nitro_enclaves: Add logic for creating an enclave VM

Add ioctl command logic for enclave VM creation. It triggers a slot
allocation. The enclave resources will be associated with this slot and
it will be used as an identifier for triggering enclave run.

Return a file descriptor, namely enclave fd. This is further used by the
associated user space enclave process to set enclave resources and
trigger enclave termination.

The poll function is implemented in order to notify the enclave process
when an enclave exits without a specific enclave termination command
trigger e.g. when an enclave crashes.

Changelog

v9 -> v10

* Update commit message to include the changelog before the SoB tag(s).

v8 -> v9

* Use the ne_devs data structure to get the refs for the NE PCI device.

v7 -> v8

* No changes.

v6 -> v7

* Use the NE misc device parent field to get the NE PCI device.
* 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

* Update the code base to init the ioctl function in this patch.
* Update documentation to kernel-doc format.

v4 -> v5

* Release the reference to the NE PCI device on create VM error.
* Close enclave fd on copy_to_user() failure; rename fd to enclave fd
  while at it.
* Remove sanity checks for situations that shouldn't happen, only if
  buggy system or broken logic at all.
* Remove log on copy_to_user() failure.

v3 -> v4

* Use dev_err instead of custom NE log pattern.
* Update the NE ioctl call to match the decoupling from the KVM API.
* Add metadata for the NUMA node for the enclave memory and CPUs.

v2 -> v3

* Remove the WARN_ON calls.
* Update static calls sanity checks.
* Update kzfree() calls to kfree().
* Remove file ops that do nothing for now - open.

v1 -> v2

* Add log pattern for NE.
* Update goto labels to match their purpose.
* Remove the BUG_ON calls.

Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Alexandru Vasile <lexnv@amazon.com>
Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
Link: https://lore.kernel.org/r/20200921121732.44291-9-andraprs@amazon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: andraprs

drivers/virt/nitro_enclaves/ne_misc_dev.c

@@ -60,9 +60,12 @@
  */
 #define NE_PARENT_VM_CID	(3)
 
+static long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+
 static const struct file_operations ne_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= noop_llseek,
+	.unlocked_ioctl	= ne_ioctl,
 };
 
 static struct miscdevice ne_misc_dev = {
@@ -119,6 +122,226 @@ struct ne_cpu_pool {
 
 static struct ne_cpu_pool ne_cpu_pool;
 
