[PATCH v1 2/4] virt: vmgenid: change implementation to use a platform driver

Sudan Landge
2024-03-19T14:33:21Z

Re-implement vmgenid as a platform driver in preparation
for adding devicetree bindings support in next commits.

Signed-off-by: Sudan Landge <sudanl@amazon.com>
---
drivers/virt/vmgenid.c | 99 +++++++++++++++++++++++++++++++-----------
1 file changed, 73 insertions(+), 26 deletions(-)

diff --git a/drivers/virt/vmgenid.c b/drivers/virt/vmgenid.c
index ea956df02874..e82b344a9d61 100644
--- a/drivers/virt/vmgenid.c
+++ b/drivers/virt/vmgenid.c
@@ -11,6 +11,8 @@
#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/random.h>
+#include <acpi/actypes.h>
+#include <linux/platform_device.h>

ACPI_MODULE_NAME("vmgenid");

@@ -21,9 +23,9 @@ struct vmgenid_state {
u8 this_id[VMGENID_SIZE];
};

-static void vmgenid_notify(struct acpi_device *device, u32 event)
+static void vmgenid_notify(struct device *device)
{
- struct vmgenid_state *state = acpi_driver_data(device);
+ struct vmgenid_state *state = device->driver_data;
char *envp[] = { "NEW_VMGENID=1", NULL };
u8 old_id[VMGENID_SIZE];

@@ -32,22 +34,34 @@ static void vmgenid_notify(struct acpi_device *device, u32 event)
if (!memcmp(old_id, state->this_id, sizeof(old_id)))
return;
add_vmfork_randomness(state->this_id, sizeof(state->this_id));
- kobject_uevent_env(&device->dev.kobj, KOBJ_CHANGE, envp);
+ kobject_uevent_env(&device->kobj, KOBJ_CHANGE, envp);
}

-static int vmgenid_add(struct acpi_device *device)
+static void vmgenid_acpi_handler(acpi_handle handle, u32 event, void *dev)
{
+ vmgenid_notify(dev);
+}
+
+static int setup_vmgenid_state(struct vmgenid_state *state, u8 *next_id)
+{
+ if (IS_ERR(next_id))
+ return PTR_ERR(next_id);
+
+ state->next_id = next_id;
+ memcpy(state->this_id, state->next_id, sizeof(state->this_id));
+ add_device_randomness(state->this_id, sizeof(state->this_id));
+ return 0;
+}
+
+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;
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"));
@@ -63,19 +77,42 @@ 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);
+
+ ret = setup_vmgenid_state(state,
+ devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB)
+ );
+ if (ret)
+ goto out;
+
+ dev->driver_data = state;
+ status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
+ vmgenid_acpi_handler, dev);
+ if (ACPI_FAILURE(status)) {
+ dev_err(dev, "Failed to install acpi notify handler");
+ ret = -ENODEV;
+ dev->driver_data = NULL;
goto out;
}
+out:
+ ACPI_FREE(parsed.pointer);
+ return ret;
+}

- memcpy(state->this_id, state->next_id, sizeof(state->this_id));
- add_device_randomness(state->this_id, sizeof(state->this_id));
+static int vmgenid_add(struct platform_device *pdev)
+{
+ struct vmgenid_state *state;
+ struct device *dev = &pdev->dev;
+ int ret = 0;

- device->driver_data = state;
+ state = devm_kmalloc(dev, sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+
+ ret = vmgenid_add_acpi(dev, state);
+
+ if (ret)
+ devm_kfree(dev, state);

-out:
- ACPI_FREE(parsed.pointer);
return ret;
}

@@ -85,17 +122,27 @@ static const struct acpi_device_id vmgenid_ids[] = {
{ }
};

-static struct acpi_driver vmgenid_driver = {
- .name = "vmgenid",
- .ids = vmgenid_ids,
- .owner = THIS_MODULE,
- .ops = {
- .add = vmgenid_add,
- .notify = vmgenid_notify
- }
+static struct platform_driver vmgenid_plaform_driver = {
+ .probe = vmgenid_add,
+ .driver = {
+ .name = "vmgenid",
+ .acpi_match_table = ACPI_PTR(vmgenid_ids),
+ .owner = THIS_MODULE,
+ },
};

-module_acpi_driver(vmgenid_driver);
+static int vmgenid_platform_device_init(void)
+{
+ return platform_driver_register(&vmgenid_plaform_driver);
+}
+
+static void vmgenid_platform_device_exit(void)
+{
+ platform_driver_unregister(&vmgenid_plaform_driver);
+}
+
+module_init(vmgenid_platform_device_init)
+module_exit(vmgenid_platform_device_exit)

MODULE_DEVICE_TABLE(acpi, vmgenid_ids);
MODULE_DESCRIPTION("Virtual Machine Generation ID");
--
2.40.1