xref: /openbmc/qemu/hw/pci/pcie.c (revision bf957284)
1 /*
2  * pcie.c
3  *
4  * Copyright (c) 2010 Isaku Yamahata <yamahata at valinux co jp>
5  *                    VA Linux Systems Japan K.K.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License along
18  * with this program; if not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include "qemu-common.h"
22 #include "hw/pci/pci_bridge.h"
23 #include "hw/pci/pcie.h"
24 #include "hw/pci/msix.h"
25 #include "hw/pci/msi.h"
26 #include "hw/pci/pci_bus.h"
27 #include "hw/pci/pcie_regs.h"
28 #include "qemu/range.h"
29 
30 //#define DEBUG_PCIE
31 #ifdef DEBUG_PCIE
32 # define PCIE_DPRINTF(fmt, ...)                                         \
33     fprintf(stderr, "%s:%d " fmt, __func__, __LINE__, ## __VA_ARGS__)
34 #else
35 # define PCIE_DPRINTF(fmt, ...) do {} while (0)
36 #endif
37 #define PCIE_DEV_PRINTF(dev, fmt, ...)                                  \
38     PCIE_DPRINTF("%s:%x "fmt, (dev)->name, (dev)->devfn, ## __VA_ARGS__)
39 
40 
41 /***************************************************************************
42  * pci express capability helper functions
43  */
44 int pcie_cap_init(PCIDevice *dev, uint8_t offset, uint8_t type, uint8_t port)
45 {
46     int pos;
47     uint8_t *exp_cap;
48 
49     assert(pci_is_express(dev));
50 
51     pos = pci_add_capability(dev, PCI_CAP_ID_EXP, offset,
52                                  PCI_EXP_VER2_SIZEOF);
53     if (pos < 0) {
54         return pos;
55     }
56     dev->exp.exp_cap = pos;
57     exp_cap = dev->config + pos;
58 
59     /* capability register
60        interrupt message number defaults to 0 */
61     pci_set_word(exp_cap + PCI_EXP_FLAGS,
62                  ((type << PCI_EXP_FLAGS_TYPE_SHIFT) & PCI_EXP_FLAGS_TYPE) |
63                  PCI_EXP_FLAGS_VER2);
64 
65     /* device capability register
66      * table 7-12:
67      * roll based error reporting bit must be set by all
68      * Functions conforming to the ECN, PCI Express Base
69      * Specification, Revision 1.1., or subsequent PCI Express Base
70      * Specification revisions.
71      */
72     pci_set_long(exp_cap + PCI_EXP_DEVCAP, PCI_EXP_DEVCAP_RBER);
73 
74     pci_set_long(exp_cap + PCI_EXP_LNKCAP,
75                  (port << PCI_EXP_LNKCAP_PN_SHIFT) |
76                  PCI_EXP_LNKCAP_ASPMS_0S |
77                  PCI_EXP_LNK_MLW_1 |
78                  PCI_EXP_LNK_LS_25);
79 
80     pci_set_word(exp_cap + PCI_EXP_LNKSTA,
81                  PCI_EXP_LNK_MLW_1 | PCI_EXP_LNK_LS_25 |PCI_EXP_LNKSTA_DLLLA);
82 
83     pci_set_long(exp_cap + PCI_EXP_DEVCAP2,
84                  PCI_EXP_DEVCAP2_EFF | PCI_EXP_DEVCAP2_EETLPP);
85 
86     pci_set_word(dev->wmask + pos + PCI_EXP_DEVCTL2, PCI_EXP_DEVCTL2_EETLPPB);
87     return pos;
88 }
89 
90 int pcie_endpoint_cap_init(PCIDevice *dev, uint8_t offset)
91 {
92     uint8_t type = PCI_EXP_TYPE_ENDPOINT;
93 
94     /*
95      * Windows guests will report Code 10, device cannot start, if
96      * a regular Endpoint type is exposed on a root complex.  These
97      * should instead be Root Complex Integrated Endpoints.
