[PATCH v1 09/15] nitro_enclaves: Add logic for enclave vcpu creation

[Andra Paraschiv <andraprs@amazon.com>]

An enclave, before being started, has its resources set. One of its
resources is CPU.

Add ioctl command logic for enclave vCPU creation. Return as result a
file descriptor that is associated with the enclave vCPU.

Signed-off-by: Alexandru Vasile <lexnv@amazon.com>
Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
---
 .../virt/amazon/nitro_enclaves/ne_misc_dev.c  | 210 ++++++++++++++++++
 1 file changed, 210 insertions(+)

diff --git a/drivers/virt/amazon/nitro_enclaves/ne_misc_dev.c b/drivers/virt/amazon/nitro_enclaves/ne_misc_dev.c
index abbebc7718c2..c9acdfd63daf 100644
--- a/drivers/virt/amazon/nitro_enclaves/ne_misc_dev.c
+++ b/drivers/virt/amazon/nitro_enclaves/ne_misc_dev.c
@@ -60,6 +60,179 @@ static struct ne_cpu_pool ne_cpu_pool;
 
 static struct mutex ne_cpu_pool_mutex;
 
+static int ne_enclave_vcpu_open(struct inode *node, struct file *file)
+{
+	return 0;
+}
+
+static long ne_enclave_vcpu_ioctl(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	switch (cmd) {
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static int ne_enclave_vcpu_release(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+static const struct file_operations ne_enclave_vcpu_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= noop_llseek,
+	.unlocked_ioctl	= ne_enclave_vcpu_ioctl,
+	.open		= ne_enclave_vcpu_open,
+	.release	= ne_enclave_vcpu_release,
+};
+
+/**
+ * ne_get_cpu_from_cpu_pool - Get a CPU from the CPU pool, if it is set.
+ *
+ * This function gets called with the ne_enclave mutex held.
+ *
+ * @ne_enclave: private data associated with the current enclave.
+ * @vcpu_id: id of the CPU to be associated with the given slot, apic id on x86.
+ *
+ * @returns: 0 on success, negative return value on failure.
+ */
+static int ne_get_cpu_from_cpu_pool(struct ne_enclave *ne_enclave, u32 *vcpu_id)
+{
+	unsigned int cpu = 0;
+	unsigned int cpu_sibling = 0;
+
+	BUG_ON(!ne_enclave);
+
+	if (WARN_ON(!vcpu_id))
+		return -EINVAL;
+
+	/* There are CPU siblings available to choose from. */
+	cpu = cpumask_any(ne_enclave->cpu_siblings);
+	if (cpu < nr_cpu_ids) {
+		cpumask_clear_cpu(cpu, ne_enclave->cpu_siblings);
+
+		*vcpu_id = cpu;
+
+		return 0;
+	}
+
+	mutex_lock(&ne_cpu_pool_mutex);
+
+	/* Choose any CPU from the available CPU pool. */
+	cpu = cpumask_any(ne_cpu_pool.avail);
+	if (cpu >= nr_cpu_ids) {
+		pr_err_ratelimited("No CPUs available in CPU pool\n");
+
+		mutex_unlock(&ne_cpu_pool_mutex);
+
+		return -EINVAL;
+	}
+
+	cpumask_clear_cpu(cpu, ne_cpu_pool.avail);
+
+	/*
+	 * Make sure the CPU siblings are not marked as
+	 * available anymore.
+	 */
+	for_each_cpu(cpu_sibling, topology_sibling_cpumask(cpu)) {
+		if (cpu_sibling != cpu) {
+			cpumask_clear_cpu(cpu_sibling, ne_cpu_pool.avail);
+
+			cpumask_set_cpu(cpu_sibling, ne_enclave->cpu_siblings);
+		}
+	}
+
+	mutex_unlock(&ne_cpu_pool_mutex);
+
+	*vcpu_id = cpu;
+
+	return 0;
+}
+
+/**
+ * ne_create_vcpu_ioctl - Add vCPU to the slot associated with the current
+ * enclave. Create vCPU file descriptor to be further used for CPU handling.
+ *
