arch/arm64/kvm/pkvm_proxy.c

// SPDX-License-Identifier: GPL-2.0

#include <linux/atomic.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/arm-smccc.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/hashtable.h>
#include <linux/init.h>
#include <linux/kmsan-checks.h>
#include <linux/mm.h>
#include <linux/preempt.h>
#include <linux/printk.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/kcov.h>
#include <linux/refcount.h>
#include <linux/log2.h>
#include <linux/uaccess.h>
#include <asm/setup.h>
#include <asm/kvm_asm.h>

#define PKVM_PROXY_HVC_IOC_TYPE 0
#define PKVM_PROXY_HELPER_IOC_TYPE 0

#define HVC_PROXY_IOCTL(hvcnum, numarg) \
	_IOC(_IOC_WRITE, PKVM_PROXY_HVC_IOC_TYPE, hvcnum, 8 * numarg)

static int pkvm_proxy_open(struct inode *inode, struct file *filep)
{
	return nonseekable_open(inode, filep);
}

static long pkvm_proxy_ioctl(struct file *filep, unsigned int cmd,
			     unsigned long uarg)
{
	uint args_size;
	u64 args[7] = {};
	int id;
	struct arm_smccc_res res;
	switch (_IOC_TYPE(cmd)) {
	case PKVM_PROXY_HVC_IOC_TYPE:
		id = _IOC_NR(cmd);
		args_size = ALIGN(_IOC_SIZE(cmd), sizeof(u64));
		if (args_size > 7 * sizeof(u64))
			return -EINVAL;
		if (copy_from_user(args, (void*)uarg, args_size)) {
			return -EACCES;
		}
		arm_smccc_1_1_hvc(KVM_HOST_SMCCC_ID(id), args[0], args[1],
				  args[2], args[3], args[4], args[5], args[6],
				  &res);
		if(res.a0 != SMCCC_RET_SUCCESS)
			return -EINVAL;
		return res.a1;
	default:
		return -ENOSYS;
	}
}

static int pkvm_proxy_close(struct inode *inode, struct file *filep)
{
	return 0;
}

static const struct file_operations pkvm_proxy_fops = {
	.open = pkvm_proxy_open,
	.unlocked_ioctl = pkvm_proxy_ioctl,
	.compat_ioctl = pkvm_proxy_ioctl,
	/* .mmap = pkvm_proxy_mmap, */
	.release = pkvm_proxy_close,
};

static int __init pkvm_proxy_init(void)
{
	/*
	 * The pkvm_proxy debugfs file won't ever get removed and thus,
	 * there is no need to protect it against removal races. The
	 * use of debugfs_create_file_unsafe() is actually safe here.
	 */
	debugfs_create_file_unsafe("pkvm_proxy", 0600, NULL, NULL, &pkvm_proxy_fops);

	return 0;
}

device_initcall(pkvm_proxy_init);