1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Xen PCI - handle PCI (INTx) and MSI infrastructure calls for PV, HVM and
4 * initial domain support. We also handle the DSDT _PRT callbacks for GSI's
5 * used in HVM and initial domain mode (PV does not parse ACPI, so it has no
6 * concept of GSIs). Under PV we hook under the pnbbios API for IRQs and
7 * 0xcf8 PCI configuration read/write.
8 *
9 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
10 * Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
11 * Stefano Stabellini <stefano.stabellini@eu.citrix.com>
12 */
13#include <linux/export.h>
14#include <linux/init.h>
15#include <linux/pci.h>
16#include <linux/acpi.h>
17
18#include <linux/io.h>
19#include <asm/io_apic.h>
20#include <asm/pci_x86.h>
21
22#include <asm/xen/hypervisor.h>
23
24#include <xen/features.h>
25#include <xen/events.h>
26#include <xen/pci.h>
27#include <asm/xen/pci.h>
28#include <asm/xen/cpuid.h>
29#include <asm/apic.h>
30#include <asm/acpi.h>
31#include <asm/i8259.h>
32
33static int xen_pcifront_enable_irq(struct pci_dev *dev)
34{
35 int rc;
36 int share = 1;
37 int pirq;
38 u8 gsi;
39
40 rc = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, val: &gsi);
41 if (rc) {
42 dev_warn(&dev->dev, "Xen PCI: failed to read interrupt line: %d\n",
43 rc);
44 return pcibios_err_to_errno(err: rc);
45 }
46 /* In PV DomU the Xen PCI backend puts the PIRQ in the interrupt line.*/
47 pirq = gsi;
48
49 if (gsi < nr_legacy_irqs())
50 share = 0;
51
52 rc = xen_bind_pirq_gsi_to_irq(gsi, pirq, shareable: share, name: "pcifront");
53 if (rc < 0) {
54 dev_warn(&dev->dev, "Xen PCI: failed to bind GSI%d (PIRQ%d) to IRQ: %d\n",
55 gsi, pirq, rc);
56 return rc;
57 }
58
59 dev->irq = rc;
60 dev_info(&dev->dev, "Xen PCI mapped GSI%d to IRQ%d\n", gsi, dev->irq);
61 return 0;
62}
63
64#ifdef CONFIG_ACPI
65static int xen_register_pirq(u32 gsi, int triggering, bool set_pirq)
66{
67 int rc, pirq = -1, irq;
68 struct physdev_map_pirq map_irq;
69 int shareable = 0;
70 char *name;
71
72 irq = xen_irq_from_gsi(gsi);
73 if (irq > 0)
74 return irq;
75
76 if (set_pirq)
77 pirq = gsi;
78
79 map_irq.domid = DOMID_SELF;
80 map_irq.type = MAP_PIRQ_TYPE_GSI;
81 map_irq.index = gsi;
82 map_irq.pirq = pirq;
83
84 rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, arg: &map_irq);
85 if (rc) {
86 printk(KERN_WARNING "xen map irq failed %d\n", rc);
87 return -1;
88 }
89
90 if (triggering == ACPI_EDGE_SENSITIVE) {
91 shareable = 0;
92 name = "ioapic-edge";
93 } else {
94 shareable = 1;
95 name = "ioapic-level";
96 }
97
98 irq = xen_bind_pirq_gsi_to_irq(gsi, pirq: map_irq.pirq, shareable, name);
99 if (irq < 0)
100 goto out;
101
102 printk(KERN_DEBUG "xen: --> pirq=%d -> irq=%d (gsi=%d)\n", map_irq.pirq, irq, gsi);
103out:
104 return irq;
105}
106
107static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
108 int trigger, int polarity)
109{
110 if (!xen_hvm_domain())
111 return -1;
112
113 return xen_register_pirq(gsi, triggering: trigger,
114 set_pirq: false /* no mapping of GSI to PIRQ */);
115}
116
117#ifdef CONFIG_XEN_PV_DOM0
118static int xen_register_gsi(u32 gsi, int triggering, int polarity)
119{
120 int rc, irq;
121 struct physdev_setup_gsi setup_gsi;
122
123 if (!xen_pv_domain())
124 return -1;
125
126 printk(KERN_DEBUG "xen: registering gsi %u triggering %d polarity %d\n",
127 gsi, triggering, polarity);
128
129 irq = xen_register_pirq(gsi, triggering, set_pirq: true);
130
131 setup_gsi.gsi = gsi;
