xref: /qemu/hw/vfio/igd.c (revision 7be29f2f1a3f5b037d27eedbd5df9f441e8c8c16)
1 /*
2  * IGD device quirks
3  *
4  * Copyright Red Hat, Inc. 2016
5  *
6  * Authors:
7  *  Alex Williamson <alex.williamson@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qemu/units.h"
15 #include "qemu/error-report.h"
16 #include "qapi/error.h"
17 #include "qapi/qmp/qerror.h"
18 #include "hw/boards.h"
19 #include "hw/hw.h"
20 #include "hw/nvram/fw_cfg.h"
21 #include "pci.h"
22 #include "pci-quirks.h"
23 #include "trace.h"
24 
25 /*
26  * Intel IGD support
27  *
28  * Obviously IGD is not a discrete device, this is evidenced not only by it
29  * being integrated into the CPU, but by the various chipset and BIOS
30  * dependencies that it brings along with it.  Intel is trying to move away
31  * from this and Broadwell and newer devices can run in what Intel calls
32  * "Universal Pass-Through" mode, or UPT.  Theoretically in UPT mode, nothing
33  * more is required beyond assigning the IGD device to a VM.  There are
34  * however support limitations to this mode.  It only supports IGD as a
35  * secondary graphics device in the VM and it doesn't officially support any
36  * physical outputs.
37  *
38  * The code here attempts to enable what we'll call legacy mode assignment,
39  * IGD retains most of the capabilities we expect for it to have on bare
40  * metal.  To enable this mode, the IGD device must be assigned to the VM
41  * at PCI address 00:02.0, it must have a ROM, it very likely needs VGA
42  * support, we must have VM BIOS support for reserving and populating some
43  * of the required tables, and we need to tweak the chipset with revisions
44  * and IDs and an LPC/ISA bridge device.  The intention is to make all of
45  * this happen automatically by installing the device at the correct VM PCI
46  * bus address.  If any of the conditions are not met, we cross our fingers
47  * and hope the user knows better.
48  *
49  * NB - It is possible to enable physical outputs in UPT mode by supplying
50  * an OpRegion table.  We don't do this by default because the guest driver
51  * behaves differently if an OpRegion is provided and no monitor is attached
52  * vs no OpRegion and a monitor being attached or not.  Effectively, if a
53  * headless setup is desired, the OpRegion gets in the way of that.
54  */
55 
56 /*
57  * This presumes the device is already known to be an Intel VGA device, so we
58  * take liberties in which device ID bits match which generation.  This should
59  * not be taken as an indication that all the devices are supported, or even
60  * supportable, some of them don't even support VT-d.
61  * See linux:include/drm/i915_pciids.h for IDs.
62  */
63 static int igd_gen(VFIOPCIDevice *vdev)
64 {
65     /*
66      * Device IDs for Broxton/Apollo Lake are 0x0a84, 0x1a84, 0x1a85, 0x5a84
67      * and 0x5a85, match bit 11:1 here
68      * Prefix 0x0a is taken by Haswell, this rule should be matched first.
69      */
70     if ((vdev->device_id & 0xffe) == 0xa84) {
71         return 9;
72     }
73 
74     switch (vdev->device_id & 0xff00) {
75     case 0x0100:    /* SandyBridge, IvyBridge */
76         return 6;
77     case 0x0400:    /* Haswell */
78     case 0x0a00:    /* Haswell */
79     case 0x0c00:    /* Haswell */
80     case 0x0d00:    /* Haswell */
81     case 0x0f00:    /* Valleyview/Bay Trail */
82         return 7;
83     case 0x1600:    /* Broadwell */
84     case 0x2200:    /* Cherryview */
85         return 8;
86     case 0x1900:    /* Skylake */
87     case 0x3100:    /* Gemini Lake */
88     case 0x5900:    /* Kaby Lake */
89     case 0x3e00:    /* Coffee Lake */
90     case 0x9B00:    /* Comet Lake */
91         return 9;
92     case 0x8A00:    /* Ice Lake */
93     case 0x4500:    /* Elkhart Lake */
94     case 0x4E00:    /* Jasper Lake */
95         return 11;
96     case 0x9A00:    /* Tiger Lake */
97     case 0x4C00:    /* Rocket Lake */
98     case 0x4600:    /* Alder Lake */
99     case 0xA700:    /* Raptor Lake */
100         return 12;
101     }
102 
103     /*
104      * Unfortunately, Intel changes it's specification quite often. This makes
105      * it impossible to use a suitable default value for unknown devices.
