acpi_vmgenid.c revision 1.3.2.2
1 1.3.2.2 martin /* $NetBSD: acpi_vmgenid.c,v 1.3.2.2 2024/10/09 13:25:12 martin Exp $ */ 2 1.3.2.2 martin 3 1.3.2.2 martin /*- 4 1.3.2.2 martin * Copyright (c) 2024 The NetBSD Foundation, Inc. 5 1.3.2.2 martin * All rights reserved. 6 1.3.2.2 martin * 7 1.3.2.2 martin * Redistribution and use in source and binary forms, with or without 8 1.3.2.2 martin * modification, are permitted provided that the following conditions 9 1.3.2.2 martin * are met: 10 1.3.2.2 martin * 1. Redistributions of source code must retain the above copyright 11 1.3.2.2 martin * notice, this list of conditions and the following disclaimer. 12 1.3.2.2 martin * 2. Redistributions in binary form must reproduce the above copyright 13 1.3.2.2 martin * notice, this list of conditions and the following disclaimer in the 14 1.3.2.2 martin * documentation and/or other materials provided with the distribution. 15 1.3.2.2 martin * 16 1.3.2.2 martin * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 1.3.2.2 martin * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 1.3.2.2 martin * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 1.3.2.2 martin * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 1.3.2.2 martin * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 1.3.2.2 martin * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 1.3.2.2 martin * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 1.3.2.2 martin * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 1.3.2.2 martin * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 1.3.2.2 martin * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 1.3.2.2 martin * POSSIBILITY OF SUCH DAMAGE. 27 1.3.2.2 martin */ 28 1.3.2.2 martin 29 1.3.2.2 martin /* 30 1.3.2.2 martin * Virtual Machine Generation ID 31 1.3.2.2 martin * 32 1.3.2.2 martin * The VMGENID is an 8-byte cookie shared between a VM host and VM 33 1.3.2.2 martin * guest. Whenever the host clones a VM, it changes the VMGENID 34 1.3.2.2 martin * and sends an ACPI notification to the guest. 35 1.3.2.2 martin * 36 1.3.2.2 martin * References: 37 1.3.2.2 martin * 38 1.3.2.2 martin * `Virtual Machine Generation ID', Microsoft, 2012-08-01. 39 1.3.2.2 martin * http://go.microsoft.com/fwlink/?LinkId=260709 40 1.3.2.2 martin * 41 1.3.2.2 martin * `Virtual Machine Generation ID Device', The QEMU Project 42 1.3.2.2 martin * Developers. 