98      */
99     if (pci_bus_is_express(dev->bus) && pci_bus_is_root(dev->bus)) {
100         type = PCI_EXP_TYPE_RC_END;
101     }
102 
103     return pcie_cap_init(dev, offset, type, 0);
104 }
105 
106 void pcie_cap_exit(PCIDevice *dev)
107 {
108     pci_del_capability(dev, PCI_CAP_ID_EXP, PCI_EXP_VER2_SIZEOF);
109 }
110 
111 uint8_t pcie_cap_get_type(const PCIDevice *dev)
112 {
113     uint32_t pos = dev->exp.exp_cap;
114     assert(pos > 0);
115     return (pci_get_word(dev->config + pos + PCI_EXP_FLAGS) &
116             PCI_EXP_FLAGS_TYPE) >> PCI_EXP_FLAGS_TYPE_SHIFT;
117 }
118 
119 /* MSI/MSI-X */
120 /* pci express interrupt message number */
121 /* 7.8.2 PCI Express Capabilities Register: Interrupt Message Number */
122 void pcie_cap_flags_set_vector(PCIDevice *dev, uint8_t vector)
123 {
124     uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
125     assert(vector < 32);
126     pci_word_test_and_clear_mask(exp_cap + PCI_EXP_FLAGS, PCI_EXP_FLAGS_IRQ);
127     pci_word_test_and_set_mask(exp_cap + PCI_EXP_FLAGS,
128                                vector << PCI_EXP_FLAGS_IRQ_SHIFT);
129 }
130 
131 uint8_t pcie_cap_flags_get_vector(PCIDevice *dev)
132 {
133     return (pci_get_word(dev->config + dev->exp.exp_cap + PCI_EXP_FLAGS) &
134             PCI_EXP_FLAGS_IRQ) >> PCI_EXP_FLAGS_IRQ_SHIFT;
135 }
136 
137 void pcie_cap_deverr_init(PCIDevice *dev)
138 {
139     uint32_t pos = dev->exp.exp_cap;
140     pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_DEVCAP,
141                                PCI_EXP_DEVCAP_RBER);
142     pci_long_test_and_set_mask(dev->wmask + pos + PCI_EXP_DEVCTL,
143                                PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE |
144                                PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE);
145     pci_long_test_and_set_mask(dev->w1cmask + pos + PCI_EXP_DEVSTA,
146                                PCI_EXP_DEVSTA_CED | PCI_EXP_DEVSTA_NFED |
147                                PCI_EXP_DEVSTA_FED | PCI_EXP_DEVSTA_URD);
148 }
149 
150 void pcie_cap_deverr_reset(PCIDevice *dev)
151 {
152     uint8_t *devctl = dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL;
153     pci_long_test_and_clear_mask(devctl,
154                                  PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE |
155                                  PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE);
156 }
157 
158 static void hotplug_event_update_event_status(PCIDevice *dev)
159 {
160     uint32_t pos = dev->exp.exp_cap;
161     uint8_t *exp_cap = dev->config + pos;
162     uint16_t sltctl = pci_get_word(exp_cap + PCI_EXP_SLTCTL);
163     uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
164 
165     dev->exp.hpev_notified = (sltctl & PCI_EXP_SLTCTL_HPIE) &&
166         (sltsta & sltctl & PCI_EXP_HP_EV_SUPPORTED);
167 }
168 
169 static void hotplug_event_notify(PCIDevice *dev)
170 {
171     bool prev = dev->exp.hpev_notified;
172 
173     hotplug_event_update_event_status(dev);
174 
175     if (prev == dev->exp.hpev_notified) {
176         return;
177     }
178 
179     /* Note: the logic above does not take into account whether interrupts
180      * are masked. The result is that interrupt will be sent when it is
181      * subsequently unmasked. This appears to be legal: Section 6.7.3.4:
182      * The Port may optionally send an MSI when there are hot-plug events that
183      * occur while interrupt generation is disabled, and interrupt generation is
184      * subsequently enabled. */
185     if (msix_enabled(dev)) {
186         msix_notify(dev, pcie_cap_flags_get_vector(dev));
187     } else if (msi_enabled(dev)) {
188         msi_notify(dev, pcie_cap_flags_get_vector(dev));
189     } else {
190         pci_set_irq(dev, dev->exp.hpev_notified);
191     }
192 }
193 
194 static void hotplug_event_clear(PCIDevice *dev)
195 {
196     hotplug_event_update_event_status(dev);
197     if (!msix_enabled(dev) && !msi_enabled(dev) && !dev->exp.hpev_notified) {
198         pci_irq_deassert(dev);
199     }
200 }
201 
202 /*
203  * A PCI Express Hot-Plug Event has occurred, so update slot status register
204  * and notify OS of the event if necessary.