106      * Return -1 for not applying any generation-specific quirks.
107      */
108     return -1;
109 }
110 
111 #define IGD_ASLS 0xfc /* ASL Storage Register */
112 #define IGD_GMCH 0x50 /* Graphics Control Register */
113 #define IGD_BDSM 0x5c /* Base Data of Stolen Memory */
114 #define IGD_BDSM_GEN11 0xc0 /* Base Data of Stolen Memory of gen 11 and later */
115 
116 #define IGD_GMCH_GEN6_GMS_SHIFT     3       /* SNB_GMCH in i915 */
117 #define IGD_GMCH_GEN6_GMS_MASK      0x1f
118 #define IGD_GMCH_GEN8_GMS_SHIFT     8       /* BDW_GMCH in i915 */
119 #define IGD_GMCH_GEN8_GMS_MASK      0xff
120 
121 static uint64_t igd_stolen_memory_size(int gen, uint32_t gmch)
122 {
123     uint64_t gms;
124 
125     if (gen < 8) {
126         gms = (gmch >> IGD_GMCH_GEN6_GMS_SHIFT) & IGD_GMCH_GEN6_GMS_MASK;
127     } else {
128         gms = (gmch >> IGD_GMCH_GEN8_GMS_SHIFT) & IGD_GMCH_GEN8_GMS_MASK;
129     }
130 
131     if (gen < 9) {
132             return gms * 32 * MiB;
133     } else {
134         if (gms < 0xf0) {
135             return gms * 32 * MiB;
136         } else {
137             return (gms - 0xf0 + 1) * 4 * MiB;
138         }
139     }
140 
141     return 0;
142 }
143 
144 /*
145  * The OpRegion includes the Video BIOS Table, which seems important for
146  * telling the driver what sort of outputs it has.  Without this, the device
147  * may work in the guest, but we may not get output.  This also requires BIOS
148  * support to reserve and populate a section of guest memory sufficient for
149  * the table and to write the base address of that memory to the ASLS register
150  * of the IGD device.
151  */
152 static bool vfio_pci_igd_opregion_init(VFIOPCIDevice *vdev,
153                                        struct vfio_region_info *info,
154                                        Error **errp)
155 {
156     int ret;
157 
158     vdev->igd_opregion = g_malloc0(info->size);
159     ret = pread(vdev->vbasedev.fd, vdev->igd_opregion,
160                 info->size, info->offset);
161     if (ret != info->size) {
162         error_setg(errp, "failed to read IGD OpRegion");
163         g_free(vdev->igd_opregion);
164         vdev->igd_opregion = NULL;
165         return false;
166     }
167 
168     /*
169      * Provide fw_cfg with a copy of the OpRegion which the VM firmware is to
170      * allocate 32bit reserved memory for, copy these contents into, and write
171      * the reserved memory base address to the device ASLS register at 0xFC.
172      * Alignment of this reserved region seems flexible, but using a 4k page
173      * alignment seems to work well.  This interface assumes a single IGD
174      * device, which may be at VM address 00:02.0 in legacy mode or another
175      * address in UPT mode.
176      *
177      * NB, there may be future use cases discovered where the VM should have
178      * direct interaction with the host OpRegion, in which case the write to
179      * the ASLS register would trigger MemoryRegion setup to enable that.
180      */
181     fw_cfg_add_file(fw_cfg_find(), "etc/igd-opregion",
182                     vdev->igd_opregion, info->size);
183 
184     trace_vfio_pci_igd_opregion_enabled(vdev->vbasedev.name);
185 
186     return true;
187 }
188 
189 static bool vfio_pci_igd_opregion_detect(VFIOPCIDevice *vdev,
190                                          struct vfio_region_info **opregion,
191                                          Error **errp)
192 {
193     int ret;
194 
195     /* Hotplugging is not supported for opregion access */
196     if (vdev->pdev.qdev.hotplugged) {
197         error_setg(errp, "IGD OpRegion is not supported on hotplugged device");
198         return false;
199     }
200 
201     ret = vfio_device_get_region_info_type(&vdev->vbasedev,
202                     VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
203                     VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION, opregion);
204     if (ret) {
205         error_setg_errno(errp, -ret,
206                          "Device does not supports IGD OpRegion feature");
207         return false;
208     }
209 
210     return true;
211 }
212 
213 /*
214  * The rather short list of registers that we copy from the host devices.
