[v6,17/21] samples: Add sample userspace Gunyah VM Manager

diff --git a/MAINTAINERS b/MAINTAINERS
index e072a0d2e553..907a2267f0ab 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8946,6 +8946,7 @@  F:	arch/arm64/gunyah/
 F:	drivers/mailbox/gunyah-msgq.c
 F:	drivers/virt/gunyah/
 F:	include/linux/gunyah*.h
+F:	samples/gunyah/
 
 HABANALABS PCI DRIVER
 M:	Oded Gabbay <ogabbay@kernel.org>
diff --git a/samples/Kconfig b/samples/Kconfig
index 0d81c00289ee..197c8a3610e7 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -263,6 +263,16 @@  config SAMPLE_CORESIGHT_SYSCFG
 	  This demonstrates how a user may create their own CoreSight
 	  configurations and easily load them into the system at runtime.
 
+config SAMPLE_GUNYAH
+	bool "Build example Gunyah Virtual Machine Manager"
+	depends on CC_CAN_LINK && HEADERS_INSTALL
+	depends on GUNYAH_VM_MANAGER
+	help
+	  Build an example Gunyah VMM userspace program capable of launching
+	  a basic virtual machine under the Gunyah hypervisor.
+	  This demonstrates how to create a virtual machine under the Gunyah
+	  hypervisor.
+
 source "samples/rust/Kconfig"
 
 endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 9832ef3f8fcb..2600bd4b82f8 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -36,3 +36,4 @@  obj-$(CONFIG_DEBUG_KMEMLEAK_TEST)	+= kmemleak/
 obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
 obj-$(CONFIG_SAMPLE_FPROBE)		+= fprobe/
 obj-$(CONFIG_SAMPLES_RUST)		+= rust/
+obj-$(CONFIG_SAMPLE_GUNYAH)		+= gunyah/
diff --git a/samples/gunyah/.gitignore b/samples/gunyah/.gitignore
new file mode 100644
index 000000000000..adc7d1589fde
--- /dev/null
+++ b/samples/gunyah/.gitignore
@@ -0,0 +1,2 @@ 
+# SPDX-License-Identifier: GPL-2.0
+/gunyah_vmm
diff --git a/samples/gunyah/Makefile b/samples/gunyah/Makefile
new file mode 100644
index 000000000000..faf14f9bb337
--- /dev/null
+++ b/samples/gunyah/Makefile
@@ -0,0 +1,6 @@ 
+# SPDX-License-Identifier: GPL-2.0-only
+
+userprogs-always-y += gunyah_vmm
+dtb-y += sample_vm.dtb
+
+userccflags += -I usr/include
diff --git a/samples/gunyah/gunyah_vmm.c b/samples/gunyah/gunyah_vmm.c
new file mode 100644
index 000000000000..ccc1786051f2
--- /dev/null
+++ b/samples/gunyah/gunyah_vmm.c
@@ -0,0 +1,270 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <getopt.h>
+#include <limits.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/sysmacros.h>
+#define __USE_GNU
+#include <sys/mman.h>
+
+#include <linux/gunyah.h>
+
+struct vm_config {
+	int image_fd;
+	int dtb_fd;
+	int ramdisk_fd;
+
+	uint64_t guest_base;
+	uint64_t guest_size;
+
+	uint64_t image_offset;
+	off_t image_size;
+	uint64_t dtb_offset;
+	off_t dtb_size;
+	uint64_t ramdisk_offset;
+	off_t ramdisk_size;
+};
+
+static struct option options[] = {
+	{ "help", no_argument, NULL, 'h' },
+	{ "image", required_argument, NULL, 'i' },
+	{ "dtb", required_argument, NULL, 'd' },
+	{ "ramdisk", optional_argument, NULL, 'r' },
+	{ "base", optional_argument, NULL, 'B' },
+	{ "size", optional_argument, NULL, 'S' },
+	{ "image_offset", optional_argument, NULL, 'I' },
+	{ "dtb_offset", optional_argument, NULL, 'D' },
+	{ "ramdisk_offset", optional_argument, NULL, 'R' },
+	{ }
+};
+
+static void print_help(char *cmd)
+{
+	printf("gunyah_vmm, a sample tool to launch Gunyah VMs\n"
+	       "Usage: %s <options>\n"
+	       "       --help,    -h  this menu\n"
+	       "       --image,   -i <image> VM image file to load (e.g. a kernel Image) [Required]\n"
+	       "       --dtb,     -d <dtb>   Devicetree to load [Required]\n"