205  *
206  * 6.7.3 PCI Express Hot-Plug Events
207  * 6.7.3.4 Software Notification of Hot-Plug Events
208  */
209 static void pcie_cap_slot_event(PCIDevice *dev, PCIExpressHotPlugEvent event)
210 {
211     /* Minor optimization: if nothing changed - no event is needed. */
212     if (pci_word_test_and_set_mask(dev->config + dev->exp.exp_cap +
213                                    PCI_EXP_SLTSTA, event)) {
214         return;
215     }
216     hotplug_event_notify(dev);
217 }
218 
219 static void pcie_cap_slot_hotplug_common(PCIDevice *hotplug_dev,
220                                          DeviceState *dev,
221                                          uint8_t **exp_cap, Error **errp)
222 {
223     *exp_cap = hotplug_dev->config + hotplug_dev->exp.exp_cap;
224     uint16_t sltsta = pci_get_word(*exp_cap + PCI_EXP_SLTSTA);
225 
226     PCIE_DEV_PRINTF(PCI_DEVICE(dev), "hotplug state: 0x%x\n", sltsta);
227     if (sltsta & PCI_EXP_SLTSTA_EIS) {
228         /* the slot is electromechanically locked.
229          * This error is propagated up to qdev and then to HMP/QMP.
230          */
231         error_setg_errno(errp, EBUSY, "slot is electromechanically locked");
232     }
233 }
234 
235 void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
236                               Error **errp)
237 {
238     uint8_t *exp_cap;
239     PCIDevice *pci_dev = PCI_DEVICE(dev);
240 
241     pcie_cap_slot_hotplug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
242 
243     /* Don't send event when device is enabled during qemu machine creation:
244      * it is present on boot, no hotplug event is necessary. We do send an
245      * event when the device is disabled later. */
246     if (!dev->hotplugged) {
247         pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
248                                    PCI_EXP_SLTSTA_PDS);
249         return;
250     }
251 
252     /* TODO: multifunction hot-plug.
253      * Right now, only a device of function = 0 is allowed to be
254      * hot plugged/unplugged.
255      */
256     assert(PCI_FUNC(pci_dev->devfn) == 0);
257 
258     pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
259                                PCI_EXP_SLTSTA_PDS);
260     pcie_cap_slot_event(PCI_DEVICE(hotplug_dev),
261                         PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
262 }
263 
264 void pcie_cap_slot_hot_unplug_request_cb(HotplugHandler *hotplug_dev,
265                                          DeviceState *dev, Error **errp)
266 {
267     uint8_t *exp_cap;
268 
269     pcie_cap_slot_hotplug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
270 
271     pcie_cap_slot_push_attention_button(PCI_DEVICE(hotplug_dev));
272 }
273 
274 /* pci express slot for pci express root/downstream port
275    PCI express capability slot registers */
276 void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot)
277 {
278     uint32_t pos = dev->exp.exp_cap;
279 
280     pci_word_test_and_set_mask(dev->config + pos + PCI_EXP_FLAGS,
281                                PCI_EXP_FLAGS_SLOT);
282 
283     pci_long_test_and_clear_mask(dev->config + pos + PCI_EXP_SLTCAP,
284                                  ~PCI_EXP_SLTCAP_PSN);
285     pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCAP,
286                                (slot << PCI_EXP_SLTCAP_PSN_SHIFT) |
287                                PCI_EXP_SLTCAP_EIP |
288                                PCI_EXP_SLTCAP_HPS |
289                                PCI_EXP_SLTCAP_HPC |
290                                PCI_EXP_SLTCAP_PIP |
291                                PCI_EXP_SLTCAP_AIP |
292                                PCI_EXP_SLTCAP_ABP);
293 
294     if (dev->cap_present & QEMU_PCIE_SLTCAP_PCP) {
295         pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCAP,
296                                    PCI_EXP_SLTCAP_PCP);
297         pci_word_test_and_clear_mask(dev->config + pos + PCI_EXP_SLTCTL,
298                                      PCI_EXP_SLTCTL_PCC);
299         pci_word_test_and_set_mask(dev->wmask + pos + PCI_EXP_SLTCTL,
300                                    PCI_EXP_SLTCTL_PCC);
301     }
302 
303     pci_word_test_and_clear_mask(dev->config + pos + PCI_EXP_SLTCTL,
304                                  PCI_EXP_SLTCTL_PIC |
305                                  PCI_EXP_SLTCTL_AIC);
306     pci_word_test_and_set_mask(dev->config + pos + PCI_EXP_SLTCTL,
307                                PCI_EXP_SLTCTL_PIC_OFF |
308                                PCI_EXP_SLTCTL_AIC_OFF);
309     pci_word_test_and_set_mask(dev->wmask + pos + PCI_EXP_SLTCTL,
310                                PCI_EXP_SLTCTL_PIC |
311                                PCI_EXP_SLTCTL_AIC |
312                                PCI_EXP_SLTCTL_HPIE |
313                                PCI_EXP_SLTCTL_CCIE |
314                                PCI_EXP_SLTCTL_PDCE |
315                                PCI_EXP_SLTCTL_ABPE);
316     /* Although reading PCI_EXP_SLTCTL_EIC returns always 0,
317      * make the bit writable here in order to detect 1b is written.
