OvmfPkg: extract VirtioLib from VirtioBlkDxe
Introduce a new library called VirtioLib, for now only collecting the following reusable functions with as little changes as possible: - VirtioWrite() - VirtioRead() - VirtioRingInit() - VirtioRingUninit() - AppendDesc() Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13842 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
jljusten
187
OvmfPkg/Include/Library/VirtioLib.h
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187
OvmfPkg/Include/Library/VirtioLib.h
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/** @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/PciIo.h>
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#include <IndustryStandard/Virtio.h>
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/**
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Write a word into Region 0 of the device specified by PciIo.
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Region 0 must be an iomem region. This is an internal function for the
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driver-specific VIRTIO_CFG_WRITE() macros.
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@param[in] PciIo Target PCI device.
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@param[in] FieldOffset Destination offset.
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@param[in] FieldSize Destination field size, must be in { 1, 2, 4, 8 }.
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@param[in] Value Little endian value to write, converted to UINT64.
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The least significant FieldSize bytes will be used.
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@return Status code returned by PciIo->Io.Write().
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**/
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EFIAPI
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EFI_STATUS
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VirtioWrite (
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IN EFI_PCI_IO_PROTOCOL *PciIo,
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IN UINTN FieldOffset,
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IN UINTN FieldSize,
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IN UINT64 Value
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);
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/**
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Read a word from Region 0 of the device specified by PciIo.
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Region 0 must be an iomem region. This is an internal function for the
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driver-specific VIRTIO_CFG_READ() macros.
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@param[in] PciIo Source PCI device.
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@param[in] FieldOffset Source offset.
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@param[in] FieldSize Source field size, must be in { 1, 2, 4, 8 }.
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@param[in] BufferSize Number of bytes available in the target buffer. Must
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equal FieldSize.
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@param[out] Buffer Target buffer.
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@return Status code returned by PciIo->Io.Read().
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**/
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EFIAPI
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EFI_STATUS
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VirtioRead (
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IN EFI_PCI_IO_PROTOCOL *PciIo,
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IN UINTN FieldOffset,
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IN UINTN FieldSize,
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IN UINTN BufferSize,
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OUT VOID *Buffer
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);
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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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Append a contiguous buffer for transmission / reception via the virtio ring.
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This function implements the following sections from virtio-0.9.5:
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- 2.4.1.1 Placing Buffers into the Descriptor Table
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- 2.4.1.2 Updating the Available Ring
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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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@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
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to 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
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host only interprets it dependent on
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VRING_DESC_F_NEXT.
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@param [in] HeadIdx The index identifying the head buffer (first
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buffer appended) belonging to this same
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request.
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@param [in out] NextAvailIdx On input, the index identifying the next
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descriptor available to carry the buffer. On
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output, incremented by one, modulo 2^16.
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**/
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VOID
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EFIAPI
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AppendDesc (
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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 UINT16 HeadIdx,
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IN OUT UINT16 *NextAvailIdx
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);
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#endif // _VIRTIO_LIB_H_
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