+/**
+ * ne_enclave_poll() - Poll functionality used for enclave out-of-band events.
+ * @file:	File associated with this poll function.
+ * @wait:	Poll table data structure.
+ *
+ * Context: Process context.
+ * Return:
+ * * Poll mask.
+ */
+static __poll_t ne_enclave_poll(struct file *file, poll_table *wait)
+{
+	__poll_t mask = 0;
+	struct ne_enclave *ne_enclave = file->private_data;
+
+	poll_wait(file, &ne_enclave->eventq, wait);
+
+	if (!ne_enclave->has_event)
+		return mask;
+
+	mask = POLLHUP;
+
+	return mask;
+}
+
+static const struct file_operations ne_enclave_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= noop_llseek,
+	.poll		= ne_enclave_poll,
+};
+
+/**
+ * ne_create_vm_ioctl() - Alloc slot to be associated with an enclave. Create
+ *			  enclave file descriptor to be further used for enclave
+ *			  resources handling e.g. memory regions and CPUs.
+ * @ne_pci_dev :	Private data associated with the PCI device.
+ * @slot_uid:		Generated unique slot id associated with an enclave.
+ *
+ * Context: Process context. This function is called with the ne_pci_dev enclave
+ *	    mutex held.
+ * Return:
+ * * Enclave fd on success.
+ * * Negative return value on failure.
+ */
+static int ne_create_vm_ioctl(struct ne_pci_dev *ne_pci_dev, u64 *slot_uid)
+{
+	struct ne_pci_dev_cmd_reply cmd_reply = {};
+	int enclave_fd = -1;
+	struct file *enclave_file = NULL;
+	unsigned int i = 0;
+	struct ne_enclave *ne_enclave = NULL;
+	struct pci_dev *pdev = ne_pci_dev->pdev;
+	int rc = -EINVAL;
+	struct slot_alloc_req slot_alloc_req = {};
+
+	mutex_lock(&ne_cpu_pool.mutex);
+
+	for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
+		if (!cpumask_empty(ne_cpu_pool.avail_threads_per_core[i]))
+			break;
+
+	if (i == ne_cpu_pool.nr_parent_vm_cores) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "No CPUs available in CPU pool\n");
+
+		mutex_unlock(&ne_cpu_pool.mutex);
+
+		return -NE_ERR_NO_CPUS_AVAIL_IN_POOL;
+	}
+
+	mutex_unlock(&ne_cpu_pool.mutex);
+
+	ne_enclave = kzalloc(sizeof(*ne_enclave), GFP_KERNEL);
+	if (!ne_enclave)
+		return -ENOMEM;
+
+	mutex_lock(&ne_cpu_pool.mutex);
+
+	ne_enclave->nr_parent_vm_cores = ne_cpu_pool.nr_parent_vm_cores;
+	ne_enclave->nr_threads_per_core = ne_cpu_pool.nr_threads_per_core;
+	ne_enclave->numa_node = ne_cpu_pool.numa_node;
+
+	mutex_unlock(&ne_cpu_pool.mutex);
+
+	ne_enclave->threads_per_core = kcalloc(ne_enclave->nr_parent_vm_cores,
+		sizeof(*ne_enclave->threads_per_core), GFP_KERNEL);
+	if (!ne_enclave->threads_per_core) {
+		rc = -ENOMEM;
+
+		goto free_ne_enclave;
+	}
+
+	for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
+		if (!zalloc_cpumask_var(&ne_enclave->threads_per_core[i], GFP_KERNEL)) {
+			rc = -ENOMEM;
+
+			goto free_cpumask;
+		}
+
+	if (!zalloc_cpumask_var(&ne_enclave->vcpu_ids, GFP_KERNEL)) {
+		rc = -ENOMEM;
+
+		goto free_cpumask;
+	}
+
+	enclave_fd = get_unused_fd_flags(O_CLOEXEC);
+	if (enclave_fd < 0) {
+		rc = enclave_fd;
+
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Error in getting unused fd [rc=%d]\n", rc);
+
+		goto free_cpumask;
+	}
+
+	enclave_file = anon_inode_getfile("ne-vm", &ne_enclave_fops, ne_enclave, O_RDWR);
+	if (IS_ERR(enclave_file)) {
+		rc = PTR_ERR(enclave_file);
+
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Error in anon inode get file [rc=%d]\n", rc);
+
+		goto put_fd;
+	}
+
+	rc = ne_do_request(pdev, SLOT_ALLOC,
+			   &slot_alloc_req, sizeof(slot_alloc_req),
+			   &cmd_reply, sizeof(cmd_reply));
+	if (rc < 0) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Error in slot alloc [rc=%d]\n", rc);
+
+		goto put_file;
+	}
+
+	init_waitqueue_head(&ne_enclave->eventq);
+	ne_enclave->has_event = false;
+	mutex_init(&ne_enclave->enclave_info_mutex);
+	ne_enclave->max_mem_regions = cmd_reply.mem_regions;
+	INIT_LIST_HEAD(&ne_enclave->mem_regions_list);
+	ne_enclave->mm = current->mm;
+	ne_enclave->slot_uid = cmd_reply.slot_uid;
+	ne_enclave->state = NE_STATE_INIT;
+
+	list_add(&ne_enclave->enclave_list_entry, &ne_pci_dev->enclaves_list);
+
+	*slot_uid = ne_enclave->slot_uid;
+
+	fd_install(enclave_fd, enclave_file);
+
+	return enclave_fd;
+
+put_file:
+	fput(enclave_file);
+put_fd:
+	put_unused_fd(enclave_fd);
+free_cpumask:
+	free_cpumask_var(ne_enclave->vcpu_ids);
+	for (i = 0; i < ne_enclave->nr_parent_vm_cores; i++)
+		free_cpumask_var(ne_enclave->threads_per_core[i]);
+	kfree(ne_enclave->threads_per_core);
+free_ne_enclave:
+	kfree(ne_enclave);
+
+	return rc;
+}
+
+/**
+ * ne_ioctl() - Ioctl function provided by the NE misc device.
+ * @file:	File associated with this ioctl function.
+ * @cmd:	The command that is set for the ioctl call.
+ * @arg:	The argument that is provided for the ioctl call.
+ *
+ * Context: Process context.
+ * Return:
+ * * Ioctl result (e.g. enclave file descriptor) on success.
+ * * Negative return value on failure.
+ */
+static long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case NE_CREATE_VM: {
+		int enclave_fd = -1;
+		struct file *enclave_file = NULL;
+		struct ne_pci_dev *ne_pci_dev = ne_devs.ne_pci_dev;
+		int rc = -EINVAL;
+		u64 slot_uid = 0;
+
+		mutex_lock(&ne_pci_dev->enclaves_list_mutex);
+
+		enclave_fd = ne_create_vm_ioctl(ne_pci_dev, &slot_uid);
+		if (enclave_fd < 0) {
+			rc = enclave_fd;
+
+			mutex_unlock(&ne_pci_dev->enclaves_list_mutex);
+
+			return rc;
+		}
+
+		mutex_unlock(&ne_pci_dev->enclaves_list_mutex);
+
+		if (copy_to_user((void __user *)arg, &slot_uid, sizeof(slot_uid))) {
+			enclave_file = fget(enclave_fd);
+			/* Decrement file refs to have release() called. */
+			fput(enclave_file);
+			fput(enclave_file);
+			put_unused_fd(enclave_fd);
+
+			return -EFAULT;
+		}
+
+		return enclave_fd;
+	}
+
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
 static int __init ne_init(void)
 {
 	mutex_init(&ne_cpu_pool.mutex);