Commit | Line | Data |
---|---|---|
f938d2c8 | 1 | /*P:100 This is the Launcher code, a simple program which lays out the |
a6bd8e13 RR |
2 | * "physical" memory for the new Guest by mapping the kernel image and |
3 | * the virtual devices, then opens /dev/lguest to tell the kernel | |
4 | * about the Guest and control it. :*/ | |
8ca47e00 RR |
5 | #define _LARGEFILE64_SOURCE |
6 | #define _GNU_SOURCE | |
7 | #include <stdio.h> | |
8 | #include <string.h> | |
9 | #include <unistd.h> | |
10 | #include <err.h> | |
11 | #include <stdint.h> | |
12 | #include <stdlib.h> | |
13 | #include <elf.h> | |
14 | #include <sys/mman.h> | |
6649bb7a | 15 | #include <sys/param.h> |
8ca47e00 RR |
16 | #include <sys/types.h> |
17 | #include <sys/stat.h> | |
18 | #include <sys/wait.h> | |
659a0e66 | 19 | #include <sys/eventfd.h> |
8ca47e00 RR |
20 | #include <fcntl.h> |
21 | #include <stdbool.h> | |
22 | #include <errno.h> | |
23 | #include <ctype.h> | |
24 | #include <sys/socket.h> | |
25 | #include <sys/ioctl.h> | |
26 | #include <sys/time.h> | |
27 | #include <time.h> | |
28 | #include <netinet/in.h> | |
29 | #include <net/if.h> | |
30 | #include <linux/sockios.h> | |
31 | #include <linux/if_tun.h> | |
32 | #include <sys/uio.h> | |
33 | #include <termios.h> | |
34 | #include <getopt.h> | |
35 | #include <zlib.h> | |
17cbca2b RR |
36 | #include <assert.h> |
37 | #include <sched.h> | |
a586d4f6 RR |
38 | #include <limits.h> |
39 | #include <stddef.h> | |
a161883a | 40 | #include <signal.h> |
b45d8cb0 | 41 | #include "linux/lguest_launcher.h" |
17cbca2b RR |
42 | #include "linux/virtio_config.h" |
43 | #include "linux/virtio_net.h" | |
44 | #include "linux/virtio_blk.h" | |
45 | #include "linux/virtio_console.h" | |
28fd6d7f | 46 | #include "linux/virtio_rng.h" |
17cbca2b | 47 | #include "linux/virtio_ring.h" |
d5d02d6d | 48 | #include "asm/bootparam.h" |
a6bd8e13 | 49 | /*L:110 We can ignore the 39 include files we need for this program, but I do |
db24e8c2 RR |
50 | * want to draw attention to the use of kernel-style types. |
51 | * | |
52 | * As Linus said, "C is a Spartan language, and so should your naming be." I | |
53 | * like these abbreviations, so we define them here. Note that u64 is always | |
54 | * unsigned long long, which works on all Linux systems: this means that we can | |
55 | * use %llu in printf for any u64. */ | |
56 | typedef unsigned long long u64; | |
57 | typedef uint32_t u32; | |
58 | typedef uint16_t u16; | |
59 | typedef uint8_t u8; | |
dde79789 | 60 | /*:*/ |
8ca47e00 RR |
61 | |
62 | #define PAGE_PRESENT 0x7 /* Present, RW, Execute */ | |
8ca47e00 RR |
63 | #define BRIDGE_PFX "bridge:" |
64 | #ifndef SIOCBRADDIF | |
65 | #define SIOCBRADDIF 0x89a2 /* add interface to bridge */ | |
66 | #endif | |
3c6b5bfa RR |
67 | /* We can have up to 256 pages for devices. */ |
68 | #define DEVICE_PAGES 256 | |
0f0c4fab RR |
69 | /* This will occupy 3 pages: it must be a power of 2. */ |
70 | #define VIRTQUEUE_NUM 256 | |
8ca47e00 | 71 | |
dde79789 RR |
72 | /*L:120 verbose is both a global flag and a macro. The C preprocessor allows |
73 | * this, and although I wouldn't recommend it, it works quite nicely here. */ | |
8ca47e00 RR |
74 | static bool verbose; |
75 | #define verbose(args...) \ | |
76 | do { if (verbose) printf(args); } while(0) | |
dde79789 RR |
77 | /*:*/ |
78 | ||
3c6b5bfa RR |
79 | /* The pointer to the start of guest memory. */ |
80 | static void *guest_base; | |
81 | /* The maximum guest physical address allowed, and maximum possible. */ | |
82 | static unsigned long guest_limit, guest_max; | |
56739c80 RR |
83 | /* The /dev/lguest file descriptor. */ |
84 | static int lguest_fd; | |
8ca47e00 | 85 | |
e3283fa0 GOC |
86 | /* a per-cpu variable indicating whose vcpu is currently running */ |
87 | static unsigned int __thread cpu_id; | |
88 | ||
dde79789 | 89 | /* This is our list of devices. */ |
8ca47e00 RR |
90 | struct device_list |
91 | { | |
17cbca2b RR |
92 | /* Counter to assign interrupt numbers. */ |
93 | unsigned int next_irq; | |
94 | ||
95 | /* Counter to print out convenient device numbers. */ | |
96 | unsigned int device_num; | |
97 | ||
dde79789 | 98 | /* The descriptor page for the devices. */ |
17cbca2b RR |
99 | u8 *descpage; |
100 | ||
dde79789 | 101 | /* A single linked list of devices. */ |
8ca47e00 | 102 | struct device *dev; |
a586d4f6 RR |
103 | /* And a pointer to the last device for easy append and also for |
104 | * configuration appending. */ | |
105 | struct device *lastdev; | |
8ca47e00 RR |
106 | }; |
107 | ||
17cbca2b RR |
108 | /* The list of Guest devices, based on command line arguments. */ |
109 | static struct device_list devices; | |
110 | ||
dde79789 | 111 | /* The device structure describes a single device. */ |
8ca47e00 RR |
112 | struct device |
113 | { | |
dde79789 | 114 | /* The linked-list pointer. */ |
8ca47e00 | 115 | struct device *next; |
17cbca2b | 116 | |
713b15b3 | 117 | /* The device's descriptor, as mapped into the Guest. */ |
8ca47e00 | 118 | struct lguest_device_desc *desc; |
17cbca2b | 119 | |
713b15b3 RR |
120 | /* We can't trust desc values once Guest has booted: we use these. */ |
121 | unsigned int feature_len; | |
122 | unsigned int num_vq; | |
123 | ||
17cbca2b RR |
124 | /* The name of this device, for --verbose. */ |
125 | const char *name; | |
8ca47e00 | 126 | |
17cbca2b RR |
127 | /* Any queues attached to this device */ |
128 | struct virtqueue *vq; | |
8ca47e00 | 129 | |
659a0e66 RR |
130 | /* Is it operational */ |
131 | bool running; | |
a007a751 | 132 | |
8ca47e00 RR |
133 | /* Device-specific data. */ |
134 | void *priv; | |
135 | }; | |
136 | ||
17cbca2b RR |
137 | /* The virtqueue structure describes a queue attached to a device. */ |
138 | struct virtqueue | |
139 | { | |
140 | struct virtqueue *next; | |
141 | ||
142 | /* Which device owns me. */ | |
143 | struct device *dev; | |
144 | ||
145 | /* The configuration for this queue. */ | |
146 | struct lguest_vqconfig config; | |
147 | ||
148 | /* The actual ring of buffers. */ | |
149 | struct vring vring; | |
150 | ||
151 | /* Last available index we saw. */ | |
152 | u16 last_avail_idx; | |
153 | ||
95c517c0 RR |
154 | /* How many are used since we sent last irq? */ |
155 | unsigned int pending_used; | |
156 | ||
659a0e66 RR |
157 | /* Eventfd where Guest notifications arrive. */ |
158 | int eventfd; | |
20887611 | 159 | |
659a0e66 RR |
160 | /* Function for the thread which is servicing this virtqueue. */ |
161 | void (*service)(struct virtqueue *vq); | |
162 | pid_t thread; | |
17cbca2b RR |
163 | }; |
164 | ||
ec04b13f BR |
165 | /* Remember the arguments to the program so we can "reboot" */ |
166 | static char **main_args; | |
167 | ||
659a0e66 RR |
168 | /* The original tty settings to restore on exit. */ |
169 | static struct termios orig_term; | |
170 | ||
f7027c63 RR |
171 | /* We have to be careful with barriers: our devices are all run in separate |
172 | * threads and so we need to make sure that changes visible to the Guest happen | |
173 | * in precise order. */ | |
174 | #define wmb() __asm__ __volatile__("" : : : "memory") | |
17cbca2b RR |
175 | |
176 | /* Convert an iovec element to the given type. | |
177 | * | |
178 | * This is a fairly ugly trick: we need to know the size of the type and | |
179 | * alignment requirement to check the pointer is kosher. It's also nice to | |
180 | * have the name of the type in case we report failure. | |
181 | * | |
182 | * Typing those three things all the time is cumbersome and error prone, so we | |
183 | * have a macro which sets them all up and passes to the real function. */ | |
184 | #define convert(iov, type) \ | |
185 | ((type *)_convert((iov), sizeof(type), __alignof__(type), #type)) | |
186 | ||
187 | static void *_convert(struct iovec *iov, size_t size, size_t align, | |
188 | const char *name) | |
189 | { | |
190 | if (iov->iov_len != size) | |
191 | errx(1, "Bad iovec size %zu for %s", iov->iov_len, name); | |
192 | if ((unsigned long)iov->iov_base % align != 0) | |
193 | errx(1, "Bad alignment %p for %s", iov->iov_base, name); | |
194 | return iov->iov_base; | |
195 | } | |
196 | ||
b5111790 RR |
197 | /* Wrapper for the last available index. Makes it easier to change. */ |
198 | #define lg_last_avail(vq) ((vq)->last_avail_idx) | |
199 | ||
17cbca2b RR |
200 | /* The virtio configuration space is defined to be little-endian. x86 is |
201 | * little-endian too, but it's nice to be explicit so we have these helpers. */ | |
202 | #define cpu_to_le16(v16) (v16) | |
203 | #define cpu_to_le32(v32) (v32) | |
204 | #define cpu_to_le64(v64) (v64) | |
205 | #define le16_to_cpu(v16) (v16) | |
206 | #define le32_to_cpu(v32) (v32) | |
a586d4f6 | 207 | #define le64_to_cpu(v64) (v64) |
17cbca2b | 208 | |
28fd6d7f RR |
209 | /* Is this iovec empty? */ |
210 | static bool iov_empty(const struct iovec iov[], unsigned int num_iov) | |
211 | { | |
212 | unsigned int i; | |
213 | ||
214 | for (i = 0; i < num_iov; i++) | |
215 | if (iov[i].iov_len) | |
216 | return false; | |
217 | return true; | |
218 | } | |
219 | ||
220 | /* Take len bytes from the front of this iovec. */ | |
221 | static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len) | |
222 | { | |
223 | unsigned int i; | |
224 | ||
225 | for (i = 0; i < num_iov; i++) { | |
226 | unsigned int used; | |
227 | ||
228 | used = iov[i].iov_len < len ? iov[i].iov_len : len; | |
229 | iov[i].iov_base += used; | |
230 | iov[i].iov_len -= used; | |
231 | len -= used; | |
232 | } | |
233 | assert(len == 0); | |
234 | } | |
235 | ||
6e5aa7ef RR |
236 | /* The device virtqueue descriptors are followed by feature bitmasks. */ |
237 | static u8 *get_feature_bits(struct device *dev) | |
