xref: /openbmc/qemu/hw/xen/xen-host-pci-device.c (revision d0b9b28a) 
1 /*
2  * Copyright (C) 2011       Citrix Ltd.
3  *
4  * This work is licensed under the terms of the GNU GPL, version 2.  See
5  * the COPYING file in the top-level directory.
6  *
7  */
8 
9 #include "qemu/osdep.h"
10 #include "qapi/error.h"
11 #include "qemu/cutils.h"
12 #include "hw/xen/xen-legacy-backend.h"
13 #include "hw/xen/xen-bus-helper.h"
14 #include "xen-host-pci-device.h"
15 
16 #define XEN_HOST_PCI_MAX_EXT_CAP \
17     ((PCIE_CONFIG_SPACE_SIZE - PCI_CONFIG_SPACE_SIZE) / (PCI_CAP_SIZEOF + 4))
18 
19 #ifdef XEN_HOST_PCI_DEVICE_DEBUG
20 #  define XEN_HOST_PCI_LOG(f, a...) fprintf(stderr, "%s: " f, __func__, ##a)
21 #else
22 #  define XEN_HOST_PCI_LOG(f, a...) (void)0
23 #endif
24 
25 /*
26  * from linux/ioport.h
27  * IO resources have these defined flags.
28  */
29 #define IORESOURCE_BITS         0x000000ff      /* Bus-specific bits */
30 
31 #define IORESOURCE_TYPE_BITS    0x00000f00      /* Resource type */
32 #define IORESOURCE_IO           0x00000100
33 #define IORESOURCE_MEM          0x00000200
34 
35 #define IORESOURCE_PREFETCH     0x00001000      /* No side effects */
36 #define IORESOURCE_MEM_64       0x00100000
37 
38 /*
39  * Non-passthrough (dom0) accesses are local PCI devices and use the given BDF
40  * Passthough (stubdom) accesses are through PV frontend PCI device.  Those
41  * either have a BDF identical to the backend's BDF (xen-backend.passthrough=1)
42  * or a local virtual BDF (xen-backend.passthrough=0)
43  *
44  * We are always given the backend's BDF and need to lookup the appropriate
45  * local BDF for sysfs access.
46  */
47 static void xen_host_pci_fill_local_addr(XenHostPCIDevice *d, Error **errp)
48 {
49     unsigned int num_devs, len, i;
50     unsigned int domain, bus, dev, func;
51     char *be_path = NULL;
52     char path[16];
53 
54     be_path = qemu_xen_xs_read(xenstore, 0, "device/pci/0/backend", &len);
55     if (!be_path) {
56         error_setg(errp, "Failed to read device/pci/0/backend");
57         goto out;
58     }
59 
60     if (xs_node_scanf(xenstore, 0, be_path, "num_devs", NULL,
61                       "%d", &num_devs) != 1) {
62         error_setg(errp, "Failed to read or parse %s/num_devs", be_path);
63         goto out;
64     }
65 
66     for (i = 0; i < num_devs; i++) {
67         snprintf(path, sizeof(path), "dev-%d", i);
68         if (xs_node_scanf(xenstore, 0, be_path, path, NULL,
69                           "%x:%x:%x.%x", &domain, &bus, &dev, &func) != 4) {
70             error_setg(errp, "Failed to read or parse %s/%s", be_path, path);
71             goto out;
72         }
73         if (domain != d->domain ||
74                 bus != d->bus ||
75                 dev != d->dev ||
76                 func != d->func)
77             continue;
78         snprintf(path, sizeof(path), "vdev-%d", i);
79         if (xs_node_scanf(xenstore, 0, be_path, path, NULL,
80                           "%x:%x:%x.%x", &domain, &bus, &dev, &func) != 4) {
81             error_setg(errp, "Failed to read or parse %s/%s", be_path, path);
82             goto out;
83         }
84         d->local_domain = domain;
85         d->local_bus = bus;
86         d->local_dev = dev;
87         d->local_func = func;
88         goto out;
89     }
90     error_setg(errp, "Failed to find PCI device %x:%x:%x.%x in xenstore",
91                d->domain, d->bus, d->dev, d->func);
92 
93 out:
94     free(be_path);
95 }
96 
97 static void xen_host_pci_sysfs_path(const XenHostPCIDevice *d,
