/* * Virtual Machine Generation ID Device * * Copyright (C) 2017 Skyport Systems. * * Author: Ben Warren * * This work is licensed under the terms of the GNU GPL, version 2 or later. * See the COPYING file in the top-level directory. * */ #include "qemu/osdep.h" #include "qapi/error.h" #include "qapi/qapi-commands-misc.h" #include "hw/acpi/acpi.h" #include "hw/acpi/aml-build.h" #include "hw/acpi/vmgenid.h" #include "hw/nvram/fw_cfg.h" #include "sysemu/sysemu.h" void vmgenid_build_acpi(VmGenIdState *vms, GArray *table_data, GArray *guid, BIOSLinker *linker) { Aml *ssdt, *dev, *scope, *method, *addr, *if_ctx; uint32_t vgia_offset; QemuUUID guid_le; /* Fill in the GUID values. These need to be converted to little-endian * first, since that's what the guest expects */ g_array_set_size(guid, VMGENID_FW_CFG_SIZE - ARRAY_SIZE(guid_le.data)); guid_le = vms->guid; qemu_uuid_bswap(&guid_le); /* The GUID is written at a fixed offset into the fw_cfg file * in order to implement the "OVMF SDT Header probe suppressor" * see docs/specs/vmgenid.txt for more details */ g_array_insert_vals(guid, VMGENID_GUID_OFFSET, guid_le.data, ARRAY_SIZE(guid_le.data)); /* Put this in a separate SSDT table */ ssdt = init_aml_allocator(); /* Reserve space for header */ acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader)); /* Storage for the GUID address */ vgia_offset = table_data->len + build_append_named_dword(ssdt->buf, "VGIA"); scope = aml_scope("\\_SB"); dev = aml_device("VGEN"); aml_append(dev, aml_name_decl("_HID", aml_string("QEMUVGID"))); aml_append(dev, aml_name_decl("_CID", aml_string("VM_Gen_Counter"))); aml_append(dev, aml_name_decl("_DDN", aml_string("VM_Gen_Counter"))); /* Simple status method to check that address is linked and non-zero */ method = aml_method("_STA", 0, AML_NOTSERIALIZED); addr = aml_local(0); aml_append(method, aml_store(aml_int(0xf), addr)); if_ctx = aml_if(aml_equal(aml_name("VGIA"), aml_int(0))); aml_append(if_ctx, aml_store(aml_int(0), addr)); aml_append(method, if_ctx); aml_append(method, aml_return(addr)); aml_append(dev, method); /* the ADDR method returns two 32-bit words representing the lower and * upper halves * of the physical address of the fw_cfg blob * (holding the GUID) */ method = aml_method("ADDR", 0, AML_NOTSERIALIZED); addr = aml_local(0); aml_append(method, aml_store(aml_package(2), addr)); aml_append(method, aml_store(aml_add(aml_name("VGIA"), aml_int(VMGENID_GUID_OFFSET), NULL), aml_index(addr, aml_int(0)))); aml_append(method, aml_store(aml_int(0), aml_index(addr, aml_int(1)))); aml_append(method, aml_return(addr)); aml_append(dev, method); aml_append(scope, dev); aml_append(ssdt, scope); /* attach an ACPI notify */ method = aml_method("\\_GPE._E05", 0, AML_NOTSERIALIZED); aml_append(method, aml_notify(aml_name("\\_SB.VGEN"), aml_int(0x80))); aml_append(ssdt, method); g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len); /* Allocate guest memory for the Data fw_cfg blob */ bios_linker_loader_alloc(linker, VMGENID_GUID_FW_CFG_FILE, guid, 4096, false /* page boundary, high memory */); /* Patch address of GUID fw_cfg blob into the ADDR fw_cfg blob * so QEMU can write the GUID there. The address is expected to be * < 4GB, but write 64 bits anyway. * The address that is patched in is offset in order to implement * the "OVMF SDT Header probe suppressor" * see docs/specs/vmgenid.txt for more details. */ bios_linker_loader_write_pointer(linker, VMGENID_ADDR_FW_CFG_FILE, 0, sizeof(uint64_t), VMGENID_GUID_FW_CFG_FILE, VMGENID_GUID_OFFSET); /* Patch address of GUID fw_cfg blob into the AML so OSPM can retrieve * and read it. Note that while we provide storage for 64 bits, only * the least-signficant 32 get patched into AML. */ bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE, vgia_offset, sizeof(uint32_t), VMGENID_GUID_FW_CFG_FILE, 0); build_header(linker, table_data, (void *)(table_data->data + table_data->len - ssdt->buf->len), "SSDT", ssdt->buf->len, 1, NULL, "VMGENID"); free_aml_allocator(); } void vmgenid_add_fw_cfg(VmGenIdState *vms, FWCfgState *s, GArray *guid) { /* Create a read-only fw_cfg file for GUID */ fw_cfg_add_file(s, VMGENID_GUID_FW_CFG_FILE, guid->data, VMGENID_FW_CFG_SIZE); /* Create a read-write fw_cfg file for Address */ fw_cfg_add_file_callback(s, VMGENID_ADDR_FW_CFG_FILE, NULL, NULL, NULL, vms->vmgenid_addr_le, ARRAY_SIZE(vms->vmgenid_addr_le), false); } static void vmgenid_update_guest(VmGenIdState *vms) { Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL); uint32_t vmgenid_addr; QemuUUID guid_le; if (obj) { /* Write the GUID to guest memory */ memcpy(&vmgenid_addr, vms->vmgenid_addr_le, sizeof(vmgenid_addr)); vmgenid_addr = le32_to_cpu(vmgenid_addr); /* A zero value in vmgenid_addr means that BIOS has not yet written * the address */ if (vmgenid_addr) { /* QemuUUID has the first three words as big-endian, and expect * that any GUIDs passed in will always be BE. The guest, * however, will expect the fields to be little-endian. * Perform a byte swap immediately before writing. */ guid_le = vms->guid; qemu_uuid_bswap(&guid_le); /* The GUID is written at a fixed offset into the fw_cfg file * in order to implement the "OVMF SDT Header probe suppressor" * see docs/specs/vmgenid.txt for more details. */ cpu_physical_memory_write(vmgenid_addr, guid_le.data, sizeof(guid_le.data)); /* Send _GPE.E05 event */ acpi_send_event(DEVICE(obj), ACPI_VMGENID_CHANGE_STATUS); } } } /* After restoring an image, we need to update the guest memory and notify * it of a potential change to VM Generation ID */ static int vmgenid_post_load(void *opaque, int version_id) { VmGenIdState *vms = opaque; vmgenid_update_guest(vms); return 0; } static const VMStateDescription vmstate_vmgenid = { .name = "vmgenid", .version_id = 1, .minimum_version_id = 1, .post_load = vmgenid_post_load, .fields = (VMStateField[]) { VMSTATE_UINT8_ARRAY(vmgenid_addr_le, VmGenIdState, sizeof(uint64_t)), VMSTATE_END_OF_LIST() }, }; static void vmgenid_handle_reset(void *opaque) { VmGenIdState *vms = VMGENID(opaque); /* Clear the guest-allocated GUID address when the VM resets */ memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); } static void vmgenid_realize(DeviceState *dev, Error **errp) { VmGenIdState *vms = VMGENID(dev); if (!bios_linker_loader_can_write_pointer()) { error_setg(errp, "%s requires DMA write support in fw_cfg, " "which this machine type does not provide", VMGENID_DEVICE); return; } /* Given that this function is executing, there is at least one VMGENID * device. Check if there are several. */ if (!find_vmgenid_dev()) { error_setg(errp, "at most one %s device is permitted", VMGENID_DEVICE); return; } qemu_register_reset(vmgenid_handle_reset, vms); vmgenid_update_guest(vms); } static Property vmgenid_device_properties[] = { DEFINE_PROP_UUID(VMGENID_GUID, VmGenIdState, guid), DEFINE_PROP_END_OF_LIST(), }; static void vmgenid_device_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); dc->vmsd = &vmstate_vmgenid; dc->realize = vmgenid_realize; dc->props = vmgenid_device_properties; dc->hotpluggable = false; set_bit(DEVICE_CATEGORY_MISC, dc->categories); } static const TypeInfo vmgenid_device_info = { .name = VMGENID_DEVICE, .parent = TYPE_DEVICE, .instance_size = sizeof(VmGenIdState), .class_init = vmgenid_device_class_init, }; static void vmgenid_register_types(void) { type_register_static(&vmgenid_device_info); } type_init(vmgenid_register_types) GuidInfo *qmp_query_vm_generation_id(Error **errp) { GuidInfo *info; VmGenIdState *vms; Object *obj = find_vmgenid_dev(); if (!obj) { error_setg(errp, "VM Generation ID device not found"); return NULL; } vms = VMGENID(obj); info = g_malloc0(sizeof(*info)); info->guid = qemu_uuid_unparse_strdup(&vms->guid); return info; }