238 | { | |
239 | return (u8 *)(dev->desc + 1) | |
713b15b3 | 240 | + dev->num_vq * sizeof(struct lguest_vqconfig); |
6e5aa7ef RR |
241 | } |
242 | ||
3c6b5bfa RR |
243 | /*L:100 The Launcher code itself takes us out into userspace, that scary place |
244 | * where pointers run wild and free! Unfortunately, like most userspace | |
245 | * programs, it's quite boring (which is why everyone likes to hack on the | |
246 | * kernel!). Perhaps if you make up an Lguest Drinking Game at this point, it | |
247 | * will get you through this section. Or, maybe not. | |
248 | * | |
249 | * The Launcher sets up a big chunk of memory to be the Guest's "physical" | |
250 | * memory and stores it in "guest_base". In other words, Guest physical == | |
251 | * Launcher virtual with an offset. | |
252 | * | |
253 | * This can be tough to get your head around, but usually it just means that we | |
254 | * use these trivial conversion functions when the Guest gives us it's | |
255 | * "physical" addresses: */ | |
256 | static void *from_guest_phys(unsigned long addr) | |
257 | { | |
258 | return guest_base + addr; | |
259 | } | |
260 | ||
261 | static unsigned long to_guest_phys(const void *addr) | |
262 | { | |
263 | return (addr - guest_base); | |
264 | } | |
265 | ||
dde79789 RR |
266 | /*L:130 |
267 | * Loading the Kernel. | |
268 | * | |
269 | * We start with couple of simple helper routines. open_or_die() avoids | |
270 | * error-checking code cluttering the callers: */ | |
8ca47e00 RR |
271 | static int open_or_die(const char *name, int flags) |
272 | { | |
273 | int fd = open(name, flags); | |
274 | if (fd < 0) | |
275 | err(1, "Failed to open %s", name); | |
276 | return fd; | |
277 | } | |
278 | ||
3c6b5bfa RR |
279 | /* map_zeroed_pages() takes a number of pages. */ |
280 | static void *map_zeroed_pages(unsigned int num) | |
8ca47e00 | 281 | { |
3c6b5bfa RR |
282 | int fd = open_or_die("/dev/zero", O_RDONLY); |
283 | void *addr; | |
8ca47e00 | 284 | |
dde79789 | 285 | /* We use a private mapping (ie. if we write to the page, it will be |
3c6b5bfa RR |
286 | * copied). */ |
287 | addr = mmap(NULL, getpagesize() * num, | |
288 | PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, fd, 0); | |
289 | if (addr == MAP_FAILED) | |
290 | err(1, "Mmaping %u pages of /dev/zero", num); | |
34bdaab4 | 291 | close(fd); |
3c6b5bfa RR |
292 | |
293 | return addr; | |
294 | } | |
295 | ||
296 | /* Get some more pages for a device. */ | |
297 | static void *get_pages(unsigned int num) | |
298 | { | |
299 | void *addr = from_guest_phys(guest_limit); | |
300 | ||
301 | guest_limit += num * getpagesize(); | |
302 | if (guest_limit > guest_max) | |
303 | errx(1, "Not enough memory for devices"); | |
304 | return addr; | |
8ca47e00 RR |
305 | } |
306 | ||
6649bb7a RM |
307 | /* This routine is used to load the kernel or initrd. It tries mmap, but if |
308 | * that fails (Plan 9's kernel file isn't nicely aligned on page boundaries), | |
309 | * it falls back to reading the memory in. */ | |
310 | static void map_at(int fd, void *addr, unsigned long offset, unsigned long len) | |
311 | { | |
312 | ssize_t r; | |
313 | ||
314 | /* We map writable even though for some segments are marked read-only. | |
315 | * The kernel really wants to be writable: it patches its own | |
316 | * instructions. | |
317 | * | |
318 | * MAP_PRIVATE means that the page won't be copied until a write is | |
319 | * done to it. This allows us to share untouched memory between | |
320 | * Guests. */ | |
321 | if (mmap(addr, len, PROT_READ|PROT_WRITE|PROT_EXEC, | |
322 | MAP_FIXED|MAP_PRIVATE, fd, offset) != MAP_FAILED) | |
323 | return; | |
324 | ||
325 | /* pread does a seek and a read in one shot: saves a few lines. */ | |
326 | r = pread(fd, addr, len, offset); | |
327 | if (r != len) | |
328 | err(1, "Reading offset %lu len %lu gave %zi", offset, len, r); | |
329 | } | |
330 | ||
dde79789 RR |
331 | /* This routine takes an open vmlinux image, which is in ELF, and maps it into |
332 | * the Guest memory. ELF = Embedded Linking Format, which is the format used | |
333 | * by all modern binaries on Linux including the kernel. | |
334 | * | |
335 | * The ELF headers give *two* addresses: a physical address, and a virtual | |
47436aa4 RR |
336 | * address. We use the physical address; the Guest will map itself to the |
337 | * virtual address. | |
dde79789 RR |
338 | * |
339 | * We return the starting address. */ | |
47436aa4 | 340 | static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr) |
8ca47e00 | 341 | { |
8ca47e00 RR |
342 | Elf32_Phdr phdr[ehdr->e_phnum]; |
343 | unsigned int i; | |
8ca47e00 | 344 | |
dde79789 RR |
345 | /* Sanity checks on the main ELF header: an x86 executable with a |
346 | * reasonable number of correctly-sized program headers. */ | |
8ca47e00 RR |
347 | if (ehdr->e_type != ET_EXEC |
348 | || ehdr->e_machine != EM_386 | |
349 | || ehdr->e_phentsize != sizeof(Elf32_Phdr) | |
350 | || ehdr->e_phnum < 1 || ehdr->e_phnum > 65536U/sizeof(Elf32_Phdr)) | |
351 | errx(1, "Malformed elf header"); | |
352 | ||
dde79789 RR |
353 | /* An ELF executable contains an ELF header and a number of "program" |
354 | * headers which indicate which parts ("segments") of the program to | |
355 | * load where. */ | |
356 | ||
357 | /* We read in all the program headers at once: */ | |
8ca47e00 RR |
358 | if (lseek(elf_fd, ehdr->e_phoff, SEEK_SET) < 0) |
359 | err(1, "Seeking to program headers"); | |
360 | if (read(elf_fd, phdr, sizeof(phdr)) != sizeof(phdr)) | |
361 | err(1, "Reading program headers"); | |
362 | ||
dde79789 | 363 | /* Try all the headers: there are usually only three. A read-only one, |
a6bd8e13 | 364 | * a read-write one, and a "note" section which we don't load. */ |
8ca47e00 | 365 | for (i = 0; i < ehdr->e_phnum; i++) { |
dde79789 | 366 | /* If this isn't a loadable segment, we ignore it */ |
8ca47e00 RR |
367 | if (phdr[i].p_type != PT_LOAD) |
368 | continue; | |
369 | ||
370 | verbose("Section %i: size %i addr %p\n", | |
371 | i, phdr[i].p_memsz, (void *)phdr[i].p_paddr); | |
372 | ||
6649bb7a | 373 | /* We map this section of the file at its physical address. */ |
3c6b5bfa | 374 | map_at(elf_fd, from_guest_phys(phdr[i].p_paddr), |
6649bb7a | 375 | phdr[i].p_offset, phdr[i].p_filesz); |
8ca47e00 RR |
376 | } |
377 | ||
814a0e5c RR |
378 | /* The entry point is given in the ELF header. */ |
379 | return ehdr->e_entry; | |
8ca47e00 RR |
380 | } |
381 | ||
dde79789 | 382 | /*L:150 A bzImage, unlike an ELF file, is not meant to be loaded. You're |
5bbf89fc RR |
383 | * supposed to jump into it and it will unpack itself. We used to have to |
384 | * perform some hairy magic because the unpacking code scared me. | |
dde79789 | 385 | * |
5bbf89fc RR |
386 | * Fortunately, Jeremy Fitzhardinge convinced me it wasn't that hard and wrote |
387 | * a small patch to jump over the tricky bits in the Guest, so now we just read | |
388 | * the funky header so we know where in the file to load, and away we go! */ | |
47436aa4 | 389 | static unsigned long load_bzimage(int fd) |
8ca47e00 | 390 | { |
43d33b21 | 391 | struct boot_params boot; |
5bbf89fc RR |
392 | int r; |
393 | /* Modern bzImages get loaded at 1M. */ | |
394 | void *p = from_guest_phys(0x100000); | |
395 | ||
396 | /* Go back to the start of the file and read the header. It should be | |
71cced6e | 397 | * a Linux boot header (see Documentation/x86/i386/boot.txt) */ |
5bbf89fc | 398 | lseek(fd, 0, SEEK_SET); |
43d33b21 | 399 | read(fd, &boot, sizeof(boot)); |
5bbf89fc | 400 | |
43d33b21 RR |
401 | /* Inside the setup_hdr, we expect the magic "HdrS" */ |
402 | if (memcmp(&boot.hdr.header, "HdrS", 4) != 0) | |
5bbf89fc RR |
403 | errx(1, "This doesn't look like a bzImage to me"); |
404 | ||
43d33b21 RR |
405 | /* Skip over the extra sectors of the header. */ |
406 | lseek(fd, (boot.hdr.setup_sects+1) * 512, SEEK_SET); | |
5bbf89fc RR |
407 | |
408 | /* Now read everything into memory. in nice big chunks. */ | |
409 | while ((r = read(fd, p, 65536)) > 0) | |
410 | p += r; | |
411 | ||
43d33b21 RR |
412 | /* Finally, code32_start tells us where to enter the kernel. */ |
413 | return boot.hdr.code32_start; | |
8ca47e00 RR |
414 | } |
415 | ||
dde79789 | 416 | /*L:140 Loading the kernel is easy when it's a "vmlinux", but most kernels |
e1e72965 RR |
417 | * come wrapped up in the self-decompressing "bzImage" format. With a little |
418 | * work, we can load those, too. */ | |
47436aa4 | 419 | static unsigned long load_kernel(int fd) |
8ca47e00 RR |
420 | { |
421 | Elf32_Ehdr hdr; | |
422 | ||
dde79789 | 423 | /* Read in the first few bytes. */ |
8ca47e00 RR |
424 | if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) |
425 | err(1, "Reading kernel"); | |
426 | ||
dde79789 | 427 | /* If it's an ELF file, it starts with "\177ELF" */ |
8ca47e00 | 428 | if (memcmp(hdr.e_ident, ELFMAG, SELFMAG) == 0) |
47436aa4 | 429 | return map_elf(fd, &hdr); |
8ca47e00 | 430 | |
a6bd8e13 | 431 | /* Otherwise we assume it's a bzImage, and try to load it. */ |
47436aa4 | 432 | return load_bzimage(fd); |
8ca47e00 RR |
433 | } |
434 | ||
dde79789 RR |
435 | /* This is a trivial little helper to align pages. Andi Kleen hated it because |
436 | * it calls getpagesize() twice: "it's dumb code." | |
437 | * | |
438 | * Kernel guys get really het up about optimization, even when it's not | |
439 | * necessary. I leave this code as a reaction against that. */ | |
8ca47e00 RR |
440 | static inline unsigned long page_align(unsigned long addr) |
441 | { | |
dde79789 | 442 | /* Add upwards and truncate downwards. */ |
8ca47e00 RR |
443 | return ((addr + getpagesize()-1) & ~(getpagesize()-1)); |
444 | } | |
445 | ||
