/* SPDX-License-Identifier: GPL-2.0-only */

#ifndef __KVM_IODEV_H__
#define __KVM_IODEV_H__

#include <linux/kvm_types.h>
#include <linux/errno.h>

struct kvm_io_device;
struct kvm_vcpu;

/**
 * kvm_io_device_ops are called under kvm slots_lock.
 * read and write handlers return 0 if the transaction has been handled,
 * or non-zero to have it passed to the next device.
 **/
struct kvm_io_device_ops {
        int (*read)(struct kvm_vcpu *vcpu,
                    struct kvm_io_device *this,
                    gpa_t addr,
                    int len,
                    void *val);
        int (*write)(struct kvm_vcpu *vcpu,
                     struct kvm_io_device *this,
                     gpa_t addr,
                     int len,
                     const void *val);
        void (*destructor)(struct kvm_io_device *this);
};


struct kvm_io_device {
        const struct kvm_io_device_ops *ops;
};

static inline void kvm_iodevice_init(struct kvm_io_device *dev,
                                     const struct kvm_io_device_ops *ops)
{
        dev->ops = ops;
}

static inline int kvm_iodevice_read(struct kvm_vcpu *vcpu,
                                    struct kvm_io_device *dev, gpa_t addr,
                                    int l, void *v)
{
        return dev->ops->read ? dev->ops->read(vcpu, dev, addr, l, v)
                                : -EOPNOTSUPP;
}

static inline int kvm_iodevice_write(struct kvm_vcpu *vcpu,
                                     struct kvm_io_device *dev, gpa_t addr,
                                     int l, const void *v)
{
        return dev->ops->write ? dev->ops->write(vcpu, dev, addr, l, v)
                                 : -EOPNOTSUPP;
}

#endif /* __KVM_IODEV_H__ */