43 1.3.2.2 martin * https://www.qemu.org/docs/master/specs/vmgenid.html 44 1.3.2.2 martin */ 45 1.3.2.2 martin 46 1.3.2.2 martin #include <sys/cdefs.h> 47 1.3.2.2 martin __KERNEL_RCSID(0, "$NetBSD: acpi_vmgenid.c,v 1.3.2.2 2024/10/09 13:25:12 martin Exp $"); 48 1.3.2.2 martin 49 1.3.2.2 martin #include <sys/device.h> 50 1.3.2.2 martin #include <sys/entropy.h> 51 1.3.2.2 martin #include <sys/module.h> 52 1.3.2.2 martin #include <sys/rndsource.h> 53 1.3.2.2 martin #include <sys/sysctl.h> 54 1.3.2.2 martin 55 1.3.2.2 martin #include <dev/acpi/acpireg.h> 56 1.3.2.2 martin #include <dev/acpi/acpivar.h> 57 1.3.2.2 martin 58 1.3.2.2 martin #define _COMPONENT ACPI_RESOURCE_COMPONENT 59 1.3.2.2 martin ACPI_MODULE_NAME ("acpi_vmgenid") 60 1.3.2.2 martin 61 1.3.2.2 martin struct acpivmgenid { 62 1.3.2.2 martin uint8_t id[16]; 63 1.3.2.2 martin } __aligned(8); 64 1.3.2.2 martin 65 1.3.2.2 martin struct acpivmgenid_softc { 66 1.3.2.2 martin device_t sc_dev; 67 1.3.2.2 martin struct acpi_devnode *sc_node; 68 1.3.2.2 martin uint64_t sc_paddr; 69 1.3.2.2 martin struct acpivmgenid *sc_vaddr; 70 1.3.2.2 martin struct krndsource sc_rndsource; 71 1.3.2.2 martin struct sysctllog *sc_sysctllog; 72 1.3.2.2 martin const struct sysctlnode *sc_sysctlroot; 73 1.3.2.2 martin }; 74 1.3.2.2 martin 75 1.3.2.2 martin static int acpivmgenid_match(device_t, cfdata_t, void *); 76 1.3.2.2 martin static void acpivmgenid_attach(device_t, device_t, void *); 77 1.3.2.2 martin static int acpivmgenid_detach(device_t, int); 78 1.3.2.2 martin static void acpivmgenid_set(struct acpivmgenid_softc *, const char *); 79 1.3.2.2 martin static void acpivmgenid_notify(ACPI_HANDLE, uint32_t, void *); 80 1.3.2.2 martin static void acpivmgenid_reset(void *); 81 1.3.2.2 martin static int acpivmgenid_sysctl(SYSCTLFN_ARGS); 82 1.3.2.2 martin 83 1.3.2.2 martin static const struct device_compatible_entry compat_data[] = { 84 1.3.2.2 martin { .compat = "VM_Gen_Counter" }, /* from the Microsoft spec */ 85 1.3.2.2 martin { .compat = "VM_GEN_COUNTER" }, /* used by qemu */ 86 1.3.2.2 martin { .compat = "VMGENCTR" }, /* recognized by Linux */ 87 1.3.2.2 martin DEVICE_COMPAT_EOL 88 1.3.2.2 martin }; 89 1.3.2.2 martin 90 1.3.2.2 martin CFATTACH_DECL_NEW(acpivmgenid, sizeof(struct acpivmgenid_softc), 91 1.3.2.2 martin acpivmgenid_match, acpivmgenid_attach, acpivmgenid_detach, NULL); 92 1.3.2.2 martin 93 1.3.2.2 martin static int 94 1.3.2.2 martin acpivmgenid_match(device_t parent, cfdata_t match, void *aux) 95 1.3.2.2 martin { 96 1.3.2.2 martin const struct acpi_attach_args *const aa = aux; 97 1.3.2.2 martin 98 1.3.2.2 martin return acpi_compatible_match(aa, compat_data); 99 1.3.2.2 martin } 100 1.3.2.2 martin 101 1.3.2.2 martin static void 102 1.3.2.2 martin acpivmgenid_attach(device_t parent, device_t self, void *aux) 103 1.3.2.2 martin { 104 1.3.2.2 martin struct acpivmgenid_softc *const sc = device_private(self); 105 1.3.2.2 martin const struct acpi_attach_args *const aa = aux; 106 1.3.2.2 martin ACPI_BUFFER addrbuf = { 107 1.3.2.2 martin .Pointer = NULL, 108 1.3.2.2 martin .Length = ACPI_ALLOCATE_BUFFER, 