dde79789 RR |
446 | /*L:180 An "initial ram disk" is a disk image loaded into memory along with |
447 | * the kernel which the kernel can use to boot from without needing any | |
448 | * drivers. Most distributions now use this as standard: the initrd contains | |
449 | * the code to load the appropriate driver modules for the current machine. | |
450 | * | |
451 | * Importantly, James Morris works for RedHat, and Fedora uses initrds for its | |
452 | * kernels. He sent me this (and tells me when I break it). */ | |
8ca47e00 RR |
453 | static unsigned long load_initrd(const char *name, unsigned long mem) |
454 | { | |
455 | int ifd; | |
456 | struct stat st; | |
457 | unsigned long len; | |
8ca47e00 RR |
458 | |
459 | ifd = open_or_die(name, O_RDONLY); | |
dde79789 | 460 | /* fstat() is needed to get the file size. */ |
8ca47e00 RR |
461 | if (fstat(ifd, &st) < 0) |
462 | err(1, "fstat() on initrd '%s'", name); | |
463 | ||
6649bb7a RM |
464 | /* We map the initrd at the top of memory, but mmap wants it to be |
465 | * page-aligned, so we round the size up for that. */ | |
8ca47e00 | 466 | len = page_align(st.st_size); |
3c6b5bfa | 467 | map_at(ifd, from_guest_phys(mem - len), 0, st.st_size); |
dde79789 RR |
468 | /* Once a file is mapped, you can close the file descriptor. It's a |
469 | * little odd, but quite useful. */ | |
8ca47e00 | 470 | close(ifd); |
6649bb7a | 471 | verbose("mapped initrd %s size=%lu @ %p\n", name, len, (void*)mem-len); |
dde79789 RR |
472 | |
473 | /* We return the initrd size. */ | |
8ca47e00 RR |
474 | return len; |
475 | } | |
e1e72965 | 476 | /*:*/ |
8ca47e00 | 477 | |
dde79789 RR |
478 | /* Simple routine to roll all the commandline arguments together with spaces |
479 | * between them. */ | |
8ca47e00 RR |
480 | static void concat(char *dst, char *args[]) |
481 | { | |
482 | unsigned int i, len = 0; | |
483 | ||
484 | for (i = 0; args[i]; i++) { | |
1ef36fa6 PB |
485 | if (i) { |
486 | strcat(dst+len, " "); | |
487 | len++; | |
488 | } | |
8ca47e00 | 489 | strcpy(dst+len, args[i]); |
1ef36fa6 | 490 | len += strlen(args[i]); |
8ca47e00 RR |
491 | } |
492 | /* In case it's empty. */ | |
493 | dst[len] = '\0'; | |
494 | } | |
495 | ||
e1e72965 RR |
496 | /*L:185 This is where we actually tell the kernel to initialize the Guest. We |
497 | * saw the arguments it expects when we looked at initialize() in lguest_user.c: | |
58a24566 MZ |
498 | * the base of Guest "physical" memory, the top physical page to allow and the |
499 | * entry point for the Guest. */ | |
56739c80 | 500 | static void tell_kernel(unsigned long start) |
8ca47e00 | 501 | { |
511801dc JS |
502 | unsigned long args[] = { LHREQ_INITIALIZE, |
503 | (unsigned long)guest_base, | |
58a24566 | 504 | guest_limit / getpagesize(), start }; |
3c6b5bfa RR |
505 | verbose("Guest: %p - %p (%#lx)\n", |
506 | guest_base, guest_base + guest_limit, guest_limit); | |
56739c80 RR |
507 | lguest_fd = open_or_die("/dev/lguest", O_RDWR); |
508 | if (write(lguest_fd, args, sizeof(args)) < 0) | |
8ca47e00 | 509 | err(1, "Writing to /dev/lguest"); |
8ca47e00 | 510 | } |
dde79789 | 511 | /*:*/ |
8ca47e00 | 512 | |
e1e72965 | 513 | /* |
dde79789 RR |
514 | * Device Handling. |
515 | * | |
e1e72965 | 516 | * When the Guest gives us a buffer, it sends an array of addresses and sizes. |
dde79789 | 517 | * We need to make sure it's not trying to reach into the Launcher itself, so |
e1e72965 | 518 | * we have a convenient routine which checks it and exits with an error message |
dde79789 RR |
519 | * if something funny is going on: |
520 | */ | |
8ca47e00 RR |
521 | static void *_check_pointer(unsigned long addr, unsigned int size, |
522 | unsigned int line) | |
523 | { | |
dde79789 RR |
524 | /* We have to separately check addr and addr+size, because size could |
525 | * be huge and addr + size might wrap around. */ | |
3c6b5bfa | 526 | if (addr >= guest_limit || addr + size >= guest_limit) |
17cbca2b | 527 | errx(1, "%s:%i: Invalid address %#lx", __FILE__, line, addr); |
dde79789 RR |
528 | /* We return a pointer for the caller's convenience, now we know it's |
529 | * safe to use. */ | |
3c6b5bfa | 530 | return from_guest_phys(addr); |
8ca47e00 | 531 | } |
dde79789 | 532 | /* A macro which transparently hands the line number to the real function. */ |
8ca47e00 RR |
533 | #define check_pointer(addr,size) _check_pointer(addr, size, __LINE__) |
534 | ||
e1e72965 RR |
535 | /* Each buffer in the virtqueues is actually a chain of descriptors. This |
536 | * function returns the next descriptor in the chain, or vq->vring.num if we're | |
537 | * at the end. */ | |
17cbca2b RR |
538 | static unsigned next_desc(struct virtqueue *vq, unsigned int i) |
539 | { | |
540 | unsigned int next; | |
541 | ||
542 | /* If this descriptor says it doesn't chain, we're done. */ | |
543 | if (!(vq->vring.desc[i].flags & VRING_DESC_F_NEXT)) | |
544 | return vq->vring.num; | |
545 | ||
546 | /* Check they're not leading us off end of descriptors. */ | |
547 | next = vq->vring.desc[i].next; | |
548 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
549 | wmb(); | |
550 | ||
551 | if (next >= vq->vring.num) | |
552 | errx(1, "Desc next is %u", next); | |
553 | ||
554 | return next; | |
555 | } | |
556 | ||
38bc2b8c RR |
557 | /* This actually sends the interrupt for this virtqueue */ |
558 | static void trigger_irq(struct virtqueue *vq) | |
559 | { | |
560 | unsigned long buf[] = { LHREQ_IRQ, vq->config.irq }; | |
561 | ||
95c517c0 RR |
562 | /* Don't inform them if nothing used. */ |
563 | if (!vq->pending_used) | |
564 | return; | |
565 | vq->pending_used = 0; | |
566 | ||
38bc2b8c RR |
567 | /* If they don't want an interrupt, don't send one, unless empty. */ |
568 | if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) | |
569 | && lg_last_avail(vq) != vq->vring.avail->idx) | |
570 | return; | |
571 | ||
572 | /* Send the Guest an interrupt tell them we used something up. */ | |
573 | if (write(lguest_fd, buf, sizeof(buf)) != 0) | |
574 | err(1, "Triggering irq %i", vq->config.irq); | |
575 | } | |
576 | ||
17cbca2b RR |
577 | /* This looks in the virtqueue and for the first available buffer, and converts |
578 | * it to an iovec for convenient access. Since descriptors consist of some | |
579 | * number of output then some number of input descriptors, it's actually two | |
580 | * iovecs, but we pack them into one and note how many of each there were. | |
581 | * | |
659a0e66 RR |
582 | * This function returns the descriptor number found. */ |
583 | static unsigned wait_for_vq_desc(struct virtqueue *vq, | |
584 | struct iovec iov[], | |
585 | unsigned int *out_num, unsigned int *in_num) | |
17cbca2b RR |
586 | { |
587 | unsigned int i, head; | |
659a0e66 RR |
588 | u16 last_avail = lg_last_avail(vq); |
589 | ||
590 | while (last_avail == vq->vring.avail->idx) { | |
591 | u64 event; | |
592 | ||
38bc2b8c RR |
593 | /* OK, tell Guest about progress up to now. */ |
594 | trigger_irq(vq); | |
595 | ||
659a0e66 RR |
596 | /* Nothing new? Wait for eventfd to tell us they refilled. */ |
597 | if (read(vq->eventfd, &event, sizeof(event)) != sizeof(event)) | |
598 | errx(1, "Event read failed?"); | |
599 | } | |
17cbca2b RR |
600 | |
601 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
b5111790 | 602 | if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num) |
17cbca2b | 603 | errx(1, "Guest moved used index from %u to %u", |
b5111790 | 604 | last_avail, vq->vring.avail->idx); |
17cbca2b | 605 | |
17cbca2b RR |
606 | /* Grab the next descriptor number they're advertising, and increment |
607 | * the index we've seen. */ | |
b5111790 RR |
608 | head = vq->vring.avail->ring[last_avail % vq->vring.num]; |
609 | lg_last_avail(vq)++; | |
17cbca2b RR |
610 | |
611 | /* If their number is silly, that's a fatal mistake. */ | |
612 | if (head >= vq->vring.num) | |
613 | errx(1, "Guest says index %u is available", head); | |
614 | ||
615 | /* When we start there are none of either input nor output. */ | |
616 | *out_num = *in_num = 0; | |
617 | ||
618 | i = head; | |
619 | do { | |
620 | /* Grab the first descriptor, and check it's OK. */ | |
621 | iov[*out_num + *in_num].iov_len = vq->vring.desc[i].len; | |
622 | iov[*out_num + *in_num].iov_base | |
623 | = check_pointer(vq->vring.desc[i].addr, | |
624 | vq->vring.desc[i].len); | |
625 | /* If this is an input descriptor, increment that count. */ | |
626 | if (vq->vring.desc[i].flags & VRING_DESC_F_WRITE) | |
627 | (*in_num)++; | |
628 | else { | |
629 | /* If it's an output descriptor, they're all supposed | |
630 | * to come before any input descriptors. */ | |
631 | if (*in_num) | |
632 | errx(1, "Descriptor has out after in"); | |
633 | (*out_num)++; | |
634 | } | |
635 | ||
636 | /* If we've got too many, that implies a descriptor loop. */ | |
637 | if (*out_num + *in_num > vq->vring.num) | |
638 | errx(1, "Looped descriptor"); | |
639 | } while ((i = next_desc(vq, i)) != vq->vring.num); | |
dde79789 | 640 | |
17cbca2b | 641 | return head; |
8ca47e00 RR |
642 | } |
643 | ||
e1e72965 | 644 | /* After we've used one of their buffers, we tell them about it. We'll then |
17cbca2b RR |
645 | * want to send them an interrupt, using trigger_irq(). */ |
646 | static void add_used(struct virtqueue *vq, unsigned int head, int len) | |
8ca47e00 | 647 | { |
17cbca2b RR |
648 | struct vring_used_elem *used; |
649 | ||
e1e72965 RR |
650 | /* The virtqueue contains a ring of used buffers. Get a pointer to the |
651 | * next entry in that used ring. */ | |
17cbca2b RR |
652 | used = &vq->vring.used->ring[vq->vring.used->idx % vq->vring.num]; |
653 | used->id = head; | |
654 | used->len = len; | |
655 | /* Make sure buffer is written before we update index. */ | |