98                                     const char *name, char *buf, ssize_t size)
99 {
100     int rc;
101 
102     rc = snprintf(buf, size, "/sys/bus/pci/devices/%04x:%02x:%02x.%d/%s",
103                   d->local_domain, d->local_bus, d->local_dev, d->local_func,
104                   name);
105     assert(rc >= 0 && rc < size);
106 }
107 
108 
109 /* This size should be enough to read the first 7 lines of a resource file */
110 #define XEN_HOST_PCI_RESOURCE_BUFFER_SIZE 400
111 static void xen_host_pci_get_resource(XenHostPCIDevice *d, Error **errp)
112 {
113     int i, rc, fd;
114     char path[PATH_MAX];
115     char buf[XEN_HOST_PCI_RESOURCE_BUFFER_SIZE];
116     unsigned long long start, end, flags, size;
117     char *endptr, *s;
118     uint8_t type;
119 
120     xen_host_pci_sysfs_path(d, "resource", path, sizeof(path));
121 
122     fd = open(path, O_RDONLY);
123     if (fd == -1) {
124         error_setg_file_open(errp, errno, path);
125         return;
126     }
127 
128     do {
129         rc = read(fd, &buf, sizeof(buf) - 1);
130         if (rc < 0 && errno != EINTR) {
131             error_setg_errno(errp, errno, "read err");
132             goto out;
133         }
134     } while (rc < 0);
135     buf[rc] = 0;
136 
137     s = buf;
138     for (i = 0; i < PCI_NUM_REGIONS; i++) {
139         type = 0;
140 
141         start = strtoll(s, &endptr, 16);
142         if (*endptr != ' ' || s == endptr) {
143             break;
144         }
145         s = endptr + 1;
146         end = strtoll(s, &endptr, 16);
147         if (*endptr != ' ' || s == endptr) {
148             break;
149         }
150         s = endptr + 1;
151         flags = strtoll(s, &endptr, 16);
152         if (*endptr != '\n' || s == endptr) {
153             break;
154         }
155         s = endptr + 1;
156 
157         if (start) {
158             size = end - start + 1;
159         } else {
160             size = 0;
161         }
162 
163         if (flags & IORESOURCE_IO) {
164             type |= XEN_HOST_PCI_REGION_TYPE_IO;
165         }
166         if (flags & IORESOURCE_MEM) {
167             type |= XEN_HOST_PCI_REGION_TYPE_MEM;
168         }
169         if (flags & IORESOURCE_PREFETCH) {
170             type |= XEN_HOST_PCI_REGION_TYPE_PREFETCH;
171         }
172         if (flags & IORESOURCE_MEM_64) {
173             type |= XEN_HOST_PCI_REGION_TYPE_MEM_64;
174         }
175 
176         if (i < PCI_ROM_SLOT) {
177             d->io_regions[i].base_addr = start;
178             d->io_regions[i].size = size;
179             d->io_regions[i].type = type;
180             d->io_regions[i].bus_flags = flags & IORESOURCE_BITS;
181         } else {
182             d->rom.base_addr = start;
183             d->rom.size = size;
184             d->rom.type = type;
185             d->rom.bus_flags = flags & IORESOURCE_BITS;
186         }
187     }
188 
189     if (i != PCI_NUM_REGIONS) {
190         error_setg(errp, "Invalid format or input too short: %s", buf);
191     }
192 
193 out:
194     close(fd);
195 }
196 
197 /* This size should be enough to read a long from a file */
198 #define XEN_HOST_PCI_GET_VALUE_BUFFER_SIZE 22
199 static void xen_host_pci_get_value(XenHostPCIDevice *d, const char *name,
200                                    unsigned int *pvalue, int base, Error **errp)
201 {
202     char path[PATH_MAX];
203     char buf[XEN_HOST_PCI_GET_VALUE_BUFFER_SIZE];
204     int fd, rc;
205     unsigned long value;
206     const char *endptr;
207 
208     xen_host_pci_sysfs_path(d, name, path, sizeof(path));
209 
210     fd = open(path, O_RDONLY);
