[PATCH v16 08/34] gunyah: vm_mgr: Introduce basic VM Manager

[Elliot Berman]

Gunyah VM manager is a kernel moduel which exposes an interface to
Gunyah userspace to load, run, and interact with other Gunyah virtual
machines. The interface is a character device at /dev/gunyah.

Add a basic VM manager driver. Upcoming patches will add more ioctls
into this driver.

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
 Documentation/userspace-api/ioctl/ioctl-number.rst |  1 +
 drivers/virt/gunyah/Makefile                       |  2 +-
 drivers/virt/gunyah/rsc_mgr.c                      | 51 ++++++++++++
 drivers/virt/gunyah/vm_mgr.c                       | 94 ++++++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.h                       | 28 +++++++
 include/uapi/linux/gunyah.h                        | 23 ++++++
 6 files changed, 198 insertions(+), 1 deletion(-)

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index d8b6cb1a3636..91e01925a41b 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -137,6 +137,7 @@ Code  Seq#    Include File                                           Comments
 'F'   DD     video/sstfb.h                                           conflict!
 'G'   00-3F  drivers/misc/sgi-gru/grulib.h                           conflict!
 'G'   00-0F  xen/gntalloc.h, xen/gntdev.h                            conflict!
+'G'   00-0F  linux/gunyah.h                                          conflict!
 'H'   00-7F  linux/hiddev.h                                          conflict!
 'H'   00-0F  linux/hidraw.h                                          conflict!
 'H'   01     linux/mei.h                                             conflict!
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index c2308389f551..ceccbbe68b38 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
-gunyah_rsc_mgr-y += rsc_mgr.o
+gunyah_rsc_mgr-y += rsc_mgr.o vm_mgr.o
 
 obj-$(CONFIG_GUNYAH) += gunyah.o gunyah_rsc_mgr.o
diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
index a3578a0c10b4..45f9514cfe0e 100644
--- a/drivers/virt/gunyah/rsc_mgr.c
+++ b/drivers/virt/gunyah/rsc_mgr.c
@@ -10,8 +10,10 @@
 #include <linux/notifier.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/miscdevice.h>
 
 #include "rsc_mgr.h"
+#include "vm_mgr.h"
 
 /* clang-format off */
 #define RM_RPC_API_VERSION_MASK		GENMASK(3, 0)
@@ -118,6 +120,7 @@ struct gunyah_rm_message {
  * @send_lock: synchronization to allow only one request to be sent at a time
  * @send_ready: completed when we know Tx message queue can take more messages
  * @nh: notifier chain for clients interested in RM notification messages
+ * @miscdev: /dev/gunyah
  */
 struct gunyah_rm {
 	struct device *dev;
@@ -133,6 +136,8 @@ struct gunyah_rm {
 	struct mutex send_lock;
 	struct completion send_ready;
 	struct blocking_notifier_head nh;
+
+	struct miscdevice miscdev;
 };
 
 /**
@@ -617,6 +622,36 @@ int gunyah_rm_notifier_unregister(struct gunyah_rm *rm,
 }
 EXPORT_SYMBOL_GPL(gunyah_rm_notifier_unregister);
 
+struct device *gunyah_rm_get(struct gunyah_rm *rm)
+{
+	return get_device(rm->miscdev.this_device);
+}
+EXPORT_SYMBOL_GPL(gunyah_rm_get);
+
+void gunyah_rm_put(struct gunyah_rm *rm)
+{
+	put_device(rm->miscdev.this_device);
+}
+EXPORT_SYMBOL_GPL(gunyah_rm_put);
+
+static long gunyah_dev_ioctl(struct file *filp, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct miscdevice *miscdev = filp->private_data;
+	struct gunyah_rm *rm = container_of(miscdev, struct gunyah_rm, miscdev);
+
+	return gunyah_dev_vm_mgr_ioctl(rm, cmd, arg);
+}
+
+static const struct file_operations gunyah_dev_fops = {
+	/* clang-format off */
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= gunyah_dev_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+	/* clang-format on */
+};
+
 static int gunyah_platform_probe_capability(struct platform_device *pdev,
 					    int idx,
 					    struct gunyah_resource *ghrsc)
@@ -702,9 +737,24 @@ static int gunyah_rm_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	rm->miscdev.name = "gunyah";
+	rm->miscdev.minor = MISC_DYNAMIC_MINOR;
+	rm->miscdev.fops = &gunyah_dev_fops;
+
+	ret = misc_register(&rm->miscdev);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
+static void gunyah_rm_remove(struct platform_device *pdev)
+{
+	struct gunyah_rm *rm = platform_get_drvdata(pdev);
+
+	misc_deregister(&rm->miscdev);
+}
+
 static const struct of_device_id gunyah_rm_of_match[] = {
 	{ .compatible = "gunyah-resource-manager" },
 	{}
@@ -713,6 +763,7 @@ MODULE_DEVICE_TABLE(of, gunyah_rm_of_match);
 