656 | wmb(); | |
657 | vq->vring.used->idx++; | |
95c517c0 | 658 | vq->pending_used++; |
8ca47e00 RR |
659 | } |
660 | ||
17cbca2b | 661 | /* And here's the combo meal deal. Supersize me! */ |
56739c80 | 662 | static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len) |
8ca47e00 | 663 | { |
17cbca2b | 664 | add_used(vq, head, len); |
56739c80 | 665 | trigger_irq(vq); |
8ca47e00 RR |
666 | } |
667 | ||
e1e72965 RR |
668 | /* |
669 | * The Console | |
670 | * | |
659a0e66 | 671 | * We associate some data with the console for our exit hack. */ |
8ca47e00 RR |
672 | struct console_abort |
673 | { | |
dde79789 | 674 | /* How many times have they hit ^C? */ |
8ca47e00 | 675 | int count; |
dde79789 | 676 | /* When did they start? */ |
8ca47e00 RR |
677 | struct timeval start; |
678 | }; | |
679 | ||
dde79789 | 680 | /* This is the routine which handles console input (ie. stdin). */ |
659a0e66 | 681 | static void console_input(struct virtqueue *vq) |
8ca47e00 | 682 | { |
8ca47e00 | 683 | int len; |
17cbca2b | 684 | unsigned int head, in_num, out_num; |
659a0e66 RR |
685 | struct console_abort *abort = vq->dev->priv; |
686 | struct iovec iov[vq->vring.num]; | |
56ae43df | 687 | |
659a0e66 RR |
688 | /* Make sure there's a descriptor waiting. */ |
689 | head = wait_for_vq_desc(vq, iov, &out_num, &in_num); | |
56ae43df | 690 | if (out_num) |
17cbca2b | 691 | errx(1, "Output buffers in console in queue?"); |
8ca47e00 | 692 | |
659a0e66 RR |
693 | /* Read it in. */ |
694 | len = readv(STDIN_FILENO, iov, in_num); | |
8ca47e00 | 695 | if (len <= 0) { |
659a0e66 | 696 | /* Ran out of input? */ |
8ca47e00 | 697 | warnx("Failed to get console input, ignoring console."); |
659a0e66 RR |
698 | /* For simplicity, dying threads kill the whole Launcher. So |
699 | * just nap here. */ | |
700 | for (;;) | |
701 | pause(); | |
8ca47e00 RR |
702 | } |
703 | ||
659a0e66 | 704 | add_used_and_trigger(vq, head, len); |
8ca47e00 | 705 | |
dde79789 RR |
706 | /* Three ^C within one second? Exit. |
707 | * | |
659a0e66 RR |
708 | * This is such a hack, but works surprisingly well. Each ^C has to |
709 | * be in a buffer by itself, so they can't be too fast. But we check | |
710 | * that we get three within about a second, so they can't be too | |
711 | * slow. */ | |
712 | if (len != 1 || ((char *)iov[0].iov_base)[0] != 3) { | |
8ca47e00 | 713 | abort->count = 0; |
659a0e66 RR |
714 | return; |
715 | } | |
8ca47e00 | 716 | |
659a0e66 RR |
717 | abort->count++; |
718 | if (abort->count == 1) | |
719 | gettimeofday(&abort->start, NULL); | |
720 | else if (abort->count == 3) { | |
721 | struct timeval now; | |
722 | gettimeofday(&now, NULL); | |
723 | /* Kill all Launcher processes with SIGINT, like normal ^C */ | |
724 | if (now.tv_sec <= abort->start.tv_sec+1) | |
725 | kill(0, SIGINT); | |
726 | abort->count = 0; | |
727 | } | |
8ca47e00 RR |
728 | } |
729 | ||
659a0e66 RR |
730 | /* This is the routine which handles console output (ie. stdout). */ |
731 | static void console_output(struct virtqueue *vq) | |
8ca47e00 | 732 | { |
17cbca2b | 733 | unsigned int head, out, in; |
17cbca2b RR |
734 | struct iovec iov[vq->vring.num]; |
735 | ||
659a0e66 RR |
736 | head = wait_for_vq_desc(vq, iov, &out, &in); |
737 | if (in) | |
738 | errx(1, "Input buffers in console output queue?"); | |
739 | while (!iov_empty(iov, out)) { | |
740 | int len = writev(STDOUT_FILENO, iov, out); | |
741 | if (len <= 0) | |
742 | err(1, "Write to stdout gave %i", len); | |
743 | iov_consume(iov, out, len); | |
17cbca2b | 744 | } |
38bc2b8c | 745 | add_used(vq, head, 0); |
a161883a RR |
746 | } |
747 | ||
e1e72965 RR |
748 | /* |
749 | * The Network | |
750 | * | |
751 | * Handling output for network is also simple: we get all the output buffers | |
659a0e66 | 752 | * and write them to /dev/net/tun. |
a6bd8e13 | 753 | */ |
659a0e66 RR |
754 | struct net_info { |
755 | int tunfd; | |
756 | }; | |
757 | ||
758 | static void net_output(struct virtqueue *vq) | |
8ca47e00 | 759 | { |
659a0e66 RR |
760 | struct net_info *net_info = vq->dev->priv; |
761 | unsigned int head, out, in; | |
17cbca2b | 762 | struct iovec iov[vq->vring.num]; |
a161883a | 763 | |
659a0e66 RR |
764 | head = wait_for_vq_desc(vq, iov, &out, &in); |
765 | if (in) | |
766 | errx(1, "Input buffers in net output queue?"); | |
767 | if (writev(net_info->tunfd, iov, out) < 0) | |
768 | errx(1, "Write to tun failed?"); | |
38bc2b8c | 769 | add_used(vq, head, 0); |
8ca47e00 RR |
770 | } |
771 | ||
4a8962e2 RR |
772 | /* Will reading from this file descriptor block? */ |
773 | static bool will_block(int fd) | |
774 | { | |
775 | fd_set fdset; | |
776 | struct timeval zero = { 0, 0 }; | |
777 | FD_ZERO(&fdset); | |
778 | FD_SET(fd, &fdset); | |
779 | return select(fd+1, &fdset, NULL, NULL, &zero) != 1; | |
780 | } | |
781 | ||
659a0e66 | 782 | /* This is where we handle packets coming in from the tun device to our |
17cbca2b | 783 | * Guest. */ |
659a0e66 | 784 | static void net_input(struct virtqueue *vq) |
8ca47e00 | 785 | { |
8ca47e00 | 786 | int len; |
659a0e66 RR |
787 | unsigned int head, out, in; |
788 | struct iovec iov[vq->vring.num]; | |
789 | struct net_info *net_info = vq->dev->priv; | |
790 | ||
791 | head = wait_for_vq_desc(vq, iov, &out, &in); | |
792 | if (out) | |
793 | errx(1, "Output buffers in net input queue?"); | |
4a8962e2 RR |
794 | |
795 | /* Deliver interrupt now, since we're about to sleep. */ | |
796 | if (vq->pending_used && will_block(net_info->tunfd)) | |
797 | trigger_irq(vq); | |
798 | ||
659a0e66 | 799 | len = readv(net_info->tunfd, iov, in); |
8ca47e00 | 800 | if (len <= 0) |
659a0e66 | 801 | err(1, "Failed to read from tun."); |
4a8962e2 | 802 | add_used(vq, head, len); |
659a0e66 | 803 | } |
dde79789 | 804 | |
659a0e66 RR |
805 | /* This is the helper to create threads. */ |
806 | static int do_thread(void *_vq) | |
807 | { | |
808 | struct virtqueue *vq = _vq; | |
17cbca2b | 809 | |
659a0e66 RR |
810 | for (;;) |
811 | vq->service(vq); | |
812 | return 0; | |
813 | } | |
17cbca2b | 814 | |
659a0e66 RR |
815 | /* When a child dies, we kill our entire process group with SIGTERM. This |
816 | * also has the side effect that the shell restores the console for us! */ | |
817 | static void kill_launcher(int signal) | |
818 | { | |
819 | kill(0, SIGTERM); | |
8ca47e00 RR |
820 | } |
821 | ||
659a0e66 | 822 | static void reset_device(struct device *dev) |
56ae43df | 823 | { |
659a0e66 RR |
824 | struct virtqueue *vq; |
825 | ||
826 | verbose("Resetting device %s\n", dev->name); | |
827 | ||
828 | /* Clear any features they've acked. */ | |
829 | memset(get_feature_bits(dev) + dev->feature_len, 0, dev->feature_len); | |
830 | ||
831 | /* We're going to be explicitly killing threads, so ignore them. */ | |
832 | signal(SIGCHLD, SIG_IGN); | |
833 | ||
834 | /* Zero out the virtqueues, get rid of their threads */ | |
835 | for (vq = dev->vq; vq; vq = vq->next) { | |
836 | if (vq->thread != (pid_t)-1) { | |
837 | kill(vq->thread, SIGTERM); | |
838 | waitpid(vq->thread, NULL, 0); | |
839 | vq->thread = (pid_t)-1; | |
840 | } | |
841 | memset(vq->vring.desc, 0, | |
842 | vring_size(vq->config.num, LGUEST_VRING_ALIGN)); | |
843 | lg_last_avail(vq) = 0; | |
844 | } | |
845 | dev->running = false; | |
846 | ||
847 | /* Now we care if threads die. */ | |
848 | signal(SIGCHLD, (void *)kill_launcher); | |
56ae43df RR |
849 | } |
850 | ||
659a0e66 | 851 | static void create_thread(struct virtqueue *vq) |
5dae785a | 852 | { |
659a0e66 RR |
853 | /* Create stack for thread and run it. Since stack grows |
854 | * upwards, we point the stack pointer to the end of this | |
855 | * region. */ | |
856 | char *stack = malloc(32768); | |
857 | unsigned long args[] = { LHREQ_EVENTFD, | |
858 | vq->config.pfn*getpagesize(), 0 }; | |
859 | ||
860 | /* Create a zero-initialized eventfd. */ | |
861 | vq->eventfd = eventfd(0, 0); | |
862 | if (vq->eventfd < 0) | |
863 | err(1, "Creating eventfd"); | |
864 | args[2] = vq->eventfd; | |
865 | ||
866 | /* Attach an eventfd to this virtqueue: it will go off | |
867 | * when the Guest does an LHCALL_NOTIFY for this vq. */ | |
868 | if (write(lguest_fd, &args, sizeof(args)) != 0) | |
869 | err(1, "Attaching eventfd"); | |
870 | ||
871 | /* CLONE_VM: because it has to access the Guest memory, and | |
872 | * SIGCHLD so we get a signal if it dies. */ | |
873 | vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq); | |
874 | if (vq->thread == (pid_t)-1) | |
875 | err(1, "Creating clone"); | |
876 | /* We close our local copy, now the child has it. */ | |
877 | close(vq->eventfd); | |
5dae785a RR |
878 | } |
879 | ||
659a0e66 | 880 | static void start_device(struct device *dev) |
6e5aa7ef | 881 | { |
659a0e66 | 882 | unsigned int i; |
6e5aa7ef RR |
883 | struct virtqueue *vq; |
884 | ||
659a0e66 RR |
885 | verbose("Device %s OK: offered", dev->name); |
886 | for (i = 0; i < dev->feature_len; i++) | |
887 | verbose(" %02x", get_feature_bits(dev)[i]); | |
888 | verbose(", accepted"); | |
889 | for (i = 0; i < dev->feature_len; i++) | |
890 | verbose(" %02x", get_feature_bits(dev) | |
891 | [dev->feature_len+i]); | |
892 | ||
893 | for (vq = dev->vq; vq; vq = vq->next) { | |
894 | if (vq->service) | |
895 | create_thread(vq); | |
896 | } | |
897 | dev->running = true; | |
898 | } | |
899 | ||
900 | static void cleanup_devices(void) | |
901 | { | |
902 | struct device *dev; | |
903 | ||
904 | for (dev = devices.dev; dev; dev = dev->next) | |
905 | reset_device(dev); | |
6e5aa7ef | 906 | |
659a0e66 RR |
907 | /* If we saved off the original terminal settings, restore them now. */ |
908 | if (orig_term.c_lflag & (ISIG|ICANON|ECHO)) | |