+	       "       --ramdisk, -r <ramdisk>  Ramdisk to load\n"
+	       "       --base,    -B <address>  Set the base address of guest's memory [Default: 0x80000000]\n"
+	       "       --size,    -S <number>   The number of bytes large to make the guest's memory [Default: 0x6400000 (100 MB)]\n"
+	       "       --image_offset, -I <number>  Offset into guest memory to load the VM image file [Default: 0x10000]\n"
+	       "        --dtb_offset,  -D <number>  Offset into guest memory to load the DTB [Default: 0]\n"
+	       "        --ramdisk_offset, -R <number>  Offset into guest memory to load a ramdisk [Default: 0x4600000]\n"
+	       , cmd);
+}
+
+int main(int argc, char **argv)
+{
+	int gunyah_fd, vm_fd, guest_fd;
+	struct gh_userspace_memory_region guest_mem_desc = { 0 };
+	struct gh_vm_dtb_config dtb_config = { 0 };
+	char *guest_mem;
+	struct vm_config config = {
+		/* Defaults good enough to boot static kernel and a basic ramdisk */
+		.ramdisk_fd = -1,
+		.guest_base = 0x80000000,
+		.guest_size = 104857600, /* 100 MB */
+		.image_offset = 0,
+		.dtb_offset = 0x45f0000,
+		.ramdisk_offset = 0x4600000, /* put at +70MB (30MB for ramdisk) */
+	};
+	struct stat st;
+	int opt, optidx, ret = 0;
+	long int l;
+
+	while ((opt = getopt_long(argc, argv, "hi:d:r:B:S:I:D:R:c:", options, &optidx)) != -1) {
+		switch (opt) {
+		case 'i':
+			config.image_fd = open(optarg, O_RDONLY | O_CLOEXEC);
+			if (config.image_fd < 0) {
+				perror("Failed to open image");
+				return -1;
+			}
+			if (stat(optarg, &st) < 0) {
+				perror("Failed to stat image");
+				return -1;
+			}
+			config.image_size = st.st_size;
+			break;
+		case 'd':
+			config.dtb_fd = open(optarg, O_RDONLY | O_CLOEXEC);
+			if (config.dtb_fd < 0) {
+				perror("Failed to open dtb");
+				return -1;
+			}
+			if (stat(optarg, &st) < 0) {
+				perror("Failed to stat dtb");
+				return -1;
+			}
+			config.dtb_size = st.st_size;
+			break;
+		case 'r':
+			config.ramdisk_fd = open(optarg, O_RDONLY | O_CLOEXEC);
+			if (config.ramdisk_fd < 0) {
+				perror("Failed to open ramdisk");
+				return -1;
+			}
+			if (stat(optarg, &st) < 0) {
+				perror("Failed to stat ramdisk");
+				return -1;
+			}
+			config.ramdisk_size = st.st_size;
+			break;
+		case 'B':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse base address");
+				return -1;
+			}
+			config.guest_base = l;
+			break;
+		case 'S':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse memory size");
+				return -1;
+			}
+			config.guest_size = l;
+			break;
+		case 'I':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse image offset");
+				return -1;
+			}
+			config.image_offset = l;
+			break;
+		case 'D':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse dtb offset");
+				return -1;
+			}
+			config.dtb_offset = l;
+			break;
+		case 'R':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse ramdisk offset");
+				return -1;
+			}
+			config.ramdisk_offset = l;
+			break;
+		case 'h':
+			print_help(argv[0]);
+			return 0;
+		default:
+			print_help(argv[0]);
+			return -1;
+		}
+	}
+
+	if (!config.image_fd || !config.dtb_fd) {
+		print_help(argv[0]);
+		return -1;
+	}
+
+	if (config.image_offset + config.image_size > config.guest_size) {
+		fprintf(stderr, "Image offset and size puts it outside guest memory. Make image smaller or increase guest memory size.\n");
+		return -1;
+	}
+
+	if (config.dtb_offset + config.dtb_size > config.guest_size) {
+		fprintf(stderr, "DTB offset and size puts it outside guest memory. Make dtb smaller or increase guest memory size.\n");
+		return -1;