 static struct platform_driver gunyah_rm_driver = {
 	.probe = gunyah_rm_probe,
+	.remove_new = gunyah_rm_remove,
 	.driver = {
 		.name = "gunyah_rsc_mgr",
 		.of_match_table = gunyah_rm_of_match,
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
new file mode 100644
index 000000000000..e9dff733e35e
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "gunyah_vm_mgr: " fmt
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+
+#include <uapi/linux/gunyah.h>
+
+#include "rsc_mgr.h"
+#include "vm_mgr.h"
+
+static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm)
+{
+	struct gunyah_vm *ghvm;
+
+	ghvm = kzalloc(sizeof(*ghvm), GFP_KERNEL);
+	if (!ghvm)
+		return ERR_PTR(-ENOMEM);
+
+	ghvm->parent = gunyah_rm_get(rm);
+	ghvm->rm = rm;
+
+	return ghvm;
+}
+
+static int gunyah_vm_release(struct inode *inode, struct file *filp)
+{
+	struct gunyah_vm *ghvm = filp->private_data;
+
+	gunyah_rm_put(ghvm->rm);
+	kfree(ghvm);
+	return 0;
+}
+
+static const struct file_operations gunyah_vm_fops = {
+	.owner = THIS_MODULE,
+	.release = gunyah_vm_release,
+	.llseek = noop_llseek,
+};
+
+static long gunyah_dev_ioctl_create_vm(struct gunyah_rm *rm, unsigned long arg)
+{
+	struct gunyah_vm *ghvm;
+	struct file *file;
+	int fd, err;
+
+	/* arg reserved for future use. */
+	if (arg)
+		return -EINVAL;
+
+	ghvm = gunyah_vm_alloc(rm);
+	if (IS_ERR(ghvm))
+		return PTR_ERR(ghvm);
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		err = fd;
+		goto err_destroy_vm;
+	}
+
+	file = anon_inode_getfile("gunyah-vm", &gunyah_vm_fops, ghvm, O_RDWR);
+	if (IS_ERR(file)) {
+		err = PTR_ERR(file);
+		goto err_put_fd;
+	}
+
+	fd_install(fd, file);
+
+	return fd;
+
+err_put_fd:
+	put_unused_fd(fd);
+err_destroy_vm:
+	gunyah_rm_put(ghvm->rm);
+	kfree(ghvm);
+	return err;
+}
+
+long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd,
+			     unsigned long arg)
+{
+	switch (cmd) {
+	case GUNYAH_CREATE_VM:
+		return gunyah_dev_ioctl_create_vm(rm, arg);
+	default:
+		return -ENOTTY;
+	}
+}
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
new file mode 100644
index 000000000000..50790d402676
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _GUNYAH_VM_MGR_PRIV_H
+#define _GUNYAH_VM_MGR_PRIV_H
+
+#include <linux/device.h>
+
+#include <uapi/linux/gunyah.h>
+
+#include "rsc_mgr.h"
+
+long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd,
+			     unsigned long arg);
+
+/**
+ * struct gunyah_vm - Main representation of a Gunyah Virtual machine
+ * @rm: Pointer to the resource manager struct to make RM calls
+ * @parent: For logging
+ */
+struct gunyah_vm {
+	struct gunyah_rm *rm;
+	struct device *parent;
+};
+
+#endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
new file mode 100644
index 000000000000..ac338ec4b85d
--- /dev/null
+++ b/include/uapi/linux/gunyah.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _UAPI_LINUX_GUNYAH_H
+#define _UAPI_LINUX_GUNYAH_H
+
+/*
+ * Userspace interface for /dev/gunyah - gunyah based virtual machine
+ */
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define GUNYAH_IOCTL_TYPE 'G'
+
+/*
+ * ioctls for /dev/gunyah fds:
+ */
+#define GUNYAH_CREATE_VM _IO(GUNYAH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
+
+#endif

-- 
2.34.1