215  * The LPC/ISA bridge values are definitely needed to support the vBIOS, the
216  * host bridge values may or may not be needed depending on the guest OS.
217  * Since we're only munging revision and subsystem values on the host bridge,
218  * we don't require our own device.  The LPC/ISA bridge needs to be our very
219  * own though.
220  */
221 typedef struct {
222     uint8_t offset;
223     uint8_t len;
224 } IGDHostInfo;
225 
226 static const IGDHostInfo igd_host_bridge_infos[] = {
227     {PCI_REVISION_ID,         2},
228     {PCI_SUBSYSTEM_VENDOR_ID, 2},
229     {PCI_SUBSYSTEM_ID,        2},
230 };
231 
232 static const IGDHostInfo igd_lpc_bridge_infos[] = {
233     {PCI_VENDOR_ID,           2},
234     {PCI_DEVICE_ID,           2},
235     {PCI_REVISION_ID,         2},
236     {PCI_SUBSYSTEM_VENDOR_ID, 2},
237     {PCI_SUBSYSTEM_ID,        2},
238 };
239 
240 static int vfio_pci_igd_copy(VFIOPCIDevice *vdev, PCIDevice *pdev,
241                              struct vfio_region_info *info,
242                              const IGDHostInfo *list, int len)
243 {
244     int i, ret;
245 
246     for (i = 0; i < len; i++) {
247         ret = pread(vdev->vbasedev.fd, pdev->config + list[i].offset,
248                     list[i].len, info->offset + list[i].offset);
249         if (ret != list[i].len) {
250             error_report("IGD copy failed: %m");
251             return -errno;
252         }
253     }
254 
255     return 0;
256 }
257 
258 /*
259  * Stuff a few values into the host bridge.
260  */
261 static int vfio_pci_igd_host_init(VFIOPCIDevice *vdev,
262                                   struct vfio_region_info *info)
263 {
264     PCIBus *bus;
265     PCIDevice *host_bridge;
266     int ret;
267 
268     bus = pci_device_root_bus(&vdev->pdev);
269     host_bridge = pci_find_device(bus, 0, PCI_DEVFN(0, 0));
270 
271     if (!host_bridge) {
272         error_report("Can't find host bridge");
273         return -ENODEV;
274     }
275 
276     ret = vfio_pci_igd_copy(vdev, host_bridge, info, igd_host_bridge_infos,
277                             ARRAY_SIZE(igd_host_bridge_infos));
278     if (!ret) {
279         trace_vfio_pci_igd_host_bridge_enabled(vdev->vbasedev.name);
280     }
281 
282     return ret;
283 }
284 
285 /*
286  * IGD LPC/ISA bridge support code.  The vBIOS needs this, but we can't write
287  * arbitrary values into just any bridge, so we must create our own.  We try
288  * to handle if the user has created it for us, which they might want to do
289  * to enable multifunction so we don't occupy the whole PCI slot.
