diff options
| -rw-r--r-- | Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml | 49 | ||||
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | drivers/virt/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/virt/vmgenid.c | 149 |
4 files changed, 165 insertions, 35 deletions
diff --git a/Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml b/Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml new file mode 100644 index 000000000000..8f20dee93e7e --- /dev/null +++ b/Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml @@ -0,0 +1,49 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/rng/microsoft,vmgenid.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Virtual Machine Generation ID + +maintainers: + - Jason A. Donenfeld <Jason@zx2c4.com> + +description: + Firmwares or hypervisors can use this devicetree to describe an + interrupt and a shared resource to inject a Virtual Machine Generation ID. + Virtual Machine Generation ID is a globally unique identifier (GUID) and + the devicetree binding follows VMGenID specification defined in + http://go.microsoft.com/fwlink/?LinkId=260709. + +properties: + compatible: + const: microsoft,vmgenid + + reg: + description: + Specifies a 16-byte VMGenID in endianness-agnostic hexadecimal format. + maxItems: 1 + + interrupts: + description: + Interrupt used to notify that a new VMGenID is available. + maxItems: 1 + +required: + - compatible + - reg + - interrupts + +additionalProperties: false + +examples: + - | + #include <dt-bindings/interrupt-controller/arm-gic.h> + rng@80000000 { + compatible = "microsoft,vmgenid"; + reg = <0x80000000 0x1000>; + interrupts = <GIC_SPI 35 IRQ_TYPE_EDGE_RISING>; + }; + +... diff --git a/MAINTAINERS b/MAINTAINERS index 7bb9b84c3b78..ca389fd49d74 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18669,6 +18669,7 @@ M: "Theodore Ts'o" <tytso@mit.edu> M: Jason A. Donenfeld <Jason@zx2c4.com> S: Maintained T: git https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git +F: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml F: drivers/char/random.c F: drivers/virt/vmgenid.c diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig index 40129b6f0eca..d8c848cf09a6 100644 --- a/drivers/virt/Kconfig +++ b/drivers/virt/Kconfig @@ -16,7 +16,6 @@ if VIRT_DRIVERS config VMGENID tristate "Virtual Machine Generation ID driver" default y - depends on ACPI help Say Y here to use the hypervisor-provided Virtual Machine Generation ID to reseed the RNG when the VM is cloned. This is highly recommended if diff --git a/drivers/virt/vmgenid.c b/drivers/virt/vmgenid.c index eba4250ab3cf..66135eac3abf 100644 --- a/drivers/virt/vmgenid.c +++ b/drivers/virt/vmgenid.c @@ -2,14 +2,16 @@ /* * Copyright (C) 2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. * - * The "Virtual Machine Generation ID" is exposed via ACPI and changes when a + * The "Virtual Machine Generation ID" is exposed via ACPI or DT and changes when a * virtual machine forks or is cloned. This driver exists for shepherding that * information to random.c. */ +#include <linux/acpi.h> +#include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/module.h> -#include <linux/acpi.h> +#include <linux/platform_device.h> #include <linux/random.h> ACPI_MODULE_NAME("vmgenid"); @@ -21,19 +23,42 @@ struct vmgenid_state { u8 this_id[VMGENID_SIZE]; }; -static int vmgenid_add(struct acpi_device *device) +static void vmgenid_notify(struct device *device) +{ + struct vmgenid_state *state = device->driver_data; + u8 old_id[VMGENID_SIZE]; + + memcpy(old_id, state->this_id, sizeof(old_id)); + memcpy(state->this_id, state->next_id, sizeof(state->this_id)); + if (!memcmp(old_id, state->this_id, sizeof(old_id))) + return; + add_vmfork_randomness(state->this_id, sizeof(state->this_id)); +} + +static void setup_vmgenid_state(struct vmgenid_state *state, void *virt_addr) +{ + state->next_id = virt_addr; + memcpy(state->this_id, state->next_id, sizeof(state->this_id)); + add_device_randomness(state->this_id, sizeof(state->this_id)); +} + +#ifdef CONFIG_ACPI +static void