/** @file
Declarations of utility functions used by virtio device drivers.
Copyright (C) 2012-2016, Red Hat, Inc.
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#ifndef _VIRTIO_LIB_H_
#define _VIRTIO_LIB_H_
#include <Protocol/VirtioDevice.h>
#include <IndustryStandard/Virtio.h>
/**
Configure a virtio ring.
This function sets up internal storage (the guest-host communication area)
and lays out several "navigation" (ie. no-ownership) pointers to parts of
that storage.
Relevant sections from the virtio-0.9.5 spec:
- 1.1 Virtqueues,
- 2.3 Virtqueue Configuration.
@param[in] The number of descriptors to allocate for the
virtio ring, as requested by the host.
@param[out] Ring The virtio ring to set up.
@retval EFI_OUT_OF_RESOURCES AllocatePages() failed to allocate contiguous
pages for the requested QueueSize. Fields of
Ring have indeterminate value.
@retval EFI_SUCCESS Allocation and setup successful. Ring->Base
(and nothing else) is responsible for
deallocation.
**/
EFI_STATUS
EFIAPI
VirtioRingInit (
IN UINT16 QueueSize,
OUT VRING *Ring
);
/**
Tear down the internal resources of a configured virtio ring.
The caller is responsible to stop the host from using this ring before
invoking this function: the VSTAT_DRIVER_OK bit must be clear in
VhdrDeviceStatus.
@param[out] Ring The virtio ring to clean up.
**/
VOID
EFIAPI
VirtioRingUninit (
IN OUT VRING *Ring
);
//
// Internal use structure for tracking the submission of a multi-descriptor
// request.
//
typedef struct {
UINT16 HeadDescIdx;
UINT16 NextDescIdx;
} DESC_INDICES;
/**
Turn off interrupt notifications from the host, and prepare for appending
multiple descriptors to the virtio ring.
The calling driver must be in VSTAT_DRIVER_OK state.
@param[in,out] Ring The virtio ring we intend to append descriptors to.
@param[out] Indices The DESC_INDICES structure to initialize.
**/
VOID
EFIAPI
VirtioPrepare (
IN OUT VRING *Ring,
OUT DESC_INDICES *Indices
);
/**
Append a contiguous buffer for transmission / reception via the virtio ring.
This function implements the following section from virtio-0.9.5:
- 2.4.1.1 Placing Buffers into the Descriptor Table
Free space is taken as granted, since the individual drivers support only
synchronous requests and host side status is processed in lock-step with
request submission. It is the calling driver's responsibility to verify the
ring size in advance.
The caller is responsible for initializing *Indices with VirtioPrepare()
first.
@param[in,out] Ring The virtio ring to append the buffer to, as a
descriptor.
@param[in] BufferPhysAddr (Guest pseudo-physical) start address of the
transmit / receive buffer.
@param[in] BufferSize Number of bytes to transmit or receive.
@param[in] Flags A bitmask of VRING_DESC_F_* flags. The caller
computes this mask dependent on further buffers to
append and transfer direction.
VRING_DESC_F_INDIRECT is unsupported. The
VRING_DESC.Next field is always set, but the host
only interprets it dependent on VRING_DESC_F_NEXT.
@param[in,out] Indices Indices->HeadDescIdx is not accessed.
On input, Indices->NextDescIdx identifies the next
descriptor to carry the buffer. On output,
Indices->NextDescIdx is incremented by one, modulo
2^16.
**/
VOID
EFIAPI
VirtioAppendDesc (
IN OUT VRING *Ring,
IN UINTN BufferPhysAddr,
IN UINT32 BufferSize,
IN UINT16 Flags,
IN OUT DESC_INDICES *Indices
);
/**
Notify the host about the descriptor chain just built, and wait until the
host processes it.
@param[in] VirtIo The target virtio device to notify.
@param[in] VirtQueueId Identifies the queue for the target device.
@param[in,out] Ring The virtio ring with descriptors to submit.
@param[in] Indices Indices->NextDescIdx is not accessed.
Indices->HeadDescIdx identifies the head descriptor
of the descriptor chain.
@param[out] UsedLen On success, the total number of bytes, consecutively
across the buffers linked by the descriptor chain,
that the host wrote. May be NULL if the caller
doesn't care, or can compute the same information
from device-specific request structures linked by the
descriptor chain.
@return Error code from VirtIo->SetQueueNotify() if it fails.
@retval EFI_SUCCESS Otherwise, the host processed all descriptors.
**/
EFI_STATUS
EFIAPI
VirtioFlush (
IN VIRTIO_DEVICE_PROTOCOL *VirtIo,
IN UINT16 VirtQueueId,
IN OUT VRING *Ring,
IN DESC_INDICES *Indices,
OUT UINT32 *UsedLen OPTIONAL
);
/**
Report the feature bits to the VirtIo 1.0 device that the VirtIo 1.0 driver
understands.
In VirtIo 1.0, a device can reject a self-inconsistent feature bitmap through
the new VSTAT_FEATURES_OK status bit. (For example if the driver requests a
higher level feature but clears a prerequisite feature.) This function is a
small wrapper around VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures() that also
verifies if the VirtIo 1.0 device accepts the feature bitmap.
@param[in] VirtIo Report feature bits to this device.
@param[in] Features The set of feature bits that the driver wishes
to report. The caller is responsible to perform
any masking before calling this function; the
value is directly written with
VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures().
@param[in,out] DeviceStatus On input, the status byte most recently written
to the device's status register. On output (even
on error), DeviceStatus will be updated so that
it is suitable for further status bit
manipulation and writing to the device's status
register.
@retval EFI_SUCCESS The device accepted the configuration in Features.
@return EFI_UNSUPPORTED The device rejected the configuration in Features.
@retval EFI_UNSUPPORTED VirtIo->Revision is smaller than 1.0.0.
@return Error codes from the SetGuestFeatures(),
SetDeviceStatus(), GetDeviceStatus() member
functions.
**/
EFI_STATUS
EFIAPI
Virtio10WriteFeatures (
IN VIRTIO_DEVICE_PROTOCOL *VirtIo,
IN UINT64 Features,
IN OUT UINT8 *DeviceStatus
);
#endif // _VIRTIO_LIB_H_