Random number generator updates for Linux 6.10-rc1.
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This commit is contained in:
Linus Torvalds
commit
f0cd69b8cc
49
Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml
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49
Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml
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@ -0,0 +1,49 @@
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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/rng/microsoft,vmgenid.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Virtual Machine Generation ID
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maintainers:
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- Jason A. Donenfeld <Jason@zx2c4.com>
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description:
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Firmwares or hypervisors can use this devicetree to describe an
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interrupt and a shared resource to inject a Virtual Machine Generation ID.
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Virtual Machine Generation ID is a globally unique identifier (GUID) and
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the devicetree binding follows VMGenID specification defined in
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http://go.microsoft.com/fwlink/?LinkId=260709.
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properties:
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compatible:
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const: microsoft,vmgenid
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reg:
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description:
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Specifies a 16-byte VMGenID in endianness-agnostic hexadecimal format.
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maxItems: 1
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interrupts:
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description:
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Interrupt used to notify that a new VMGenID is available.
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maxItems: 1
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required:
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- compatible
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- reg
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- interrupts
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additionalProperties: false
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examples:
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- |
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#include <dt-bindings/interrupt-controller/arm-gic.h>
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rng@80000000 {
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compatible = "microsoft,vmgenid";
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reg = <0x80000000 0x1000>;
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interrupts = <GIC_SPI 35 IRQ_TYPE_EDGE_RISING>;
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};
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...
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@ -18669,6 +18669,7 @@ M: "Theodore Ts'o" <tytso@mit.edu>
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M: Jason A. Donenfeld <Jason@zx2c4.com>
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S: Maintained
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T: git https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git
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F: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml
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F: drivers/char/random.c
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F: drivers/virt/vmgenid.c
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@ -16,7 +16,6 @@ if VIRT_DRIVERS
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config VMGENID
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tristate "Virtual Machine Generation ID driver"
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default y
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depends on ACPI
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help
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Say Y here to use the hypervisor-provided Virtual Machine Generation ID
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to reseed the RNG when the VM is cloned. This is highly recommended if
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@ -2,14 +2,16 @@
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/*
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* Copyright (C) 2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*
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* The "Virtual Machine Generation ID" is exposed via ACPI and changes when a
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* The "Virtual Machine Generation ID" is exposed via ACPI or DT and changes when a
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* virtual machine forks or is cloned. This driver exists for shepherding that
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* information to random.c.
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*/
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#include <linux/acpi.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/acpi.h>
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#include <linux/platform_device.h>
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#include <linux/random.h>
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ACPI_MODULE_NAME("vmgenid");
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@ -21,19 +23,42 @@ struct vmgenid_state {
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u8 this_id[VMGENID_SIZE];
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};
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static int vmgenid_add(struct acpi_device *device)
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static void vmgenid_notify(struct device *device)
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{
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struct vmgenid_state *state = device->driver_data;
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u8 old_id[VMGENID_SIZE];
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memcpy(old_id, state->this_id, sizeof(old_id));
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memcpy(state->this_id, state->next_id, sizeof(state->this_id));
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if (!memcmp(old_id, state->this_id, sizeof(old_id)))
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return;
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add_vmfork_randomness(state->this_id, sizeof(state->this_id));
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}
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static void setup_vmgenid_state(struct vmgenid_state *state, void *virt_addr)
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{
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state->next_id = virt_addr;
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memcpy(state->this_id, state->next_id, sizeof(state->this_id));
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add_device_randomness(state->this_id, sizeof(state->this_id));
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}
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#ifdef CONFIG_ACPI
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static void vmgenid_acpi_handler(acpi_handle __always_unused handle,
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u32 __always_unused event, void *dev)
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{
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vmgenid_notify(dev);
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}
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static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *state)
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{
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struct acpi_device *device = ACPI_COMPANION(dev);
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struct acpi_buffer parsed = { ACPI_ALLOCATE_BUFFER };
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struct vmgenid_state *state;
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union acpi_object *obj;
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phys_addr_t phys_addr;
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acpi_status status;
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void *virt_addr;
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int ret = 0;
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state = devm_kmalloc(&device->dev, sizeof(*state), GFP_KERNEL);
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if (!state)