290  */
291 static void vfio_pci_igd_lpc_bridge_realize(PCIDevice *pdev, Error **errp)
292 {
293     if (pdev->devfn != PCI_DEVFN(0x1f, 0)) {
294         error_setg(errp, "VFIO dummy ISA/LPC bridge must have address 1f.0");
295     }
296 }
297 
298 static void vfio_pci_igd_lpc_bridge_class_init(ObjectClass *klass,
299                                                const void *data)
300 {
301     DeviceClass *dc = DEVICE_CLASS(klass);
302     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
303 
304     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
305     dc->desc = "VFIO dummy ISA/LPC bridge for IGD assignment";
306     dc->hotpluggable = false;
307     k->realize = vfio_pci_igd_lpc_bridge_realize;
308     k->class_id = PCI_CLASS_BRIDGE_ISA;
309 }
310 
311 static const TypeInfo vfio_pci_igd_lpc_bridge_info = {
312     .name = "vfio-pci-igd-lpc-bridge",
313     .parent = TYPE_PCI_DEVICE,
314     .class_init = vfio_pci_igd_lpc_bridge_class_init,
315     .interfaces = (const InterfaceInfo[]) {
316         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
317         { },
318     },
319 };
320 
321 static void vfio_pci_igd_register_types(void)
322 {
323     type_register_static(&vfio_pci_igd_lpc_bridge_info);
324 }
325 
326 type_init(vfio_pci_igd_register_types)
327 
328 static int vfio_pci_igd_lpc_init(VFIOPCIDevice *vdev,
329                                  struct vfio_region_info *info)
330 {
331     PCIDevice *lpc_bridge;
332     int ret;
333 
334     lpc_bridge = pci_find_device(pci_device_root_bus(&vdev->pdev),
335                                  0, PCI_DEVFN(0x1f, 0));
336     if (!lpc_bridge) {
337         lpc_bridge = pci_create_simple(pci_device_root_bus(&vdev->pdev),
338                                  PCI_DEVFN(0x1f, 0), "vfio-pci-igd-lpc-bridge");
339     }
340 
341     ret = vfio_pci_igd_copy(vdev, lpc_bridge, info, igd_lpc_bridge_infos,
342                             ARRAY_SIZE(igd_lpc_bridge_infos));
343     if (!ret) {
344         trace_vfio_pci_igd_lpc_bridge_enabled(vdev->vbasedev.name);
345     }
346 
347     return ret;
348 }
349 
350 static bool vfio_pci_igd_setup_lpc_bridge(VFIOPCIDevice *vdev, Error **errp)
351 {
352     struct vfio_region_info *host = NULL;
353     struct vfio_region_info *lpc = NULL;
354     PCIDevice *lpc_bridge;
355     int ret;
356 
357     /*
358      * Copying IDs or creating new devices are not supported on hotplug
359      */
360     if (vdev->pdev.qdev.hotplugged) {
361         error_setg(errp, "IGD LPC is not supported on hotplugged device");
362         return false;
363     }
364 
365     /*
366      * We need to create an LPC/ISA bridge at PCI bus address 00:1f.0 that we
367      * can stuff host values into, so if there's already one there and it's not
368      * one we can hack on, this quirk is no-go.  Sorry Q35.
369      */
370     lpc_bridge = pci_find_device(pci_device_root_bus(&vdev->pdev),
371                                  0, PCI_DEVFN(0x1f, 0));
372     if (lpc_bridge && !object_dynamic_cast(OBJECT(lpc_bridge),
373                                            "vfio-pci-igd-lpc-bridge")) {
374         error_setg(errp,
375                    "Cannot create LPC bridge due to existing device at 1f.0");
376         return false;
377     }
378 
379     /*
380      * Check whether we have all the vfio device specific regions to
381      * support LPC quirk (added in Linux v4.6).
382      */
383     ret = vfio_device_get_region_info_type(&vdev->vbasedev,
384                         VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
385                         VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG, &lpc);
386     if (ret) {
387         error_setg(errp, "IGD LPC bridge access is not supported by kernel");
388         return false;
389     }
390 
391     ret = vfio_device_get_region_info_type(&vdev->vbasedev,
392                         VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
393                         VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG, &host);
394     if (ret) {
395         error_setg(errp, "IGD host bridge access is not supported by kernel");
396         return false;
397     }
398 
399     /* Create/modify LPC bridge */
400     ret = vfio_pci_igd_lpc_init(vdev, lpc);
401     if (ret) {
