[PATCH v8 12/18] nitro_enclaves: Add logic for starting an enclave

[Andra Paraschiv <andraprs@amazon.com>]

After all the enclave resources are set, the enclave is ready for
beginning to run.

Add ioctl command logic for starting an enclave after all its resources,
memory regions and CPUs, have been set.

The enclave start information includes the local channel addressing -
vsock CID - and the flags associated with the enclave.

Signed-off-by: Alexandru Vasile <lexnv@amazon.com>
Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
Changelog

v7 -> v8

* Add check for invalid enclave CID value e.g. well-known CIDs and
  parent VM CID.
* Add custom error code for incorrect flag in enclave start info and
  invalid enclave CID.

v6 -> v7

* Update the naming and add more comments to make more clear the logic
  of handling full CPU cores and dedicating them to the enclave.

v5 -> v6

* Check for invalid enclave start flags.
* Update documentation to kernel-doc format.

v4 -> v5

* Add early exit on enclave start ioctl function call error.
* Move sanity checks in the enclave start ioctl function, outside of the
  switch-case block.
* Remove log on copy_from_user() / copy_to_user() failure.

v3 -> v4

* Use dev_err instead of custom NE log pattern.
* Update the naming for the ioctl command from metadata to info.
* Check for minimum enclave memory size.

v2 -> v3

* Remove the WARN_ON calls.
* Update static calls sanity checks.

v1 -> v2

* Add log pattern for NE.
* Check if enclave state is init when starting an enclave.
* Remove the BUG_ON calls.
---
 drivers/virt/nitro_enclaves/ne_misc_dev.c | 155 ++++++++++++++++++++++
 1 file changed, 155 insertions(+)

diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
index 9912d78c0905..5ec7fdf9d08e 100644
--- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -989,6 +989,77 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
 	return rc;
 }
 
+/**
+ * ne_start_enclave_ioctl() - Trigger enclave start after the enclave resources,
+ *			      such as memory and CPU, have been set.
+ * @ne_enclave :		Private data associated with the current enclave.
+ * @enclave_start_info :	Enclave info that includes enclave cid and flags.
+ *
+ * Context: Process context. This function is called with the ne_enclave mutex held.
+ * Return:
+ * * 0 on success.
+ * * Negative return value on failure.
+ */
+static int ne_start_enclave_ioctl(struct ne_enclave *ne_enclave,
+	struct ne_enclave_start_info *enclave_start_info)
+{
+	struct ne_pci_dev_cmd_reply cmd_reply = {};
+	unsigned int cpu = 0;
+	struct enclave_start_req enclave_start_req = {};
+	unsigned int i = 0;
+	int rc = -EINVAL;
+
+	if (!ne_enclave->nr_mem_regions) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Enclave has no mem regions\n");
+
+		return -NE_ERR_NO_MEM_REGIONS_ADDED;
+	}
+
+	if (ne_enclave->mem_size < NE_MIN_ENCLAVE_MEM_SIZE) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Enclave memory is less than %ld\n",
+				    NE_MIN_ENCLAVE_MEM_SIZE);
+
+		return -NE_ERR_ENCLAVE_MEM_MIN_SIZE;
+	}
+
+	if (!ne_enclave->nr_vcpus) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Enclave has no vCPUs\n");
+
+		return -NE_ERR_NO_VCPUS_ADDED;
+	}
+
+	for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
+		for_each_cpu(cpu, ne_enclave->threads_per_core[i])
+			if (!cpumask_test_cpu(cpu, ne_enclave->vcpu_ids)) {
+				dev_err_ratelimited(ne_misc_dev.this_device,
+						    "Full CPU cores not used\n");
+
+				return -NE_ERR_FULL_CORES_NOT_USED;
+			}
+
+	enclave_start_req.enclave_cid = enclave_start_info->enclave_cid;
+	enclave_start_req.flags = enclave_start_info->flags;
+	enclave_start_req.slot_uid = ne_enclave->slot_uid;
+
+	rc = ne_do_request(ne_enclave->pdev, ENCLAVE_START, &enclave_start_req,
+			   sizeof(enclave_start_req), &cmd_reply, sizeof(cmd_reply));
+	if (rc < 0) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Error in enclave start [rc=%d]\n", rc);
+
+		return rc;
+	}
+
+	ne_enclave->state = NE_STATE_RUNNING;
+
+	enclave_start_info->enclave_cid = cmd_reply.enclave_cid;
+
+	return 0;
+}
+
 /**
  * ne_enclave_ioctl() - Ioctl function provided by the enclave file.
  * @file:	File associated with this ioctl function.
@@ -1147,6 +1218,90 @@ static long ne_enclave_ioctl(struct file *file, unsigned int cmd, unsigned long
 		return 0;
 	}
 