109 1.3.2.2 martin }; 110 1.3.2.2 martin ACPI_OBJECT *addrobj, *addrarr; 111 1.3.2.2 martin ACPI_STATUS rv; 112 1.3.2.2 martin int error; 113 1.3.2.2 martin 114 1.3.2.2 martin aprint_naive(": ACPI VM Generation ID\n"); 115 1.3.2.2 martin aprint_normal(": ACPI VM Generation ID\n"); 116 1.3.2.2 martin 117 1.3.2.2 martin sc->sc_dev = self; 118 1.3.2.2 martin sc->sc_node = aa->aa_node; 119 1.3.2.2 martin 120 1.3.2.2 martin /* 121 1.3.2.2 martin * Get the address from the ADDR object, which is a package of 122 1.3.2.2 martin * two 32-bit integers representing the low and high halves of 123 1.3.2.2 martin * a 64-bit physical address. 124 1.3.2.2 martin */ 125 1.3.2.2 martin rv = AcpiEvaluateObjectTyped(sc->sc_node->ad_handle, "ADDR", NULL, 126 1.3.2.2 martin &addrbuf, ACPI_TYPE_PACKAGE); 127 1.3.2.2 martin if (ACPI_FAILURE(rv)) { 128 1.3.2.2 martin aprint_error_dev(self, "failed to get ADDR: %s\n", 129 1.3.2.2 martin AcpiFormatException(rv)); 130 1.3.2.2 martin goto out; 131 1.3.2.2 martin } 132 1.3.2.2 martin addrobj = addrbuf.Pointer; 133 1.3.2.2 martin if (addrobj->Type != ACPI_TYPE_PACKAGE || 134 1.3.2.2 martin addrobj->Package.Count != 2) { 135 1.3.2.2 martin aprint_error_dev(self, "invalid ADDR\n"); 136 1.3.2.2 martin goto out; 137 1.3.2.2 martin } 138 1.3.2.2 martin addrarr = addrobj->Package.Elements; 139 1.3.2.2 martin if (addrarr[0].Type != ACPI_TYPE_INTEGER || 140 1.3.2.2 martin addrarr[1].Type != ACPI_TYPE_INTEGER || 141 1.3.2.2 martin addrarr[0].Integer.Value > UINT32_MAX || 142 1.3.2.2 martin addrarr[1].Integer.Value > UINT32_MAX) { 143 1.3.2.2 martin aprint_error_dev(self, "invalid ADDR\n"); 144 1.3.2.2 martin goto out; 145 1.3.2.2 martin } 146 1.3.2.2 martin sc->sc_paddr = (ACPI_PHYSICAL_ADDRESS)addrarr[0].Integer.Value; 147 1.3.2.2 martin sc->sc_paddr |= (ACPI_PHYSICAL_ADDRESS)addrarr[1].Integer.Value << 32; 148 1.3.2.2 martin aprint_normal_dev(self, "paddr=0x%"PRIx64"\n", (uint64_t)sc->sc_paddr); 149 1.3.2.2 martin 150 1.3.2.2 martin /* 151 1.3.2.2 martin * Map the physical address into virtual address space. 152 1.3.2.2 martin */ 153 1.3.2.2 martin sc->sc_vaddr = AcpiOsMapMemory(sc->sc_paddr, sizeof(*sc->sc_vaddr)); 154 1.3.2.2 martin if (sc->sc_vaddr == NULL) { 155 1.3.2.2 martin aprint_error_dev(self, "failed to map address\n"); 156 1.3.2.2 martin goto out; 157 1.3.2.2 martin } 158 1.3.2.2 martin 159 1.3.2.2 martin /* 160 1.3.2.2 martin * Register a random source so we can attribute samples. 161 1.3.2.2 martin */ 162 1.3.2.2 martin rnd_attach_source(&sc->sc_rndsource, device_xname(self), 163 1.3.2.2 martin RND_TYPE_UNKNOWN, RND_FLAG_COLLECT_TIME|RND_FLAG_COLLECT_VALUE); 164 1.3.2.2 martin 165 1.3.2.2 martin /* 166 1.3.2.2 martin * Register an ACPI notifier so that we can detect changes. 