[PATCH v4] drivers/misc: vm_gen_counter: initial driver implementation

[Or Idgar]

From: Or Idgar 

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 
---

Changes in v4:
- variable phy_addr changed to phys_addr (nit)
- using iomem functions to support arch portability

 Documentation/ABI/testing/sysfs-hypervisor |  13 +++
 drivers/misc/Kconfig   |   6 ++
 drivers/misc/Makefile  |   1 +
 drivers/misc/vmgenid.c | 142 +
 4 files changed, 162 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 ..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 
+   Gal Hammer 
+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 ..6c8d8fe75335
--- /dev/null
+++ b/drivers/misc/vmgenid.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtual Machine Generation ID driver
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All rights reserved.
+ * Authors:
+ *   Or Idgar 
+ *   Gal Hammer 
+ *
+ */
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Or Idgar ");
+MODULE_AUTHOR("Gal Hammer ");
+MODULE_DESCRIPTION("Virtual Machine Generation ID");
+MODULE_VERSION("0.1");
+
+ACPI_MODULE_NAME("vmgenid");
+
+static u64 phys_addr;
+
+static ssize_t generation_id_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+   void __iomem *uuid_map;
+   uuid_t uuid;
+   ssize_t result;
+
+   uuid_map = acpi_os_map_iomem(phys_addr, sizeof(uuid_t));
+   if (!uuid_map)
+   return -EFAULT;
+
+   memcpy_fromio(, uuid_map, sizeof(uuid_t));
+   result = sprintf(buf, "%pUl\n", );
+   acpi_os_unmap_iomem(uuid_map, 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)
+{
+   void __iomem *uuid_map;
+
+   uuid_map = acpi_os_map_iomem(phys_addr, sizeof(uuid_t));
+   if (!uuid_map)
+   return -EFAULT;
+   memcpy_fromio(buf, uuid_map, sizeof(uuid_t));
+   acpi_os_unmap_iomem(uuid_map, sizeof(uuid_t));
+   return sizeof(uuid_t);
+}
+static DEVICE_ATTR_RO(raw);
+
+static struct attribute *vmgenid_attrs[] = {
+   _attr_generation_id.attr,
+   _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;
+

[PATCH v4] drivers/misc: vm_gen_counter: initial driver implementation

[Or Idgar]

From: Or Idgar 

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 
---

Changes in v4:
- variable phy_addr changed to phys_addr (nit)
- using iomem functions to support arch portability

 Documentation/ABI/testing/sysfs-hypervisor |  13 +++
 drivers/misc/Kconfig   |   6 ++
 drivers/misc/Makefile  |   1 +
 drivers/misc/vmgenid.c | 142 +
 4 files changed, 162 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 ..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 
+   Gal Hammer 
+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 ..6c8d8fe75335
--- /dev/null
+++ b/drivers/misc/vmgenid.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtual Machine Generation ID driver
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All rights reserved.
+ * Authors:
+ *   Or Idgar 
+ *   Gal Hammer 
+ *
+ */
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Or Idgar ");
+MODULE_AUTHOR("Gal Hammer ");
+MODULE_DESCRIPTION("Virtual Machine Generation ID");
+MODULE_VERSION("0.1");
+
+ACPI_MODULE_NAME("vmgenid");
+
+static u64 phys_addr;
+
+static ssize_t generation_id_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+   void __iomem *uuid_map;
+   uuid_t uuid;
+   ssize_t result;
+
+   uuid_map = acpi_os_map_iomem(phys_addr, sizeof(uuid_t));
+   if (!uuid_map)
+   return -EFAULT;
+
+   memcpy_fromio(, uuid_map, sizeof(uuid_t));
+   result = sprintf(buf, "%pUl\n", );
+   acpi_os_unmap_iomem(uuid_map, 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)
+{
+   void __iomem *uuid_map;
+
+   uuid_map = acpi_os_map_iomem(phys_addr, sizeof(uuid_t));
+   if (!uuid_map)
+   return -EFAULT;
+   memcpy_fromio(buf, uuid_map, sizeof(uuid_t));
+   acpi_os_unmap_iomem(uuid_map, sizeof(uuid_t));
+   return sizeof(uuid_t);
+}
+static DEVICE_ATTR_RO(raw);
+
+static struct attribute *vmgenid_attrs[] = {
+   _attr_generation_id.attr,
+   _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, );
+   if (ACPI_FAILURE(status)) {
+