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return -ENOMEM;
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status = acpi_evaluate_object(device->handle, "ADDR", NULL, &parsed);
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if (ACPI_FAILURE(status)) {
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ACPI_EXCEPTION((AE_INFO, status, "Evaluating ADDR"));
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@ -49,52 +74,108 @@ static int vmgenid_add(struct acpi_device *device)
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phys_addr = (obj->package.elements[0].integer.value << 0) |
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(obj->package.elements[1].integer.value << 32);
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state->next_id = devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB);
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if (IS_ERR(state->next_id)) {
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ret = PTR_ERR(state->next_id);
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virt_addr = devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB);
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if (IS_ERR(virt_addr)) {
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ret = PTR_ERR(virt_addr);
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goto out;
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}
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setup_vmgenid_state(state, virt_addr);
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status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
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vmgenid_acpi_handler, dev);
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if (ACPI_FAILURE(status)) {
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ret = -ENODEV;
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goto out;
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}
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memcpy(state->this_id, state->next_id, sizeof(state->this_id));
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add_device_randomness(state->this_id, sizeof(state->this_id));
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device->driver_data = state;
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dev->driver_data = state;
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out:
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ACPI_FREE(parsed.pointer);
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return ret;
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}
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static void vmgenid_notify(struct acpi_device *device, u32 event)
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#else
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static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *state)
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{
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struct vmgenid_state *state = acpi_driver_data(device);
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u8 old_id[VMGENID_SIZE];
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return -EINVAL;
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}
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#endif
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memcpy(old_id, state->this_id, sizeof(old_id));
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memcpy(state->this_id, state->next_id, sizeof(state->this_id));
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if (!memcmp(old_id, state->this_id, sizeof(old_id)))
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return;
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add_vmfork_randomness(state->this_id, sizeof(state->this_id));
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static irqreturn_t vmgenid_of_irq_handler(int __always_unused irq, void *dev)
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{
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vmgenid_notify(dev);
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return IRQ_HANDLED;
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}
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static const struct acpi_device_id vmgenid_ids[] = {
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static int vmgenid_add_of(struct platform_device *pdev,
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struct vmgenid_state *state)
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{
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void *virt_addr;
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int ret;
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virt_addr = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
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if (IS_ERR(virt_addr))
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return PTR_ERR(virt_addr);
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setup_vmgenid_state(state, virt_addr);
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ret = platform_get_irq(pdev, 0);
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if (ret < 0)
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return ret;
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ret = devm_request_irq(&pdev->dev, ret, vmgenid_of_irq_handler,
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IRQF_SHARED, "vmgenid", &pdev->dev);
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if (ret < 0)
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return ret;
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pdev->dev.driver_data = state;
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return 0;
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}
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static int vmgenid_add(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct vmgenid_state *state;
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int ret;
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state = devm_kmalloc(dev, sizeof(*state), GFP_KERNEL);
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if (!state)
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return -ENOMEM;
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if (dev->of_node)
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ret = vmgenid_add_of(pdev, state);
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else
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ret = vmgenid_add_acpi(dev, state);
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if (ret < 0)
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devm_kfree(dev, state);
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return ret;
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}
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static const struct of_device_id vmgenid_of_ids[] = {
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{ .compatible = "microsoft,vmgenid", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, vmgenid_of_ids);
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static const struct acpi_device_id vmgenid_acpi_ids[] = {
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{ "VMGENCTR", 0 },
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{ "VM_GEN_COUNTER", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, vmgenid_acpi_ids);
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static struct acpi_driver vmgenid_driver = {
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.name = "vmgenid",
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.ids = vmgenid_ids,
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.ops = {
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.add = vmgenid_add,
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.notify = vmgenid_notify
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}
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static struct platform_driver vmgenid_plaform_driver = {
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.probe = vmgenid_add,
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.driver = {
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.name = "vmgenid",
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.acpi_match_table = vmgenid_acpi_ids,
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.of_match_table = vmgenid_of_ids,
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},
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};
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module_acpi_driver(vmgenid_driver);
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module_platform_driver(vmgenid_plaform_driver)
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MODULE_DEVICE_TABLE(acpi, vmgenid_ids);
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MODULE_DESCRIPTION("Virtual Machine Generation ID");
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
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