From: Or Idgar <orid...@gmail.com> This patch is a driver which expose the Virtual Machine Generation ID via sysfs. The ID is a UUID value used to differentiate between virtual machines.
The VM-Generation ID is a feature defined by Microsoft (paper: http://go.microsoft.com/fwlink/?LinkId=260709) and supported by multiple hypervisor vendors. Signed-off-by: Or Idgar <orid...@gmail.com> --- Changes in v3 from v1 (v2 lack of patch changelog): - replaced GPL2 section with SPDX line. - including linux/kobject.h for hypervisor_kobj. - using acpi_os_map_memory instead acpi_os_map_iomem. Documentation/ABI/testing/sysfs-hypervisor | 13 +++ drivers/misc/Kconfig | 6 ++ drivers/misc/Makefile | 1 + drivers/misc/vmgenid.c | 140 +++++++++++++++++++++++++++++ 4 files changed, 160 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-hypervisor create mode 100644 drivers/misc/vmgenid.c diff --git a/Documentation/ABI/testing/sysfs-hypervisor b/Documentation/ABI/testing/sysfs-hypervisor new file mode 100644 index 000000000000..2f9a7b8eab70 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-hypervisor @@ -0,0 +1,13 @@ +What: /sys/hypervisor/vm_gen_counter +Date: February 2018 +Contact: Or Idgar <id...@virtualoco.com> + Gal Hammer <gham...@redhat.com> +Description: Expose the virtual machine generation ID. The directory + contains two files: "generation_id" and "raw". Both files + represent the same information. + + "generation_id" file is a UUID string + representation. + + "raw" file is a 128-bit integer + representation (binary). diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 03605f8fc0dc..5a74802bdfb4 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -500,6 +500,12 @@ config MISC_RTSX tristate default MISC_RTSX_PCI || MISC_RTSX_USB +config VMGENID + tristate "Virtual Machine Generation ID driver" + help + This is a Virtual Machine Generation ID driver which provides + a virtual machine unique identifier. + source "drivers/misc/c2port/Kconfig" source "drivers/misc/eeprom/Kconfig" source "drivers/misc/cb710/Kconfig" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index c3c8624f4d95..067aa666bb6a 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -57,6 +57,7 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o obj-$(CONFIG_OCXL) += ocxl/ obj-$(CONFIG_MISC_RTSX) += cardreader/ +obj-$(CONFIG_VMGENID) += vmgenid.o lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o lkdtm-$(CONFIG_LKDTM) += lkdtm_bugs.o diff --git a/drivers/misc/vmgenid.c b/drivers/misc/vmgenid.c new file mode 100644 index 000000000000..6b7ec9bd45e8 --- /dev/null +++ b/drivers/misc/vmgenid.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Virtual Machine Generation ID driver + * + * Copyright (C) 2018 Red Hat, Inc. All rights reserved. + * Authors: + * Or Idgar <orid...@gmail.com> + * Gal Hammer <gham...@redhat.com> + * + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/kobject.h> +#include <linux/acpi.h> +#include <linux/uuid.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Or Idgar <orid...@gmail.com>"); +MODULE_AUTHOR("Gal Hammer <gham...@redhat.com>"); +MODULE_DESCRIPTION("Virtual Machine Generation ID"); +MODULE_VERSION("0.1"); + +ACPI_MODULE_NAME("vmgenid"); + +static u64 phy_addr; + +static ssize_t generation_id_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + uuid_t *uuidp; + ssize_t result; + + uuidp = acpi_os_map_memory(phy_addr, sizeof(uuid_t)); + if (!uuidp) + return -EFAULT; + + result = sprintf(buf, "%pUl\n", uuidp); + acpi_os_unmap_memory(uuidp, sizeof(uuid_t)); + return result; +} +static DEVICE_ATTR_RO(generation_id); + +static ssize_t raw_show(struct device *_d, + struct device_attribute *attr, + char *buf) +{ + uuid_t *uuidp; + + uuidp = acpi_os_map_memory(phy_addr, sizeof(uuid_t)); + if (!uuidp) + return -EFAULT; + memcpy(buf, uuidp, sizeof(uuid_t)); + acpi_os_unmap_memory(uuidp, sizeof(uuid_t)); + return sizeof(uuid_t); +} +static DEVICE_ATTR_RO(raw); + +static struct attribute *vmgenid_attrs[] = { + &dev_attr_generation_id.attr, + &dev_attr_raw.attr, + NULL, +}; +static const struct attribute_group vmgenid_group = { + .name = "vm_gen_counter", + .attrs = vmgenid_attrs, +}; + +static int get_vmgenid(acpi_handle handle) +{ + int i; + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + acpi_status status; + union acpi_object *pss; + union acpi_object *element; + + status = acpi_evaluate_object(handle, "ADDR", NULL, &buffer); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _ADDR")); + return -ENODEV; + } + pss = buffer.pointer; + if (!pss || pss->type != ACPI_TYPE_PACKAGE || pss->package.count != 2) + return -EFAULT; + + phy_addr = 0; + for (i = 0; i < pss->package.count; i++) { + element = &(pss->package.elements[i]); + if (element->type != ACPI_TYPE_INTEGER) + return -EFAULT; + phy_addr |= element->integer.value << i*32; + } + return 0; +} + +static int acpi_vmgenid_add(struct acpi_device *device) +{ + int retval; + + if (!device) + return -EINVAL; + retval = get_vmgenid(device->handle); + if (retval < 0) + return retval; + return sysfs_create_group(hypervisor_kobj, &vmgenid_group); +} + +static int acpi_vmgenid_remove(struct acpi_device *device) +{ + sysfs_remove_group(hypervisor_kobj, &vmgenid_group); + return 0; +} + +static const struct acpi_device_id vmgenid_ids[] = { + {"QEMUVGID", 0}, + {"", 0}, +}; + +static struct acpi_driver acpi_vmgenid_driver = { + .name = "vm_gen_counter", + .ids = vmgenid_ids, + .owner = THIS_MODULE, + .ops = { + .add = acpi_vmgenid_add, + .remove = acpi_vmgenid_remove, + } +}; + +static int __init vmgenid_init(void) +{ + return acpi_bus_register_driver(&acpi_vmgenid_driver); +} + +static void __exit vmgenid_exit(void) +{ + acpi_bus_unregister_driver(&acpi_vmgenid_driver); +} + +module_init(vmgenid_init); +module_exit(vmgenid_exit); -- 2.14.3