909 | tcsetattr(STDIN_FILENO, TCSANOW, &orig_term); | |
910 | } | |
6e5aa7ef | 911 | |
659a0e66 RR |
912 | /* When the Guest tells us they updated the status field, we handle it. */ |
913 | static void update_device_status(struct device *dev) | |
914 | { | |
915 | /* A zero status is a reset, otherwise it's a set of flags. */ | |
916 | if (dev->desc->status == 0) | |
917 | reset_device(dev); | |
918 | else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) { | |
a007a751 | 919 | warnx("Device %s configuration FAILED", dev->name); |
659a0e66 RR |
920 | if (dev->running) |
921 | reset_device(dev); | |
a007a751 | 922 | } else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) { |
659a0e66 RR |
923 | if (!dev->running) |
924 | start_device(dev); | |
6e5aa7ef RR |
925 | } |
926 | } | |
927 | ||
17cbca2b | 928 | /* This is the generic routine we call when the Guest uses LHCALL_NOTIFY. */ |
56739c80 | 929 | static void handle_output(unsigned long addr) |
8ca47e00 RR |
930 | { |
931 | struct device *i; | |
17cbca2b | 932 | |
659a0e66 | 933 | /* Check each device. */ |
17cbca2b | 934 | for (i = devices.dev; i; i = i->next) { |
659a0e66 RR |
935 | struct virtqueue *vq; |
936 | ||
a007a751 | 937 | /* Notifications to device descriptors update device status. */ |
6e5aa7ef | 938 | if (from_guest_phys(addr) == i->desc) { |
a007a751 | 939 | update_device_status(i); |
6e5aa7ef RR |
940 | return; |
941 | } | |
942 | ||
659a0e66 | 943 | /* Devices *can* be used before status is set to DRIVER_OK. */ |
17cbca2b | 944 | for (vq = i->vq; vq; vq = vq->next) { |
659a0e66 | 945 | if (addr != vq->config.pfn*getpagesize()) |
6e5aa7ef | 946 | continue; |
659a0e66 RR |
947 | if (i->running) |
948 | errx(1, "Notification on running %s", i->name); | |
949 | start_device(i); | |
6e5aa7ef | 950 | return; |
8ca47e00 RR |
951 | } |
952 | } | |
dde79789 | 953 | |
17cbca2b RR |
954 | /* Early console write is done using notify on a nul-terminated string |
955 | * in Guest memory. */ | |
956 | if (addr >= guest_limit) | |
957 | errx(1, "Bad NOTIFY %#lx", addr); | |
958 | ||
959 | write(STDOUT_FILENO, from_guest_phys(addr), | |
960 | strnlen(from_guest_phys(addr), guest_limit - addr)); | |
8ca47e00 RR |
961 | } |
962 | ||
dde79789 RR |
963 | /*L:190 |
964 | * Device Setup | |
965 | * | |
966 | * All devices need a descriptor so the Guest knows it exists, and a "struct | |
967 | * device" so the Launcher can keep track of it. We have common helper | |
a6bd8e13 RR |
968 | * routines to allocate and manage them. |
969 | */ | |
8ca47e00 | 970 | |
a586d4f6 RR |
971 | /* The layout of the device page is a "struct lguest_device_desc" followed by a |
972 | * number of virtqueue descriptors, then two sets of feature bits, then an | |
973 | * array of configuration bytes. This routine returns the configuration | |
974 | * pointer. */ | |
975 | static u8 *device_config(const struct device *dev) | |
976 | { | |
977 | return (void *)(dev->desc + 1) | |
713b15b3 RR |
978 | + dev->num_vq * sizeof(struct lguest_vqconfig) |
979 | + dev->feature_len * 2; | |
17cbca2b RR |
980 | } |
981 | ||
a586d4f6 RR |
982 | /* This routine allocates a new "struct lguest_device_desc" from descriptor |
983 | * table page just above the Guest's normal memory. It returns a pointer to | |
984 | * that descriptor. */ | |
985 | static struct lguest_device_desc *new_dev_desc(u16 type) | |
17cbca2b | 986 | { |
a586d4f6 RR |
987 | struct lguest_device_desc d = { .type = type }; |
988 | void *p; | |
17cbca2b | 989 | |
a586d4f6 RR |
990 | /* Figure out where the next device config is, based on the last one. */ |
991 | if (devices.lastdev) | |
992 | p = device_config(devices.lastdev) | |
993 | + devices.lastdev->desc->config_len; | |
994 | else | |
995 | p = devices.descpage; | |
17cbca2b | 996 | |
a586d4f6 RR |
997 | /* We only have one page for all the descriptors. */ |
998 | if (p + sizeof(d) > (void *)devices.descpage + getpagesize()) | |
999 | errx(1, "Too many devices"); | |
17cbca2b | 1000 | |
a586d4f6 RR |
1001 | /* p might not be aligned, so we memcpy in. */ |
1002 | return memcpy(p, &d, sizeof(d)); | |
17cbca2b RR |
1003 | } |
1004 | ||
a586d4f6 RR |
1005 | /* Each device descriptor is followed by the description of its virtqueues. We |
1006 | * specify how many descriptors the virtqueue is to have. */ | |
17cbca2b | 1007 | static void add_virtqueue(struct device *dev, unsigned int num_descs, |
659a0e66 | 1008 | void (*service)(struct virtqueue *)) |
17cbca2b RR |
1009 | { |
1010 | unsigned int pages; | |
1011 | struct virtqueue **i, *vq = malloc(sizeof(*vq)); | |
1012 | void *p; | |
1013 | ||
a6bd8e13 | 1014 | /* First we need some memory for this virtqueue. */ |
2966af73 | 1015 | pages = (vring_size(num_descs, LGUEST_VRING_ALIGN) + getpagesize() - 1) |
42b36cc0 | 1016 | / getpagesize(); |
17cbca2b RR |
1017 | p = get_pages(pages); |
1018 | ||
d1c856e0 RR |
1019 | /* Initialize the virtqueue */ |
1020 | vq->next = NULL; | |
1021 | vq->last_avail_idx = 0; | |
1022 | vq->dev = dev; | |
659a0e66 RR |
1023 | vq->service = service; |
1024 | vq->thread = (pid_t)-1; | |
d1c856e0 | 1025 | |
17cbca2b RR |
1026 | /* Initialize the configuration. */ |
1027 | vq->config.num = num_descs; | |
1028 | vq->config.irq = devices.next_irq++; | |
1029 | vq->config.pfn = to_guest_phys(p) / getpagesize(); | |
1030 | ||
1031 | /* Initialize the vring. */ | |
2966af73 | 1032 | vring_init(&vq->vring, num_descs, p, LGUEST_VRING_ALIGN); |
17cbca2b | 1033 | |
a586d4f6 RR |
1034 | /* Append virtqueue to this device's descriptor. We use |
1035 | * device_config() to get the end of the device's current virtqueues; | |
1036 | * we check that we haven't added any config or feature information | |
1037 | * yet, otherwise we'd be overwriting them. */ | |
1038 | assert(dev->desc->config_len == 0 && dev->desc->feature_len == 0); | |
1039 | memcpy(device_config(dev), &vq->config, sizeof(vq->config)); | |
713b15b3 | 1040 | dev->num_vq++; |
a586d4f6 RR |
1041 | dev->desc->num_vq++; |
1042 | ||
1043 | verbose("Virtqueue page %#lx\n", to_guest_phys(p)); | |
17cbca2b RR |
1044 | |
1045 | /* Add to tail of list, so dev->vq is first vq, dev->vq->next is | |
1046 | * second. */ | |
1047 | for (i = &dev->vq; *i; i = &(*i)->next); | |
1048 | *i = vq; | |
8ca47e00 RR |
1049 | } |
1050 | ||
6e5aa7ef | 1051 | /* The first half of the feature bitmask is for us to advertise features. The |
a6bd8e13 | 1052 | * second half is for the Guest to accept features. */ |
a586d4f6 RR |
1053 | static void add_feature(struct device *dev, unsigned bit) |
1054 | { | |
6e5aa7ef | 1055 | u8 *features = get_feature_bits(dev); |
a586d4f6 RR |
1056 | |
1057 | /* We can't extend the feature bits once we've added config bytes */ | |
1058 | if (dev->desc->feature_len <= bit / CHAR_BIT) { | |
1059 | assert(dev->desc->config_len == 0); | |
713b15b3 | 1060 | dev->feature_len = dev->desc->feature_len = (bit/CHAR_BIT) + 1; |
a586d4f6 RR |
1061 | } |
1062 | ||
a586d4f6 RR |
1063 | features[bit / CHAR_BIT] |= (1 << (bit % CHAR_BIT)); |
1064 | } | |
1065 | ||
1066 | /* This routine sets the configuration fields for an existing device's | |
1067 | * descriptor. It only works for the last device, but that's OK because that's | |
1068 | * how we use it. */ | |
1069 | static void set_config(struct device *dev, unsigned len, const void *conf) | |
1070 | { | |
1071 | /* Check we haven't overflowed our single page. */ | |
1072 | if (device_config(dev) + len > devices.descpage + getpagesize()) | |
1073 | errx(1, "Too many devices"); | |
1074 | ||
1075 | /* Copy in the config information, and store the length. */ | |
1076 | memcpy(device_config(dev), conf, len); | |
1077 | dev->desc->config_len = len; | |
1078 | } | |
1079 | ||
17cbca2b | 1080 | /* This routine does all the creation and setup of a new device, including |
a6bd8e13 RR |
1081 | * calling new_dev_desc() to allocate the descriptor and device memory. |
1082 | * | |
1083 | * See what I mean about userspace being boring? */ | |
659a0e66 | 1084 | static struct device *new_device(const char *name, u16 type) |
8ca47e00 RR |
1085 | { |
1086 | struct device *dev = malloc(sizeof(*dev)); | |
1087 | ||
dde79789 | 1088 | /* Now we populate the fields one at a time. */ |
17cbca2b | 1089 | dev->desc = new_dev_desc(type); |
17cbca2b | 1090 | dev->name = name; |
d1c856e0 | 1091 | dev->vq = NULL; |
713b15b3 RR |
1092 | dev->feature_len = 0; |
1093 | dev->num_vq = 0; | |
659a0e66 | 1094 | dev->running = false; |
a586d4f6 RR |
1095 | |
1096 | /* Append to device list. Prepending to a single-linked list is | |
1097 | * easier, but the user expects the devices to be arranged on the bus | |
1098 | * in command-line order. The first network device on the command line | |
1099 | * is eth0, the first block device /dev/vda, etc. */ | |
1100 | if (devices.lastdev) | |
1101 | devices.lastdev->next = dev; | |
1102 | else | |
1103 | devices.dev = dev; | |
1104 | devices.lastdev = dev; | |
1105 | ||
8ca47e00 RR |
1106 | return dev; |
1107 | } | |
1108 | ||
dde79789 RR |
1109 | /* Our first setup routine is the console. It's a fairly simple device, but |
1110 | * UNIX tty handling makes it uglier than it could be. */ | |
17cbca2b | 1111 | static void setup_console(void) |
8ca47e00 RR |
1112 | { |
1113 | struct device *dev; | |
1114 | ||
dde79789 | 1115 | /* If we can save the initial standard input settings... */ |
8ca47e00 RR |
1116 | if (tcgetattr(STDIN_FILENO, &orig_term) == 0) { |
1117 | struct termios term = orig_term; | |
dde79789 RR |
1118 | /* Then we turn off echo, line buffering and ^C etc. We want a |
1119 | * raw input stream to the Guest. */ | |
8ca47e00 RR |
1120 | term.c_lflag &= ~(ISIG|ICANON|ECHO); |
1121 | tcsetattr(STDIN_FILENO, TCSANOW, &term); | |
