// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2020-2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*/
/**
* DOC: Nitro Enclaves (NE) PCI device driver.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nitro_enclaves.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <linux/wait.h>
#include "ne_misc_dev.h"
#include "ne_pci_dev.h"
/**
* NE_DEFAULT_TIMEOUT_MSECS - Default timeout to wait for a reply from
* the NE PCI device.
*/
#define NE_DEFAULT_TIMEOUT_MSECS (120000) /* 120 sec */
static const struct pci_device_id ne_pci_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMAZON, PCI_DEVICE_ID_NE) },
{ 0, }
};
MODULE_DEVICE_TABLE(pci, ne_pci_ids);
/**
* ne_submit_request() - Submit command request to the PCI device based on the
* command type.
* @pdev: PCI device to send the command to.
* @cmd_type: Command type of the request sent to the PCI device.
* @cmd_request: Command request payload.
* @cmd_request_size: Size of the command request payload.
*
* Context: Process context. This function is called with the ne_pci_dev mutex held.
*/
static void ne_submit_request(struct pci_dev *pdev, enum ne_pci_dev_cmd_type cmd_type,
void *cmd_request, size_t cmd_request_size)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
memcpy_toio(ne_pci_dev->iomem_base + NE_SEND_DATA, cmd_request, cmd_request_size);
iowrite32(cmd_type, ne_pci_dev->iomem_base + NE_COMMAND);
}
/**
* ne_retrieve_reply() - Retrieve reply from the PCI device.
* @pdev: PCI device to receive the reply from.
* @cmd_reply: Command reply payload.
* @cmd_reply_size: Size of the command reply payload.
*
* Context: Process context. This function is called with the ne_pci_dev mutex held.
*/
static void ne_retrieve_reply(struct pci_dev *pdev, struct ne_pci_dev_cmd_reply *cmd_reply,
size_t cmd_reply_size)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
memcpy_fromio(cmd_reply, ne_pci_dev->iomem_base + NE_RECV_DATA, cmd_reply_size);
}
/**
* ne_wait_for_reply() - Wait for a reply of a PCI device command.
* @pdev: PCI device for which a reply is waited.
*
* Context: Process context. This function is called with the ne_pci_dev mutex held.
* Return:
* * 0 on success.
* * Negative return value on failure.
*/
static int ne_wait_for_reply(struct pci_dev *pdev)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
int rc = -EINVAL;
/*
* TODO: Update to _interruptible and handle interrupted wait event
* e.g. -ERESTARTSYS, incoming signals + update timeout, if needed.
*/
rc = wait_event_timeout(ne_pci_dev->cmd_reply_wait_q,
atomic_read(&ne_pci_dev->cmd_reply_avail) != 0,
msecs_to_jiffies(NE_DEFAULT_TIMEOUT_MSECS));
if (!rc)
return -ETIMEDOUT;
return 0;
}
int ne_do_request(struct pci_dev *pdev, enum ne_pci_dev_cmd_type cmd_type,
void *cmd_request, size_t cmd_request_size,
struct ne_pci_dev_cmd_reply *cmd_reply, size_t cmd_reply_size)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
int rc = -EINVAL;
if (cmd_type <= INVALID_CMD || cmd_type >= MAX_CMD) {
dev_err_ratelimited(&pdev->dev, "Invalid cmd type=%u\n", cmd_type);
return -EINVAL;
}
if (!cmd_request) {
dev_err_ratelimited(&pdev->dev, "Null cmd request for cmd type=%u\n",
cmd_type);
return -EINVAL;
}
if (cmd_request_size > NE_SEND_DATA_SIZE) {
dev_err_ratelimited(&pdev->dev, "Invalid req size=%zu for cmd type=%u\n",
cmd_request_size, cmd_type);
return -EINVAL;
}
if (!cmd_reply) {
dev_err_ratelimited(&pdev->dev, "Null cmd reply for cmd type=%u\n",
cmd_type);
return -EINVAL;
}
if (cmd_reply_size > NE_RECV_DATA_SIZE) {
dev_err_ratelimited(&pdev->dev, "Invalid reply size=%zu for cmd type=%u\n",
cmd_reply_size, cmd_type);
return -EINVAL;
}
/*
* Use this mutex so that the PCI device handles one command request at
* a time.
