nitro_enclaves: Handle PCI device command requests
The Nitro Enclaves PCI device exposes a MMIO space that this driver uses to submit command requests and to receive command replies e.g. for enclave creation / termination or setting enclave resources. Add logic for handling PCI device command requests based on the given command type. Register an MSI-X interrupt vector for command reply notifications to handle this type of communication events. Changelog v9 -> v10 * Update commit message to include the changelog before the SoB tag(s). v8 -> v9 * No changes. v7 -> v8 * Update function signature for submit request and retrive reply functions as they only returned 0, no error code. * Include command type value in the error logs of ne_do_request(). v6 -> v7 * No changes. v5 -> v6 * Update documentation to kernel-doc format. v4 -> v5 * Remove sanity checks for situations that shouldn't happen, only if buggy system or broken logic at all. v3 -> v4 * Use dev_err instead of custom NE log pattern. * Return IRQ_NONE when interrupts are not handled. v2 -> v3 * Remove the WARN_ON calls. * Update static calls sanity checks. * Remove "ratelimited" from the logs that are not in the ioctl call paths. v1 -> v2 * Add log pattern for NE. * Remove the BUG_ON calls. * Update goto labels to match their purpose. * Add fix for kbuild report: https://lore.kernel.org/lkml/202004231644.xTmN4Z1z%25lkp@intel.com/ Reviewed-by: Alexander Graf <graf@amazon.com> Signed-off-by: Alexandru-Catalin Vasile <lexnv@amazon.com> Signed-off-by: Andra Paraschiv <andraprs@amazon.com> Link: https://lore.kernel.org/r/20200921121732.44291-6-andraprs@amazon.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andra Paraschiv
Greg Kroah-Hartman
Родитель
89308c11ae
Коммит
ad2b6980d0
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@ -33,6 +33,172 @@ static const struct pci_device_id ne_pci_ids[] = {
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MODULE_DEVICE_TABLE(pci, ne_pci_ids);
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/**
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* ne_submit_request() - Submit command request to the PCI device based on the
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* command type.
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* @pdev: PCI device to send the command to.
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* @cmd_type: Command type of the request sent to the PCI device.
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* @cmd_request: Command request payload.
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* @cmd_request_size: Size of the command request payload.
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*
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* Context: Process context. This function is called with the ne_pci_dev mutex held.
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*/
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static void ne_submit_request(struct pci_dev *pdev, enum ne_pci_dev_cmd_type cmd_type,
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void *cmd_request, size_t cmd_request_size)
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{
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struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
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memcpy_toio(ne_pci_dev->iomem_base + NE_SEND_DATA, cmd_request, cmd_request_size);
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iowrite32(cmd_type, ne_pci_dev->iomem_base + NE_COMMAND);
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}
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/**
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* ne_retrieve_reply() - Retrieve reply from the PCI device.
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* @pdev: PCI device to receive the reply from.
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* @cmd_reply: Command reply payload.
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* @cmd_reply_size: Size of the command reply payload.
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*
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* Context: Process context. This function is called with the ne_pci_dev mutex held.
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*/
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static void ne_retrieve_reply(struct pci_dev *pdev, struct ne_pci_dev_cmd_reply *cmd_reply,
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size_t cmd_reply_size)
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{
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struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
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memcpy_fromio(cmd_reply, ne_pci_dev->iomem_base + NE_RECV_DATA, cmd_reply_size);
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}
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/**
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* ne_wait_for_reply() - Wait for a reply of a PCI device command.
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* @pdev: PCI device for which a reply is waited.
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*
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* Context: Process context. This function is called with the ne_pci_dev mutex held.
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* Return:
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* * 0 on success.
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* * Negative return value on failure.
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*/
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static int ne_wait_for_reply(struct pci_dev *pdev)
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{
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struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
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int rc = -EINVAL;
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/*
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* TODO: Update to _interruptible and handle interrupted wait event
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* e.g. -ERESTARTSYS, incoming signals + update timeout, if needed.
