ANDROID: gunyah: auth_mgr: Introduce auth_mgr within vm_mgr

Add an IOCTL to choose the authentication mechanism for a Virtual Machine.
vm_mgr can setup differently authenticated VMs based on the ops setup by
the auth_mgr chosen by the VMM.

Bug: 399219478
Change-Id: Ibb6bb30e3f422e606500c04714cda27b2276baf6
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>

drivers/virt/gunyah/vm_mgr.c

@@ -33,6 +33,7 @@
 #define GUNYAH_EVENT_DESTROY_VM 1
 
 static DEFINE_XARRAY(gunyah_vm_functions);
+static DEFINE_XARRAY(gunyah_auth_vm_mgr);
 
 static inline int gunyah_vm_fill_boot_context(struct gunyah_vm *ghvm)
 {
@@ -53,6 +54,59 @@ static inline int gunyah_vm_fill_boot_context(struct gunyah_vm *ghvm)
 	return 0;
 }
 
+int gunyah_auth_vm_mgr_register(struct gunyah_auth_vm_mgr *auth_vm)
+{
+	if (!auth_vm->vm_attach || !auth_vm->vm_detach)
+		return -EINVAL;
+
+	return xa_err(xa_store(&gunyah_auth_vm_mgr, auth_vm->type, auth_vm, GFP_KERNEL));
+}
+EXPORT_SYMBOL_GPL(gunyah_auth_vm_mgr_register);
+
+void gunyah_auth_vm_mgr_unregister(struct gunyah_auth_vm_mgr *auth_vm)
+{
+	/* Expecting unregister to only come when unloading a module */
+	WARN_ON(auth_vm->mod && module_refcount(auth_vm->mod));
+	xa_erase(&gunyah_auth_vm_mgr, auth_vm->type);
+}
+EXPORT_SYMBOL_GPL(gunyah_auth_vm_mgr_unregister);
+
+static struct gunyah_auth_vm_mgr *gunyah_get_auth_vm_mgr(u32 auth_type)
+{
+	struct gunyah_auth_vm_mgr *auth_vm;
+
+	auth_vm = xa_load(&gunyah_auth_vm_mgr, auth_type);
+	if (!auth_vm || !try_module_get(auth_vm->mod))
+		auth_vm = ERR_PTR(-ENOENT);
+
+	return auth_vm;
+}
+
+static void gunyah_put_auth_vm_mgr(struct gunyah_vm *ghvm)
+{
+	struct gunyah_auth_vm_mgr *auth_vm;
+
+	auth_vm = xa_load(&gunyah_auth_vm_mgr, ghvm->auth);
+	if (!auth_vm)
+		return;
+
+	auth_vm->vm_detach(ghvm);
+	module_put(auth_vm->mod);
+}
+
+static long gunyah_vm_set_auth_type(struct gunyah_vm *ghvm,
+				struct gunyah_auth_desc *auth_desc)
+{
+	struct gunyah_auth_vm_mgr *auth_vm;
+
+	auth_vm = gunyah_get_auth_vm_mgr(auth_desc->type);
+	if (IS_ERR(auth_vm))
+		return PTR_ERR(auth_vm);
+
+	/* The auth mgr should be populating the auth_vm_mgr_ops*/
+	return auth_vm->vm_attach(ghvm, auth_desc);
+}
+
 static int gunyah_generic_pre_vm_configure(struct gunyah_vm *ghvm)
 {
 	/*
@@ -1016,6 +1070,14 @@ static long gunyah_vm_ioctl(struct file *filp, unsigned int cmd,
 
 		return gunyah_vm_set_boot_context(ghvm, &boot_ctx);
 	}
+	case GH_VM_ANDROID_SET_AUTH_TYPE: {
+		struct gunyah_auth_desc auth_desc;
+
+		if (copy_from_user(&auth_desc, argp, sizeof(auth_desc)))
+			return -EFAULT;
+
+		return gunyah_vm_set_auth_type(ghvm, &auth_desc);
+	}
 	default:
 		r = -ENOTTY;
 		break;
@@ -1103,6 +1165,7 @@ static void _gunyah_vm_put(struct kref *kref)
 	xa_for_each(&ghvm->boot_context, index, entry)
 		kfree(entry);
 
+	gunyah_put_auth_vm_mgr(ghvm);
 	xa_destroy(&ghvm->boot_context);
 	gunyah_rm_put(ghvm->rm);
 	mmdrop(ghvm->mm_s);

include/linux/gunyah.h

@@ -49,6 +49,24 @@ struct gunyah_auth_vm_mgr_ops {
 	void (*vm_start_fail)(struct gunyah_vm *ghvm);
 };
 
+/**
+ * struct gunyah_auth_vm - Represents an authentication type handler
+ * @type: value from &enum gunyah_auth_type
+ * @name: friendly name for debug purposes
+ * @mod: owner of the auth type
+ * @vm_attach: attach ops/private_data with the VM.
+ * @vm_detach: detach ops/private_data with the VM.
+ */
+struct gunyah_auth_vm_mgr {
+	u32 type;
+	const char *name;
+	struct module *mod;
+	long (*vm_attach)(struct gunyah_vm *ghvm, struct gunyah_auth_desc *d);
+	void (*vm_detach)(struct gunyah_vm *ghvm);
+};
+int gunyah_auth_vm_mgr_register(struct gunyah_auth_vm_mgr *auth_vm);
+void gunyah_auth_vm_mgr_unregister(struct gunyah_auth_vm_mgr *auth_vm);
+
 struct gunyah_vm_function_instance;
 /**
  * struct gunyah_vm_function - Represents a function type

include/uapi/linux/gunyah.h

@@ -420,4 +420,40 @@ struct gunyah_map_cma_mem_args {
 };
 
 #define GH_VM_ANDROID_MAP_CMA_MEM _IOW(GH_ANDROID_IOCTL_TYPE, 0x15, struct gunyah_map_cma_mem_args)
+
+/**
+ * enum gunyah_auth_type - Valid types of authentication supported by Gunyah
+ */
+enum gunyah_auth_type {
+	GUNYAH_QCOM_TRUSTED_VM_TYPE = 1,
+};
+
+/**
+ * struct gunyah_qtvm_auth_arg - Argument to QTVM auth vm manager
+ * @vm_id: The VM ID that Gunyah associates with the QTVM.
+ * @peripheral_id: Also called pas_id which firmware needs for authenticating the QTVM.
+ * @guest_phys_addr: Address where the VM image should be mapped to.
+ * @size: Size of the VM image
+ */
+struct gunyah_qtvm_auth_arg {
+	__u16 vm_id;
+	__u32 peripheral_id;
+	__u64 guest_phys_addr;
+	__u64 size;
+};
+
+/**
+ * struct gunyah_auth_desc - Arguments to match with an auth vm manager
+ * @type: Type of the authentication mechanism. See &enum gunyah_auth_type.
+ * @arg_size: Size of argument to pass to the auth vm mgr. arg_size <= GUNYAH_FN_MAX_ARG_SIZE
+ * @arg: Pointer to argument given to the auth vm mgr. See &enum gunyah_auth_type for expected
+ *       arguments for a function type.
+ */
+struct gunyah_auth_desc {
+	__u32 type;
+	__u32 arg_size;
+	__u64 arg;
+};
+#define GH_VM_ANDROID_SET_AUTH_TYPE		_IOW(GH_ANDROID_IOCTL_TYPE, 0x16, \
+							struct gunyah_auth_desc)
 #endif