mirror of https://github.com/acidanthera/audk.git
186 lines
5.4 KiB
C
186 lines
5.4 KiB
C
/** @file
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Declarations of utility functions used by virtio device drivers.
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Copyright (C) 2012, Red Hat, Inc.
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This program and the accompanying materials are licensed and made available
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under the terms and conditions of the BSD License which accompanies this
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distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
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WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#ifndef _VIRTIO_LIB_H_
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#define _VIRTIO_LIB_H_
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#include <Protocol/VirtioDevice.h>
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#include <IndustryStandard/Virtio.h>
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/**
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Configure a virtio ring.
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This function sets up internal storage (the guest-host communication area)
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and lays out several "navigation" (ie. no-ownership) pointers to parts of
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that storage.
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Relevant sections from the virtio-0.9.5 spec:
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- 1.1 Virtqueues,
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- 2.3 Virtqueue Configuration.
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@param[in] The number of descriptors to allocate for the
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virtio ring, as requested by the host.
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@param[out] Ring The virtio ring to set up.
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@retval EFI_OUT_OF_RESOURCES AllocatePages() failed to allocate contiguous
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pages for the requested QueueSize. Fields of
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Ring have indeterminate value.
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@retval EFI_SUCCESS Allocation and setup successful. Ring->Base
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(and nothing else) is responsible for
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deallocation.
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**/
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EFI_STATUS
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EFIAPI
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VirtioRingInit (
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IN UINT16 QueueSize,
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OUT VRING *Ring
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);
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/**
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Tear down the internal resources of a configured virtio ring.
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The caller is responsible to stop the host from using this ring before
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invoking this function: the VSTAT_DRIVER_OK bit must be clear in
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VhdrDeviceStatus.
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@param[out] Ring The virtio ring to clean up.
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**/
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VOID
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EFIAPI
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VirtioRingUninit (
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IN OUT VRING *Ring
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);
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//
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// Internal use structure for tracking the submission of a multi-descriptor
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// request.
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//
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typedef struct {
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UINT16 HeadDescIdx;
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UINT16 NextDescIdx;
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} DESC_INDICES;
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/**
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Turn off interrupt notifications from the host, and prepare for appending
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multiple descriptors to the virtio ring.
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The calling driver must be in VSTAT_DRIVER_OK state.
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@param[in,out] Ring The virtio ring we intend to append descriptors to.
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@param[out] Indices The DESC_INDICES structure to initialize.
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**/
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VOID
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EFIAPI
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VirtioPrepare (
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IN OUT VRING *Ring,
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OUT DESC_INDICES *Indices
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);
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/**
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Append a contiguous buffer for transmission / reception via the virtio ring.
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This function implements the following section from virtio-0.9.5:
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- 2.4.1.1 Placing Buffers into the Descriptor Table
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Free space is taken as granted, since the individual drivers support only
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synchronous requests and host side status is processed in lock-step with
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request submission. It is the calling driver's responsibility to verify the
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ring size in advance.
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The caller is responsible for initializing *Indices with VirtioPrepare()
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first.
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@param[in,out] Ring The virtio ring to append the buffer to, as a
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descriptor.
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@param[in] BufferPhysAddr (Guest pseudo-physical) start address of the
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transmit / receive buffer.
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@param[in] BufferSize Number of bytes to transmit or receive.
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@param[in] Flags A bitmask of VRING_DESC_F_* flags. The caller
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computes this mask dependent on further buffers to
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append and transfer direction.
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VRING_DESC_F_INDIRECT is unsupported. The
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VRING_DESC.Next field is always set, but the host
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only interprets it dependent on VRING_DESC_F_NEXT.
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@param[in,out] Indices Indices->HeadDescIdx is not accessed.
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On input, Indices->NextDescIdx identifies the next
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descriptor to carry the buffer. On output,
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Indices->NextDescIdx is incremented by one, modulo
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2^16.
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**/
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VOID
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EFIAPI
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VirtioAppendDesc (
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IN OUT VRING *Ring,
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IN UINTN BufferPhysAddr,
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IN UINT32 BufferSize,
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IN UINT16 Flags,
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IN OUT DESC_INDICES *Indices
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);
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/**
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Notify the host about the descriptor chain just built, and wait until the
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host processes it.
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@param[in] VirtIo The target virtio device to notify.
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@param[in] VirtQueueId Identifies the queue for the target device.
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@param[in,out] Ring The virtio ring with descriptors to submit.
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@param[in] Indices Indices->NextDescIdx is not accessed.
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Indices->HeadDescIdx identifies the head descriptor
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of the descriptor chain.
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@return Error code from VirtIo->SetQueueNotify() if it fails.
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@retval EFI_SUCCESS Otherwise, the host processed all descriptors.
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**/
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EFI_STATUS
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EFIAPI
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VirtioFlush (
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IN VIRTIO_DEVICE_PROTOCOL *VirtIo,
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IN UINT16 VirtQueueId,
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IN OUT VRING *Ring,
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IN DESC_INDICES *Indices
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);
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#endif // _VIRTIO_LIB_H_
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