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/** @file
Declarations of utility functions used by virtio device drivers.
Copyright (C) 2012, 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/PciIo.h>
#include <IndustryStandard/Virtio.h>
/**
Write a word into Region 0 of the device specified by PciIo.
Region 0 must be an iomem region. This is an internal function for the
driver-specific VIRTIO_CFG_WRITE() macros.
@param[in] PciIo Target PCI device.
@param[in] FieldOffset Destination offset.
@param[in] FieldSize Destination field size, must be in { 1, 2, 4, 8 }.
@param[in] Value Little endian value to write, converted to UINT64.
The least significant FieldSize bytes will be used.
@return Status code returned by PciIo->Io.Write().
**/
EFI_STATUS
EFIAPI
VirtioWrite (
IN EFI_PCI_IO_PROTOCOL *PciIo,
IN UINTN FieldOffset,
IN UINTN FieldSize,
IN UINT64 Value
);
/**
Read a word from Region 0 of the device specified by PciIo.
Region 0 must be an iomem region. This is an internal function for the
driver-specific VIRTIO_CFG_READ() macros.
@param[in] PciIo Source PCI device.
@param[in] FieldOffset Source offset.
@param[in] FieldSize Source field size, must be in { 1, 2, 4, 8 }.
@param[in] BufferSize Number of bytes available in the target buffer. Must
equal FieldSize.
@param[out] Buffer Target buffer.
@return Status code returned by PciIo->Io.Read().
**/
EFI_STATUS
EFIAPI
VirtioRead (
IN EFI_PCI_IO_PROTOCOL *PciIo,
IN UINTN FieldOffset,
IN UINTN FieldSize,
IN UINTN BufferSize,
OUT VOID *Buffer
);
/**
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] PciIo The target virtio PCI 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.
@return Error code from VirtioWrite() if it fails.
@retval EFI_SUCCESS Otherwise, the host processed all descriptors.
**/
EFI_STATUS
EFIAPI
VirtioFlush (
IN EFI_PCI_IO_PROTOCOL *PciIo,
IN UINT16 VirtQueueId,
IN OUT VRING *Ring,
IN DESC_INDICES *Indices
);
#endif // _VIRTIO_LIB_H_
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