211     if (fd == -1) {
212         error_setg_file_open(errp, errno, path);
213         return;
214     }
215 
216     do {
217         rc = read(fd, &buf, sizeof(buf) - 1);
218         if (rc < 0 && errno != EINTR) {
219             error_setg_errno(errp, errno, "read err");
220             goto out;
221         }
222     } while (rc < 0);
223 
224     buf[rc] = 0;
225     rc = qemu_strtoul(buf, &endptr, base, &value);
226     if (!rc) {
227         assert(value <= UINT_MAX);
228         *pvalue = value;
229     } else {
230         error_setg_errno(errp, -rc, "failed to parse value '%s'", buf);
231     }
232 
233 out:
234     close(fd);
235 }
236 
237 static inline void xen_host_pci_get_hex_value(XenHostPCIDevice *d,
238                                               const char *name,
239                                               unsigned int *pvalue,
240                                               Error **errp)
241 {
242     xen_host_pci_get_value(d, name, pvalue, 16, errp);
243 }
244 
245 static inline void xen_host_pci_get_dec_value(XenHostPCIDevice *d,
246                                               const char *name,
247                                               unsigned int *pvalue,
248                                               Error **errp)
249 {
250     xen_host_pci_get_value(d, name, pvalue, 10, errp);
251 }
252 
253 static bool xen_host_pci_dev_is_virtfn(XenHostPCIDevice *d)
254 {
255     char path[PATH_MAX];
256     struct stat buf;
257 
258     xen_host_pci_sysfs_path(d, "physfn", path, sizeof(path));
259 
260     return !stat(path, &buf);
261 }
262 
263 static void xen_host_pci_config_open(XenHostPCIDevice *d, Error **errp)
264 {
265     char path[PATH_MAX];
266 
267     xen_host_pci_sysfs_path(d, "config", path, sizeof(path));
268 
269     d->config_fd = open(path, O_RDWR);
270     if (d->config_fd == -1) {
271         error_setg_file_open(errp, errno, path);
272     }
273 }
274 
275 static int xen_host_pci_config_read(XenHostPCIDevice *d,
276                                     int pos, void *buf, int len)
277 {
278     int rc;
279 
280     do {
281         rc = pread(d->config_fd, buf, len, pos);
282     } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
283     if (rc != len) {
284         return -errno;
285     }
286     return 0;
287 }
288 
289 static int xen_host_pci_config_write(XenHostPCIDevice *d,
290                                      int pos, const void *buf, int len)
291 {
292     int rc;
293 
294     do {
295         rc = pwrite(d->config_fd, buf, len, pos);
296     } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
297     if (rc != len) {
298         return -errno;
299     }
300     return 0;
301 }
302 
303 
304 int xen_host_pci_get_byte(XenHostPCIDevice *d, int pos, uint8_t *p)
305 {
306     uint8_t buf;
307     int rc = xen_host_pci_config_read(d, pos, &buf, 1);
308     if (!rc) {
309         *p = buf;
310     }
311     return rc;
312 }
313 
314 int xen_host_pci_get_word(XenHostPCIDevice *d, int pos, uint16_t *p)
315 {
316     uint16_t buf;
317     int rc = xen_host_pci_config_read(d, pos, &buf, 2);
318     if (!rc) {
319         *p = le16_to_cpu(buf);
320     }
321     return rc;
322 }
323 
324 int xen_host_pci_get_long(XenHostPCIDevice *d, int pos, uint32_t *p)
325 {
326     uint32_t buf;
327     int rc = xen_host_pci_config_read(d, pos, &buf, 4);
328     if (!rc) {
329         *p = le32_to_cpu(buf);
330     }
331     return rc;
332 }
333 
334 int xen_host_pci_get_block(XenHostPCIDevice *d, int pos, uint8_t *buf, int len)
335 {
