[PATCH v7 12/20] 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.

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>
---
 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 drivers/virt/gunyah/Kconfig                   |  10 ++
 drivers/virt/gunyah/Makefile                  |   3 +
 drivers/virt/gunyah/gunyah_rsc_mgr.c          |  32 +++-
 drivers/virt/gunyah/vm_mgr.c                  | 155 ++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.h                  |  31 ++++
 include/uapi/linux/gunyah.h                   |  23 +++
 7 files changed, 249 insertions(+), 6 deletions(-)
 create mode 100644 drivers/virt/gunyah/vm_mgr.c
 create mode 100644 drivers/virt/gunyah/vm_mgr.h
 create mode 100644 include/uapi/linux/gunyah.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 5f81e2a24a5c..81456c34c85d 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -136,6 +136,7 @@ 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/Kconfig b/drivers/virt/gunyah/Kconfig
index 0bb497372d4e..5856b7c5157b 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -16,4 +16,14 @@ config GUNYAH_RESOURCE_MANAGER
 	tristate
 	depends on MAILBOX
 	select GUNYAH_MESSAGE_QUEUES
+
+config GUNYAH_VM_MANAGER
+	tristate "Gunyah VM Manager"
+	depends on MAILBOX
+	select GUNYAH_RESOURCE_MANAGER
+	help
+	  Gunyah VM manager is a kernel module which exposes an interface to
+	  Gunyah userspace to load, run, and interact with other Gunyah
+	  virtual machines. This module is required to launch other virtual
+	  machines.
 endif
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index b62ac4045621..ae628424719b 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,3 +1,6 @@
 obj-$(CONFIG_GUNYAH) += gunyah.o
 
 obj-$(CONFIG_GUNYAH_RESOURCE_MANAGER) += gunyah_rsc_mgr.o gunyah_rm_rpc.o
+
+gunyah_vm_mgr-y += vm_mgr.o
+obj-$(CONFIG_GUNYAH_VM_MANAGER) += gunyah_vm_mgr.o
diff --git a/drivers/virt/gunyah/gunyah_rsc_mgr.c b/drivers/virt/gunyah/gunyah_rsc_mgr.c
index 2fae62bbfe49..47cf107ce894 100644
--- a/drivers/virt/gunyah/gunyah_rsc_mgr.c
+++ b/drivers/virt/gunyah/gunyah_rsc_mgr.c
@@ -7,25 +7,45 @@
 #include <linux/platform_device.h>
 
 #include "rsc_mgr.h"
+#include "vm_mgr.h"
+
+struct gh_rsc_mgr {
+	struct gh_rm_rpc *rpc;
+	struct gh_vm_mgr *vm_mgr;
+};
 
 static int gh_rm_drv_probe(struct platform_device *pdev)
 {
-	struct gh_rm_rpc *rsc_mgr;
+	struct gh_rsc_mgr *rsc_mgr;
 
-	rsc_mgr = gh_rm_rpc_init(pdev);
-	if (IS_ERR(rsc_mgr))
-		return PTR_ERR(rsc_mgr);
+	rsc_mgr = devm_kzalloc(&pdev->dev, sizeof(*rsc_mgr), GFP_KERNEL);
+	if (!rsc_mgr)
+		return -ENOMEM;
 
 	platform_set_drvdata(pdev, rsc_mgr);
 
+	rsc_mgr->rpc = gh_rm_rpc_init(pdev);
+	if (IS_ERR(rsc_mgr->rpc))
+		return PTR_ERR(rsc_mgr->rpc);
+
+	rsc_mgr->vm_mgr = gh_vm_mgr_init(&pdev->dev, rsc_mgr->rpc);
+	if (IS_ERR(rsc_mgr->vm_mgr)) {
+		dev_warn(&pdev->dev, "Failed to initialize vm manager: %ld\n",
+			PTR_ERR(rsc_mgr->vm_mgr));
+		rsc_mgr->vm_mgr = NULL;
+	}
+
 	return 0;
 }
 
 static int gh_rm_drv_remove(struct platform_device *pdev)
 {
-	struct gh_rm_rpc *rsc_mgr = platform_get_drvdata(pdev);
+	struct gh_rsc_mgr *rsc_mgr = platform_get_drvdata(pdev);
+
+	if (rsc_mgr->vm_mgr)
+		gh_vm_mgr_remove(rsc_mgr->vm_mgr);
 