402         error_setg(errp, "Failed to create/modify LPC bridge for IGD");
403         return false;
404     }
405 
406     /* Stuff some host values into the VM PCI host bridge */
407     ret = vfio_pci_igd_host_init(vdev, host);
408     if (ret) {
409         error_setg(errp, "Failed to modify host bridge for IGD");
410         return false;
411     }
412 
413     return true;
414 }
415 
416 static bool vfio_pci_igd_override_gms(int gen, uint32_t gms, uint32_t *gmch)
417 {
418     bool ret = false;
419 
420     if (gen == -1) {
421         error_report("x-igd-gms is not supported on this device");
422     } else if (gen < 8) {
423         if (gms <= 0x10) {
424             *gmch &= ~(IGD_GMCH_GEN6_GMS_MASK << IGD_GMCH_GEN6_GMS_SHIFT);
425             *gmch |= gms << IGD_GMCH_GEN6_GMS_SHIFT;
426             ret = true;
427         } else {
428             error_report(QERR_INVALID_PARAMETER_VALUE, "x-igd-gms", "0~0x10");
429         }
430     } else if (gen == 8) {
431         if (gms <= 0x40) {
432             *gmch &= ~(IGD_GMCH_GEN8_GMS_MASK << IGD_GMCH_GEN8_GMS_SHIFT);
433             *gmch |= gms << IGD_GMCH_GEN8_GMS_SHIFT;
434             ret = true;
435         } else {
436             error_report(QERR_INVALID_PARAMETER_VALUE, "x-igd-gms", "0~0x40");
437         }
438     } else {
439         /* 0x0  to 0x40: 32MB increments starting at 0MB */
440         /* 0xf0 to 0xfe: 4MB increments starting at 4MB */
441         if ((gms <= 0x40) || (gms >= 0xf0 && gms <= 0xfe)) {
442             *gmch &= ~(IGD_GMCH_GEN8_GMS_MASK << IGD_GMCH_GEN8_GMS_SHIFT);
443             *gmch |= gms << IGD_GMCH_GEN8_GMS_SHIFT;
444             ret = true;
445         } else {
446             error_report(QERR_INVALID_PARAMETER_VALUE,
447                          "x-igd-gms", "0~0x40 or 0xf0~0xfe");
448         }
449     }
450 
451     return ret;
452 }
453 
454 #define IGD_GGC_MMIO_OFFSET     0x108040
455 #define IGD_BDSM_MMIO_OFFSET    0x1080C0
456 
457 void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr)
458 {
459     VFIOQuirk *ggc_quirk, *bdsm_quirk;
460     VFIOConfigMirrorQuirk *ggc_mirror, *bdsm_mirror;
461     int gen;
462 
463     if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
464         !vfio_is_vga(vdev) || nr != 0) {
465         return;
466     }
467 
468     /* Only on IGD Gen6-12 device needs quirks in BAR 0 */
469     gen = igd_gen(vdev);
470     if (gen < 6) {
471         return;
472     }
473 
474     if (vdev->igd_gms) {
475         ggc_quirk = vfio_quirk_alloc(1);
476         ggc_mirror = ggc_quirk->data = g_malloc0(sizeof(*ggc_mirror));
477         ggc_mirror->mem = ggc_quirk->mem;
478         ggc_mirror->vdev = vdev;
479         ggc_mirror->bar = nr;
480         ggc_mirror->offset = IGD_GGC_MMIO_OFFSET;
481         ggc_mirror->config_offset = IGD_GMCH;
482 
483         memory_region_init_io(ggc_mirror->mem, OBJECT(vdev),
484                               &vfio_generic_mirror_quirk, ggc_mirror,
485                               "vfio-igd-ggc-quirk", 2);
486         memory_region_add_subregion_overlap(vdev->bars[nr].region.mem,
487                                             ggc_mirror->offset, ggc_mirror->mem,
488                                             1);
489 
490         QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, ggc_quirk, next);
491     }
492 
493     bdsm_quirk = vfio_quirk_alloc(1);
494     bdsm_mirror = bdsm_quirk->data = g_malloc0(sizeof(*bdsm_mirror));
495     bdsm_mirror->mem = bdsm_quirk->mem;
496     bdsm_mirror->vdev = vdev;
497     bdsm_mirror->bar = nr;
498     bdsm_mirror->offset = IGD_BDSM_MMIO_OFFSET;
499     bdsm_mirror->config_offset = (gen < 11) ? IGD_BDSM : IGD_BDSM_GEN11;
500 
501     memory_region_init_io(bdsm_mirror->mem, OBJECT(vdev),
502                           &vfio_generic_mirror_quirk, bdsm_mirror,
503                           "vfio-igd-bdsm-quirk", (gen < 11) ? 4 : 8);
504     memory_region_add_subregion_overlap(vdev->bars[nr].region.mem,
505                                         bdsm_mirror->offset, bdsm_mirror->mem,
506                                         1);
507 
508     QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, bdsm_quirk, next);
509 }
510 
511 static bool vfio_pci_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
512 {
513     struct vfio_region_info *opregion = NULL;
