[v8,03/20] virt: geniezone: Add GenieZone hypervisor driver

diff --git a/MAINTAINERS b/MAINTAINERS
index ac2b1c91f4b5..682396176290 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8985,6 +8985,9 @@  M:	Ze-Yu Wang <ze-yu.wang@mediatek.com>
 M:	Yi-De Wu <yi-de.wu@mediatek.com>
 F:	Documentation/devicetree/bindings/hypervisor/mediatek,geniezone-hyp.yaml
 F:	Documentation/virt/geniezone/
+F:	arch/arm64/geniezone/
+F:	drivers/virt/geniezone/
+F:	include/linux/gzvm_drv.h
 
 GENWQE (IBM Generic Workqueue Card)
 M:	Frank Haverkamp <haver@linux.ibm.com>
diff --git a/arch/arm64/Kbuild b/arch/arm64/Kbuild
index 5bfbf7d79c99..0c3cca572919 100644
--- a/arch/arm64/Kbuild
+++ b/arch/arm64/Kbuild
@@ -4,6 +4,7 @@  obj-$(CONFIG_KVM)	+= kvm/
 obj-$(CONFIG_XEN)	+= xen/
 obj-$(subst m,y,$(CONFIG_HYPERV))	+= hyperv/
 obj-$(CONFIG_CRYPTO)	+= crypto/
+obj-$(CONFIG_MTK_GZVM)	+= geniezone/
 
 # for cleaning
 subdir- += boot
diff --git a/arch/arm64/geniezone/Makefile b/arch/arm64/geniezone/Makefile
new file mode 100644
index 000000000000..2957898cdd05
--- /dev/null
+++ b/arch/arm64/geniezone/Makefile
@@ -0,0 +1,9 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Main Makefile for gzvm, this one includes drivers/virt/geniezone/Makefile
+#
+include $(srctree)/drivers/virt/geniezone/Makefile
+
+gzvm-y += vm.o
+
+obj-$(CONFIG_MTK_GZVM) += gzvm.o
diff --git a/arch/arm64/geniezone/gzvm_arch_common.h b/arch/arm64/geniezone/gzvm_arch_common.h
new file mode 100644
index 000000000000..f5bddcfe3a1f
--- /dev/null
+++ b/arch/arm64/geniezone/gzvm_arch_common.h
@@ -0,0 +1,44 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#ifndef __GZVM_ARCH_COMMON_H__
+#define __GZVM_ARCH_COMMON_H__
+
+#include <linux/arm-smccc.h>
+
+enum {
+	GZVM_FUNC_PROBE = 12,
+	NR_GZVM_FUNC,
+};
+
+#define SMC_ENTITY_MTK			59
+#define GZVM_FUNCID_START		(0x1000)
+#define GZVM_HCALL_ID(func)						\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64,	\
+			   SMC_ENTITY_MTK, (GZVM_FUNCID_START + (func)))
+
+#define MT_HVC_GZVM_PROBE		GZVM_HCALL_ID(GZVM_FUNC_PROBE)
+
+/**
+ * gzvm_hypcall_wrapper() - the wrapper for hvc calls
+ * @a0: arguments passed in registers 0
+ * @a1: arguments passed in registers 1
+ * @a2: arguments passed in registers 2
+ * @a3: arguments passed in registers 3
+ * @a4: arguments passed in registers 4
+ * @a5: arguments passed in registers 5
+ * @a6: arguments passed in registers 6
+ * @a7: arguments passed in registers 7
+ * @res: result values from registers 0 to 3
+ *
+ * Return: The wrapper helps caller to convert geniezone errno to Linux errno.
+ */
+int gzvm_hypcall_wrapper(unsigned long a0, unsigned long a1,
+			 unsigned long a2, unsigned long a3,
+			 unsigned long a4, unsigned long a5,
+			 unsigned long a6, unsigned long a7,
+			 struct arm_smccc_res *res);
+
+#endif /* __GZVM_ARCH_COMMON_H__ */
diff --git a/arch/arm64/geniezone/vm.c b/arch/arm64/geniezone/vm.c
new file mode 100644
index 000000000000..e313aadec212
--- /dev/null
+++ b/arch/arm64/geniezone/vm.c
@@ -0,0 +1,47 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+
+#include <linux/gzvm_drv.h>
+#include "gzvm_arch_common.h"
+
+/**
+ * gzvm_hypcall_wrapper() - the wrapper for hvc calls
+ * @a0: arguments passed in registers 0
+ * @a1: arguments passed in registers 1
+ * @a2: arguments passed in registers 2
+ * @a3: arguments passed in registers 3
+ * @a4: arguments passed in registers 4
+ * @a5: arguments passed in registers 5
+ * @a6: arguments passed in registers 6
+ * @a7: arguments passed in registers 7
+ * @res: result values from registers 0 to 3
+ *
+ * Return: The wrapper helps caller to convert geniezone errno to Linux errno.
+ */
+int gzvm_hypcall_wrapper(unsigned long a0, unsigned long a1,
+			 unsigned long a2, unsigned long a3,
+			 unsigned long a4, unsigned long a5,
+			 unsigned long a6, unsigned long a7,
+			 struct arm_smccc_res *res)
+{
+	arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res);
+	return gzvm_err_to_errno(res->a0);
+}
+
+int gzvm_arch_probe(void)
+{
+	struct arm_smccc_res res;
+	int ret;
+
+	ret = gzvm_hypcall_wrapper(MT_HVC_GZVM_PROBE, 0, 0, 0, 0, 0, 0, 0, &res);
+	if (ret)
+		return -ENXIO;
+
+	return 0;
+}
diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index 40129b6f0eca..b4e9bddbcee7 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -50,4 +50,6 @@  source "drivers/virt/acrn/Kconfig"
 
 source "drivers/virt/coco/Kconfig"
 