8ca47e00 RR |
1122 | } |
1123 | ||
659a0e66 RR |
1124 | dev = new_device("console", VIRTIO_ID_CONSOLE); |
1125 | ||
dde79789 | 1126 | /* We store the console state in dev->priv, and initialize it. */ |
8ca47e00 RR |
1127 | dev->priv = malloc(sizeof(struct console_abort)); |
1128 | ((struct console_abort *)dev->priv)->count = 0; | |
8ca47e00 | 1129 | |
56ae43df RR |
1130 | /* The console needs two virtqueues: the input then the output. When |
1131 | * they put something the input queue, we make sure we're listening to | |
1132 | * stdin. When they put something in the output queue, we write it to | |
e1e72965 | 1133 | * stdout. */ |
659a0e66 RR |
1134 | add_virtqueue(dev, VIRTQUEUE_NUM, console_input); |
1135 | add_virtqueue(dev, VIRTQUEUE_NUM, console_output); | |
17cbca2b | 1136 | |
659a0e66 | 1137 | verbose("device %u: console\n", ++devices.device_num); |
8ca47e00 | 1138 | } |
17cbca2b | 1139 | /*:*/ |
8ca47e00 | 1140 | |
17cbca2b RR |
1141 | /*M:010 Inter-guest networking is an interesting area. Simplest is to have a |
1142 | * --sharenet=<name> option which opens or creates a named pipe. This can be | |
1143 | * used to send packets to another guest in a 1:1 manner. | |
dde79789 | 1144 | * |
17cbca2b RR |
1145 | * More sopisticated is to use one of the tools developed for project like UML |
1146 | * to do networking. | |
dde79789 | 1147 | * |
17cbca2b RR |
1148 | * Faster is to do virtio bonding in kernel. Doing this 1:1 would be |
1149 | * completely generic ("here's my vring, attach to your vring") and would work | |
1150 | * for any traffic. Of course, namespace and permissions issues need to be | |
1151 | * dealt with. A more sophisticated "multi-channel" virtio_net.c could hide | |
1152 | * multiple inter-guest channels behind one interface, although it would | |
1153 | * require some manner of hotplugging new virtio channels. | |
1154 | * | |
1155 | * Finally, we could implement a virtio network switch in the kernel. :*/ | |
8ca47e00 RR |
1156 | |
1157 | static u32 str2ip(const char *ipaddr) | |
1158 | { | |
dec6a2be | 1159 | unsigned int b[4]; |
8ca47e00 | 1160 | |
dec6a2be MM |
1161 | if (sscanf(ipaddr, "%u.%u.%u.%u", &b[0], &b[1], &b[2], &b[3]) != 4) |
1162 | errx(1, "Failed to parse IP address '%s'", ipaddr); | |
1163 | return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3]; | |
1164 | } | |
1165 | ||
1166 | static void str2mac(const char *macaddr, unsigned char mac[6]) | |
1167 | { | |
1168 | unsigned int m[6]; | |
1169 | if (sscanf(macaddr, "%02x:%02x:%02x:%02x:%02x:%02x", | |
1170 | &m[0], &m[1], &m[2], &m[3], &m[4], &m[5]) != 6) | |
1171 | errx(1, "Failed to parse mac address '%s'", macaddr); | |
1172 | mac[0] = m[0]; | |
1173 | mac[1] = m[1]; | |
1174 | mac[2] = m[2]; | |
1175 | mac[3] = m[3]; | |
1176 | mac[4] = m[4]; | |
1177 | mac[5] = m[5]; | |
8ca47e00 RR |
1178 | } |
1179 | ||
dde79789 RR |
1180 | /* This code is "adapted" from libbridge: it attaches the Host end of the |
1181 | * network device to the bridge device specified by the command line. | |
1182 | * | |
1183 | * This is yet another James Morris contribution (I'm an IP-level guy, so I | |
1184 | * dislike bridging), and I just try not to break it. */ | |
8ca47e00 RR |
1185 | static void add_to_bridge(int fd, const char *if_name, const char *br_name) |
1186 | { | |
1187 | int ifidx; | |
1188 | struct ifreq ifr; | |
1189 | ||
1190 | if (!*br_name) | |
1191 | errx(1, "must specify bridge name"); | |
1192 | ||
1193 | ifidx = if_nametoindex(if_name); | |
1194 | if (!ifidx) | |
1195 | errx(1, "interface %s does not exist!", if_name); | |
1196 | ||
1197 | strncpy(ifr.ifr_name, br_name, IFNAMSIZ); | |
dec6a2be | 1198 | ifr.ifr_name[IFNAMSIZ-1] = '\0'; |
8ca47e00 RR |
1199 | ifr.ifr_ifindex = ifidx; |
1200 | if (ioctl(fd, SIOCBRADDIF, &ifr) < 0) | |
1201 | err(1, "can't add %s to bridge %s", if_name, br_name); | |
1202 | } | |
1203 | ||
dde79789 RR |
1204 | /* This sets up the Host end of the network device with an IP address, brings |
1205 | * it up so packets will flow, the copies the MAC address into the hwaddr | |
17cbca2b | 1206 | * pointer. */ |
dec6a2be | 1207 | static void configure_device(int fd, const char *tapif, u32 ipaddr) |
8ca47e00 RR |
1208 | { |
1209 | struct ifreq ifr; | |
1210 | struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr; | |
1211 | ||
1212 | memset(&ifr, 0, sizeof(ifr)); | |
dec6a2be MM |
1213 | strcpy(ifr.ifr_name, tapif); |
1214 | ||
1215 | /* Don't read these incantations. Just cut & paste them like I did! */ | |
8ca47e00 RR |
1216 | sin->sin_family = AF_INET; |
1217 | sin->sin_addr.s_addr = htonl(ipaddr); | |
1218 | if (ioctl(fd, SIOCSIFADDR, &ifr) != 0) | |
dec6a2be | 1219 | err(1, "Setting %s interface address", tapif); |
8ca47e00 RR |
1220 | ifr.ifr_flags = IFF_UP; |
1221 | if (ioctl(fd, SIOCSIFFLAGS, &ifr) != 0) | |
dec6a2be MM |
1222 | err(1, "Bringing interface %s up", tapif); |
1223 | } | |
1224 | ||
dec6a2be | 1225 | static int get_tun_device(char tapif[IFNAMSIZ]) |
8ca47e00 | 1226 | { |
8ca47e00 | 1227 | struct ifreq ifr; |
dec6a2be MM |
1228 | int netfd; |
1229 | ||
1230 | /* Start with this zeroed. Messy but sure. */ | |
1231 | memset(&ifr, 0, sizeof(ifr)); | |
8ca47e00 | 1232 | |
dde79789 RR |
1233 | /* We open the /dev/net/tun device and tell it we want a tap device. A |
1234 | * tap device is like a tun device, only somehow different. To tell | |
1235 | * the truth, I completely blundered my way through this code, but it | |
1236 | * works now! */ | |
8ca47e00 | 1237 | netfd = open_or_die("/dev/net/tun", O_RDWR); |
398f187d | 1238 | ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR; |
8ca47e00 RR |
1239 | strcpy(ifr.ifr_name, "tap%d"); |
1240 | if (ioctl(netfd, TUNSETIFF, &ifr) != 0) | |
1241 | err(1, "configuring /dev/net/tun"); | |
dec6a2be | 1242 | |
398f187d RR |
1243 | if (ioctl(netfd, TUNSETOFFLOAD, |
1244 | TUN_F_CSUM|TUN_F_TSO4|TUN_F_TSO6|TUN_F_TSO_ECN) != 0) | |
1245 | err(1, "Could not set features for tun device"); | |
1246 | ||
dde79789 RR |
1247 | /* We don't need checksums calculated for packets coming in this |
1248 | * device: trust us! */ | |
8ca47e00 RR |
1249 | ioctl(netfd, TUNSETNOCSUM, 1); |
1250 | ||
dec6a2be MM |
1251 | memcpy(tapif, ifr.ifr_name, IFNAMSIZ); |
1252 | return netfd; | |
1253 | } | |
1254 | ||
1255 | /*L:195 Our network is a Host<->Guest network. This can either use bridging or | |
1256 | * routing, but the principle is the same: it uses the "tun" device to inject | |
1257 | * packets into the Host as if they came in from a normal network card. We | |
1258 | * just shunt packets between the Guest and the tun device. */ | |
1259 | static void setup_tun_net(char *arg) | |
1260 | { | |
1261 | struct device *dev; | |
659a0e66 RR |
1262 | struct net_info *net_info = malloc(sizeof(*net_info)); |
1263 | int ipfd; | |
dec6a2be MM |
1264 | u32 ip = INADDR_ANY; |
1265 | bool bridging = false; | |
1266 | char tapif[IFNAMSIZ], *p; | |
1267 | struct virtio_net_config conf; | |
1268 | ||
659a0e66 | 1269 | net_info->tunfd = get_tun_device(tapif); |
dec6a2be | 1270 | |
17cbca2b | 1271 | /* First we create a new network device. */ |
659a0e66 RR |
1272 | dev = new_device("net", VIRTIO_ID_NET); |
1273 | dev->priv = net_info; | |
dde79789 | 1274 | |
56ae43df RR |
1275 | /* Network devices need a receive and a send queue, just like |
1276 | * console. */ | |
659a0e66 RR |
1277 | add_virtqueue(dev, VIRTQUEUE_NUM, net_input); |
1278 | add_virtqueue(dev, VIRTQUEUE_NUM, net_output); | |
8ca47e00 | 1279 | |
dde79789 RR |
1280 | /* We need a socket to perform the magic network ioctls to bring up the |
1281 | * tap interface, connect to the bridge etc. Any socket will do! */ | |
8ca47e00 RR |
1282 | ipfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP); |
1283 | if (ipfd < 0) | |
1284 | err(1, "opening IP socket"); | |
1285 | ||
dde79789 | 1286 | /* If the command line was --tunnet=bridge:<name> do bridging. */ |
8ca47e00 | 1287 | if (!strncmp(BRIDGE_PFX, arg, strlen(BRIDGE_PFX))) { |
dec6a2be MM |
1288 | arg += strlen(BRIDGE_PFX); |
1289 | bridging = true; | |
1290 | } | |
1291 | ||
1292 | /* A mac address may follow the bridge name or IP address */ | |
1293 | p = strchr(arg, ':'); | |
1294 | if (p) { | |
1295 | str2mac(p+1, conf.mac); | |
40c42076 | 1296 | add_feature(dev, VIRTIO_NET_F_MAC); |
dec6a2be | 1297 | *p = '\0'; |
dec6a2be MM |
1298 | } |
1299 | ||
1300 | /* arg is now either an IP address or a bridge name */ | |
1301 | if (bridging) | |
1302 | add_to_bridge(ipfd, tapif, arg); | |
1303 | else | |
8ca47e00 RR |
1304 | ip = str2ip(arg); |
1305 | ||
dec6a2be MM |
1306 | /* Set up the tun device. */ |
1307 | configure_device(ipfd, tapif, ip); | |
8ca47e00 | 1308 | |
20887611 | 1309 | add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY); |
398f187d RR |
1310 | /* Expect Guest to handle everything except UFO */ |
1311 | add_feature(dev, VIRTIO_NET_F_CSUM); | |
1312 | add_feature(dev, VIRTIO_NET_F_GUEST_CSUM); | |
398f187d RR |
1313 | add_feature(dev, VIRTIO_NET_F_GUEST_TSO4); |
1314 | add_feature(dev, VIRTIO_NET_F_GUEST_TSO6); | |
1315 | add_feature(dev, VIRTIO_NET_F_GUEST_ECN); | |
1316 | add_feature(dev, VIRTIO_NET_F_HOST_TSO4); | |
1317 | add_feature(dev, VIRTIO_NET_F_HOST_TSO6); | |
1318 | add_feature(dev, VIRTIO_NET_F_HOST_ECN); | |
a586d4f6 | 1319 | set_config(dev, sizeof(conf), &conf); |
8ca47e00 | 1320 | |
a586d4f6 | 1321 | /* We don't need the socket any more; setup is done. */ |
8ca47e00 RR |
1322 | close(ipfd); |
1323 | ||
dec6a2be MM |
1324 | devices.device_num++; |
1325 | ||
1326 | if (bridging) | |
1327 | verbose("device %u: tun %s attached to bridge: %s\n", | |
1328 | devices.device_num, tapif, arg); | |
1329 | else | |
