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audk/OvmfPkg/VirtioBlkDxe/VirtioBlk.c

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/** @file
This driver produces Block I/O Protocol instances for virtio-blk devices.
The implementation is basic:
- No attach/detach (ie. removable media).
- Although the non-blocking interfaces of EFI_BLOCK_IO2_PROTOCOL could be a
good match for multiple in-flight virtio-blk requests, we stick to
synchronous requests and EFI_BLOCK_IO_PROTOCOL for now.
Copyright (C) 2012, Red Hat, Inc.
Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
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/Pci.h>
#include <IndustryStandard/VirtioBlk.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
#include <Library/VirtioLib.h>
#include "VirtioBlk.h"
/**
Convenience macros to read and write region 0 IO space elements of the
virtio-blk PCI device, for configuration purposes.
The following macros make it possible to specify only the "core parameters"
for such accesses and to derive the rest. By the time VIRTIO_CFG_WRITE()
returns, the transaction will have been completed.
@param[in] Dev Pointer to the VBLK_DEV structure whose PCI IO space
we're accessing. Dev->PciIo must be valid.
@param[in] Field A field name from VBLK_HDR, identifying the virtio-blk
configuration item to access.
@param[in] Value (VIRTIO_CFG_WRITE() only.) The value to write to the
selected configuration item.
@param[out] Pointer (VIRTIO_CFG_READ() only.) The object to receive the
value read from the configuration item. Its type must be
one of UINT8, UINT16, UINT32, UINT64.
@return Status code returned by VirtioWrite() / VirtioRead().
**/
#define VIRTIO_CFG_WRITE(Dev, Field, Value) (VirtioWrite ( \
(Dev)->PciIo, \
OFFSET_OF_VBLK (Field), \
SIZE_OF_VBLK (Field), \
(Value) \
))
#define VIRTIO_CFG_READ(Dev, Field, Pointer) (VirtioRead ( \
(Dev)->PciIo, \
OFFSET_OF_VBLK (Field), \
SIZE_OF_VBLK (Field), \
sizeof *(Pointer), \
(Pointer) \
))
//
// UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol
// Driver Writer's Guide for UEFI 2.3.1 v1.01,
// 24.2 Block I/O Protocol Implementations
//
EFI_STATUS
EFIAPI
VirtioBlkReset (
IN EFI_BLOCK_IO_PROTOCOL *This,
IN BOOLEAN ExtendedVerification
)
{
//
// If we managed to initialize and install the driver, then the device is
// working correctly.
//
return EFI_SUCCESS;
}
/**
Verify correctness of the read/write (not flush) request submitted to the
EFI_BLOCK_IO_PROTOCOL instance.
This function provides most verification steps described in:
UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
Protocol,
- EFI_BLOCK_IO_PROTOCOL.ReadBlocks()
- EFI_BLOCK_IO_PROTOCOL.WriteBlocks()
Driver Writer's Guide for UEFI 2.3.1 v1.01,
- 24.2.2. ReadBlocks() and ReadBlocksEx() Implementation
- 24.2.3 WriteBlocks() and WriteBlockEx() Implementation
Request sizes are limited to 1 GB (checked). This is not a practical
limitation, just conformance to virtio-0.9.5, 2.3.2 Descriptor Table: "no
descriptor chain may be more than 2^32 bytes long in total".
Some Media characteristics are hardcoded in VirtioBlkInit() below (like
non-removable media, no restriction on buffer alignment etc); we rely on
those here without explicit mention.
@param[in] Media The EFI_BLOCK_IO_MEDIA characteristics for
this driver instance, extracted from the
underlying virtio-blk device at initialization
time. We validate the request against this set
of attributes.
@param[in] Lba Logical Block Address: number of logical
blocks to skip from the beginning of the
device.
@param[in] PositiveBufferSize Size of buffer to transfer, in bytes. The
caller is responsible to ensure this parameter
is positive.
@param[in] RequestIsWrite TRUE iff data transfer goes from guest to
device.
@@return Validation result to be forwarded outwards by
ReadBlocks() and WriteBlocks, as required by
the specs above.