514     int ret, gen;
515     uint64_t gms_size = 0;
516     uint64_t *bdsm_size;
517     uint32_t gmch;
518     bool legacy_mode_enabled = false;
519     Error *err = NULL;
520 
521     if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
522         !vfio_is_vga(vdev)) {
523         return true;
524     }
525 
526     /* IGD device always comes with OpRegion */
527     if (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp)) {
528         return true;
529     }
530     info_report("OpRegion detected on Intel display %x.", vdev->device_id);
531 
532     gen = igd_gen(vdev);
533     gmch = vfio_pci_read_config(&vdev->pdev, IGD_GMCH, 4);
534 
535     /*
536      * For backward compatibility, enable legacy mode when
537      * - Device geneation is 6 to 9 (including both)
538      * - Machine type is i440fx (pc_piix)
539      * - IGD device is at guest BDF 00:02.0
540      * - Not manually disabled by x-igd-legacy-mode=off
541      */
542     if ((vdev->igd_legacy_mode != ON_OFF_AUTO_OFF) &&
543         (gen >= 6 && gen <= 9) &&
544         !strcmp(MACHINE_GET_CLASS(qdev_get_machine())->family, "pc_piix") &&
545         (&vdev->pdev == pci_find_device(pci_device_root_bus(&vdev->pdev),
546         0, PCI_DEVFN(0x2, 0)))) {
547         /*
548          * IGD legacy mode requires:
549          * - VBIOS in ROM BAR or file
550          * - VGA IO/MMIO ranges are claimed by IGD
551          * - OpRegion
552          * - Same LPC bridge and Host bridge VID/DID/SVID/SSID as host
553          */
554         struct vfio_region_info *rom = NULL;
555 
556         legacy_mode_enabled = true;
557         info_report("IGD legacy mode enabled, "
558                     "use x-igd-legacy-mode=off to disable it if unwanted.");
559 
560         /*
561          * Most of what we're doing here is to enable the ROM to run, so if
562          * there's no ROM, there's no point in setting up this quirk.
563          * NB. We only seem to get BIOS ROMs, so UEFI VM would need CSM support.
564          */
565         ret = vfio_device_get_region_info(&vdev->vbasedev,
566                                           VFIO_PCI_ROM_REGION_INDEX, &rom);
567         if ((ret || !rom->size) && !vdev->pdev.romfile) {
568             error_setg(&err, "Device has no ROM");
569             goto error;
570         }
571 
572         /*
573          * If IGD VGA Disable is clear (expected) and VGA is not already
574          * enabled, try to enable it. Probably shouldn't be using legacy mode
575          * without VGA, but also no point in us enabling VGA if disabled in
576          * hardware.
577          */
578         if (!(gmch & 0x2) && !vdev->vga && !vfio_populate_vga(vdev, &err)) {
579             error_setg(&err, "Unable to enable VGA access");
580             goto error;
581         }
582 
583         /* Enable OpRegion and LPC bridge quirk */
584         vdev->features |= VFIO_FEATURE_ENABLE_IGD_OPREGION;
585         vdev->features |= VFIO_FEATURE_ENABLE_IGD_LPC;
586     } else if (vdev->igd_legacy_mode == ON_OFF_AUTO_ON) {
587         error_setg(&err,
588                    "Machine is not i440fx, assigned BDF is not 00:02.0, "
589                    "or device %04x (gen %d) doesn't support legacy mode",
590                    vdev->device_id, gen);
591         goto error;
592     }
593 
594     /* Setup OpRegion access */
595     if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) &&
596         !vfio_pci_igd_opregion_init(vdev, opregion, errp)) {
597         goto error;
598     }
599 
600     /* Setup LPC bridge / Host bridge PCI IDs */
601     if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_LPC) &&
602         !vfio_pci_igd_setup_lpc_bridge(vdev, errp)) {
603         goto error;
604     }
605 
606     /*
607      * ASLS (OpRegion address) is read-only, emulated
608      * It contains HPA, guest firmware need to reprogram it with GPA.
609      */
610     pci_set_long(vdev->pdev.config + IGD_ASLS, 0);
611     pci_set_long(vdev->pdev.wmask + IGD_ASLS, ~0);
612     pci_set_long(vdev->emulated_config_bits + IGD_ASLS, ~0);
613 
614     /*
615      * Allow user to override dsm size using x-igd-gms option, in multiples of
616      * 32MiB. This option should only be used when the desired size cannot be
617      * set from DVMT Pre-Allocated option in host BIOS.