132 setup_gsi.triggering = (triggering == ACPI_EDGE_SENSITIVE ? 0 : 1);
133 setup_gsi.polarity = (polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
134
135 rc = HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, arg: &setup_gsi);
136 if (rc == -EEXIST)
137 printk(KERN_INFO "Already setup the GSI :%d\n", gsi);
138 else if (rc) {
139 printk(KERN_ERR "Failed to setup GSI :%d, err_code:%d\n",
140 gsi, rc);
141 }
142
143 return irq;
144}
145
146static int acpi_register_gsi_xen(struct device *dev, u32 gsi,
147 int trigger, int polarity)
148{
149 return xen_register_gsi(gsi, triggering: trigger, polarity);
150}
151#endif
152#endif
153
154#if defined(CONFIG_PCI_MSI)
155#include <linux/msi.h>
156
157struct xen_pci_frontend_ops *xen_pci_frontend;
158EXPORT_SYMBOL_GPL(xen_pci_frontend);
159
160struct xen_msi_ops {
161 int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
162 void (*teardown_msi_irqs)(struct pci_dev *dev);
163};
164
165static struct xen_msi_ops xen_msi_ops __ro_after_init;
166
167static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
168{
169 int irq, ret, i;
170 struct msi_desc *msidesc;
171 int *v;
172
173 if (type == PCI_CAP_ID_MSI && nvec > 1)
174 return 1;
175
176 v = kcalloc(max(1, nvec), sizeof(int), GFP_KERNEL);
177 if (!v)
178 return -ENOMEM;
179
180 if (type == PCI_CAP_ID_MSIX)
181 ret = xen_pci_frontend_enable_msix(dev, vectors: v, nvec);
182 else
183 ret = xen_pci_frontend_enable_msi(dev, vectors: v);
184 if (ret)
185 goto error;
186 i = 0;
187 msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
188 irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq: v[i],
189 nvec: (type == PCI_CAP_ID_MSI) ? nvec : 1,
190 name: (type == PCI_CAP_ID_MSIX) ?
191 "pcifront-msi-x" :
192 "pcifront-msi",
193 DOMID_SELF);
194 if (irq < 0) {
195 ret = irq;
196 goto free;
197 }
198 i++;
199 }
200 kfree(objp: v);
201 return msi_device_populate_sysfs(dev: &dev->dev);
202
203error:
204 if (ret == -ENOSYS)
205 dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
206 else if (ret)
207 dev_err(&dev->dev, "Xen PCI frontend error: %d!\n", ret);
208free:
209 kfree(objp: v);
210 return ret;
211}
212
213static void xen_msi_compose_msg(struct pci_dev *pdev, unsigned int pirq,
214 struct msi_msg *msg)
215{
216 /*
217 * We set vector == 0 to tell the hypervisor we don't care about
218 * it, but we want a pirq setup instead. We use the dest_id fields
219 * to pass the pirq that we want.
220 */
221 memset(msg, 0, sizeof(*msg));
222 msg->address_hi = X86_MSI_BASE_ADDRESS_HIGH;
223 msg->arch_addr_hi.destid_8_31 = pirq >> 8;
224 msg->arch_addr_lo.destid_0_7 = pirq & 0xFF;
225 msg->arch_addr_lo.base_address = X86_MSI_BASE_ADDRESS_LOW;
226 msg->arch_data.delivery_mode = APIC_DELIVERY_MODE_EXTINT;
227}
228
229static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
230{
231 int irq, pirq;
232 struct msi_desc *msidesc;
233 struct msi_msg msg;
234
235 if (type == PCI_CAP_ID_MSI && nvec > 1)
236 return 1;
237
238 msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
239 pirq = xen_allocate_pirq_msi(dev, msidesc);
240 if (pirq < 0) {
241 irq = -ENODEV;
242 goto error;
243 }
244 xen_msi_compose_msg(pdev: dev, pirq, msg: &msg);
245 __pci_write_msi_msg(entry: msidesc, msg: &msg);
246 dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
247 irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
248 nvec: (type == PCI_CAP_ID_MSI) ? nvec : 1,
249 name: (type == PCI_CAP_ID_MSIX) ?