+source "drivers/virt/geniezone/Kconfig"
+
 endif
diff --git a/drivers/virt/geniezone/Kconfig b/drivers/virt/geniezone/Kconfig
new file mode 100644
index 000000000000..b17c06c91074
--- /dev/null
+++ b/drivers/virt/geniezone/Kconfig
@@ -0,0 +1,16 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+
+config MTK_GZVM
+	tristate "GenieZone Hypervisor driver for guest VM operation"
+	depends on ARM64 && EVENTFD
+	help
+	  This driver, gzvm, enables to run guest VMs on MTK GenieZone
+	  hypervisor. It exports kvm-like interfaces for VMM (e.g., crosvm) in
+	  order to operate guest VMs on GenieZone hypervisor.
+
+	  GenieZone hypervisor now only supports MediaTek SoC and arm64
+	  architecture.
+
+	  Select M if you want it be built as a module (gzvm.ko).
+
+	  If unsure, say N.
diff --git a/drivers/virt/geniezone/Makefile b/drivers/virt/geniezone/Makefile
new file mode 100644
index 000000000000..8c1f0053e773
--- /dev/null
+++ b/drivers/virt/geniezone/Makefile
@@ -0,0 +1,10 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for GenieZone driver, this file should be include in arch's
+# to avoid two ko being generated.
+#
+
+GZVM_DIR ?= ../../../drivers/virt/geniezone
+
+gzvm-y := $(GZVM_DIR)/gzvm_main.o
+
diff --git a/drivers/virt/geniezone/gzvm_main.c b/drivers/virt/geniezone/gzvm_main.c
new file mode 100644
index 000000000000..f7d4f0646d97
--- /dev/null
+++ b/drivers/virt/geniezone/gzvm_main.c
@@ -0,0 +1,89 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/kdev_t.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/gzvm_drv.h>
+
+/**
+ * gzvm_err_to_errno() - Convert geniezone return value to standard errno
+ *
+ * @err: Return value from geniezone function return
+ *
+ * Return: Standard errno
+ */
+int gzvm_err_to_errno(unsigned long err)
+{
+	int gz_err = (int)err;
+
+	switch (gz_err) {
+	case 0:
+		return 0;
+	case ERR_NO_MEMORY:
+		return -ENOMEM;
+	case ERR_NOT_SUPPORTED:
+		return -EOPNOTSUPP;
+	case ERR_NOT_IMPLEMENTED:
+		return -EOPNOTSUPP;
+	case ERR_FAULT:
+		return -EFAULT;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static const struct file_operations gzvm_chardev_ops = {
+	.llseek		= noop_llseek,
+};
+
+static struct miscdevice gzvm_dev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = KBUILD_MODNAME,
+	.fops = &gzvm_chardev_ops,
+};
+
+static int gzvm_drv_probe(struct platform_device *pdev)
+{
+	if (gzvm_arch_probe() != 0) {
+		dev_err(&pdev->dev, "Not found available conduit\n");
+		return -ENODEV;
+	}
+
+	return misc_register(&gzvm_dev);
+}
+
+static int gzvm_drv_remove(struct platform_device *pdev)
+{
+	misc_deregister(&gzvm_dev);
+	return 0;
+}
+
+static const struct of_device_id gzvm_of_match[] = {
+	{ .compatible = "mediatek,geniezone-hyp" },
+	{/* sentinel */},
+};
+
+static struct platform_driver gzvm_driver = {
+	.probe = gzvm_drv_probe,
+	.remove = gzvm_drv_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.owner = THIS_MODULE,
+		.of_match_table = gzvm_of_match,
+	},
+};
+
+module_platform_driver(gzvm_driver);
+
+MODULE_DEVICE_TABLE(of, gzvm_of_match);
+MODULE_AUTHOR("MediaTek");
+MODULE_DESCRIPTION("GenieZone interface for VMM");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/gzvm_drv.h b/include/linux/gzvm_drv.h
new file mode 100644
index 000000000000..907f2f984de9
--- /dev/null
+++ b/include/linux/gzvm_drv.h
@@ -0,0 +1,25 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#ifndef __GZVM_DRV_H__
+#define __GZVM_DRV_H__
+
+/*
+ * These are the definitions of APIs between GenieZone hypervisor and driver,
+ * there's no need to be visible to uapi. Furthermore, we need GenieZone
+ * specific error code in order to map to Linux errno
+ */
+#define NO_ERROR                (0)
+#define ERR_NO_MEMORY           (-5)
+#define ERR_NOT_SUPPORTED       (-24)
+#define ERR_NOT_IMPLEMENTED     (-27)
+#define ERR_FAULT               (-40)
+
+int gzvm_err_to_errno(unsigned long err);
+
+/* arch-dependant functions */
+int gzvm_arch_probe(void);
+
+#endif /* __GZVM_DRV_H__ */