**/
STATIC
EFI_STATUS
EFIAPI
VerifyReadWriteRequest (
IN EFI_BLOCK_IO_MEDIA *Media,
IN EFI_LBA Lba,
IN UINTN PositiveBufferSize,
IN BOOLEAN RequestIsWrite
)
{
UINTN BlockCount;
ASSERT (PositiveBufferSize > 0);
if (PositiveBufferSize > SIZE_1GB ||
PositiveBufferSize % Media->BlockSize > 0) {
return EFI_BAD_BUFFER_SIZE;
}
BlockCount = PositiveBufferSize / Media->BlockSize;
//
// Avoid unsigned wraparound on either side in the second comparison.
//
if (Lba > Media->LastBlock || BlockCount - 1 > Media->LastBlock - Lba) {
return EFI_INVALID_PARAMETER;
}
if (RequestIsWrite && Media->ReadOnly) {
return EFI_WRITE_PROTECTED;
}
return EFI_SUCCESS;
}
/**
Format a read / write / flush request as three consecutive virtio
descriptors, push them to the host, and poll for the response.
This is the main workhorse function. Two use cases are supported, read/write
and flush. The function may only be called after the request parameters have
been verified by
- specific checks in ReadBlocks() / WriteBlocks() / FlushBlocks(), and
- VerifyReadWriteRequest() (for read/write only).
Parameters handled commonly:
@param[in] Dev The virtio-blk device the request is targeted
at.
Flush request:
@param[in] Lba Must be zero.
@param[in] BufferSize Must be zero.
@param[in out] Buffer Ignored by the function.
@param[in] RequestIsWrite Must be TRUE.
Read/Write request:
@param[in] Lba Logical Block Address: number of logical blocks
to skip from the beginning of the device.
@param[in] BufferSize Size of buffer to transfer, in bytes. The caller
is responsible to ensure this parameter is
positive.
@param[in out] Buffer The guest side area to read data from the device
into, or write data to the device from.
@param[in] RequestIsWrite TRUE iff data transfer goes from guest to
device.
Return values are common to both use cases, and are appropriate to be
forwarded by the EFI_BLOCK_IO_PROTOCOL functions (ReadBlocks(),
WriteBlocks(), FlushBlocks()).
@retval EFI_SUCCESS Transfer complete.
@retval EFI_DEVICE_ERROR Failed to notify host side via PCI write, or
unable to parse host response, or host response
is not VIRTIO_BLK_S_OK.
**/
STATIC
EFI_STATUS
EFIAPI
SynchronousRequest (
IN VBLK_DEV *Dev,
IN EFI_LBA Lba,
IN UINTN BufferSize,
IN OUT volatile VOID *Buffer,
IN BOOLEAN RequestIsWrite
)
{
UINT32 BlockSize;
volatile VIRTIO_BLK_REQ Request;
volatile UINT8 HostStatus;
DESC_INDICES Indices;
BlockSize = Dev->BlockIoMedia.BlockSize;
//
// ensured by VirtioBlkInit()
//
ASSERT (BlockSize > 0);
ASSERT (BlockSize % 512 == 0);
//
// ensured by contract above, plus VerifyReadWriteRequest()
//
ASSERT (BufferSize % BlockSize == 0);
//
// Prepare virtio-blk request header, setting zero size for flush.
// IO Priority is homogeneously 0.
//
Request.Type = RequestIsWrite ?
(BufferSize == 0 ? VIRTIO_BLK_T_FLUSH : VIRTIO_BLK_T_OUT) :
VIRTIO_BLK_T_IN;
Request.IoPrio = 0;
Request.Sector = MultU64x32(Lba, BlockSize / 512);
VirtioPrepare (&Dev->Ring, &Indices);
//
// preset a host status for ourselves that we do not accept as success
//
HostStatus = VIRTIO_BLK_S_IOERR;
//
// ensured by VirtioBlkInit() -- this predicate, in combination with the
// lock-step progress, ensures we don't have to track free descriptors.
//
ASSERT (Dev->Ring.QueueSize >= 3);
//
// virtio-blk header in first desc
//
VirtioAppendDesc (&Dev->Ring, (UINTN) &Request, sizeof Request,
VRING_DESC_F_NEXT, &Indices);
//
// data buffer for read/write in second desc
//
if (BufferSize > 0) {
//
// From virtio-0.9.5, 2.3.2 Descriptor Table:
// "no descriptor chain may be more than 2^32 bytes long in total".
//
// The predicate is ensured by the call contract above (for flush), or
// VerifyReadWriteRequest() (for read/write). It also implies that
// converting BufferSize to UINT32 will not truncate it.