318      * pcie_cap_slot_write_config() test-and-clear the bit, so
319      * this bit always returns 0 to the guest.
320      */
321     pci_word_test_and_set_mask(dev->wmask + pos + PCI_EXP_SLTCTL,
322                                PCI_EXP_SLTCTL_EIC);
323 
324     pci_word_test_and_set_mask(dev->w1cmask + pos + PCI_EXP_SLTSTA,
325                                PCI_EXP_HP_EV_SUPPORTED);
326 
327     dev->exp.hpev_notified = false;
328 
329     qbus_set_hotplug_handler(BUS(pci_bridge_get_sec_bus(PCI_BRIDGE(dev))),
330                              DEVICE(dev), NULL);
331 }
332 
333 void pcie_cap_slot_reset(PCIDevice *dev)
334 {
335     uint8_t *exp_cap = dev->config + dev->exp.exp_cap;
336     uint8_t port_type = pcie_cap_get_type(dev);
337 
338     assert(port_type == PCI_EXP_TYPE_DOWNSTREAM ||
339            port_type == PCI_EXP_TYPE_ROOT_PORT);
340 
341     PCIE_DEV_PRINTF(dev, "reset\n");
342 
343     pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTCTL,
344                                  PCI_EXP_SLTCTL_EIC |
345                                  PCI_EXP_SLTCTL_PIC |
346                                  PCI_EXP_SLTCTL_AIC |
347                                  PCI_EXP_SLTCTL_HPIE |
348                                  PCI_EXP_SLTCTL_CCIE |
349                                  PCI_EXP_SLTCTL_PDCE |
350                                  PCI_EXP_SLTCTL_ABPE);
351     pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTCTL,
352                                PCI_EXP_SLTCTL_AIC_OFF);
353 
354     if (dev->cap_present & QEMU_PCIE_SLTCAP_PCP) {
355         /* Downstream ports enforce device number 0. */
356         bool populated = pci_bridge_get_sec_bus(PCI_BRIDGE(dev))->devices[0];
357         uint16_t pic;
358 
359         if (populated) {
360             pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTCTL,
361                                          PCI_EXP_SLTCTL_PCC);
362         } else {
363             pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTCTL,
364                                        PCI_EXP_SLTCTL_PCC);
365         }
366 
367         pic = populated ? PCI_EXP_SLTCTL_PIC_ON : PCI_EXP_SLTCTL_PIC_OFF;
368         pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTCTL, pic);
369     }
370 
371     pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
372                                  PCI_EXP_SLTSTA_EIS |/* on reset,
373                                                         the lock is released */
374                                  PCI_EXP_SLTSTA_CC |
375                                  PCI_EXP_SLTSTA_PDC |
376                                  PCI_EXP_SLTSTA_ABP);
377 
378     hotplug_event_update_event_status(dev);
379 }
380 
381 static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, void *opaque)
382 {
383     object_unparent(OBJECT(dev));
384 }
385 
386 void pcie_cap_slot_write_config(PCIDevice *dev,
387                                 uint32_t addr, uint32_t val, int len)
388 {
389     uint32_t pos = dev->exp.exp_cap;
390     uint8_t *exp_cap = dev->config + pos;
391     uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
392 
393     if (ranges_overlap(addr, len, pos + PCI_EXP_SLTSTA, 2)) {
394         hotplug_event_clear(dev);
395     }
396 
397     if (!ranges_overlap(addr, len, pos + PCI_EXP_SLTCTL, 2)) {
398         return;
399     }
400 
401     if (pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTCTL,
402                                      PCI_EXP_SLTCTL_EIC)) {
403         sltsta ^= PCI_EXP_SLTSTA_EIS; /* toggle PCI_EXP_SLTSTA_EIS bit */
404         pci_set_word(exp_cap + PCI_EXP_SLTSTA, sltsta);
405         PCIE_DEV_PRINTF(dev, "PCI_EXP_SLTCTL_EIC: "
406                         "sltsta -> 0x%02"PRIx16"\n",
407                         sltsta);
408     }
409 
410     /*
411      * If the slot is polulated, power indicator is off and power
412      * controller is off, it is safe to detach the devices.