*/
mutex_lock(&ne_pci_dev->pci_dev_mutex);
atomic_set(&ne_pci_dev->cmd_reply_avail, 0);
ne_submit_request(pdev, cmd_type, cmd_request, cmd_request_size);
rc = ne_wait_for_reply(pdev);
if (rc < 0) {
dev_err_ratelimited(&pdev->dev, "Error in wait for reply for cmd type=%u [rc=%d]\n",
cmd_type, rc);
goto unlock_mutex;
}
ne_retrieve_reply(pdev, cmd_reply, cmd_reply_size);
atomic_set(&ne_pci_dev->cmd_reply_avail, 0);
if (cmd_reply->rc < 0) {
rc = cmd_reply->rc;
dev_err_ratelimited(&pdev->dev, "Error in cmd process logic, cmd type=%u [rc=%d]\n",
cmd_type, rc);
goto unlock_mutex;
}
rc = 0;
unlock_mutex:
mutex_unlock(&ne_pci_dev->pci_dev_mutex);
return rc;
}
/**
* ne_reply_handler() - Interrupt handler for retrieving a reply matching a
* request sent to the PCI device for enclave lifetime
* management.
* @irq: Received interrupt for a reply sent by the PCI device.
* @args: PCI device private data structure.
*
* Context: Interrupt context.
* Return:
* * IRQ_HANDLED on handled interrupt.
*/
static irqreturn_t ne_reply_handler(int irq, void *args)
{
struct ne_pci_dev *ne_pci_dev = (struct ne_pci_dev *)args;
atomic_set(&ne_pci_dev->cmd_reply_avail, 1);
/* TODO: Update to _interruptible. */
wake_up(&ne_pci_dev->cmd_reply_wait_q);
return IRQ_HANDLED;
}
/**
* ne_event_work_handler() - Work queue handler for notifying enclaves on a
* state change received by the event interrupt
* handler.
* @work: Item containing the NE PCI device for which an out-of-band event
* was issued.
*
* An out-of-band event is being issued by the Nitro Hypervisor when at least
* one enclave is changing state without client interaction.
*
* Context: Work queue context.
*/
static void ne_event_work_handler(struct work_struct *work)
{
struct ne_pci_dev_cmd_reply cmd_reply = {};
struct ne_enclave *ne_enclave = NULL;
struct ne_pci_dev *ne_pci_dev =
container_of(work, struct ne_pci_dev, notify_work);
struct pci_dev *pdev = ne_pci_dev->pdev;
int rc = -EINVAL;
struct slot_info_req slot_info_req = {};
mutex_lock(&ne_pci_dev->enclaves_list_mutex);
/*
* Iterate over all enclaves registered for the Nitro Enclaves
* PCI device and determine for which enclave(s) the out-of-band event
* is corresponding to.
*/
list_for_each_entry(ne_enclave, &ne_pci_dev->enclaves_list, enclave_list_entry) {
mutex_lock(&ne_enclave->enclave_info_mutex);
/*
* Enclaves that were never started cannot receive out-of-band
* events.
*/
if (ne_enclave->state != NE_STATE_RUNNING)
goto unlock;
slot_info_req.slot_uid = ne_enclave->slot_uid;
rc = ne_do_request(pdev, SLOT_INFO,
&slot_info_req, sizeof(slot_info_req),
&cmd_reply, sizeof(cmd_reply));
if (rc < 0)
dev_err(&pdev->dev, "Error in slot info [rc=%d]\n", rc);
/* Notify enclave process that the enclave state changed. */
if (ne_enclave->state != cmd_reply.state) {
ne_enclave->state = cmd_reply.state;
ne_enclave->has_event = true;
wake_up_interruptible(&ne_enclave->eventq);
}
unlock:
mutex_unlock(&ne_enclave->enclave_info_mutex);
}
mutex_unlock(&ne_pci_dev->enclaves_list_mutex);
}
/**
* ne_event_handler() - Interrupt handler for PCI device out-of-band events.
* This interrupt does not supply any data in the MMIO
* region. It notifies a change in the state of any of
* the launched enclaves.
* @irq: Received interrupt for an out-of-band event.
* @args: PCI device private data structure.
*
* Context: Interrupt context.
* Return:
* * IRQ_HANDLED on handled interrupt.
*/
static irqreturn_t ne_event_handler(int irq, void *args)
{
struct ne_pci_dev *ne_pci_dev = (struct ne_pci_dev *)args;
queue_work(ne_pci_dev->event_wq, &ne_pci_dev->notify_work);
return IRQ_HANDLED;
}
/**
* ne_setup_msix() - Setup MSI-X vectors for the PCI device.
* @pdev: PCI device to setup the MSI-X for.
*
* Context: Process context.
* Return:
* * 0 on success.
* * Negative return value on failure.
*/
static int ne_setup_msix(struct pci_dev *pdev)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
int nr_vecs = 0;
int rc = -EINVAL;
nr_vecs = pci_msix_vec_count(pdev);
if (nr_vecs < 0) {
rc = nr_vecs;
dev_err(&pdev->dev, "Error in getting vec count [rc=%d]\n", rc);
return rc;
}
rc = pci_alloc_irq_vectors(pdev, nr_vecs, nr_vecs, PCI_IRQ_MSIX);
if (rc < 0) {
dev_err(&pdev->dev, "Error in alloc MSI-X vecs [rc=%d]\n", rc);
return rc;
}
/*
* This IRQ gets triggered every time the PCI device responds to a
* command request. The reply is then retrieved, reading from the MMIO
* space of the PCI device.
