ksymtab_size = shdr[i].sh_size;
360 		j = shdr[i].sh_link;
361 		if (shdr[j].sh_offset == 0)
362 			continue; /* Can this happen? */
363 		kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
364 		break;
365 	}
366 
367 	if (ksymtab == 0 || kstrtab == 0) {
368 		xc_printf(
369     "Unable to load ELF symtab: could not find symtab or strtab\n");
370 		return;
371 	}
372 }
373 #endif
374 
375 static caddr_t
376 xen_pv_parse_preload_data(u_int64_t modulep)
377 {
378 	/* Parse the extra boot information given by Xen */
379 	xen_pv_set_env();
380 	xen_pv_set_boothowto();
381 
382 #ifdef DDB
383 	xen_pv_parse_symtab();
384 #endif
385 
386 	return (NULL);
387 }
388 
389 static void
390 xen_pv_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
391 {
392 	struct xen_memory_map memmap;
393 	u_int32_t size;
394 	int rc;
395 
396 	/* Fetch the E820 map from Xen */
397 	memmap.nr_entries = MAX_E820_ENTRIES;
398 	set_xen_guest_handle(memmap.buffer, xen_smap);
399 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
400 	if (rc)
401 		panic("unable to fetch Xen E820 memory map");
402 	size = memmap.nr_entries * sizeof(xen_smap[0]);
403 
404 	bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
405 }
406