250 "msi-x" : "msi",
251 DOMID_SELF);
252 if (irq < 0)
253 goto error;
254 dev_dbg(&dev->dev,
255 "xen: msi --> pirq=%d --> irq=%d\n", pirq, irq);
256 }
257 return msi_device_populate_sysfs(dev: &dev->dev);
258
259error:
260 dev_err(&dev->dev, "Failed to create MSI%s! ret=%d!\n",
261 type == PCI_CAP_ID_MSI ? "" : "-X", irq);
262 return irq;
263}
264
265#ifdef CONFIG_XEN_PV_DOM0
266static bool __read_mostly pci_seg_supported = true;
267
268static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
269{
270 int ret = 0;
271 struct msi_desc *msidesc;
272
273 msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
274 struct physdev_map_pirq map_irq;
275 domid_t domid;
276
277 domid = ret = xen_find_device_domain_owner(dev);
278 /* N.B. Casting int's -ENODEV to uint16_t results in 0xFFED,
279 * hence check ret value for < 0. */
280 if (ret < 0)
281 domid = DOMID_SELF;
282
283 memset(&map_irq, 0, sizeof(map_irq));
284 map_irq.domid = domid;
285 map_irq.type = MAP_PIRQ_TYPE_MSI_SEG;
286 map_irq.index = -1;
287 map_irq.pirq = -1;
288 map_irq.bus = dev->bus->number |
289 (pci_domain_nr(bus: dev->bus) << 16);
290 map_irq.devfn = dev->devfn;
291
292 if (type == PCI_CAP_ID_MSI && nvec > 1) {
293 map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
294 map_irq.entry_nr = nvec;
295 } else if (type == PCI_CAP_ID_MSIX) {
296 int pos;
297 unsigned long flags;
298 u32 table_offset, bir;
299
300 pos = dev->msix_cap;
301 pci_read_config_dword(dev, where: pos + PCI_MSIX_TABLE,
302 val: &table_offset);
303 bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);
304 flags = pci_resource_flags(dev, bir);
305 if (!flags || (flags & IORESOURCE_UNSET))
306 return -EINVAL;
307
308 map_irq.table_base = pci_resource_start(dev, bir);
309 map_irq.entry_nr = msidesc->msi_index;
310 }
311
312 ret = -EINVAL;
313 if (pci_seg_supported)
314 ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
315 arg: &map_irq);
316 if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
317 /*
318 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
319 * there's nothing else we can do in this case.
320 * Just set ret > 0 so driver can retry with
321 * single MSI.
322 */
323 ret = 1;
324 goto out;
325 }
326 if (ret == -EINVAL && !pci_domain_nr(bus: dev->bus)) {
327 map_irq.type = MAP_PIRQ_TYPE_MSI;
328 map_irq.index = -1;
329 map_irq.pirq = -1;
330 map_irq.bus = dev->bus->number;
331 ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
332 arg: &map_irq);
333 if (ret != -EINVAL)
334 pci_seg_supported = false;
335 }
336 if (ret) {
337 dev_warn(&dev->dev, "xen map irq failed %d for %d domain\n",
338 ret, domid);
339 goto out;
340 }
341
342 ret = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq: map_irq.pirq,
343 nvec: (type == PCI_CAP_ID_MSI) ? nvec : 1,
344 name: (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
345 domid);
346 if (ret < 0)
347 goto out;
348 }
349 ret = msi_device_populate_sysfs(dev: &dev->dev);
350out:
351 return ret;
352}
353
354bool xen_initdom_restore_msi(struct pci_dev *dev)
355{
356 int ret = 0;
357
358 if (!xen_initial_domain())
359 return true;
360
361 if (pci_seg_supported) {
362 struct physdev_pci_device restore_ext;
363
364 restore_ext.seg = pci_domain_nr(bus: dev->bus);
365 restore_ext.bus = dev->bus->number;
366 restore_ext.devfn = dev->devfn;
367 ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi_ext,
368 arg: &restore_ext);
369 if (ret == -ENOSYS)
370 pci_seg_supported = false;