//
ASSERT (BufferSize <= SIZE_1GB);
//
// VRING_DESC_F_WRITE is interpreted from the host's point of view.
//
VirtioAppendDesc (&Dev->Ring, (UINTN) Buffer, (UINT32) BufferSize,
VRING_DESC_F_NEXT | (RequestIsWrite ? 0 : VRING_DESC_F_WRITE),
&Indices);
}
//
// host status in last (second or third) desc
//
VirtioAppendDesc (&Dev->Ring, (UINTN) &HostStatus, sizeof HostStatus,
VRING_DESC_F_WRITE, &Indices);
//
// virtio-blk's only virtqueue is #0, called "requestq" (see Appendix D).
//
if (VirtioFlush (Dev->PciIo, 0, &Dev->Ring, &Indices) == EFI_SUCCESS &&
HostStatus == VIRTIO_BLK_S_OK) {
return EFI_SUCCESS;
}
return EFI_DEVICE_ERROR;
}
/**
ReadBlocks() operation for virtio-blk.
See
- UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
Protocol, EFI_BLOCK_IO_PROTOCOL.ReadBlocks().
- Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.2. ReadBlocks() and
ReadBlocksEx() Implementation.
Parameter checks and conformant return values are implemented in
VerifyReadWriteRequest() and SynchronousRequest().
A zero BufferSize doesn't seem to be prohibited, so do nothing in that case,
successfully.
**/
EFI_STATUS
EFIAPI
VirtioBlkReadBlocks (
IN EFI_BLOCK_IO_PROTOCOL *This,
IN UINT32 MediaId,
IN EFI_LBA Lba,
IN UINTN BufferSize,
OUT VOID *Buffer
)
{
VBLK_DEV *Dev;
EFI_STATUS Status;
if (BufferSize == 0) {
return EFI_SUCCESS;
}
Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
Status = VerifyReadWriteRequest (
&Dev->BlockIoMedia,
Lba,
BufferSize,
FALSE // RequestIsWrite
);
if (EFI_ERROR (Status)) {
return Status;
}
return SynchronousRequest (
Dev,
Lba,
BufferSize,
Buffer,
FALSE // RequestIsWrite
);
}
/**
WriteBlocks() operation for virtio-blk.
See
- UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
Protocol, EFI_BLOCK_IO_PROTOCOL.WriteBlocks().
- Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.3 WriteBlocks() and
WriteBlockEx() Implementation.
Parameter checks and conformant return values are implemented in
VerifyReadWriteRequest() and SynchronousRequest().
A zero BufferSize doesn't seem to be prohibited, so do nothing in that case,
successfully.
**/
EFI_STATUS
EFIAPI
VirtioBlkWriteBlocks (
IN EFI_BLOCK_IO_PROTOCOL *This,
IN UINT32 MediaId,
IN EFI_LBA Lba,
IN UINTN BufferSize,
IN VOID *Buffer
)
{
VBLK_DEV *Dev;
EFI_STATUS Status;
if (BufferSize == 0) {
return EFI_SUCCESS;
}
Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
Status = VerifyReadWriteRequest (
&Dev->BlockIoMedia,
Lba,
BufferSize,
TRUE // RequestIsWrite
);
if (EFI_ERROR (Status)) {
return Status;
}
return SynchronousRequest (
Dev,
Lba,
BufferSize,
Buffer,
TRUE // RequestIsWrite
);
}
/**
FlushBlocks() operation for virtio-blk.
See
- UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
Protocol, EFI_BLOCK_IO_PROTOCOL.FlushBlocks().
- Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.4 FlushBlocks() and
FlushBlocksEx() Implementation.
If the underlying virtio-blk device doesn't support flushing (ie.
write-caching), then this function should not be called by higher layers,
according to EFI_BLOCK_IO_MEDIA characteristics set in VirtioBlkInit().
Should they do nonetheless, we do nothing, successfully.
**/
EFI_STATUS
EFIAPI
VirtioBlkFlushBlocks (
IN EFI_BLOCK_IO_PROTOCOL *This
)
{
VBLK_DEV *Dev;
Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
return Dev->BlockIoMedia.WriteCaching ?
