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%25...@intel.com/ Signed-off-by: Alexandru-Catalin Vasile <le...@amazon.com> Signed-off-by: Andra Paraschiv <andra...@amazon.com> Reviewed-by: Alexander Graf <g...@amazon.com> --- drivers/virt/nitro_enclaves/ne_pci_dev.c | 189 +++++++++++++++++++++++ 1 file changed, 189 insertions(+) diff --git a/drivers/virt/nitro_enclaves/ne_pci_dev.c b/drivers/virt/nitro_enclaves/ne_pci_dev.c index 32f07345c3b5..cedc4dd2dd39 100644 --- a/drivers/virt/nitro_enclaves/ne_pci_dev.c +++ b/drivers/virt/nitro_enclaves/ne_pci_dev.c @@ -33,6 +33,172 @@ static const struct pci_device_id ne_pci_ids[] = { 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_setup_msix() - Setup MSI-X vectors for the PCI device. * @pdev: PCI device to setup the MSI-X for. @@ -44,6 +210,7 @@ MODULE_DEVICE_TABLE(pci, ne_pci_ids); */ 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; @@ -63,7 +230,25 @@ static int ne_setup_msix(struct pci_dev *pdev) 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; + } + return 0; + +free_irq_vectors: + pci_free_irq_vectors(pdev); + + return rc; } /** @@ -74,6 +259,10 @@ static int ne_setup_msix(struct pci_dev *pdev) */ 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_REPLY), ne_pci_dev); + pci_free_irq_vectors(pdev); } -- 2.20.1 (Apple Git-117) Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in Romania. Registration number J22/2621/2005.
