1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2020 Beckhoff Automation GmbH & Co. KG 5 * Author: Corvin Köhne <c.koehne@beckhoff.com> 6 */ 7 8 #include <sys/types.h> 9 #include <sys/mman.h> 10 #include <sys/sysctl.h> 11 12 #include <dev/pci/pcireg.h> 13 14 #include <err.h> 15 #include <errno.h> 16 #include <fcntl.h> 17 #include <string.h> 18 #include <unistd.h> 19 20 #include "amd64/e820.h" 21 #include "pci_gvt-d-opregion.h" 22 #include "pci_passthru.h" 23 24 #define KB (1024UL) 25 #define MB (1024 * KB) 26 #define GB (1024 * MB) 27 28 #ifndef _PATH_MEM 29 #define _PATH_MEM "/dev/mem" 30 #endif 31 32 #define PCI_VENDOR_INTEL 0x8086 33 34 #define PCIR_BDSM 0x5C /* Base of Data Stolen Memory register */ 35 #define PCIR_ASLS_CTL 0xFC /* Opregion start address register */ 36 37 #define PCIM_BDSM_GSM_ALIGNMENT \ 38 0x00100000 /* Graphics Stolen Memory is 1 MB aligned */ 39 40 #define GVT_D_MAP_GSM 0 41 #define GVT_D_MAP_OPREGION 1 42 43 static int 44 gvt_d_probe(struct pci_devinst *const pi) 45 { 46 struct passthru_softc *sc; 47 uint16_t vendor; 48 uint8_t class; 49 50 sc = pi->pi_arg; 51 52 vendor = pci_host_read_config(passthru_get_sel(sc), PCIR_VENDOR, 0x02); 53 if (vendor != PCI_VENDOR_INTEL) 54 return (ENXIO); 55 56 class = pci_host_read_config(passthru_get_sel(sc), PCIR_CLASS, 0x01); 57 if (class != PCIC_DISPLAY) 58 return (ENXIO); 59 60 return (0); 61 } 62 63 static vm_paddr_t 64 gvt_d_alloc_mmio_memory(const vm_paddr_t host_address, const vm_paddr_t length, 65 const vm_paddr_t alignment, const enum e820_memory_type type) 66 { 67 vm_paddr_t address; 68 69 /* Try to reuse host address. */ 70 address = e820_alloc(host_address, length, E820_ALIGNMENT_NONE, type, 71 E820_ALLOCATE_SPECIFIC); 72 if (address != 0) { 73 return (address); 74 } 75 76 /* 77 * We're not able to reuse the host address. Fall back to the highest usable 78 * address below 4 GB. 79 */ 80 return ( 81 e820_alloc(4 * GB, length, alignment, type, E820_ALLOCATE_HIGHEST)); 82 } 83 84 /* 85 * Note that the graphics stolen memory is somehow confusing. On the one hand 86 * the Intel Open Source HD Graphics Programmers' Reference Manual states that 87 * it's only GPU accessible. As the CPU can't access the area, the guest 88 * shouldn't need it. On the other hand, the Intel GOP driver refuses to work 89 * properly, if it's not set to a proper address. 90 * 91 * Intel itself maps it into the guest by EPT [1]. At the moment, we're not 92 * aware of any situation where this EPT mapping is required, so we don't do it 93 * yet. 94 * 95 * Intel also states that the Windows driver for Tiger Lake reads the address of 96 * the graphics stolen memory [2]. As the GVT-d code doesn't support Tiger Lake 97 * in its first implementation, we can't check how it behaves. We should keep an 98 * eye on it. 99 * 100 * [1] 101 * https://github.com/projectacrn/acrn-hypervisor/blob/e28d6fbfdfd556ff1bc3ff330e41d4ddbaa0f897/devicemodel/hw/pci/passthrough.c#L655-L657 102 * [2] 103 * https://github.com/projectacrn/acrn-hypervisor/blob/e28d6fbfdfd556ff1bc3ff330e41d4ddbaa0f897/devicemodel/hw/pci/passthrough.c#L626-L629 104 */ 105 static int 106 gvt_d_setup_gsm(struct pci_devinst *const pi) 107 { 108 struct passthru_softc *sc; 109 struct passthru_mmio_mapping *gsm; 110 size_t sysctl_len; 111 uint32_t bdsm; 112 int error; 113 114 sc = pi->pi_arg; 115 116 gsm = passthru_get_mmio(sc, GVT_D_MAP_GSM); 117 if (gsm == NULL) { 118 warnx("%s: Unable to access gsm", __func__); 119 return (-1); 120 } 121 122 sysctl_len = sizeof(gsm->hpa); 123 error = sysctlbyname("hw.intel_graphics_stolen_base", &gsm->hpa, 124 &sysctl_len, NULL, 0); 125 if (error) { 126 warn("%s: Unable to get graphics stolen memory base", 127 __func__); 128 return (-1); 129 } 130 sysctl_len = sizeof(gsm->len); 131 error = sysctlbyname("hw.intel_graphics_stolen_size", &gsm->len, 132 &sysctl_len, NULL, 0); 133 if (error) { 134 warn("%s: Unable to get graphics stolen memory length", 135 __func__); 136 return (-1); 137 } 138 gsm->hva = NULL; /* unused */ 139 gsm->gva = NULL; /* unused */ 140 gsm->gpa = gvt_d_alloc_mmio_memory(gsm->hpa, gsm->len, 141 PCIM_BDSM_GSM_ALIGNMENT, E820_TYPE_RESERVED); 142 if (gsm->gpa == 0) { 143 warnx( 144 "%s: Unable to add Graphics Stolen Memory to E820 table (hpa 0x%lx len 0x%lx)", 145 __func__, gsm->hpa, gsm->len); 146 e820_dump_table(); 147 return (-1); 148 } 149 if (gsm->gpa != gsm->hpa) { 150 /* 151 * ACRN source code implies that graphics driver for newer Intel 152 * platforms like Tiger Lake will read the Graphics Stolen Memory 153 * address from an MMIO register. We have three options to solve this 154 * issue: 155 * 1. Patch the value in the MMIO register 156 * This could have unintended side effects. Without any 157 * documentation how this register is used by the GPU, don't do 158 * it. 159 * 2. Trap the MMIO register 160 * It's not possible to trap a single MMIO register. We need to 161 * trap a whole page. Trapping a bunch of MMIO register could 162 * degrade the performance noticeably. We have to test it. 163 * 3. Use an 1:1 host to guest mapping 164 * Maybe not always possible. As far as we know, no supported 165 * platform requires a 1:1 mapping. For that reason, just log a 166 * warning. 167 */ 168 warnx( 169 "Warning: Unable to reuse host address of Graphics Stolen Memory. GPU passthrough might not work properly."); 170 } 171 172 bdsm = pci_host_read_config(passthru_get_sel(sc), PCIR_BDSM, 4); 173 pci_set_cfgdata32(pi, PCIR_BDSM, 174 gsm->gpa | (bdsm & (PCIM_BDSM_GSM_ALIGNMENT - 1))); 175 176 return (set_pcir_handler(sc, PCIR_BDSM, 4, passthru_cfgread_emulate, 177 passthru_cfgwrite_emulate)); 178 } 179 180 static int 181 gvt_d_setup_opregion(struct pci_devinst *const pi) 182 { 183 struct passthru_softc *sc; 184 struct passthru_mmio_mapping *opregion; 185 struct igd_opregion_header *header; 186 uint64_t asls; 187 int memfd; 188 189 sc = pi->pi_arg; 190 191 memfd = open(_PATH_MEM, O_RDONLY, 0); 192 if (memfd < 0) { 193 warn("%s: Failed to open %s", __func__, _PATH_MEM); 194 return (-1); 195 } 196 197 