SynchronousRequest (
Dev,
0, // Lba
0, // BufferSize
NULL, // Buffer
TRUE // RequestIsWrite
) :
EFI_SUCCESS;
}
/**
Device probe function for this driver.
The DXE core calls this function for any given device in order to see if the
driver can drive the device.
Specs relevant in the general sense:
- UEFI Spec 2.3.1 + Errata C:
- 6.3 Protocol Handler Services -- for accessing the underlying device
- 10.1 EFI Driver Binding Protocol -- for exporting ourselves
- Driver Writer's Guide for UEFI 2.3.1 v1.01:
- 5.1.3.4 OpenProtocol() and CloseProtocol() -- for accessing the
underlying device
- 9 Driver Binding Protocol -- for exporting ourselves
Specs relevant in the specific sense:
- UEFI Spec 2.3.1 + Errata C, 13.4 EFI PCI I/O Protocol
- Driver Writer's Guide for UEFI 2.3.1 v1.01, 18 PCI Driver Design
Guidelines, 18.3 PCI drivers.
@param[in] This The EFI_DRIVER_BINDING_PROTOCOL object
incorporating this driver (independently of
any device).
@param[in] DeviceHandle The device to probe.
@param[in] RemainingDevicePath Relevant only for bus drivers, ignored.
@retval EFI_SUCCESS The driver supports the device being probed.
@retval EFI_UNSUPPORTED Based on virtio-blk PCI discovery, we do not support
the device.
@return Error codes from the OpenProtocol() boot service or
the PciIo protocol.
**/
EFI_STATUS
EFIAPI
VirtioBlkDriverBindingSupported (
IN EFI_DRIVER_BINDING_PROTOCOL *This,
IN EFI_HANDLE DeviceHandle,
IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath
)
{
EFI_STATUS Status;
EFI_PCI_IO_PROTOCOL *PciIo;
PCI_TYPE00 Pci;
//
// Attempt to open the device with the PciIo set of interfaces. On success,
// the protocol is "instantiated" for the PCI device. Covers duplicate open
// attempts (EFI_ALREADY_STARTED).
//
Status = gBS->OpenProtocol (
DeviceHandle, // candidate device
&gEfiPciIoProtocolGuid, // for generic PCI access
(VOID **)&PciIo, // handle to instantiate
This->DriverBindingHandle, // requestor driver identity
DeviceHandle, // ControllerHandle, according to
// the UEFI Driver Model
EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive PciIo access to
// the device; to be released
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Read entire PCI configuration header for more extensive check ahead.
//
Status = PciIo->Pci.Read (
PciIo, // (protocol, device)
// handle
EfiPciIoWidthUint32, // access width & copy
// mode
0, // Offset
sizeof Pci / sizeof (UINT32), // Count
&Pci // target buffer
);
if (Status == EFI_SUCCESS) {
//
// virtio-0.9.5, 2.1 PCI Discovery
//
Status = (Pci.Hdr.VendorId == 0x1AF4 &&
Pci.Hdr.DeviceId >= 0x1000 && Pci.Hdr.DeviceId <= 0x103F &&
Pci.Hdr.RevisionID == 0x00 &&
Pci.Device.SubsystemID == 0x02) ? EFI_SUCCESS : EFI_UNSUPPORTED;
}
//
// We needed PCI IO access only transitorily, to see whether we support the
// device or not.
//
gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
This->DriverBindingHandle, DeviceHandle);
return Status;
}
/**
Set up all BlockIo and virtio-blk aspects of this driver for the specified
device.
@param[in out] Dev The driver instance to configure. The caller is
responsible for Dev->PciIo's validity (ie. working IO
access to the underlying virtio-blk PCI device).
@retval EFI_SUCCESS Setup complete.
@retval EFI_UNSUPPORTED The driver is unable to work with the virtio ring or
virtio-blk attributes the host provides.
@return Error codes from VirtioRingInit() or
VIRTIO_CFG_READ() / VIRTIO_CFG_WRITE().
**/
STATIC
EFI_STATUS
EFIAPI
VirtioBlkInit (
IN OUT VBLK_DEV *Dev
)
{
UINT8 NextDevStat;
EFI_STATUS Status;
UINT32 Features;
UINT64 NumSectors;
UINT32 BlockSize;
UINT16 QueueSize;
//
// Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.
