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audk/OvmfPkg/Library/VirtioLib/VirtioLib.c

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/** @file
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.
**/
#include <IndustryStandard/Pci22.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/VirtioLib.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
)
{
UINTN Count;
EFI_PCI_IO_PROTOCOL_WIDTH Width;
Count = 1;
switch (FieldSize) {
case 1:
Width = EfiPciIoWidthUint8;
break;
case 2:
Width = EfiPciIoWidthUint16;
break;
case 8:
Count = 2;
// fall through
case 4:
Width = EfiPciIoWidthUint32;
break;
default:
ASSERT (FALSE);
return EFI_INVALID_PARAMETER;
}
return PciIo->Io.Write (
PciIo,
Width,
PCI_BAR_IDX0,
FieldOffset,
Count,
&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
)
{
UINTN Count;
EFI_PCI_IO_PROTOCOL_WIDTH Width;
ASSERT (FieldSize == BufferSize);
Count = 1;
switch (FieldSize) {
case 1:
Width = EfiPciIoWidthUint8;
break;
case 2:
Width = EfiPciIoWidthUint16;
break;
case 8:
Count = 2;
// fall through
case 4:
Width = EfiPciIoWidthUint32;
break;
default:
ASSERT (FALSE);
return EFI_INVALID_PARAMETER;
}
return PciIo->Io.Read (
PciIo,
Width,
PCI_BAR_IDX0,
FieldOffset,
Count,
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
)
{
UINTN RingSize;
volatile UINT8 *RingPagesPtr;
RingSize = ALIGN_VALUE (
sizeof *Ring->Desc * QueueSize +
sizeof *Ring->Avail.Flags +
sizeof *Ring->Avail.Idx +
sizeof *Ring->Avail.Ring * QueueSize +
sizeof *Ring->Avail.UsedEvent,
EFI_PAGE_SIZE);
RingSize += ALIGN_VALUE (
sizeof *Ring->Used.Flags +
sizeof *Ring->Used.Idx +
sizeof *Ring->Used.UsedElem * QueueSize +
sizeof *Ring->Used.AvailEvent,
EFI_PAGE_SIZE);
Ring->NumPages = EFI_SIZE_TO_PAGES (RingSize);
Ring->Base = AllocatePages (Ring->NumPages);
if (Ring->Base == NULL) {
return EFI_OUT_OF_RESOURCES;
}
SetMem (Ring->Base, RingSize, 0x00);
RingPagesPtr = Ring->Base;
Ring->Desc = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Desc * QueueSize;
Ring->Avail.Flags = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Avail.Flags;
Ring->Avail.Idx = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Avail.Idx;
Ring->Avail.Ring = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Avail.Ring * QueueSize;
Ring->Avail.UsedEvent = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Avail.UsedEvent;
RingPagesPtr = (volatile UINT8 *) Ring->Base +
ALIGN_VALUE (RingPagesPtr - (volatile UINT8 *) Ring->Base,
EFI_PAGE_SIZE);
Ring->Used.Flags = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Used.Flags;
Ring->Used.Idx = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Used.Idx;
Ring->Used.UsedElem = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Used.UsedElem * QueueSize;
Ring->Used.AvailEvent = (volatile VOID *) RingPagesPtr;
RingPagesPtr += sizeof *Ring->Used.AvailEvent;
Ring->QueueSize = QueueSize;
return EFI_SUCCESS;
}
/**
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
)
{
FreePages (Ring->Base, Ring->NumPages);
SetMem (Ring, sizeof *Ring, 0x00);
}
/**
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
)
{
//
// Prepare for virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device.
// We're going to poll the answer, the host should not send an interrupt.
//
*Ring->Avail.Flags = (UINT16) VRING_AVAIL_F_NO_INTERRUPT;
//
// Prepare for virtio-0.9.5, 2.4.1 Supplying Buffers to the Device.
//
Indices->HeadIdx = *Ring->Avail.Idx;
Indices->NextAvailIdx = Indices->HeadIdx;
}
/**
Append a contiguous buffer for transmission / reception via the virtio ring.
This function implements the following sections from virtio-0.9.5:
- 2.4.1.1 Placing Buffers into the Descriptor Table
- 2.4.1.2 Updating the Available Ring
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.
In *Indices:
@param [in] HeadIdx The index identifying the head buffer (first
buffer appended) belonging to this same
request.
@param [in out] NextAvailIdx On input, the index identifying the next
descriptor available to carry the buffer. On
output, 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
)
{
volatile VRING_DESC *Desc;
Desc = &Ring->Desc[Indices->NextAvailIdx % Ring->QueueSize];
Desc->Addr = BufferPhysAddr;
Desc->Len = BufferSize;
Desc->Flags = Flags;
Ring->Avail.Ring[Indices->NextAvailIdx++ % Ring->QueueSize] =
Indices->HeadIdx % Ring->QueueSize;
Desc->Next = Indices->NextAvailIdx % Ring->QueueSize;
}
/**
Notify the host about appended descriptors and wait until it processes the
last one (ie. all of them).
@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 The function waits until the host processes
descriptors up to Indices->NextAvailIdx.
@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
)
{
EFI_STATUS Status;
UINTN PollPeriodUsecs;
//
// virtio-0.9.5, 2.4.1.3 Updating the Index Field
//
MemoryFence();
*Ring->Avail.Idx = Indices->NextAvailIdx;
//
// virtio-0.9.5, 2.4.1.4 Notifying the Device -- gratuitous notifications are
// OK.
//
MemoryFence();
Status = VirtioWrite (
PciIo,
OFFSET_OF (VIRTIO_HDR, VhdrQueueNotify),
sizeof (UINT16),
VirtQueueId
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
// Wait until the host processes and acknowledges our descriptor chain. The
// condition we use for polling is greatly simplified and relies on the
// synchronous, lock-step progress.
//
// Keep slowing down until we reach a poll period of slightly above 1 ms.
//
PollPeriodUsecs = 1;
MemoryFence();
while (*Ring->Used.Idx != Indices->NextAvailIdx) {
gBS->Stall (PollPeriodUsecs); // calls AcpiTimerLib::MicroSecondDelay
if (PollPeriodUsecs < 1024) {
PollPeriodUsecs *= 2;
}
MemoryFence();
}
return EFI_SUCCESS;
}
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