336     return xen_host_pci_config_read(d, pos, buf, len);
337 }
338 
339 int xen_host_pci_set_byte(XenHostPCIDevice *d, int pos, uint8_t data)
340 {
341     return xen_host_pci_config_write(d, pos, &data, 1);
342 }
343 
344 int xen_host_pci_set_word(XenHostPCIDevice *d, int pos, uint16_t data)
345 {
346     data = cpu_to_le16(data);
347     return xen_host_pci_config_write(d, pos, &data, 2);
348 }
349 
350 int xen_host_pci_set_long(XenHostPCIDevice *d, int pos, uint32_t data)
351 {
352     data = cpu_to_le32(data);
353     return xen_host_pci_config_write(d, pos, &data, 4);
354 }
355 
356 int xen_host_pci_set_block(XenHostPCIDevice *d, int pos, uint8_t *buf, int len)
357 {
358     return xen_host_pci_config_write(d, pos, buf, len);
359 }
360 
361 int xen_host_pci_find_ext_cap_offset(XenHostPCIDevice *d, uint32_t cap)
362 {
363     uint32_t header = 0;
364     int max_cap = XEN_HOST_PCI_MAX_EXT_CAP;
365     int pos = PCI_CONFIG_SPACE_SIZE;
366 
367     do {
368         if (xen_host_pci_get_long(d, pos, &header)) {
369             break;
370         }
371         /*
372          * If we have no capabilities, this is indicated by cap ID,
373          * cap version and next pointer all being 0.
374          */
375         if (header == 0) {
376             break;
377         }
378 
379         if (PCI_EXT_CAP_ID(header) == cap) {
380             return pos;
381         }
382 
383         pos = PCI_EXT_CAP_NEXT(header);
384         if (pos < PCI_CONFIG_SPACE_SIZE) {
385             break;
386         }
387 
388         max_cap--;
389     } while (max_cap > 0);
390 
391     return -1;
392 }
393 
394 void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t domain,
395                              uint8_t bus, uint8_t dev, uint8_t func,
396                              Error **errp)
397 {
398     ERRP_GUARD();
399     unsigned int v;
400 
401     d->config_fd = -1;
402     d->domain = domain;
403     d->bus = bus;
404     d->dev = dev;
405     d->func = func;
406 
407     if (xen_is_stubdomain) {
408         xen_host_pci_fill_local_addr(d, errp);
409         if (*errp) {
410             goto error;
411         }
412     } else {
413         d->local_domain = d->domain;
414         d->local_bus = d->bus;
415         d->local_dev = d->dev;
416         d->local_func = d->func;
417     }
418 
419     xen_host_pci_config_open(d, errp);
420     if (*errp) {
421         goto error;
422     }
423 
424     xen_host_pci_get_resource(d, errp);
425     if (*errp) {
426         goto error;
427     }
428 
429     xen_host_pci_get_hex_value(d, "vendor", &v, errp);
430     if (*errp) {
431         goto error;
432     }
433     d->vendor_id = v;
434 
435     xen_host_pci_get_hex_value(d, "device", &v, errp);
436     if (*errp) {
437         goto error;
438     }
439     d->device_id = v;
440 
441     xen_host_pci_get_dec_value(d, "irq", &v, errp);
442     if (*errp) {
443         goto error;
444     }
445     d->irq = v;
446 
447     xen_host_pci_get_hex_value(d, "class", &v, errp);
448     if (*errp) {
449         goto error;
450     }
451     d->class_code = v;
452 
453     d->is_virtfn = xen_host_pci_dev_is_virtfn(d);
454 
455     return;
456 
457 error:
458 
459     if (d->config_fd >= 0) {
460         close(d->config_fd);
461         d->config_fd = -1;
462     }
463 }
464 
465 bool xen_host_pci_device_closed(XenHostPCIDevice *d)
466 {
467     return d->config_fd == -1;
468 }
469 
470 void xen_host_pci_device_put(XenHostPCIDevice *d)
471 {
472     if (d->config_fd >= 0) {
473         close(d->config_fd);
474         d->config_fd = -1;
475     }
476 }
477