//
NextDevStat = 0; // step 1 -- reset device
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
NextDevStat |= VSTAT_ACK; // step 2 -- acknowledge device presence
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
NextDevStat |= VSTAT_DRIVER; // step 3 -- we know how to drive it
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// step 4a -- retrieve and validate features
//
Status = VIRTIO_CFG_READ (Dev, Generic.VhdrDeviceFeatureBits, &Features);
if (EFI_ERROR (Status)) {
goto Failed;
}
Status = VIRTIO_CFG_READ (Dev, VhdrCapacity, &NumSectors);
if (EFI_ERROR (Status)) {
goto Failed;
}
if (NumSectors == 0) {
Status = EFI_UNSUPPORTED;
goto Failed;
}
if (Features & VIRTIO_BLK_F_BLK_SIZE) {
Status = VIRTIO_CFG_READ (Dev, VhdrBlkSize, &BlockSize);
if (EFI_ERROR (Status)) {
goto Failed;
}
if (BlockSize == 0 || BlockSize % 512 != 0 ||
ModU64x32 (NumSectors, BlockSize / 512) != 0) {
//
// We can only handle a logical block consisting of whole sectors,
// and only a disk composed of whole logical blocks.
//
Status = EFI_UNSUPPORTED;
goto Failed;
}
}
else {
BlockSize = 512;
}
//
// step 4b -- allocate virtqueue
//
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrQueueSelect, 0);
if (EFI_ERROR (Status)) {
goto Failed;
}
Status = VIRTIO_CFG_READ (Dev, Generic.VhdrQueueSize, &QueueSize);
if (EFI_ERROR (Status)) {
goto Failed;
}
if (QueueSize < 3) { // SynchronousRequest() uses at most three descriptors
Status = EFI_UNSUPPORTED;
goto Failed;
}
Status = VirtioRingInit (QueueSize, &Dev->Ring);
if (EFI_ERROR (Status)) {
goto Failed;
}
//
// step 4c -- Report GPFN (guest-physical frame number) of queue. If anything
// fails from here on, we must release the ring resources.
//
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrQueueAddress,
(UINTN) Dev->Ring.Base >> EFI_PAGE_SHIFT);
if (EFI_ERROR (Status)) {
goto ReleaseQueue;
}
//
// step 5 -- Report understood features. There are no virtio-blk specific
// features to negotiate in virtio-0.9.5, plus we do not want any of the
// device-independent (known or unknown) VIRTIO_F_* capabilities (see
// Appendix B).
//
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrGuestFeatureBits, 0);
if (EFI_ERROR (Status)) {
goto ReleaseQueue;
}
//
// step 6 -- initialization complete
//
NextDevStat |= VSTAT_DRIVER_OK;
Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
if (EFI_ERROR (Status)) {
goto ReleaseQueue;
}
//
// Populate the exported interface's attributes; see UEFI spec v2.3.1 +
// Errata C, 12.8 EFI Block I/O Protocol. We stick to the lowest possible
// EFI_BLOCK_IO_PROTOCOL revision for now.
//
Dev->BlockIo.Revision = 0;
Dev->BlockIo.Media = &Dev->BlockIoMedia;
Dev->BlockIo.Reset = &VirtioBlkReset;
Dev->BlockIo.ReadBlocks = &VirtioBlkReadBlocks;
Dev->BlockIo.WriteBlocks = &VirtioBlkWriteBlocks;
Dev->BlockIo.FlushBlocks = &VirtioBlkFlushBlocks;
Dev->BlockIoMedia.MediaId = 0;
Dev->BlockIoMedia.RemovableMedia = FALSE;
Dev->BlockIoMedia.MediaPresent = TRUE;
Dev->BlockIoMedia.LogicalPartition = FALSE;
Dev->BlockIoMedia.ReadOnly = !!(Features & VIRTIO_BLK_F_RO);
Dev->BlockIoMedia.WriteCaching = !!(Features & VIRTIO_BLK_F_FLUSH);
Dev->BlockIoMedia.BlockSize = BlockSize;
Dev->BlockIoMedia.IoAlign = 0;
Dev->BlockIoMedia.LastBlock = DivU64x32 (NumSectors,
BlockSize / 512) - 1;
return EFI_SUCCESS;
ReleaseQueue:
VirtioRingUninit (&Dev->Ring);
Failed:
//
// Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device
// Status. PCI IO access failure here should not mask the original error.