413      */
414     if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
415         ((val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF)) {
416             PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
417             pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
418                                 pcie_unplug_device, NULL);
419 
420             pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
421                                          PCI_EXP_SLTSTA_PDS);
422             pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
423                                        PCI_EXP_SLTSTA_PDC);
424     }
425 
426     hotplug_event_notify(dev);
427 
428     /*
429      * 6.7.3.2 Command Completed Events
430      *
431      * Software issues a command to a hot-plug capable Downstream Port by
432      * issuing a write transaction that targets any portion of the Port’s Slot
433      * Control register. A single write to the Slot Control register is
434      * considered to be a single command, even if the write affects more than
435      * one field in the Slot Control register. In response to this transaction,
436      * the Port must carry out the requested actions and then set the
437      * associated status field for the command completed event. */
438 
439     /* Real hardware might take a while to complete requested command because
440      * physical movement would be involved like locking the electromechanical
441      * lock.  However in our case, command is completed instantaneously above,
442      * so send a command completion event right now.
443      */
444     pcie_cap_slot_event(dev, PCI_EXP_HP_EV_CCI);
445 }
446 
447 int pcie_cap_slot_post_load(void *opaque, int version_id)
448 {
449     PCIDevice *dev = opaque;
450     hotplug_event_update_event_status(dev);
451     return 0;
452 }
453 
454 void pcie_cap_slot_push_attention_button(PCIDevice *dev)
455 {
456     pcie_cap_slot_event(dev, PCI_EXP_HP_EV_ABP);
457 }
458 
459 /* root control/capabilities/status. PME isn't emulated for now */
460 void pcie_cap_root_init(PCIDevice *dev)
461 {
462     pci_set_word(dev->wmask + dev->exp.exp_cap + PCI_EXP_RTCTL,
463                  PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE |
464                  PCI_EXP_RTCTL_SEFEE);
465 }
466 
467 void pcie_cap_root_reset(PCIDevice *dev)
468 {
469     pci_set_word(dev->config + dev->exp.exp_cap + PCI_EXP_RTCTL, 0);
470 }
471 
472 /* function level reset(FLR) */
473 void pcie_cap_flr_init(PCIDevice *dev)
474 {
475     pci_long_test_and_set_mask(dev->config + dev->exp.exp_cap + PCI_EXP_DEVCAP,
476                                PCI_EXP_DEVCAP_FLR);
477 
478     /* Although reading BCR_FLR returns always 0,
479      * the bit is made writable here in order to detect the 1b is written
480      * pcie_cap_flr_write_config() test-and-clear the bit, so
481      * this bit always returns 0 to the guest.
482      */
483     pci_word_test_and_set_mask(dev->wmask + dev->exp.exp_cap + PCI_EXP_DEVCTL,
484                                PCI_EXP_DEVCTL_BCR_FLR);
485 }
486 
487 void pcie_cap_flr_write_config(PCIDevice *dev,
488                                uint32_t addr, uint32_t val, int len)
489 {
490     uint8_t *devctl = dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL;
491     if (pci_get_word(devctl) & PCI_EXP_DEVCTL_BCR_FLR) {
492         /* Clear PCI_EXP_DEVCTL_BCR_FLR after invoking the reset handler
493            so the handler can detect FLR by looking at this bit. */
494         pci_device_reset(dev);
495         pci_word_test_and_clear_mask(devctl, PCI_EXP_DEVCTL_BCR_FLR);
496     }
497 }
498 
499 /* Alternative Routing-ID Interpretation (ARI)
500  * forwarding support for root and downstream ports
501  */
502 void pcie_cap_arifwd_init(PCIDevice *dev)
503 {
504     uint32_t pos = dev->exp.exp_cap;
505     pci_long_test_and_set_mask(dev->config + pos + PCI_EXP_DEVCAP2,
506                                PCI_EXP_DEVCAP2_ARI);
507     pci_long_test_and_set_mask(dev->wmask + pos + PCI_EXP_DEVCTL2,
508                                PCI_EXP_DEVCTL2_ARI);
509 }
510 
511 void pcie_cap_arifwd_reset(PCIDevice *dev)
