virt/kvm/iodev.h

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program; if not, write to the Free Software
  13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  14  */
  15
  16 #ifndef __KVM_IODEV_H__
  17 #define __KVM_IODEV_H__
  18
  19 #include <linux/kvm_types.h>
  20 #include <asm/errno.h>
  21
  22 struct kvm_io_device;
  23
  24 /**
  25  * kvm_io_device_ops are called under kvm slots_lock.
  26  * read and write handlers return 0 if the transaction has been handled,
  27  * or non-zero to have it passed to the next device.
  28  **/
  29 struct kvm_io_device_ops {
  30         int (*read)(struct kvm_io_device *this,
  31                     gpa_t addr,
  32                     int len,
  33                     void *val);
  34         int (*write)(struct kvm_io_device *this,
  35                      gpa_t addr,
  36                      int len,
  37                      const void *val);
  38         void (*destructor)(struct kvm_io_device *this);
  39 };
  40
  41
  42 struct kvm_io_device {
  43         const struct kvm_io_device_ops *ops;
  44 };
  45
  46 static inline void kvm_iodevice_init(struct kvm_io_device *dev,
  47                                      const struct kvm_io_device_ops *ops)
  48 {
  49         dev->ops = ops;
  50 }
  51
  52 static inline int kvm_iodevice_read(struct kvm_io_device *dev,
  53                                     gpa_t addr, int l, void *v)
  54 {
  55         return dev->ops->read ? dev->ops->read(dev, addr, l, v) : -EOPNOTSUPP;
  56 }
  57
  58 static inline int kvm_iodevice_write(struct kvm_io_device *dev,
  59                                      gpa_t addr, int l, const void *v)
  60 {
  61         return dev->ops->write ? dev->ops->write(dev, addr, l, v) : -EOPNOTSUPP;
  62 }
  63
  64 static inline void kvm_iodevice_destructor(struct kvm_io_device *dev)
  65 {
  66         if (dev->ops->destructor)
  67                 dev->ops->destructor(dev);
  68 }
  69
  70 #endif /* __KVM_IODEV_H__ */