+ * This function gets called with the ne_enclave mutex held.
+ *
+ * @ne_enclave: private data associated with the current enclave.
+ * @vcpu_id: id of the CPU to be associated with the given slot, apic id on x86.
+ *
+ * @returns: vCPU fd on success, negative return value on failure.
+ */
+static int ne_create_vcpu_ioctl(struct ne_enclave *ne_enclave, u32 vcpu_id)
+{
+	struct ne_pci_dev_cmd_reply cmd_reply = {};
+	int fd = 0;
+	struct file *file = NULL;
+	struct ne_vcpu_id *ne_vcpu_id = NULL;
+	int rc = -EINVAL;
+	struct slot_add_vcpu_req slot_add_vcpu_req = {};
+
+	BUG_ON(!ne_enclave);
+	BUG_ON(!ne_enclave->pdev);
+
+	if (ne_enclave->mm != current->mm)
+		return -EIO;
+
+	ne_vcpu_id = kzalloc(sizeof(*ne_vcpu_id), GFP_KERNEL);
+	if (!ne_vcpu_id)
+		return -ENOMEM;
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		rc = fd;
+
+		pr_err_ratelimited("Failure in getting unused fd [rc=%d]\n",
+				   rc);
+
+		goto err_get_unused_fd;
+	}
+
+	/* TODO: Include (vcpu) id in the ne-vm-vcpu naming. */
+	file = anon_inode_getfile("ne-vm-vcpu", &ne_enclave_vcpu_fops,
+				  ne_enclave, O_RDWR);
+	if (IS_ERR(file)) {
+		rc = PTR_ERR(file);
+
+		pr_err_ratelimited("Failure in anon inode get file [rc=%d]\n",
+				   rc);
+
+		goto err_anon_inode_getfile;
+	}
+
+	slot_add_vcpu_req.slot_uid = ne_enclave->slot_uid;
+	slot_add_vcpu_req.vcpu_id = vcpu_id;
+
+	rc = ne_do_request(ne_enclave->pdev, SLOT_ADD_VCPU, &slot_add_vcpu_req,
+			   sizeof(slot_add_vcpu_req), &cmd_reply,
+			   sizeof(cmd_reply));
+	if (rc < 0) {
+		pr_err_ratelimited("Failure in slot add vcpu [rc=%d]\n", rc);
+
+		goto err_slot_add_vcpu;
+	}
+
+	ne_vcpu_id->vcpu_id = vcpu_id;
+
+	list_add(&ne_vcpu_id->vcpu_id_list_entry, &ne_enclave->vcpu_ids_list);
+
+	fd_install(fd, file);
+
+	return fd;
+
+err_slot_add_vcpu:
+	fput(file);
+err_anon_inode_getfile:
+	put_unused_fd(fd);
+err_get_unused_fd:
+	kzfree(ne_vcpu_id);
+	return rc;
+}
+
 static int ne_enclave_open(struct inode *node, struct file *file)
 {
 	return 0;
@@ -68,7 +241,44 @@ static int ne_enclave_open(struct inode *node, struct file *file)
 static long ne_enclave_ioctl(struct file *file, unsigned int cmd,
 			     unsigned long arg)
 {
+	struct ne_enclave *ne_enclave = file->private_data;
+
+	BUG_ON(!ne_enclave);
+
 	switch (cmd) {
+	case KVM_CREATE_VCPU: {
+		int rc = -EINVAL;
+		u32 vcpu_id = 0;
+
+		if (copy_from_user(&vcpu_id, (void *)arg, sizeof(vcpu_id))) {
+			pr_err_ratelimited("Failure in copy from user\n");
+
+			return -EFAULT;
+		}
+
+		mutex_lock(&ne_enclave->enclave_info_mutex);
+
+		/* Use the CPU pool for choosing a CPU for the enclave. */
+		rc = ne_get_cpu_from_cpu_pool(ne_enclave, &vcpu_id);
+		if (rc < 0) {
+			pr_err_ratelimited("Failure in get CPU from pool\n");
+
+			mutex_unlock(&ne_enclave->enclave_info_mutex);
+
+			return -EINVAL;
+		}
+
+		rc = ne_create_vcpu_ioctl(ne_enclave, vcpu_id);
+
+		/* Put back the CPU in enclave cpu pool, if add vcpu error. */
+		if (rc < 0)
+			cpumask_set_cpu(vcpu_id, ne_enclave->cpu_siblings);
+
+		mutex_unlock(&ne_enclave->enclave_info_mutex);
+
+		return rc;
+	}
+
 	default:
 		return -ENOTTY;
 	}
-- 
2.20.1 (Apple Git-117)




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