167 1.3.2.2 martin */ 168 1.3.2.2 martin (void)acpi_register_notify(sc->sc_node, acpivmgenid_notify); 169 1.3.2.2 martin 170 1.3.2.2 martin /* 171 1.3.2.2 martin * Now that we have registered a random source and a notifier, 172 1.3.2.2 martin * read out the first value. 173 1.3.2.2 martin */ 174 1.3.2.2 martin acpivmgenid_set(sc, "initial"); 175 1.3.2.2 martin 176 1.3.2.2 martin /* 177 1.3.2.2 martin * Attach a sysctl tree, rooted at hw.acpivmgenidN. 178 1.3.2.2 martin */ 179 1.3.2.2 martin error = sysctl_createv(&sc->sc_sysctllog, 0, NULL, &sc->sc_sysctlroot, 180 1.3.2.2 martin CTLFLAG_PERMANENT, CTLTYPE_NODE, device_xname(self), 181 1.3.2.2 martin SYSCTL_DESCR("Virtual Machine Generation ID device"), 182 1.3.2.2 martin NULL, 0, NULL, 0, 183 1.3.2.2 martin CTL_HW, CTL_CREATE, CTL_EOL); 184 1.3.2.2 martin if (error) { 185 1.3.2.2 martin aprint_error_dev(self, "failed to create sysctl hw.%s: %d\n", 186 1.3.2.2 martin device_xname(self), error); 187 1.3.2.2 martin goto out; 188 1.3.2.2 martin } 189 1.3.2.2 martin 190 1.3.2.2 martin /* 191 1.3.2.2 martin * hw.acpivmgenidN.id (`struct', 16-byte array) 192 1.3.2.2 martin */ 193 1.3.2.2 martin error = sysctl_createv(&sc->sc_sysctllog, 0, &sc->sc_sysctlroot, NULL, 194 1.3.2.2 martin CTLFLAG_PERMANENT|CTLFLAG_READONLY|CTLFLAG_PRIVATE, CTLTYPE_STRUCT, 195 1.3.2.2 martin "id", SYSCTL_DESCR("Virtual Machine Generation ID"), 196 1.3.2.2 martin &acpivmgenid_sysctl, 0, sc, sizeof(struct acpivmgenid), 197 1.3.2.2 martin CTL_CREATE, CTL_EOL); 198 1.3.2.2 martin if (error) { 199 1.3.2.2 martin aprint_error_dev(self, 200 1.3.2.2 martin "failed to create sysctl hw.%s.id: %d\n", 201 1.3.2.2 martin device_xname(self), error); 202 1.3.2.2 martin goto out; 203 1.3.2.2 martin } 204 1.3.2.2 martin 205 1.3.2.2 martin /* 206 1.3.2.2 martin * hw.acpivmgenidN.paddr (64-bit integer) 207 1.3.2.2 martin */ 208 1.3.2.2 martin __CTASSERT(sizeof(ACPI_PHYSICAL_ADDRESS) == sizeof(quad_t)); 209 1.3.2.2 martin error = sysctl_createv(&sc->sc_sysctllog, 0, &sc->sc_sysctlroot, NULL, 210 1.3.2.2 martin CTLFLAG_PERMANENT|CTLFLAG_READONLY|CTLFLAG_PRIVATE, CTLTYPE_QUAD, 211 1.3.2.2 martin "paddr", SYSCTL_DESCR("Physical address of VM Generation ID"), 212 1.3.2.2 martin NULL, 0, &sc->sc_paddr, sizeof(sc->sc_paddr), 213 1.3.2.2 martin CTL_CREATE, CTL_EOL); 214 1.3.2.2 martin if (error) { 215 1.3.2.2 martin aprint_error_dev(self, 216 1.3.2.2 martin "failed to create sysctl hw.