1330 | verbose("device %u: tun %s: %s\n", | |
1331 | devices.device_num, tapif, arg); | |
8ca47e00 | 1332 | } |
17cbca2b | 1333 | |
e1e72965 RR |
1334 | /* Our block (disk) device should be really simple: the Guest asks for a block |
1335 | * number and we read or write that position in the file. Unfortunately, that | |
1336 | * was amazingly slow: the Guest waits until the read is finished before | |
1337 | * running anything else, even if it could have been doing useful work. | |
17cbca2b | 1338 | * |
e1e72965 RR |
1339 | * We could use async I/O, except it's reputed to suck so hard that characters |
1340 | * actually go missing from your code when you try to use it. | |
17cbca2b RR |
1341 | * |
1342 | * So we farm the I/O out to thread, and communicate with it via a pipe. */ | |
1343 | ||
e1e72965 | 1344 | /* This hangs off device->priv. */ |
17cbca2b RR |
1345 | struct vblk_info |
1346 | { | |
1347 | /* The size of the file. */ | |
1348 | off64_t len; | |
1349 | ||
1350 | /* The file descriptor for the file. */ | |
1351 | int fd; | |
1352 | ||
1353 | /* IO thread listens on this file descriptor [0]. */ | |
1354 | int workpipe[2]; | |
1355 | ||
1356 | /* IO thread writes to this file descriptor to mark it done, then | |
1357 | * Launcher triggers interrupt to Guest. */ | |
1358 | int done_fd; | |
1359 | }; | |
1360 | ||
e1e72965 RR |
1361 | /*L:210 |
1362 | * The Disk | |
1363 | * | |
1364 | * Remember that the block device is handled by a separate I/O thread. We head | |
1365 | * straight into the core of that thread here: | |
1366 | */ | |
659a0e66 | 1367 | static void blk_request(struct virtqueue *vq) |
17cbca2b | 1368 | { |
659a0e66 | 1369 | struct vblk_info *vblk = vq->dev->priv; |
17cbca2b RR |
1370 | unsigned int head, out_num, in_num, wlen; |
1371 | int ret; | |
cb38fa23 | 1372 | u8 *in; |
17cbca2b | 1373 | struct virtio_blk_outhdr *out; |
659a0e66 | 1374 | struct iovec iov[vq->vring.num]; |
17cbca2b RR |
1375 | off64_t off; |
1376 | ||
659a0e66 RR |
1377 | /* Get the next request. */ |
1378 | head = wait_for_vq_desc(vq, iov, &out_num, &in_num); | |
17cbca2b | 1379 | |
e1e72965 RR |
1380 | /* Every block request should contain at least one output buffer |
1381 | * (detailing the location on disk and the type of request) and one | |
1382 | * input buffer (to hold the result). */ | |
17cbca2b RR |
1383 | if (out_num == 0 || in_num == 0) |
1384 | errx(1, "Bad virtblk cmd %u out=%u in=%u", | |
1385 | head, out_num, in_num); | |
1386 | ||
1387 | out = convert(&iov[0], struct virtio_blk_outhdr); | |
cb38fa23 | 1388 | in = convert(&iov[out_num+in_num-1], u8); |
17cbca2b RR |
1389 | off = out->sector * 512; |
1390 | ||
e1e72965 RR |
1391 | /* The block device implements "barriers", where the Guest indicates |
1392 | * that it wants all previous writes to occur before this write. We | |
1393 | * don't have a way of asking our kernel to do a barrier, so we just | |
1394 | * synchronize all the data in the file. Pretty poor, no? */ | |
17cbca2b RR |
1395 | if (out->type & VIRTIO_BLK_T_BARRIER) |
1396 | fdatasync(vblk->fd); | |
1397 | ||
e1e72965 RR |
1398 | /* In general the virtio block driver is allowed to try SCSI commands. |
1399 | * It'd be nice if we supported eject, for example, but we don't. */ | |
17cbca2b RR |
1400 | if (out->type & VIRTIO_BLK_T_SCSI_CMD) { |
1401 | fprintf(stderr, "Scsi commands unsupported\n"); | |
cb38fa23 | 1402 | *in = VIRTIO_BLK_S_UNSUPP; |
1200e646 | 1403 | wlen = sizeof(*in); |
17cbca2b RR |
1404 | } else if (out->type & VIRTIO_BLK_T_OUT) { |
1405 | /* Write */ | |
1406 | ||
1407 | /* Move to the right location in the block file. This can fail | |
1408 | * if they try to write past end. */ | |
1409 | if (lseek64(vblk->fd, off, SEEK_SET) != off) | |
1410 | err(1, "Bad seek to sector %llu", out->sector); | |
1411 | ||
1412 | ret = writev(vblk->fd, iov+1, out_num-1); | |
1413 | verbose("WRITE to sector %llu: %i\n", out->sector, ret); | |
1414 | ||
1415 | /* Grr... Now we know how long the descriptor they sent was, we | |
1416 | * make sure they didn't try to write over the end of the block | |
1417 | * file (possibly extending it). */ | |
1418 | if (ret > 0 && off + ret > vblk->len) { | |
1419 | /* Trim it back to the correct length */ | |
1420 | ftruncate64(vblk->fd, vblk->len); | |
1421 | /* Die, bad Guest, die. */ | |
1422 | errx(1, "Write past end %llu+%u", off, ret); | |
1423 | } | |
1200e646 | 1424 | wlen = sizeof(*in); |
cb38fa23 | 1425 | *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); |
17cbca2b RR |
1426 | } else { |
1427 | /* Read */ | |
1428 | ||
1429 | /* Move to the right location in the block file. This can fail | |
1430 | * if they try to read past end. */ | |
1431 | if (lseek64(vblk->fd, off, SEEK_SET) != off) | |
1432 | err(1, "Bad seek to sector %llu", out->sector); | |
1433 | ||
1434 | ret = readv(vblk->fd, iov+1, in_num-1); | |
1435 | verbose("READ from sector %llu: %i\n", out->sector, ret); | |
1436 | if (ret >= 0) { | |
1200e646 | 1437 | wlen = sizeof(*in) + ret; |
cb38fa23 | 1438 | *in = VIRTIO_BLK_S_OK; |
17cbca2b | 1439 | } else { |
1200e646 | 1440 | wlen = sizeof(*in); |
cb38fa23 | 1441 | *in = VIRTIO_BLK_S_IOERR; |
17cbca2b RR |
1442 | } |
1443 | } | |
1444 | ||
d1881d31 RR |
1445 | /* OK, so we noted that it was pretty poor to use an fdatasync as a |
1446 | * barrier. But Christoph Hellwig points out that we need a sync | |
1447 | * *afterwards* as well: "Barriers specify no reordering to the front | |
1448 | * or the back." And Jens Axboe confirmed it, so here we are: */ | |
1449 | if (out->type & VIRTIO_BLK_T_BARRIER) | |
1450 | fdatasync(vblk->fd); | |
1451 | ||
38bc2b8c | 1452 | add_used(vq, head, wlen); |
17cbca2b RR |
1453 | } |
1454 | ||
e1e72965 | 1455 | /*L:198 This actually sets up a virtual block device. */ |
17cbca2b RR |
1456 | static void setup_block_file(const char *filename) |
1457 | { | |
17cbca2b RR |
1458 | struct device *dev; |
1459 | struct vblk_info *vblk; | |
a586d4f6 | 1460 | struct virtio_blk_config conf; |
17cbca2b | 1461 | |
17cbca2b | 1462 | /* The device responds to return from I/O thread. */ |
659a0e66 | 1463 | dev = new_device("block", VIRTIO_ID_BLOCK); |
17cbca2b | 1464 | |
e1e72965 | 1465 | /* The device has one virtqueue, where the Guest places requests. */ |
659a0e66 | 1466 | add_virtqueue(dev, VIRTQUEUE_NUM, blk_request); |
17cbca2b RR |
1467 | |
1468 | /* Allocate the room for our own bookkeeping */ | |
1469 | vblk = dev->priv = malloc(sizeof(*vblk)); | |
1470 | ||
1471 | /* First we open the file and store the length. */ | |
1472 | vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE); | |
1473 | vblk->len = lseek64(vblk->fd, 0, SEEK_END); | |
1474 | ||
a586d4f6 RR |
1475 | /* We support barriers. */ |
1476 | add_feature(dev, VIRTIO_BLK_F_BARRIER); | |
1477 | ||
17cbca2b | 1478 | /* Tell Guest how many sectors this device has. */ |
a586d4f6 | 1479 | conf.capacity = cpu_to_le64(vblk->len / 512); |
17cbca2b RR |
1480 | |
1481 | /* Tell Guest not to put in too many descriptors at once: two are used | |
1482 | * for the in and out elements. */ | |
a586d4f6 RR |
1483 | add_feature(dev, VIRTIO_BLK_F_SEG_MAX); |
1484 | conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2); | |
1485 | ||
1486 | set_config(dev, sizeof(conf), &conf); | |
17cbca2b | 1487 | |
17cbca2b | 1488 | verbose("device %u: virtblock %llu sectors\n", |
659a0e66 | 1489 | ++devices.device_num, le64_to_cpu(conf.capacity)); |
17cbca2b | 1490 | } |
28fd6d7f | 1491 | |
659a0e66 RR |
1492 | struct rng_info { |
1493 | int rfd; | |
1494 | }; | |
1495 | ||
28fd6d7f RR |
1496 | /* Our random number generator device reads from /dev/random into the Guest's |
1497 | * input buffers. The usual case is that the Guest doesn't want random numbers | |
1498 | * and so has no buffers although /dev/random is still readable, whereas | |
1499 | * console is the reverse. | |
1500 | * | |
1501 | * The same logic applies, however. */ | |
659a0e66 | 1502 | static void rng_input(struct virtqueue *vq) |
28fd6d7f RR |
1503 | { |
1504 | int len; | |
1505 | unsigned int head, in_num, out_num, totlen = 0; | |
659a0e66 RR |
1506 | struct rng_info *rng_info = vq->dev->priv; |
1507 | struct iovec iov[vq->vring.num]; | |
28fd6d7f RR |
1508 | |
1509 | /* First we need a buffer from the Guests's virtqueue. */ | |
659a0e66 | 1510 | head = wait_for_vq_desc(vq, iov, &out_num, &in_num); |
28fd6d7f RR |
1511 | if (out_num) |
1512 | errx(1, "Output buffers in rng?"); | |
1513 | ||
1514 | /* This is why we convert to iovecs: the readv() call uses them, and so | |
1515 | * it reads straight into the Guest's buffer. We loop to make sure we | |
1516 | * fill it. */ | |
1517 | while (!iov_empty(iov, in_num)) { | |
659a0e66 | 1518 | len = readv(rng_info->rfd, iov, in_num); |
28fd6d7f RR |
1519 | if (len <= 0) |
1520 | err(1, "Read from /dev/random gave %i", len); | |
1521 | iov_consume(iov, in_num, len); | |
1522 | totlen += len; | |
1523 | } | |
1524 | ||
1525 | /* Tell the Guest about the new input. */ | |
38bc2b8c | 1526 | add_used(vq, head, totlen); |
28fd6d7f RR |
1527 | } |
1528 | ||
1529 | /* And this creates a "hardware" random number device for the Guest. */ | |
1530 | static void setup_rng(void) | |
1531 | { | |
1532 | struct device *dev; | |
659a0e66 | 1533 | struct rng_info *rng_info = malloc(sizeof(*rng_info)); |
28fd6d7f | 1534 | |
659a0e66 | 1535 | rng_info->rfd = open_or_die("/dev/random", O_RDONLY); |
28fd6d7f RR |
1536 | |
1537 | /* The device responds to return from I/O thread. */ | |
659a0e66 RR |
1538 | dev = new_device("rng", VIRTIO_ID_RNG); |
1539 | dev->priv = rng_info; | |
28fd6d7f RR |
1540 | |
1541 | /* The device has one virtqueue, where the Guest places inbufs. */ | |