*/
rc = request_irq(pci_irq_vector(pdev, NE_VEC_REPLY), ne_reply_handler,
0, "enclave_cmd", ne_pci_dev);
if (rc < 0) {
dev_err(&pdev->dev, "Error in request irq reply [rc=%d]\n", rc);
goto free_irq_vectors;
}
ne_pci_dev->event_wq = create_singlethread_workqueue("ne_pci_dev_wq");
if (!ne_pci_dev->event_wq) {
rc = -ENOMEM;
dev_err(&pdev->dev, "Cannot get wq for dev events [rc=%d]\n", rc);
goto free_reply_irq_vec;
}
INIT_WORK(&ne_pci_dev->notify_work, ne_event_work_handler);
/*
* This IRQ gets triggered every time any enclave's state changes. Its
* handler then scans for the changes and propagates them to the user
* space.
*/
rc = request_irq(pci_irq_vector(pdev, NE_VEC_EVENT), ne_event_handler,
0, "enclave_evt", ne_pci_dev);
if (rc < 0) {
dev_err(&pdev->dev, "Error in request irq event [rc=%d]\n", rc);
goto destroy_wq;
}
return 0;
destroy_wq:
destroy_workqueue(ne_pci_dev->event_wq);
free_reply_irq_vec:
free_irq(pci_irq_vector(pdev, NE_VEC_REPLY), ne_pci_dev);
free_irq_vectors:
pci_free_irq_vectors(pdev);
return rc;
}
/**
* ne_teardown_msix() - Teardown MSI-X vectors for the PCI device.
* @pdev: PCI device to teardown the MSI-X for.
*
* Context: Process context.
*/
static void ne_teardown_msix(struct pci_dev *pdev)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
free_irq(pci_irq_vector(pdev, NE_VEC_EVENT), ne_pci_dev);
flush_work(&ne_pci_dev->notify_work);
destroy_workqueue(ne_pci_dev->event_wq);
free_irq(pci_irq_vector(pdev, NE_VEC_REPLY), ne_pci_dev);
pci_free_irq_vectors(pdev);
}
/**
* ne_pci_dev_enable() - Select the PCI device version and enable it.
* @pdev: PCI device to select version for and then enable.
*
* Context: Process context.
* Return:
* * 0 on success.
* * Negative return value on failure.
*/
static int ne_pci_dev_enable(struct pci_dev *pdev)
{
u8 dev_enable_reply = 0;
u16 dev_version_reply = 0;
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
iowrite16(NE_VERSION_MAX, ne_pci_dev->iomem_base + NE_VERSION);
dev_version_reply = ioread16(ne_pci_dev->iomem_base + NE_VERSION);
if (dev_version_reply != NE_VERSION_MAX) {
dev_err(&pdev->dev, "Error in pci dev version cmd\n");
return -EIO;
}
iowrite8(NE_ENABLE_ON, ne_pci_dev->iomem_base + NE_ENABLE);
dev_enable_reply = ioread8(ne_pci_dev->iomem_base + NE_ENABLE);
if (dev_enable_reply != NE_ENABLE_ON) {
dev_err(&pdev->dev, "Error in pci dev enable cmd\n");
return -EIO;
}
return 0;
}
/**
* ne_pci_dev_disable() - Disable the PCI device.
* @pdev: PCI device to disable.
*
* Context: Process context.
*/
static void ne_pci_dev_disable(struct pci_dev *pdev)
{
u8 dev_disable_reply = 0;
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
const unsigned int sleep_time = 10; /* 10 ms */
unsigned int sleep_time_count = 0;
iowrite8(NE_ENABLE_OFF, ne_pci_dev->iomem_base + NE_ENABLE);
/*
* Check for NE_ENABLE_OFF in a loop, to handle cases when the device
* state is not immediately set to disabled and going through a
* transitory state of disabling.
*/
while (sleep_time_count < NE_DEFAULT_TIMEOUT_MSECS) {
dev_disable_reply = ioread8(ne_pci_dev->iomem_base + NE_ENABLE);
if (dev_disable_reply == NE_ENABLE_OFF)
return;
msleep_interruptible(sleep_time);
sleep_time_count += sleep_time;
}
dev_disable_reply = ioread8(ne_pci_dev->iomem_base + NE_ENABLE);
if (dev_disable_reply != NE_ENABLE_OFF)
dev_err(&pdev->dev, "Error in pci dev disable cmd\n");
}
/**
* ne_pci_probe() - Probe function for the NE PCI device.