-	gh_rm_rpc_remove(rsc_mgr);
+	gh_rm_rpc_remove(rsc_mgr->rpc);
 
 	return 0;
 }
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
new file mode 100644
index 000000000000..deb8e0bf4a4d
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "gh_vm_mgr: " fmt
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+
+#include <uapi/linux/gunyah.h>
+
+#include "vm_mgr.h"
+
+static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gh_vm_mgr *vm_mgr)
+{
+	struct gunyah_vm *ghvm;
+	int ret;
+
+	ret = gh_rm_alloc_vmid(vm_mgr->rm, 0);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	ghvm = kzalloc(sizeof(*ghvm), GFP_KERNEL);
+	if (!ghvm)
+		return ghvm;
+
+	ghvm->vmid = ret;
+
+	return ghvm;
+}
+
+static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	long r;
+
+	switch (cmd) {
+	default:
+		r = -ENOTTY;
+		break;
+	}
+
+	return r;
+}
+
+static int gh_vm_release(struct inode *inode, struct file *filp)
+{
+	struct gunyah_vm *ghvm = filp->private_data;
+
+	kfree(ghvm);
+	return 0;
+}
+
+static const struct file_operations gh_vm_fops = {
+	.unlocked_ioctl = gh_vm_ioctl,
+	.release = gh_vm_release,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek = noop_llseek,
+};
+
+static long gh_dev_ioctl_create_vm(struct gh_vm_mgr *vm_mgr, 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(vm_mgr);
+	if (IS_ERR_OR_NULL(ghvm))
+		return PTR_ERR(ghvm) ? : -ENOMEM;
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		err = fd;
+		goto err_destroy_vm;
+	}
+
+	file = anon_inode_getfile("gunyah-vm", &gh_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:
+	kfree(ghvm);
+	return err;
+}
+
+static long gh_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct miscdevice *miscdev = filp->private_data;
+	struct gh_vm_mgr *vm_mgr = container_of(miscdev, struct gh_vm_mgr, miscdev);
+
+	switch (cmd) {
+	case GH_CREATE_VM:
+		return gh_dev_ioctl_create_vm(vm_mgr, arg);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct file_operations gh_dev_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= gh_dev_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
+struct gh_vm_mgr *gh_vm_mgr_init(struct device *dev, struct gh_rm_rpc *rm)
+{
+	struct gh_vm_mgr *vm_mgr;
+	int ret;
+
+	vm_mgr = kzalloc(sizeof(*vm_mgr), GFP_KERNEL);
+	if (!vm_mgr)
+		return ERR_PTR(-ENOMEM);
+
+	vm_mgr->dev = dev;
+	vm_mgr->rm = rm;
+	vm_mgr->miscdev.name = "gunyah";
+	vm_mgr->miscdev.minor = MISC_DYNAMIC_MINOR;
+	vm_mgr->miscdev.fops = &gh_dev_fops;
+
+	ret = misc_register(&vm_mgr->miscdev);
+	if (ret) {
+		kfree(vm_mgr);
+		return ERR_PTR(ret);
+	}
+
+	return vm_mgr;
+}
+EXPORT_SYMBOL_GPL(gh_vm_mgr_init);
+
+void gh_vm_mgr_remove(struct gh_vm_mgr *vm_mgr)
+{
+	misc_deregister(&vm_mgr->miscdev);
+	kfree(vm_mgr);
+}
+EXPORT_SYMBOL_GPL(gh_vm_mgr_remove);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah VM Manager");
+
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
new file mode 100644
index 000000000000..9e9dfb1c0268
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _GH_PRIV_VM_MGR_H
+#define _GH_PRIV_VM_MGR_H
+
+#include <linux/gunyah_rsc_mgr.h>
+
+#include <uapi/linux/gunyah.h>
+
+struct gh_vm_mgr {
+	struct device *dev;
+	struct gh_rm_rpc *rm;
+	struct miscdevice miscdev;
+};
+
+#if IS_ENABLED(CONFIG_GUNYAH_VM_MANAGER)
+struct gh_vm_mgr *gh_vm_mgr_init(struct device *dev, struct gh_rm_rpc *rm);
+void gh_vm_mgr_remove(struct gh_vm_mgr *vm_mgr);
+#else
+static inline struct gh_vm_mgr *gh_vm_mgr_init(struct gh_rm_rpc *rm) { return NULL; }
+static inline void gh_vm_mgr_remove(struct gh_vm_mgr *vm_mgr) { }
+#endif
+
+struct gunyah_vm {
+	u16 vmid;
+};
+
+#endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
new file mode 100644
index 000000000000..88a40d6e0b96
--- /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 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _UAPI_LINUX_GUNYAH
+#define _UAPI_LINUX_GUNYAH
+
+/*
+ * Userspace interface for /dev/gunyah - gunyah based virtual machine
+ */
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define GH_IOCTL_TYPE			'G'
+
+/*
+ * ioctls for /dev/gunyah fds:
+ */
+#define GH_CREATE_VM			_IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
+
+#endif
-- 
2.25.1