+	case NE_START_ENCLAVE: {
+		struct ne_enclave_start_info enclave_start_info = {};
+		int rc = -EINVAL;
+
+		if (copy_from_user(&enclave_start_info, (void __user *)arg,
+				   sizeof(enclave_start_info)))
+			return -EFAULT;
+
+		if (enclave_start_info.flags >= NE_ENCLAVE_START_MAX_FLAG_VAL) {
+			dev_err_ratelimited(ne_misc_dev.this_device,
+					    "Incorrect flag in enclave start info\n");
+
+			return -NE_ERR_INVALID_FLAG_VALUE;
+		}
+
+		/*
+		 * Do not use well-known CIDs - 0, 1, 2 - for enclaves.
+		 * VMADDR_CID_ANY = -1U
+		 * VMADDR_CID_HYPERVISOR = 0
+		 * VMADDR_CID_LOCAL = 1
+		 * VMADDR_CID_HOST = 2
+		 * Note: 0 is used as a placeholder to auto-generate an enclave CID.
+		 * http://man7.org/linux/man-pages/man7/vsock.7.html
+		 */
+		if (enclave_start_info.enclave_cid > 0 &&
+		    enclave_start_info.enclave_cid <= VMADDR_CID_HOST) {
+			dev_err_ratelimited(ne_misc_dev.this_device,
+					    "Well-known CID value, not to be used for enclaves\n");
+
+			return -NE_ERR_INVALID_ENCLAVE_CID;
+		}
+
+		if (enclave_start_info.enclave_cid == U32_MAX) {
+			dev_err_ratelimited(ne_misc_dev.this_device,
+					    "Well-known CID value, not to be used for enclaves\n");
+
+			return -NE_ERR_INVALID_ENCLAVE_CID;
+		}
+
+		/*
+		 * Do not use the CID of the primary / parent VM for enclaves.
+		 */
+		if (enclave_start_info.enclave_cid == NE_PARENT_VM_CID) {
+			dev_err_ratelimited(ne_misc_dev.this_device,
+					    "CID of the parent VM, not to be used for enclaves\n");
+
+			return -NE_ERR_INVALID_ENCLAVE_CID;
+		}
+
+		/* 64-bit CIDs are not yet supported for the vsock device. */
+		if (enclave_start_info.enclave_cid > U32_MAX) {
+			dev_err_ratelimited(ne_misc_dev.this_device,
+					    "64-bit CIDs not yet supported for the vsock device\n");
+
+			return -NE_ERR_INVALID_ENCLAVE_CID;
+		}
+
+		mutex_lock(&ne_enclave->enclave_info_mutex);
+
+		if (ne_enclave->state != NE_STATE_INIT) {
+			dev_err_ratelimited(ne_misc_dev.this_device,
+					    "Enclave is not in init state\n");
+
+			mutex_unlock(&ne_enclave->enclave_info_mutex);
+
+			return -NE_ERR_NOT_IN_INIT_STATE;
+		}
+
+		rc = ne_start_enclave_ioctl(ne_enclave, &enclave_start_info);
+		if (rc < 0) {
+			mutex_unlock(&ne_enclave->enclave_info_mutex);
+
+			return rc;
+		}
+
+		mutex_unlock(&ne_enclave->enclave_info_mutex);
+
+		if (copy_to_user((void __user *)arg, &enclave_start_info,
+				 sizeof(enclave_start_info)))
+			return -EFAULT;
+
+		return 0;
+	}
+
 	default:
 		return -ENOTTY;
 	}
-- 
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.