//
NextDevStat |= VSTAT_FAILED;
VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
return Status; // reached only via Failed above
}
/**
Uninitialize the internals of a virtio-blk device that has been successfully
set up with VirtioBlkInit().
@param[in out] Dev The device to clean up.
**/
STATIC
VOID
EFIAPI
VirtioBlkUninit (
IN OUT VBLK_DEV *Dev
)
{
//
// Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When
// VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from
// the old comms area.
//
VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, 0);
VirtioRingUninit (&Dev->Ring);
SetMem (&Dev->BlockIo, sizeof Dev->BlockIo, 0x00);
SetMem (&Dev->BlockIoMedia, sizeof Dev->BlockIoMedia, 0x00);
}
/**
After we've pronounced support for a specific device in
DriverBindingSupported(), we start managing said device (passed in by the
Driver Exeuction Environment) with the following service.
See DriverBindingSupported() for specification references.
@param[in] This The EFI_DRIVER_BINDING_PROTOCOL object
incorporating this driver (independently of
any device).
@param[in] DeviceHandle The supported device to drive.
@param[in] RemainingDevicePath Relevant only for bus drivers, ignored.
@retval EFI_SUCCESS Driver instance has been created and
initialized for the virtio-blk PCI device, it
is now accessibla via EFI_BLOCK_IO_PROTOCOL.
@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
@return Error codes from the OpenProtocol() boot
service, the PciIo protocol, VirtioBlkInit(),
or the InstallProtocolInterface() boot service.
**/
EFI_STATUS
EFIAPI
VirtioBlkDriverBindingStart (
IN EFI_DRIVER_BINDING_PROTOCOL *This,
IN EFI_HANDLE DeviceHandle,
IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath
)
{
VBLK_DEV *Dev;
EFI_STATUS Status;
Dev = (VBLK_DEV *) AllocateZeroPool (sizeof *Dev);
if (Dev == NULL) {
return EFI_OUT_OF_RESOURCES;
}
Status = gBS->OpenProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
(VOID **)&Dev->PciIo, This->DriverBindingHandle,
DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);
if (EFI_ERROR (Status)) {
goto FreeVirtioBlk;
}
//
// We must retain and ultimately restore the original PCI attributes of the
// device. See Driver Writer's Guide for UEFI 2.3.1 v1.01, 18.3 PCI drivers /
// 18.3.2 Start() and Stop().
//
// The third parameter ("Attributes", input) is ignored by the Get operation.
// The fourth parameter ("Result", output) is ignored by the Enable and Set
// operations.
//
// For virtio-blk we only need IO space access.
//
Status = Dev->PciIo->Attributes (Dev->PciIo, EfiPciIoAttributeOperationGet,
0, &Dev->OriginalPciAttributes);
if (EFI_ERROR (Status)) {
goto ClosePciIo;
}
Status = Dev->PciIo->Attributes (Dev->PciIo,
EfiPciIoAttributeOperationEnable,
EFI_PCI_IO_ATTRIBUTE_IO, NULL);
if (EFI_ERROR (Status)) {
goto ClosePciIo;
}
//
// PCI IO access granted, configure virtio-blk device.
//
Status = VirtioBlkInit (Dev);
if (EFI_ERROR (Status)) {
goto RestorePciAttributes;
}
//
// Setup complete, attempt to export the driver instance's BlockIo interface.
//
Dev->Signature = VBLK_SIG;
Status = gBS->InstallProtocolInterface (&DeviceHandle,
&gEfiBlockIoProtocolGuid, EFI_NATIVE_INTERFACE,
&Dev->BlockIo);
if (EFI_ERROR (Status)) {
goto UninitDev;
}
return EFI_SUCCESS;
UninitDev:
VirtioBlkUninit (Dev);
RestorePciAttributes:
Dev->PciIo->Attributes (Dev->PciIo, EfiPciIoAttributeOperationSet,
Dev->OriginalPciAttributes, NULL);
ClosePciIo:
gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
This->DriverBindingHandle, DeviceHandle);
FreeVirtioBlk:
FreePool (Dev);
return Status;
}
/**
Stop driving a virtio-blk device and remove its BlockIo interface.
This function replays the success path of DriverBindingStart() in reverse.
The host side virtio-blk device is reset, so that the OS boot loader or the
OS may reinitialize it.
