Messages in this thread | | | Subject | Re: [PATCH v4 06/18] nitro_enclaves: Handle out-of-band PCI device events | From | Alexander Graf <> | Date | Thu, 2 Jul 2020 17:24:11 +0200 |
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On 22.06.20 22:03, Andra Paraschiv wrote: > In addition to the replies sent by the Nitro Enclaves PCI device in > response to command requests, out-of-band enclave events can happen e.g. > an enclave crashes. In this case, the Nitro Enclaves driver needs to be > aware of the event and notify the corresponding user space process that > abstracts the enclave. > > Register an MSI-X interrupt vector to be used for this kind of > out-of-band events. The interrupt notifies that the state of an enclave > changed and the driver logic scans the state of each running enclave to > identify for which this notification is intended. > > Create an workqueue to handle the out-of-band events. Notify user space > enclave process that is using a polling mechanism on the enclave fd. > > Signed-off-by: Alexandru-Catalin Vasile <lexnv@amazon.com> > Signed-off-by: Andra Paraschiv <andraprs@amazon.com> > --- > Changelog > > 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. > * Update goto labels to match their purpose. > --- > drivers/virt/nitro_enclaves/ne_pci_dev.c | 122 +++++++++++++++++++++++ > 1 file changed, 122 insertions(+) > > diff --git a/drivers/virt/nitro_enclaves/ne_pci_dev.c b/drivers/virt/nitro_enclaves/ne_pci_dev.c > index c24230cfe7c0..9a137862cade 100644 > --- a/drivers/virt/nitro_enclaves/ne_pci_dev.c > +++ b/drivers/virt/nitro_enclaves/ne_pci_dev.c > @@ -239,6 +239,93 @@ static irqreturn_t ne_reply_handler(int irq, void *args) > return IRQ_HANDLED; > } > > +/** > + * ne_event_work_handler - Work queue handler for notifying enclaves on > + * a state change received by the event interrupt handler. > + * > + * An out-of-band event is being issued by the Nitro Hypervisor when at least > + * one enclave is changing state without client interaction. > + * > + * @work: item containing the Nitro Enclaves PCI device for which a > + * out-of-band event was issued. > + */ > +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); > + int rc = -EINVAL; > + struct slot_info_req slot_info_req = {}; > + > + if (!ne_pci_dev) > + return;
How?
> + > + 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(ne_enclave->pdev, SLOT_INFO, &slot_info_req, > + sizeof(slot_info_req), &cmd_reply, > + sizeof(cmd_reply)); > + if (rc < 0) > + dev_err(&ne_enclave->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. > + * > + * @returns: IRQ_HANDLED on handled interrupt, IRQ_NONE otherwise. > + */ > +static irqreturn_t ne_event_handler(int irq, void *args) > +{ > + struct ne_pci_dev *ne_pci_dev = (struct ne_pci_dev *)args; > + > + if (!ne_pci_dev) > + return IRQ_NONE;
How can this happen?
Alex
> + > + 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. > * > @@ -284,8 +371,37 @@ static int ne_setup_msix(struct pci_dev *pdev) > 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); > > @@ -304,6 +420,12 @@ static void ne_teardown_msix(struct pci_dev *pdev) > if (!ne_pci_dev) > return; > > + free_irq(pci_irq_vector(pdev, NE_VEC_EVENT), ne_pci_dev); > + > + flush_work(&ne_pci_dev->notify_work); > + flush_workqueue(ne_pci_dev->event_wq); > + destroy_workqueue(ne_pci_dev->event_wq); > + > free_irq(pci_irq_vector(pdev, NE_VEC_REPLY), ne_pci_dev); > > pci_free_irq_vectors(pdev); >
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