[PATCH 10/40] nitro_enclaves: Add NE_CREATE_VM2 with a launch flag word

[Alexander Graf <graf@amazon.com>]

In preparation to support Nitro Sandboxes, whose properties the
hypervisor needs before it allocates a slot, add NE_CREATE_VM2. It takes
a word of launch flags for the slot. The slot id comes back in the
same struct ne_create_vm_args.

No flag is defined in this patch, so any set bit fails with
-NE_ERR_INVALID_FLAG_VALUE.

Signed-off-by: Alexander Graf <graf@amazon.com>
---
 drivers/virt/nitro_enclaves/ne_misc_dev.c | 53 +++++++++++++++++++++--
 include/uapi/linux/nitro_enclaves.h       | 48 ++++++++++++++++++++
 2 files changed, 97 insertions(+), 4 deletions(-)

diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
index 38345ad7c7985..68c497df4f14b 100644
--- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
@@ -2452,6 +2452,8 @@ static const struct file_operations ne_enclave_fops = {
  *			  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.
+ * @flags:		Launch-time flag word from NE_CREATE_VM2, or zero when
+ *			the caller used the flag-less NE_CREATE_VM.
  * @slot_uid:		User pointer to store the generated unique slot id
  *			associated with an enclave to.
  *
@@ -2461,7 +2463,8 @@ static const struct file_operations ne_enclave_fops = {
  * * Enclave fd on success.
  * * Negative return value on failure.
  */
-static int ne_create_vm_ioctl(struct ne_pci_dev *ne_pci_dev, u64 __user *slot_uid)
+static int ne_create_vm_ioctl(struct ne_pci_dev *ne_pci_dev, u64 flags,
+			      u64 __user *slot_uid)
 {
 	struct ne_pci_dev_cmd_reply cmd_reply = {};
 	int enclave_fd = -1;
@@ -2472,6 +2475,13 @@ static int ne_create_vm_ioctl(struct ne_pci_dev *ne_pci_dev, u64 __user *slot_ui
 	int rc = -EINVAL;
 	struct slot_alloc_req slot_alloc_req = {};
 
+	if (flags) {
+		dev_err_ratelimited(ne_misc_dev.this_device,
+				    "Unknown launch flag bit set 0x%llx\n", flags);
+
+		return -NE_ERR_INVALID_FLAG_VALUE;
+	}
+
 	mutex_lock(&ne_cpu_pool.mutex);
 
 	for (i = 0; i < ne_cpu_pool.nr_parent_vm_cores; i++)
@@ -2626,7 +2636,44 @@ static long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		if (ne_pci_dev) {
 			rc = mutex_lock_killable(&ne_pci_dev->enclaves_list_mutex);
 			if (!rc) {
-				rc = ne_create_vm_ioctl(ne_pci_dev, slot_uid);
+				rc = ne_create_vm_ioctl(ne_pci_dev, 0, slot_uid);
+				mutex_unlock(&ne_pci_dev->enclaves_list_mutex);
+			}
+		}
+
+		up_read(&ne_devs.lock);
+
+		return rc;
+	}
+	}
+
+	/* Extensible Argument ioctls */
+	switch (NE_EA_IOCTL(cmd)) {
+	case NE_EA_IOCTL(NE_CREATE_VM2): {
+		struct ne_create_vm_args args;
+		struct ne_create_vm_args __user *uargs = (void __user *)arg;
+		unsigned int usize = _IOC_SIZE(cmd);
+		struct ne_pci_dev *ne_pci_dev;
+		int rc;
+
+		if (usize < offsetofend(struct ne_create_vm_args, slot_uid))
+			return -EINVAL;
+
+		rc = copy_struct_from_user(&args, sizeof(args), uargs, usize);
+		if (rc)
+			return rc;
+
+		rc = down_read_killable(&ne_devs.lock);
+		if (rc)
+			return rc;
+
+		rc = -ENODEV;
+		ne_pci_dev = ne_devs.ne_pci_dev;
+		if (ne_pci_dev) {
+			rc = mutex_lock_killable(&ne_pci_dev->enclaves_list_mutex);
+			if (!rc) {
+				rc = ne_create_vm_ioctl(ne_pci_dev, args.flags,
+							&uargs->slot_uid);
 				mutex_unlock(&ne_pci_dev->enclaves_list_mutex);
 			}
 		}
@@ -2639,8 +2686,6 @@ static long ne_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	default:
 		return -ENOTTY;
 	}
-
-	return 0;
 }
 
 /*
diff --git a/include/uapi/linux/nitro_enclaves.h b/include/uapi/linux/nitro_enclaves.h
index 16515fe27b692..8e43be9a0a1fa 100644
--- a/include/uapi/linux/nitro_enclaves.h
+++ b/include/uapi/linux/nitro_enclaves.h
@@ -46,6 +46,54 @@
  */
 #define NE_CREATE_VM			_IOR(0xAE, 0x20, __u64)
 
+/**
+ * struct ne_create_vm_args - NE_CREATE_VM2 argument (in / out).
+ * @flags:	Launch-time flag word (in). Flags select properties of the
+ *		enclave slot that the hypervisor has to know at allocation
+ *		time. NE_ENCLAVE_DEBUG_MODE stays a start-time property and
+ *		is rejected here.
+ * @slot_uid:	Generated unique slot id associated with an enclave (out).
+ */
+struct ne_create_vm_args {
+	__u64	flags;
+	__u64	slot_uid;
+};
+
+/**
+ * NE_CREATE_VM2 - As NE_CREATE_VM, additionally taking a launch-time flag
+ *		   word. The flags carry properties of the slot that have to
+ *		   be decided when the slot is allocated rather than when the
+ *		   enclave starts.
+ *
+ *		   NE_CREATE_VM continues to work; calling it is equivalent
+ *		   to calling NE_CREATE_VM2 with a zero flag word.
+ *
+ *		   The argument is read with copy_struct_from_user(), so a
+ *		   caller built against a header that predates a field this
+ *		   kernel knows leaves that field zero, and a caller that
+ *		   sets a field this kernel does not know is refused.
+ *
+ * Context: Process context.
+ * Return:
+ * * Enclave file descriptor		- As for NE_CREATE_VM.
+ * *  -1				- There was a failure in the ioctl logic.
+ * On failure, errno is set to:
+ * * ENODEV				- The NE PCI device is not available.
+ * * EFAULT				- Argument read or write failure.
+ * * NE_ERR_INVALID_FLAG_VALUE		- Unknown flag bit set, or
+ *					  NE_ENCLAVE_DEBUG_MODE set.
+ * * EINVAL				- The argument stops before @slot_uid.
+ * * E2BIG				- The argument carries a field this kernel
+ *					  does not know, set to a non-zero value.
+ * * ENOMEM				- Memory allocation failure for internal
+ *					  bookkeeping variables.
+ * * NE_ERR_NO_CPUS_AVAIL_IN_POOL	- No NE CPU pool set / no CPUs available
+ *					  in the pool.
+ * * Error codes from get_unused_fd_flags() and anon_inode_getfile().
+ * * Error codes from the NE PCI device request.
+ */
+#define NE_CREATE_VM2			_IOWR(0xAE, 0x30, struct ne_create_vm_args)
+
 /**
  * NE_ADD_VCPU - The command is used to set a vCPU for an enclave. The vCPU can
  *		 be auto-chosen from the NE CPU pool or it can be set by the
-- 
2.47.1