512 {
513     uint8_t *devctl2 = dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL2;
514     pci_long_test_and_clear_mask(devctl2, PCI_EXP_DEVCTL2_ARI);
515 }
516 
517 bool pcie_cap_is_arifwd_enabled(const PCIDevice *dev)
518 {
519     if (!pci_is_express(dev)) {
520         return false;
521     }
522     if (!dev->exp.exp_cap) {
523         return false;
524     }
525 
526     return pci_get_long(dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL2) &
527         PCI_EXP_DEVCTL2_ARI;
528 }
529 
530 /**************************************************************************
531  * pci express extended capability list management functions
532  * uint16_t ext_cap_id (16 bit)
533  * uint8_t cap_ver (4 bit)
534  * uint16_t cap_offset (12 bit)
535  * uint16_t ext_cap_size
536  */
537 
538 static uint16_t pcie_find_capability_list(PCIDevice *dev, uint16_t cap_id,
539                                           uint16_t *prev_p)
540 {
541     uint16_t prev = 0;
542     uint16_t next;
543     uint32_t header = pci_get_long(dev->config + PCI_CONFIG_SPACE_SIZE);
544 
545     if (!header) {
546         /* no extended capability */
547         next = 0;
548         goto out;
549     }
550     for (next = PCI_CONFIG_SPACE_SIZE; next;
551          prev = next, next = PCI_EXT_CAP_NEXT(header)) {
552 
553         assert(next >= PCI_CONFIG_SPACE_SIZE);
554         assert(next <= PCIE_CONFIG_SPACE_SIZE - 8);
555 
556         header = pci_get_long(dev->config + next);
557         if (PCI_EXT_CAP_ID(header) == cap_id) {
558             break;
559         }
560     }
561 
562 out:
563     if (prev_p) {
564         *prev_p = prev;
565     }
566     return next;
567 }
568 
569 uint16_t pcie_find_capability(PCIDevice *dev, uint16_t cap_id)
570 {
571     return pcie_find_capability_list(dev, cap_id, NULL);
572 }
573 
574 static void pcie_ext_cap_set_next(PCIDevice *dev, uint16_t pos, uint16_t next)
575 {
576     uint32_t header = pci_get_long(dev->config + pos);
577     assert(!(next & (PCI_EXT_CAP_ALIGN - 1)));
578     header = (header & ~PCI_EXT_CAP_NEXT_MASK) |
579         ((next << PCI_EXT_CAP_NEXT_SHIFT) & PCI_EXT_CAP_NEXT_MASK);
580     pci_set_long(dev->config + pos, header);
581 }
582 
583 /*
584  * caller must supply valid (offset, size) * such that the range shouldn't
585  * overlap with other capability or other registers.
586  * This function doesn't check it.
587  */
588 void pcie_add_capability(PCIDevice *dev,
589                          uint16_t cap_id, uint8_t cap_ver,
590                          uint16_t offset, uint16_t size)
591 {
592     uint32_t header;
593     uint16_t next;
594 
595     assert(offset >= PCI_CONFIG_SPACE_SIZE);
596     assert(offset < offset + size);
597     assert(offset + size < PCIE_CONFIG_SPACE_SIZE);
598     assert(size >= 8);
599     assert(pci_is_express(dev));
600 
601     if (offset == PCI_CONFIG_SPACE_SIZE) {
602         header = pci_get_long(dev->config + offset);
603         next = PCI_EXT_CAP_NEXT(header);
604     } else {
605         uint16_t prev;
606 
607         /* 0 is reserved cap id. use internally to find the last capability
608            in the linked list */
609         next = pcie_find_capability_list(dev, 0, &prev);
610 
611         assert(prev >= PCI_CONFIG_SPACE_SIZE);
612         assert(next == 0);
613         pcie_ext_cap_set_next(dev, prev, offset);
614     }
615     pci_set_long(dev->config + offset, PCI_EXT_CAP(cap_id, cap_ver, next));
616 
617     /* Make capability read-only by default */
618     memset(dev->wmask + offset, 0, size);
619     memset(dev->w1cmask + offset, 0, size);
620     /* Check capability by default */
621     memset(dev->cmask + offset, 0xFF, size);
622 }
623 
624 /**************************************************************************
625  * pci express extended capability helper functions
626  */
627 
628 /* ARI */
629 void pcie_ari_init(PCIDevice *dev, uint16_t offset, uint16_t nextfn)
630 {
631     pcie_add_capability(dev, PCI_EXT_CAP_ID_ARI, PCI_ARI_VER,
632                         offset, PCI_ARI_SIZEOF);
633     pci_set_long(dev->config + offset + PCI_ARI_CAP, (nextfn & 0xff) << 8);
634 }
635