%s.paddr: %d\n", 217 1.3.2.2 martin device_xname(self), error); 218 1.3.2.2 martin goto out; 219 1.3.2.2 martin } 220 1.3.2.2 martin 221 1.3.2.2 martin out: ACPI_FREE(addrbuf.Pointer); 222 1.3.2.2 martin } 223 1.3.2.2 martin 224 1.3.2.2 martin static int 225 1.3.2.2 martin acpivmgenid_detach(device_t self, int flags) 226 1.3.2.2 martin { 227 1.3.2.2 martin struct acpivmgenid_softc *const sc = device_private(self); 228 1.3.2.2 martin int error; 229 1.3.2.2 martin 230 1.3.2.2 martin error = config_detach_children(self, flags); 231 1.3.2.2 martin if (error) 232 1.3.2.2 martin return error; 233 1.3.2.2 martin 234 1.3.2.2 martin sysctl_teardown(&sc->sc_sysctllog); 235 1.3.2.2 martin acpi_deregister_notify(sc->sc_node); 236 1.3.2.2 martin rnd_detach_source(&sc->sc_rndsource); 237 1.3.2.2 martin if (sc->sc_vaddr) { 238 1.3.2.2 martin AcpiOsUnmapMemory(sc->sc_vaddr, sizeof(*sc->sc_vaddr)); 239 1.3.2.2 martin sc->sc_vaddr = NULL; /* paranoia */ 240 1.3.2.2 martin } 241 1.3.2.2 martin sc->sc_paddr = 0; /* paranoia */ 242 1.3.2.2 martin 243 1.3.2.2 martin return 0; 244 1.3.2.2 martin } 245 1.3.2.2 martin 246 1.3.2.2 martin static void 247 1.3.2.2 martin acpivmgenid_set(struct acpivmgenid_softc *sc, const char *prefix) 248 1.3.2.2 martin { 249 1.3.2.2 martin struct acpivmgenid vmgenid; 250 1.3.2.2 martin char vmgenidstr[2*__arraycount(vmgenid.id) + 1]; 251 1.3.2.2 martin unsigned i; 252 1.3.2.2 martin 253 1.3.2.2 martin /* 254 1.3.2.2 martin * Grab the current VM generation ID. No obvious way to make 255 1.3.2.2 martin * this atomic, so let's hope if it changes in the middle we'll 256 1.3.2.2 martin * get another notification. 257 1.3.2.2 martin */ 258 1.3.2.2 martin memcpy(&vmgenid, sc->sc_vaddr, sizeof(vmgenid)); 259 1.3.2.2 martin 260 1.3.2.2 martin /* 261 1.3.2.2 martin * Print the VM generation ID to the console for posterity. 262 1.3.2.2 martin */ 263 1.3.2.2 martin for (i = 0; i < __arraycount(vmgenid.id); i++) { 264 1.3.2.2 martin vmgenidstr[2*i] = "0123456789abcdef"[vmgenid.id[i] >> 4]; 265 1.3.2.2 martin vmgenidstr[2*i + 1] = "0123456789abcdef"[vmgenid.id[i] & 0xf]; 266 1.3.2.2 martin } 267 1.3.2.2 martin vmgenidstr[2*sizeof(vmgenid)] = '\0'; 268 1.3.2.2 martin aprint_verbose_dev(sc->sc_dev, "%s: %s\n", prefix, vmgenidstr); 269 1.3.2.2 martin 270 1.3.2.2 martin /* 271 1.3.2.2 martin * Enter the new VM generation ID into the entropy pool. 272 1.3.2.2 martin */ 273 1.3.2.2 martin rnd_add_data(&sc->sc_rndsource, &vmgenid, sizeof(vmgenid), 0); 274 1.3.2.2 martin } 275 1.3.2.2 martin 276 1.3.2.2 martin static void 277 1.3.2.2 martin acpivmgenid_notify(ACPI_HANDLE hdl, uint32_t notify, void *opaque) 278 1.3.2.2 martin { 279 1.3.2.2 martin const device_t self = opaque; 280 1.3.2.2 martin struct acpivmgenid_softc *const sc = device_private(self); 281 1.3.2.2 martin 282 1.3.2.2 martin if (notify != 0x80) { 283 1.3.2.2 martin aprint_debug_dev(self, "unknown notify 0x%02x\n", notify); 284 1.3.2.2 martin return; 285 1.3.2.2 martin } 286 1.3.2.2 martin 287 1.3.2.2 martin (void)AcpiOsExecute(OSL_NOTIFY_HANDLER, &acpivmgenid_reset, sc); 