* @pdev: PCI device to match with the NE PCI driver.
* @id : PCI device id table associated with the NE PCI driver.
*
* Context: Process context.
* Return:
* * 0 on success.
* * Negative return value on failure.
*/
static int ne_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct ne_pci_dev *ne_pci_dev = NULL;
int rc = -EINVAL;
ne_pci_dev = kzalloc(sizeof(*ne_pci_dev), GFP_KERNEL);
if (!ne_pci_dev)
return -ENOMEM;
rc = pci_enable_device(pdev);
if (rc < 0) {
dev_err(&pdev->dev, "Error in pci dev enable [rc=%d]\n", rc);
goto free_ne_pci_dev;
}
pci_set_master(pdev);
rc = pci_request_regions_exclusive(pdev, "nitro_enclaves");
if (rc < 0) {
dev_err(&pdev->dev, "Error in pci request regions [rc=%d]\n", rc);
goto disable_pci_dev;
}
ne_pci_dev->iomem_base = pci_iomap(pdev, PCI_BAR_NE, 0);
if (!ne_pci_dev->iomem_base) {
rc = -ENOMEM;
dev_err(&pdev->dev, "Error in pci iomap [rc=%d]\n", rc);
goto release_pci_regions;
}
pci_set_drvdata(pdev, ne_pci_dev);
rc = ne_setup_msix(pdev);
if (rc < 0) {
dev_err(&pdev->dev, "Error in pci dev msix setup [rc=%d]\n", rc);
goto iounmap_pci_bar;
}
ne_pci_dev_disable(pdev);
rc = ne_pci_dev_enable(pdev);
if (rc < 0) {
dev_err(&pdev->dev, "Error in ne_pci_dev enable [rc=%d]\n", rc);
goto teardown_msix;
}
atomic_set(&ne_pci_dev->cmd_reply_avail, 0);
init_waitqueue_head(&ne_pci_dev->cmd_reply_wait_q);
INIT_LIST_HEAD(&ne_pci_dev->enclaves_list);
mutex_init(&ne_pci_dev->enclaves_list_mutex);
mutex_init(&ne_pci_dev->pci_dev_mutex);
ne_pci_dev->pdev = pdev;
ne_devs.ne_pci_dev = ne_pci_dev;
rc = misc_register(ne_devs.ne_misc_dev);
if (rc < 0) {
dev_err(&pdev->dev, "Error in misc dev register [rc=%d]\n", rc);
goto disable_ne_pci_dev;
}
return 0;
disable_ne_pci_dev:
ne_devs.ne_pci_dev = NULL;
ne_pci_dev_disable(pdev);
teardown_msix:
ne_teardown_msix(pdev);
iounmap_pci_bar:
pci_set_drvdata(pdev, NULL);
pci_iounmap(pdev, ne_pci_dev->iomem_base);
release_pci_regions:
pci_release_regions(pdev);
disable_pci_dev:
pci_disable_device(pdev);
free_ne_pci_dev:
kfree(ne_pci_dev);
return rc;
}
/**
* ne_pci_remove() - Remove function for the NE PCI device.
* @pdev: PCI device associated with the NE PCI driver.
*
* Context: Process context.
*/
static void ne_pci_remove(struct pci_dev *pdev)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
misc_deregister(ne_devs.ne_misc_dev);
ne_devs.ne_pci_dev = NULL;
ne_pci_dev_disable(pdev);
ne_teardown_msix(pdev);
pci_set_drvdata(pdev, NULL);
pci_iounmap(pdev, ne_pci_dev->iomem_base);
pci_release_regions(pdev);
pci_disable_device(pdev);
kfree(ne_pci_dev);
}
/**
* ne_pci_shutdown() - Shutdown function for the NE PCI device.
* @pdev: PCI device associated with the NE PCI driver.
*
* Context: Process context.
*/
static void ne_pci_shutdown(struct pci_dev *pdev)
{
struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
if (!ne_pci_dev)
return;
misc_deregister(ne_devs.ne_misc_dev);
ne_devs.ne_pci_dev = NULL;
ne_pci_dev_disable(pdev);
ne_teardown_msix(pdev);
pci_set_drvdata(pdev, NULL);
pci_iounmap(pdev, ne_pci_dev->iomem_base);
pci_release_regions(pdev);
pci_disable_device(pdev);
kfree(ne_pci_dev);
}
/*
* TODO: Add suspend / resume functions for power management w/ CONFIG_PM, if
* needed.
*/
/* NE PCI device driver. */
struct pci_driver ne_pci_driver = {
.name = "nitro_enclaves",
.id_table = ne_pci_ids,
.probe = ne_pci_probe,
.remove = ne_pci_remove,
.shutdown = ne_pci_shutdown,
};
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