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

Andra Paraschiv
2020-04-21T18:43:31Z

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)