618      */
619     if (vdev->igd_gms) {
620         if (!vfio_pci_igd_override_gms(gen, vdev->igd_gms, &gmch)) {
621             return false;
622         }
623 
624         /* GMCH is read-only, emulated */
625         pci_set_long(vdev->pdev.config + IGD_GMCH, gmch);
626         pci_set_long(vdev->pdev.wmask + IGD_GMCH, 0);
627         pci_set_long(vdev->emulated_config_bits + IGD_GMCH, ~0);
628     }
629 
630     if (gen > 0) {
631         gms_size = igd_stolen_memory_size(gen, gmch);
632 
633         /* BDSM is read-write, emulated. BIOS needs to be able to write it */
634         if (gen < 11) {
635             pci_set_long(vdev->pdev.config + IGD_BDSM, 0);
636             pci_set_long(vdev->pdev.wmask + IGD_BDSM, ~0);
637             pci_set_long(vdev->emulated_config_bits + IGD_BDSM, ~0);
638         } else {
639             pci_set_quad(vdev->pdev.config + IGD_BDSM_GEN11, 0);
640             pci_set_quad(vdev->pdev.wmask + IGD_BDSM_GEN11, ~0);
641             pci_set_quad(vdev->emulated_config_bits + IGD_BDSM_GEN11, ~0);
642         }
643     }
644 
645     /*
646      * Request reserved memory for stolen memory via fw_cfg.  VM firmware
647      * must allocate a 1MB aligned reserved memory region below 4GB with
648      * the requested size (in bytes) for use by the IGD device. The base
649      * address of this reserved memory region must be written to the
650      * device BDSM register.
651      * For newer device without BDSM register, this fw_cfg item is 0.
652      */
653     bdsm_size = g_malloc(sizeof(*bdsm_size));
654     *bdsm_size = cpu_to_le64(gms_size);
655     fw_cfg_add_file(fw_cfg_find(), "etc/igd-bdsm-size",
656                     bdsm_size, sizeof(*bdsm_size));
657 
658     trace_vfio_pci_igd_bdsm_enabled(vdev->vbasedev.name, (gms_size / MiB));
659 
660     return true;
661 
662 error:
663     /*
664      * When legacy mode is implicity enabled, continue on error,
665      * to keep compatibility
666      */
667     if (legacy_mode_enabled && (vdev->igd_legacy_mode == ON_OFF_AUTO_AUTO)) {
668         error_report_err(err);
669         error_report("IGD legacy mode disabled");
670         return true;
671     }
672 
673     error_propagate(errp, err);
674     return false;
675 }
676 
677 /*
678  * KVMGT/GVT-g vGPU exposes an emulated OpRegion. So far, users have to specify
679  * x-igd-opregion=on to enable the access.
680  * TODO: Check VID/DID and enable opregion access automatically
681  */
682 static bool vfio_pci_kvmgt_config_quirk(VFIOPCIDevice *vdev, Error **errp)
683 {
684     struct vfio_region_info *opregion = NULL;
685     int gen;
686 
687     if (!vfio_pci_is(vdev, PCI_VENDOR_ID_INTEL, PCI_ANY_ID) ||
688         !vfio_is_vga(vdev)) {
689         return true;
690     }
691 
692     /* FIXME: Cherryview is Gen8, but don't support GVT-g */
693     gen = igd_gen(vdev);
694     if (gen != 8 && gen != 9) {
695         return true;
696     }
697 
698     if (!vfio_pci_igd_opregion_detect(vdev, &opregion, errp)) {
699         /* Should never reach here, KVMGT always emulates OpRegion */
700         return false;
701     }
702 
703     if ((vdev->features & VFIO_FEATURE_ENABLE_IGD_OPREGION) &&
704         !vfio_pci_igd_opregion_init(vdev, opregion, errp)) {
705         return false;
706     }
707 
708     return true;
709 }
710 
711 bool vfio_probe_igd_config_quirk(VFIOPCIDevice *vdev, Error **errp)
712 {
713     /* KVMGT/GVT-g vGPU is exposed as mdev */
714     if (vdev->vbasedev.mdev) {
715         return vfio_pci_kvmgt_config_quirk(vdev, errp);
716     }
717 
718     return vfio_pci_igd_config_quirk(vdev, errp);
719 }
720