vmgenid_acpi_handler(acpi_handle __always_unused handle, + u32 __always_unused event, void *dev) +{ + vmgenid_notify(dev); +} + +static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *state) { + struct acpi_device *device = ACPI_COMPANION(dev); struct acpi_buffer parsed = { ACPI_ALLOCATE_BUFFER }; - struct vmgenid_state *state; union acpi_object *obj; phys_addr_t phys_addr; acpi_status status; + void *virt_addr; int ret = 0; - state = devm_kmalloc(&device->dev, sizeof(*state), GFP_KERNEL); - if (!state) - return -ENOMEM; - status = acpi_evaluate_object(device->handle, "ADDR", NULL, &parsed); if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Evaluating ADDR")); @@ -49,52 +74,108 @@ static int vmgenid_add(struct acpi_device *device) phys_addr = (obj->package.elements[0].integer.value << 0) | (obj->package.elements[1].integer.value << 32); - state->next_id = devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB); - if (IS_ERR(state->next_id)) { - ret = PTR_ERR(state->next_id); + + virt_addr = devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB); + if (IS_ERR(virt_addr)) { + ret = PTR_ERR(virt_addr); goto out; } + setup_vmgenid_state(state, virt_addr); - memcpy(state->this_id, state->next_id, sizeof(state->this_id)); - add_device_randomness(state->this_id, sizeof(state->this_id)); - - device->driver_data = state; + status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY, + vmgenid_acpi_handler, dev); + if (ACPI_FAILURE(status)) { + ret = -ENODEV; + goto out; + } + dev->driver_data = state; out: ACPI_FREE(parsed.pointer); return ret; } +#else +static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *state) +{ + return -EINVAL; +} +#endif -static void vmgenid_notify(struct acpi_device *device, u32 event) +static irqreturn_t vmgenid_of_irq_handler(int __always_unused irq, void *dev) { - struct vmgenid_state *state = acpi_driver_data(device); - u8 old_id[VMGENID_SIZE]; + vmgenid_notify(dev); + return IRQ_HANDLED; +} - memcpy(old_id, state->this_id, sizeof(old_id)); - memcpy(state->this_id, state->next_id, sizeof(state->this_id)); - if (!memcmp(old_id, state->this_id, sizeof(old_id))) - return; - add_vmfork_randomness(state->this_id, sizeof(state->this_id)); +static int vmgenid_add_of(struct platform_device *pdev, + struct vmgenid_state *state) +{ + void *virt_addr; + int ret; + + virt_addr = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); + if (IS_ERR(virt_addr)) + return PTR_ERR(virt_addr); + + setup_vmgenid_state(state, virt_addr); + + ret = platform_get_irq(pdev, 0); + if (ret < 0) + return ret; + + ret = devm_request_irq(&pdev->dev, ret, vmgenid_of_irq_handler, + IRQF_SHARED, "vmgenid", &pdev->dev); + if (ret < 0) + return ret; + + pdev->dev.driver_data = state; + return 0; } -static const struct acpi_device_id vmgenid_ids[] = { +static int vmgenid_add(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct vmgenid_state *state; + int ret; + + state = devm_kmalloc(dev, sizeof(*state), GFP_KERNEL); + if (!state) + return -ENOMEM; + + if (dev->of_node) + ret = vmgenid_add_of(pdev, state); + else + ret = vmgenid_add_acpi(dev, state); + + if (ret < 0) + devm_kfree(dev, state); + return ret; +} + +static const struct of_device_id vmgenid_of_ids[] = { + { .compatible = "microsoft,vmgenid", }, + { }, +}; +MODULE_DEVICE_TABLE(of, vmgenid_of_ids); + +static const struct acpi_device_id vmgenid_acpi_ids[] = { { "VMGENCTR", 0 }, { "VM_GEN_COUNTER", 0 }, { } }; - -static struct acpi_driver vmgenid_driver = { - .name = "vmgenid", - .ids = vmgenid_ids, - .ops = { - .add = vmgenid_add, - .notify = vmgenid_notify - } +MODULE_DEVICE_TABLE(acpi, vmgenid_acpi_ids); + +static struct platform_driver vmgenid_plaform_driver = { + .probe = vmgenid_add, + .driver = { + .name = "vmgenid", + .acpi_match_table = vmgenid_acpi_ids, + .of_match_table = vmgenid_of_ids, + }, }; -module_acpi_driver(vmgenid_driver); +module_platform_driver(vmgenid_plaform_driver) -MODULE_DEVICE_TABLE(acpi, vmgenid_ids); MODULE_DESCRIPTION("Virtual Machine Generation ID"); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>"); |