659a0e66 | 1542 | add_virtqueue(dev, VIRTQUEUE_NUM, rng_input); |
28fd6d7f RR |
1543 | |
1544 | verbose("device %u: rng\n", devices.device_num++); | |
1545 | } | |
a6bd8e13 | 1546 | /* That's the end of device setup. */ |
ec04b13f | 1547 | |
a6bd8e13 | 1548 | /*L:230 Reboot is pretty easy: clean up and exec() the Launcher afresh. */ |
ec04b13f BR |
1549 | static void __attribute__((noreturn)) restart_guest(void) |
1550 | { | |
1551 | unsigned int i; | |
1552 | ||
8c79873d RR |
1553 | /* Since we don't track all open fds, we simply close everything beyond |
1554 | * stderr. */ | |
ec04b13f BR |
1555 | for (i = 3; i < FD_SETSIZE; i++) |
1556 | close(i); | |
8c79873d | 1557 | |
659a0e66 RR |
1558 | /* Reset all the devices (kills all threads). */ |
1559 | cleanup_devices(); | |
1560 | ||
ec04b13f BR |
1561 | execv(main_args[0], main_args); |
1562 | err(1, "Could not exec %s", main_args[0]); | |
1563 | } | |
8ca47e00 | 1564 | |
a6bd8e13 | 1565 | /*L:220 Finally we reach the core of the Launcher which runs the Guest, serves |
dde79789 | 1566 | * its input and output, and finally, lays it to rest. */ |
56739c80 | 1567 | static void __attribute__((noreturn)) run_guest(void) |
8ca47e00 RR |
1568 | { |
1569 | for (;;) { | |
17cbca2b | 1570 | unsigned long notify_addr; |
8ca47e00 RR |
1571 | int readval; |
1572 | ||
1573 | /* We read from the /dev/lguest device to run the Guest. */ | |
e3283fa0 GOC |
1574 | readval = pread(lguest_fd, ¬ify_addr, |
1575 | sizeof(notify_addr), cpu_id); | |
8ca47e00 | 1576 | |
17cbca2b RR |
1577 | /* One unsigned long means the Guest did HCALL_NOTIFY */ |
1578 | if (readval == sizeof(notify_addr)) { | |
1579 | verbose("Notify on address %#lx\n", notify_addr); | |
56739c80 | 1580 | handle_output(notify_addr); |
dde79789 | 1581 | /* ENOENT means the Guest died. Reading tells us why. */ |
8ca47e00 RR |
1582 | } else if (errno == ENOENT) { |
1583 | char reason[1024] = { 0 }; | |
e3283fa0 | 1584 | pread(lguest_fd, reason, sizeof(reason)-1, cpu_id); |
8ca47e00 | 1585 | errx(1, "%s", reason); |
ec04b13f BR |
1586 | /* ERESTART means that we need to reboot the guest */ |
1587 | } else if (errno == ERESTART) { | |
1588 | restart_guest(); | |
659a0e66 RR |
1589 | /* Anything else means a bug or incompatible change. */ |
1590 | } else | |
8ca47e00 | 1591 | err(1, "Running guest failed"); |
8ca47e00 RR |
1592 | } |
1593 | } | |
a6bd8e13 | 1594 | /*L:240 |
e1e72965 RR |
1595 | * This is the end of the Launcher. The good news: we are over halfway |
1596 | * through! The bad news: the most fiendish part of the code still lies ahead | |
1597 | * of us. | |
dde79789 | 1598 | * |
e1e72965 RR |
1599 | * Are you ready? Take a deep breath and join me in the core of the Host, in |
1600 | * "make Host". | |
1601 | :*/ | |
8ca47e00 RR |
1602 | |
1603 | static struct option opts[] = { | |
1604 | { "verbose", 0, NULL, 'v' }, | |
8ca47e00 RR |
1605 | { "tunnet", 1, NULL, 't' }, |
1606 | { "block", 1, NULL, 'b' }, | |
28fd6d7f | 1607 | { "rng", 0, NULL, 'r' }, |
8ca47e00 RR |
1608 | { "initrd", 1, NULL, 'i' }, |
1609 | { NULL }, | |
1610 | }; | |
1611 | static void usage(void) | |
1612 | { | |
1613 | errx(1, "Usage: lguest [--verbose] " | |
dec6a2be | 1614 | "[--tunnet=(<ipaddr>:<macaddr>|bridge:<bridgename>:<macaddr>)\n" |
8ca47e00 RR |
1615 | "|--block=<filename>|--initrd=<filename>]...\n" |
1616 | "<mem-in-mb> vmlinux [args...]"); | |
1617 | } | |
1618 | ||
3c6b5bfa | 1619 | /*L:105 The main routine is where the real work begins: */ |
8ca47e00 RR |
1620 | int main(int argc, char *argv[]) |
1621 | { | |
47436aa4 RR |
1622 | /* Memory, top-level pagetable, code startpoint and size of the |
1623 | * (optional) initrd. */ | |
58a24566 | 1624 | unsigned long mem = 0, start, initrd_size = 0; |
56739c80 RR |
1625 | /* Two temporaries. */ |
1626 | int i, c; | |
3c6b5bfa | 1627 | /* The boot information for the Guest. */ |
43d33b21 | 1628 | struct boot_params *boot; |
dde79789 | 1629 | /* If they specify an initrd file to load. */ |
8ca47e00 RR |
1630 | const char *initrd_name = NULL; |
1631 | ||
ec04b13f BR |
1632 | /* Save the args: we "reboot" by execing ourselves again. */ |
1633 | main_args = argv; | |
ec04b13f | 1634 | |
659a0e66 RR |
1635 | /* First we initialize the device list. We keep a pointer to the last |
1636 | * device, and the next interrupt number to use for devices (1: | |
1637 | * remember that 0 is used by the timer). */ | |
a586d4f6 | 1638 | devices.lastdev = NULL; |
17cbca2b | 1639 | devices.next_irq = 1; |
8ca47e00 | 1640 | |
e3283fa0 | 1641 | cpu_id = 0; |
dde79789 RR |
1642 | /* We need to know how much memory so we can set up the device |
1643 | * descriptor and memory pages for the devices as we parse the command | |
1644 | * line. So we quickly look through the arguments to find the amount | |
1645 | * of memory now. */ | |
6570c459 RR |
1646 | for (i = 1; i < argc; i++) { |
1647 | if (argv[i][0] != '-') { | |
3c6b5bfa RR |
1648 | mem = atoi(argv[i]) * 1024 * 1024; |
1649 | /* We start by mapping anonymous pages over all of | |
1650 | * guest-physical memory range. This fills it with 0, | |
1651 | * and ensures that the Guest won't be killed when it | |
1652 | * tries to access it. */ | |
1653 | guest_base = map_zeroed_pages(mem / getpagesize() | |
1654 | + DEVICE_PAGES); | |
1655 | guest_limit = mem; | |
1656 | guest_max = mem + DEVICE_PAGES*getpagesize(); | |
17cbca2b | 1657 | devices.descpage = get_pages(1); |
6570c459 RR |
1658 | break; |
1659 | } | |
1660 | } | |
dde79789 RR |
1661 | |
1662 | /* The options are fairly straight-forward */ | |
8ca47e00 RR |
1663 | while ((c = getopt_long(argc, argv, "v", opts, NULL)) != EOF) { |
1664 | switch (c) { | |
1665 | case 'v': | |
1666 | verbose = true; | |
1667 | break; | |
8ca47e00 | 1668 | case 't': |
17cbca2b | 1669 | setup_tun_net(optarg); |
8ca47e00 RR |
1670 | break; |
1671 | case 'b': | |
17cbca2b | 1672 | setup_block_file(optarg); |
8ca47e00 | 1673 | break; |
28fd6d7f RR |
1674 | case 'r': |
1675 | setup_rng(); | |
1676 | break; | |
8ca47e00 RR |
1677 | case 'i': |
1678 | initrd_name = optarg; | |
1679 | break; | |
1680 | default: | |
1681 | warnx("Unknown argument %s", argv[optind]); | |
1682 | usage(); | |
1683 | } | |
1684 | } | |
dde79789 RR |
1685 | /* After the other arguments we expect memory and kernel image name, |
1686 | * followed by command line arguments for the kernel. */ | |
8ca47e00 RR |
1687 | if (optind + 2 > argc) |
1688 | usage(); | |
1689 | ||
3c6b5bfa RR |
1690 | verbose("Guest base is at %p\n", guest_base); |
1691 | ||
dde79789 | 1692 | /* We always have a console device */ |
17cbca2b | 1693 | setup_console(); |
8ca47e00 | 1694 | |
8ca47e00 | 1695 | /* Now we load the kernel */ |
47436aa4 | 1696 | start = load_kernel(open_or_die(argv[optind+1], O_RDONLY)); |
8ca47e00 | 1697 | |
3c6b5bfa RR |
1698 | /* Boot information is stashed at physical address 0 */ |
1699 | boot = from_guest_phys(0); | |
1700 | ||
dde79789 | 1701 | /* Map the initrd image if requested (at top of physical memory) */ |
8ca47e00 RR |
1702 | if (initrd_name) { |
1703 | initrd_size = load_initrd(initrd_name, mem); | |
dde79789 RR |
1704 | /* These are the location in the Linux boot header where the |
1705 | * start and size of the initrd are expected to be found. */ | |
43d33b21 RR |
1706 | boot->hdr.ramdisk_image = mem - initrd_size; |
1707 | boot->hdr.ramdisk_size = initrd_size; | |
dde79789 | 1708 | /* The bootloader type 0xFF means "unknown"; that's OK. */ |
43d33b21 | 1709 | boot->hdr.type_of_loader = 0xFF; |
8ca47e00 RR |
1710 | } |
1711 | ||
dde79789 RR |
1712 | /* The Linux boot header contains an "E820" memory map: ours is a |
1713 | * simple, single region. */ | |
43d33b21 RR |
1714 | boot->e820_entries = 1; |
1715 | boot->e820_map[0] = ((struct e820entry) { 0, mem, E820_RAM }); | |
dde79789 | 1716 | /* The boot header contains a command line pointer: we put the command |
43d33b21 RR |
1717 | * line after the boot header. */ |
1718 | boot->hdr.cmd_line_ptr = to_guest_phys(boot + 1); | |
e1e72965 | 1719 | /* We use a simple helper to copy the arguments separated by spaces. */ |
43d33b21 | 1720 | concat((char *)(boot + 1), argv+optind+2); |
dde79789 | 1721 | |
814a0e5c | 1722 | /* Boot protocol version: 2.07 supports the fields for lguest. */ |
43d33b21 | 1723 | boot->hdr.version = 0x207; |
814a0e5c RR |
1724 | |
1725 | /* The hardware_subarch value of "1" tells the Guest it's an lguest. */ | |
43d33b21 | 1726 | boot->hdr.hardware_subarch = 1; |
814a0e5c | 1727 | |
43d33b21 RR |
1728 | /* Tell the entry path not to try to reload segment registers. */ |
1729 | boot->hdr.loadflags |= KEEP_SEGMENTS; | |
8ca47e00 | 1730 | |
dde79789 RR |
1731 | /* We tell the kernel to initialize the Guest: this returns the open |
1732 | * /dev/lguest file descriptor. */ | |
56739c80 | 1733 | tell_kernel(start); |
dde79789 | 1734 | |
659a0e66 RR |
1735 | /* Ensure that we terminate if a child dies. */ |
1736 | signal(SIGCHLD, kill_launcher); | |
1737 | ||
1738 | /* If we exit via err(), this kills all the threads, restores tty. */ | |
1739 | atexit(cleanup_devices); | |
8ca47e00 | 1740 | |
dde79789 | 1741 | /* Finally, run the Guest. This doesn't return. */ |
56739c80 | 1742 | run_guest(); |
8ca47e00 | 1743 | } |
f56a384e RR |
1744 | /*:*/ |
1745 | ||
1746 | /*M:999 | |
1747 | * Mastery is done: you now know everything I do. | |
1748 | * | |
1749 | * But surely you have seen code, features and bugs in your wanderings which | |
1750 | * you now yearn to attack? That is the real game, and I look forward to you | |
1751 | * patching and forking lguest into the Your-Name-Here-visor. | |
1752 | * | |
1753 | * Farewell, and good coding! | |
1754 | * Rusty Russell. | |
1755 | */ |