371 WARN(ret && ret != -ENOSYS, "restore_msi_ext -> %d\n", ret);
372 }
373 if (!pci_seg_supported) {
374 struct physdev_restore_msi restore;
375
376 restore.bus = dev->bus->number;
377 restore.devfn = dev->devfn;
378 ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi, arg: &restore);
379 WARN(ret && ret != -ENOSYS, "restore_msi -> %d\n", ret);
380 }
381 return false;
382}
383#else /* CONFIG_XEN_PV_DOM0 */
384#define xen_initdom_setup_msi_irqs NULL
385#endif /* !CONFIG_XEN_PV_DOM0 */
386
387static void xen_teardown_msi_irqs(struct pci_dev *dev)
388{
389 struct msi_desc *msidesc;
390 int i;
391
392 msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_ASSOCIATED) {
393 for (i = 0; i < msidesc->nvec_used; i++)
394 xen_destroy_irq(irq: msidesc->irq + i);
395 msidesc->irq = 0;
396 }
397
398 msi_device_destroy_sysfs(dev: &dev->dev);
399}
400
401static void xen_pv_teardown_msi_irqs(struct pci_dev *dev)
402{
403 if (dev->msix_enabled)
404 xen_pci_frontend_disable_msix(dev);
405 else
406 xen_pci_frontend_disable_msi(dev);
407
408 xen_teardown_msi_irqs(dev);
409}
410
411static int xen_msi_domain_alloc_irqs(struct irq_domain *domain,
412 struct device *dev, int nvec)
413{
414 int type;
415
416 if (WARN_ON_ONCE(!dev_is_pci(dev)))
417 return -EINVAL;
418
419 type = to_pci_dev(dev)->msix_enabled ? PCI_CAP_ID_MSIX : PCI_CAP_ID_MSI;
420
421 return xen_msi_ops.setup_msi_irqs(to_pci_dev(dev), nvec, type);
422}
423
424static void xen_msi_domain_free_irqs(struct irq_domain *domain,
425 struct device *dev)
426{
427 if (WARN_ON_ONCE(!dev_is_pci(dev)))
428 return;
429
430 xen_msi_ops.teardown_msi_irqs(to_pci_dev(dev));
431}
432
433static struct msi_domain_ops xen_pci_msi_domain_ops = {
434 .domain_alloc_irqs = xen_msi_domain_alloc_irqs,
435 .domain_free_irqs = xen_msi_domain_free_irqs,
436};
437
438static struct msi_domain_info xen_pci_msi_domain_info = {
439 .flags = MSI_FLAG_PCI_MSIX | MSI_FLAG_FREE_MSI_DESCS |
440 MSI_FLAG_DEV_SYSFS | MSI_FLAG_NO_MASK,
441 .ops = &xen_pci_msi_domain_ops,
442};
443
444/*
445 * This irq domain is a blatant violation of the irq domain design, but
446 * distangling XEN into real irq domains is not a job for mere mortals with
447 * limited XENology. But it's the least dangerous way for a mere mortal to
448 * get rid of the arch_*_msi_irqs() hackery in order to store the irq
449 * domain pointer in struct device. This irq domain wrappery allows to do
450 * that without breaking XEN terminally.
451 */
452static __init struct irq_domain *xen_create_pci_msi_domain(void)
453{
454 struct irq_domain *d = NULL;
455 struct fwnode_handle *fn;
456
457 fn = irq_domain_alloc_named_fwnode(name: "XEN-MSI");
458 if (fn)
459 d = msi_create_irq_domain(fwnode: fn, info: &xen_pci_msi_domain_info, NULL);
460
461 /* FIXME: No idea how to survive if this fails */
462 BUG_ON(!d);
463
464 return d;
465}
466
467static __init void xen_setup_pci_msi(void)
468{
469 if (xen_pv_domain()) {
470 if (xen_initial_domain())
471 xen_msi_ops.setup_msi_irqs = xen_initdom_setup_msi_irqs;
472 else
473 xen_msi_ops.setup_msi_irqs = xen_setup_msi_irqs;
474 xen_msi_ops.teardown_msi_irqs = xen_pv_teardown_msi_irqs;
475 } else if (xen_hvm_domain()) {
476 xen_msi_ops.setup_msi_irqs = xen_hvm_setup_msi_irqs;
477 xen_msi_ops.teardown_msi_irqs = xen_teardown_msi_irqs;
478 } else {
479 WARN_ON_ONCE(1);
480 return;
481 }
482
483 /*
484 * Override the PCI/MSI irq domain init function. No point
485 * in allocating the native domain and never use it.