+	}
+
+	if (config.ramdisk_fd == -1 &&
+		config.ramdisk_offset + config.ramdisk_size > config.guest_size) {
+		fprintf(stderr, "Ramdisk offset and size puts it outside guest memory. Make ramdisk smaller or increase guest memory size.\n");
+		return -1;
+	}
+
+	gunyah_fd = open("/dev/gunyah", O_RDWR | O_CLOEXEC);
+	if (gunyah_fd < 0) {
+		perror("Failed to open /dev/gunyah");
+		return -1;
+	}
+
+	vm_fd = ioctl(gunyah_fd, GH_CREATE_VM, 0);
+	if (vm_fd < 0) {
+		perror("Failed to create vm");
+		return -1;
+	}
+
+	guest_fd = memfd_create("guest_memory", MFD_CLOEXEC);
+	if (guest_fd < 0) {
+		perror("Failed to create guest memfd");
+		return -1;
+	}
+
+	if (ftruncate(guest_fd, config.guest_size) < 0) {
+		perror("Failed to grow guest memory");
+		return -1;
+	}
+
+	guest_mem = mmap(NULL, config.guest_size, PROT_READ | PROT_WRITE, MAP_SHARED, guest_fd, 0);
+	if (guest_mem == MAP_FAILED) {
+		perror("Not enough memory");
+		return -1;
+	}
+
+	if (read(config.image_fd, guest_mem + config.image_offset, config.image_size) < 0) {
+		perror("Failed to read image into guest memory");
+		return -1;
+	}
+
+	if (read(config.dtb_fd, guest_mem + config.dtb_offset, config.dtb_size) < 0) {
+		perror("Failed to read dtb into guest memory");
+		return -1;
+	}
+
+	if (config.ramdisk_fd > 0 &&
+		read(config.ramdisk_fd, guest_mem + config.ramdisk_offset,
+			config.ramdisk_size) < 0) {
+		perror("Failed to read ramdisk into guest memory");
+		return -1;
+	}
+
+	guest_mem_desc.label = 0;
+	guest_mem_desc.flags = GH_MEM_ALLOW_READ | GH_MEM_ALLOW_WRITE | GH_MEM_ALLOW_EXEC;
+	guest_mem_desc.guest_phys_addr = config.guest_base;
+	guest_mem_desc.memory_size = config.guest_size;
+	guest_mem_desc.userspace_addr = (__u64)guest_mem;
+
+	if (ioctl(vm_fd, GH_VM_SET_USER_MEM_REGION, &guest_mem_desc) < 0) {
+		perror("Failed to register guest memory with VM");
+		return -1;
+	}
+
+	dtb_config.gpa = config.dtb_offset;
+	dtb_config.size = config.dtb_size;
+	if (ioctl(vm_fd, GH_VM_SET_DTB_CONFIG, &dtb_config) < 0) {
+		perror("Failed to set DTB configuration for VM");
+		return -1;
+	}
+
+	ret = ioctl(vm_fd, GH_VM_START);
+	if (ret) {
+		perror("GH_VM_START failed");
+		return -1;
+	}
+
+	while (1)
+		sleep(10);
+
+	return 0;
+}
diff --git a/samples/gunyah/sample_vm.dts b/samples/gunyah/sample_vm.dts
new file mode 100644
index 000000000000..1c410d58c298
--- /dev/null
+++ b/samples/gunyah/sample_vm.dts
@@ -0,0 +1,69 @@ 
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+/dts-v1/;
+
+/ {
+	#address-cells = <2>;
+	#size-cells = <2>;
+	interrupt-parent = <&intc>;
+
+	chosen {
+		bootargs = "nokaslr";
+	};
+
+	cpus {
+		#address-cells = <0x2>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			compatible = "arm,armv8";
+			reg = <0 0>;
+		};
+	};
+
+	intc: interrupt-controller@3FFF0000 {
+		compatible = "arm,gic-v3";
+		#interrupt-cells = <3>;
+		#address-cells = <2>;
+		#size-cells = <2>;
+		interrupt-controller;
+		reg = <0 0x3FFF0000 0 0x10000>,
+		      <0 0x3FFD0000 0 0x20000>;
+	};
+
+	timer {
+		compatible = "arm,armv8-timer";
+		always-on;
+		interrupts = <1 13 0x108>,
+			     <1 14 0x108>,
+			     <1 11 0x108>,
+			     <1 10 0x108>;
+		clock-frequency = <19200000>;
+	};
+
+	gunyah-vm-config {
+		image-name = "linux_vm_0";
+		os-type = "linux";
+
+		memory {
+			#address-cells = <2>;
+			#size-cells = <2>;
+
+			base-address = <0 0x80000000>;
+		};
+
+		interrupts {
+			config = <&intc>;
+		};
+
+		vcpus {
+			affinity-map = < 0 >;
+			sched-priority = < (-1) >;
+			sched-timeslice = < 2000 >;
+		};
+	};
+};