288 1.3.2.2 martin } 289 1.3.2.2 martin 290 1.3.2.2 martin static void 291 1.3.2.2 martin acpivmgenid_reset(void *cookie) 292 1.3.2.2 martin { 293 1.3.2.2 martin struct acpivmgenid_softc *const sc = cookie; 294 1.3.2.2 martin 295 1.3.2.2 martin /* 296 1.3.2.2 martin * Reset the system entropy pool's measure of entropy (not the 297 1.3.2.2 martin * data, just the system's assessment of whether it has 298 1.3.2.2 martin * entropy), and gather more entropy from any synchronous 299 1.3.2.2 martin * sources we have available like CPU RNG instructions. We 300 1.3.2.2 martin * can't be interrupted by a signal so ignore return value. 301 1.3.2.2 martin */ 302 1.3.2.2 martin entropy_reset(); 303 1.3.2.2 martin (void)entropy_gather(); 304 1.3.2.2 martin 305 1.3.2.2 martin /* 306 1.3.2.2 martin * Grab the current VM generation ID to put it into the entropy 307 1.3.2.2 martin * pool; then force consolidation so it affects all subsequent 308 1.3.2.2 martin * draws from the entropy pool and the entropy epoch advances. 309 1.3.2.2 martin */ 310 1.3.2.2 martin acpivmgenid_set(sc, "cloned"); 311 1.3.2.2 martin entropy_consolidate(); 312 1.3.2.2 martin } 313 1.3.2.2 martin 314 1.3.2.2 martin static int 315 1.3.2.2 martin acpivmgenid_sysctl(SYSCTLFN_ARGS) 316 1.3.2.2 martin { 317 1.3.2.2 martin struct sysctlnode node = *rnode; 318 1.3.2.2 martin struct acpivmgenid_softc *const sc = node.sysctl_data; 319 1.3.2.2 martin 320 1.3.2.2 martin node.sysctl_data = sc->sc_vaddr; 321 1.3.2.2 martin return sysctl_lookup(SYSCTLFN_CALL(&node)); 322 1.3.2.2 martin } 323 1.3.2.2 martin 324 1.3.2.2 martin MODULE(MODULE_CLASS_DRIVER, acpivmgenid, NULL); 325 1.3.2.2 martin 326 1.3.2.2 martin #ifdef _MODULE 327 1.3.2.2 martin #include "ioconf.c" 328 1.3.2.2 martin #endif 329 1.3.2.2 martin 330 1.3.2.2 martin static int 331 1.3.2.2 martin acpivmgenid_modcmd(modcmd_t cmd, void *opaque) 332 1.3.2.2 martin { 333 1.3.2.2 martin int error = 0; 334 1.3.2.2 martin 335 1.3.2.2 martin switch (cmd) { 336 1.3.2.2 martin case MODULE_CMD_INIT: 337 1.3.2.2 martin #ifdef _MODULE 338 1.3.2.2 martin error = config_init_component(cfdriver_ioconf_acpivmgenid, 339 1.3.2.2 martin cfattach_ioconf_acpivmgenid, cfdata_ioconf_acpivmgenid); 340 1.3.2.2 martin #endif 341 1.3.2.2 martin return error; 342 1.3.2.2 martin case MODULE_CMD_FINI: 343 1.3.2.2 martin #ifdef _MODULE 344 1.3.2.2 martin error = config_fini_component(cfdriver_ioconf_acpivmgenid, 345 1.3.2.2 martin cfattach_ioconf_acpivmgenid, cfdata_ioconf_acpivmgenid); 346 1.3.2.2 martin #endif 347 1.3.2.2 martin return error; 348 1.3.2.2 martin default: 349 1.3.2.2 martin return ENOTTY; 350 1.3.2.2 martin } 351 1.3.2.2 martin } 352
Indexes created Fri Oct 03 02:09:57 GMT 2025