486 */
487 x86_init.irqs.create_pci_msi_domain = xen_create_pci_msi_domain;
488}
489
490#else /* CONFIG_PCI_MSI */
491static inline void xen_setup_pci_msi(void) { }
492#endif /* CONFIG_PCI_MSI */
493
494int __init pci_xen_init(void)
495{
496 if (!xen_pv_domain() || xen_initial_domain())
497 return -ENODEV;
498
499 printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");
500
501 pcibios_set_cache_line_size();
502
503 pcibios_enable_irq = xen_pcifront_enable_irq;
504 pcibios_disable_irq = NULL;
505
506 /* Keep ACPI out of the picture */
507 acpi_noirq_set();
508
509 xen_setup_pci_msi();
510 return 0;
511}
512
513#ifdef CONFIG_PCI_MSI
514static void __init xen_hvm_msi_init(void)
515{
516 if (!apic_is_disabled) {
517 /*
518 * If hardware supports (x2)APIC virtualization (as indicated
519 * by hypervisor's leaf 4) then we don't need to use pirqs/
520 * event channels for MSI handling and instead use regular
521 * APIC processing
522 */
523 uint32_t eax = cpuid_eax(op: xen_cpuid_base() + 4);
524
525 if (((eax & XEN_HVM_CPUID_X2APIC_VIRT) && x2apic_mode) ||
526 ((eax & XEN_HVM_CPUID_APIC_ACCESS_VIRT) && boot_cpu_has(X86_FEATURE_APIC)))
527 return;
528 }
529 xen_setup_pci_msi();
530}
531#endif
532
533int __init pci_xen_hvm_init(void)
534{
535 if (!xen_have_vector_callback || !xen_feature(XENFEAT_hvm_pirqs))
536 return 0;
537
538#ifdef CONFIG_ACPI
539 /*
540 * We don't want to change the actual ACPI delivery model,
541 * just how GSIs get registered.
542 */
543 __acpi_register_gsi = acpi_register_gsi_xen_hvm;
544 __acpi_unregister_gsi = NULL;
545#endif
546
547#ifdef CONFIG_PCI_MSI
548 /*
549 * We need to wait until after x2apic is initialized
550 * before we can set MSI IRQ ops.
551 */
552 x86_platform.apic_post_init = xen_hvm_msi_init;
553#endif
554 return 0;
555}
556
557#ifdef CONFIG_XEN_PV_DOM0
558int __init pci_xen_initial_domain(void)
559{
560 int irq;
561
562 xen_setup_pci_msi();
563 __acpi_register_gsi = acpi_register_gsi_xen;
564 __acpi_unregister_gsi = NULL;
565 /*
566 * Pre-allocate the legacy IRQs. Use NR_LEGACY_IRQS here
567 * because we don't have a PIC and thus nr_legacy_irqs() is zero.
568 */
569 for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
570 int trigger, polarity;
571
572 if (acpi_get_override_irq(gsi: irq, trigger: &trigger, polarity: &polarity) == -1)
573 continue;
574
575 xen_register_pirq(gsi: irq,
576 triggering: trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE,
577 set_pirq: true /* Map GSI to PIRQ */);
578 }
579 if (0 == nr_ioapics) {
580 for (irq = 0; irq < nr_legacy_irqs(); irq++)
581 xen_bind_pirq_gsi_to_irq(gsi: irq, pirq: irq, shareable: 0, name: "xt-pic");
582 }
583 return 0;
584}
585#endif
586
587

source code of linux/arch/x86/pci/xen.c