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*/
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rc = wait_event_timeout(ne_pci_dev->cmd_reply_wait_q,
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atomic_read(&ne_pci_dev->cmd_reply_avail) != 0,
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msecs_to_jiffies(NE_DEFAULT_TIMEOUT_MSECS));
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if (!rc)
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return -ETIMEDOUT;
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return 0;
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}
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int ne_do_request(struct pci_dev *pdev, enum ne_pci_dev_cmd_type cmd_type,
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void *cmd_request, size_t cmd_request_size,
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struct ne_pci_dev_cmd_reply *cmd_reply, size_t cmd_reply_size)
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{
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struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
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int rc = -EINVAL;
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if (cmd_type <= INVALID_CMD || cmd_type >= MAX_CMD) {
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dev_err_ratelimited(&pdev->dev, "Invalid cmd type=%u\n", cmd_type);
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return -EINVAL;
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}
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if (!cmd_request) {
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dev_err_ratelimited(&pdev->dev, "Null cmd request for cmd type=%u\n",
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cmd_type);
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return -EINVAL;
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}
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if (cmd_request_size > NE_SEND_DATA_SIZE) {
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dev_err_ratelimited(&pdev->dev, "Invalid req size=%zu for cmd type=%u\n",
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cmd_request_size, cmd_type);
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return -EINVAL;
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}
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if (!cmd_reply) {
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dev_err_ratelimited(&pdev->dev, "Null cmd reply for cmd type=%u\n",
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cmd_type);
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return -EINVAL;
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}
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if (cmd_reply_size > NE_RECV_DATA_SIZE) {
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dev_err_ratelimited(&pdev->dev, "Invalid reply size=%zu for cmd type=%u\n",
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cmd_reply_size, cmd_type);
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return -EINVAL;
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}
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/*
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* Use this mutex so that the PCI device handles one command request at
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* a time.
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*/
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mutex_lock(&ne_pci_dev->pci_dev_mutex);
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atomic_set(&ne_pci_dev->cmd_reply_avail, 0);
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ne_submit_request(pdev, cmd_type, cmd_request, cmd_request_size);
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rc = ne_wait_for_reply(pdev);
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if (rc < 0) {
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dev_err_ratelimited(&pdev->dev, "Error in wait for reply for cmd type=%u [rc=%d]\n",
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cmd_type, rc);
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goto unlock_mutex;
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}
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ne_retrieve_reply(pdev, cmd_reply, cmd_reply_size);
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atomic_set(&ne_pci_dev->cmd_reply_avail, 0);
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if (cmd_reply->rc < 0) {
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rc = cmd_reply->rc;
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dev_err_ratelimited(&pdev->dev, "Error in cmd process logic, cmd type=%u [rc=%d]\n",
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cmd_type, rc);
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goto unlock_mutex;
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}
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rc = 0;
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unlock_mutex:
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mutex_unlock(&ne_pci_dev->pci_dev_mutex);
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return rc;
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}
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/**
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* ne_reply_handler() - Interrupt handler for retrieving a reply matching a
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* request sent to the PCI device for enclave lifetime
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* management.
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* @irq: Received interrupt for a reply sent by the PCI device.
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* @args: PCI device private data structure.
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*
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* Context: Interrupt context.
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* Return:
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* * IRQ_HANDLED on handled interrupt.
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*/
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static irqreturn_t ne_reply_handler(int irq, void *args)
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{
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struct ne_pci_dev *ne_pci_dev = (struct ne_pci_dev *)args;
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atomic_set(&ne_pci_dev->cmd_reply_avail, 1);
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/* TODO: Update to _interruptible. */
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wake_up(&ne_pci_dev->cmd_reply_wait_q);
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return IRQ_HANDLED;
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}
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/**
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* ne_setup_msix() - Setup MSI-X vectors for the PCI device.
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* @pdev: PCI device to setup the MSI-X for.
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@ -44,6 +210,7 @@ MODULE_DEVICE_TABLE(pci, ne_pci_ids);
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*/
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static int ne_setup_msix(struct pci_dev *pdev)
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{
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struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
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int nr_vecs = 0;
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int rc = -EINVAL;
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@ -63,7 +230,25 @@ static int ne_setup_msix(struct pci_dev *pdev)
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return rc;
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}
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/*
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* This IRQ gets triggered every time the PCI device responds to a
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* command request. The reply is then retrieved, reading from the MMIO
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* space of the PCI device.
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*/
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rc = request_irq(pci_irq_vector(pdev, NE_VEC_REPLY), ne_reply_handler,
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0, "enclave_cmd", ne_pci_dev);
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if (rc < 0) {
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dev_err(&pdev->dev, "Error in request irq reply [rc=%d]\n", rc);
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goto free_irq_vectors;
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}
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return 0;
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free_irq_vectors:
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pci_free_irq_vectors(pdev);
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return rc;
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}
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/**
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@ -74,6 +259,10 @@ static int ne_setup_msix(struct pci_dev *pdev)
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*/
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static void ne_teardown_msix(struct pci_dev *pdev)
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{
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struct ne_pci_dev *ne_pci_dev = pci_get_drvdata(pdev);
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free_irq(pci_irq_vector(pdev, NE_VEC_REPLY), ne_pci_dev);
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pci_free_irq_vectors(pdev);
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}
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