opregion = passthru_get_mmio(sc, GVT_D_MAP_OPREGION); 198 if (opregion == NULL) { 199 warnx("%s: Unable to access opregion", __func__); 200 close(memfd); 201 return (-1); 202 } 203 204 asls = pci_host_read_config(passthru_get_sel(sc), PCIR_ASLS_CTL, 4); 205 206 header = mmap(NULL, sizeof(*header), PROT_READ, MAP_SHARED, memfd, 207 asls); 208 if (header == MAP_FAILED) { 209 warn("%s: Unable to map OpRegion header", __func__); 210 close(memfd); 211 return (-1); 212 } 213 if (memcmp(header->sign, IGD_OPREGION_HEADER_SIGN, 214 sizeof(header->sign)) != 0) { 215 warnx("%s: Invalid OpRegion signature", __func__); 216 munmap(header, sizeof(*header)); 217 close(memfd); 218 return (-1); 219 } 220 221 opregion->hpa = asls; 222 opregion->len = header->size * KB; 223 munmap(header, sizeof(header)); 224 225 opregion->hva = mmap(NULL, opregion->len * KB, PROT_READ, MAP_SHARED, 226 memfd, opregion->hpa); 227 if (opregion->hva == MAP_FAILED) { 228 warn("%s: Unable to map host OpRegion", __func__); 229 close(memfd); 230 return (-1); 231 } 232 close(memfd); 233 234 opregion->gpa = gvt_d_alloc_mmio_memory(opregion->hpa, opregion->len, 235 E820_ALIGNMENT_NONE, E820_TYPE_NVS); 236 if (opregion->gpa == 0) { 237 warnx( 238 "%s: Unable to add OpRegion to E820 table (hpa 0x%lx len 0x%lx)", 239 __func__, opregion->hpa, opregion->len); 240 e820_dump_table(); 241 return (-1); 242 } 243 opregion->gva = vm_map_gpa(pi->pi_vmctx, opregion->gpa, opregion->len); 244 if (opregion->gva == NULL) { 245 warnx("%s: Unable to map guest OpRegion", __func__); 246 return (-1); 247 } 248 if (opregion->gpa != opregion->hpa) { 249 /* 250 * A 1:1 host to guest mapping is not required but this could 251 * change in the future. 252 */ 253 warnx( 254 "Warning: Unable to reuse host address of OpRegion. GPU passthrough might not work properly."); 255 } 256 257 memcpy(opregion->gva, opregion->hva, opregion->len); 258 259 pci_set_cfgdata32(pi, PCIR_ASLS_CTL, opregion->gpa); 260 261 return (set_pcir_handler(sc, PCIR_ASLS_CTL, 4, passthru_cfgread_emulate, 262 passthru_cfgwrite_emulate)); 263 } 264 265 static int 266 gvt_d_init(struct pci_devinst *const pi, nvlist_t *const nvl __unused) 267 { 268 int error; 269 270 if ((error = gvt_d_setup_gsm(pi)) != 0) { 271 warnx("%s: Unable to setup Graphics Stolen Memory", __func__); 272 goto done; 273 } 274 275 if ((error = gvt_d_setup_opregion(pi)) != 0) { 276 warnx("%s: Unable to setup OpRegion", __func__); 277 goto done; 278 } 279 280 done: 281 return (error); 282 } 283 284 static void 285 gvt_d_deinit(struct pci_devinst *const pi) 286 { 287 struct passthru_softc *sc; 288 struct passthru_mmio_mapping *opregion; 289 290 sc = pi->pi_arg; 291 292 opregion = passthru_get_mmio(sc, GVT_D_MAP_OPREGION); 293 294 /* HVA is only set, if it's initialized */ 295 if (opregion->hva) 296 munmap((void *)opregion->hva, opregion->len); 297 } 298 299 static struct passthru_dev gvt_d_dev = { 300 .probe = gvt_d_probe, 301 .init = gvt_d_init, 302 .deinit = gvt_d_deinit, 303 }; 304 PASSTHRU_DEV_SET(gvt_d_dev); 305