@param[in] This The EFI_DRIVER_BINDING_PROTOCOL object
incorporating this driver (independently of any
device).
@param[in] DeviceHandle Stop driving this device.
@param[in] NumberOfChildren Since this function belongs to a device driver
only (as opposed to a bus driver), the caller
environment sets NumberOfChildren to zero, and
we ignore it.
@param[in] ChildHandleBuffer Ignored (corresponding to NumberOfChildren).
**/
EFI_STATUS
EFIAPI
VirtioBlkDriverBindingStop (
IN EFI_DRIVER_BINDING_PROTOCOL *This,
IN EFI_HANDLE DeviceHandle,
IN UINTN NumberOfChildren,
IN EFI_HANDLE *ChildHandleBuffer
)
{
EFI_STATUS Status;
EFI_BLOCK_IO_PROTOCOL *BlockIo;
VBLK_DEV *Dev;
Status = gBS->OpenProtocol (
DeviceHandle, // candidate device
&gEfiBlockIoProtocolGuid, // retrieve the BlockIo iface
(VOID **)&BlockIo, // target pointer
This->DriverBindingHandle, // requestor driver identity
DeviceHandle, // requesting lookup for dev.
EFI_OPEN_PROTOCOL_GET_PROTOCOL // lookup only, no ref. added
);
if (EFI_ERROR (Status)) {
return Status;
}
Dev = VIRTIO_BLK_FROM_BLOCK_IO (BlockIo);
//
// Handle Stop() requests for in-use driver instances gracefully.
//
Status = gBS->UninstallProtocolInterface (DeviceHandle,
&gEfiBlockIoProtocolGuid, &Dev->BlockIo);
if (EFI_ERROR (Status)) {
return Status;
}
VirtioBlkUninit (Dev);
Dev->PciIo->Attributes (Dev->PciIo, EfiPciIoAttributeOperationSet,
Dev->OriginalPciAttributes, NULL);
gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
This->DriverBindingHandle, DeviceHandle);
FreePool (Dev);
return EFI_SUCCESS;
}
//
// The static object that groups the Supported() (ie. probe), Start() and
// Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
// C, 10.1 EFI Driver Binding Protocol.
//
STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {
&VirtioBlkDriverBindingSupported,
&VirtioBlkDriverBindingStart,
&VirtioBlkDriverBindingStop,
0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
NULL, // ImageHandle, to be overwritten by
// EfiLibInstallDriverBindingComponentName2() in VirtioBlkEntryPoint()
NULL // DriverBindingHandle, ditto
};
//
// The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
// EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
// in English, for display on standard console devices. This is recommended for
// UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
// Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
//
// Device type names ("Virtio Block Device") are not formatted because the
// driver supports only that device type. Therefore the driver name suffices
// for unambiguous identification.
//
STATIC
EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {
{ "eng;en", L"Virtio Block Driver" },
{ NULL, NULL }
};
STATIC
EFI_COMPONENT_NAME_PROTOCOL gComponentName;
EFI_STATUS
EFIAPI
VirtioBlkGetDriverName (
IN EFI_COMPONENT_NAME_PROTOCOL *This,
IN CHAR8 *Language,
OUT CHAR16 **DriverName
)
{
return LookupUnicodeString2 (
Language,
This->SupportedLanguages,
mDriverNameTable,
DriverName,
(BOOLEAN)(This == &gComponentName) // Iso639Language
);
}
EFI_STATUS
EFIAPI
VirtioBlkGetDeviceName (
IN EFI_COMPONENT_NAME_PROTOCOL *This,
IN EFI_HANDLE DeviceHandle,
IN EFI_HANDLE ChildHandle,
IN CHAR8 *Language,
OUT CHAR16 **ControllerName
)
{
return EFI_UNSUPPORTED;
}
STATIC
EFI_COMPONENT_NAME_PROTOCOL gComponentName = {
&VirtioBlkGetDriverName,
&VirtioBlkGetDeviceName,
"eng" // SupportedLanguages, ISO 639-2 language codes
};
STATIC
EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {
(EFI_COMPONENT_NAME2_GET_DRIVER_NAME) &VirtioBlkGetDriverName,
(EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioBlkGetDeviceName,
"en" // SupportedLanguages, RFC 4646 language codes
};
//
// Entry point of this driver.
//
EFI_STATUS
EFIAPI
VirtioBlkEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
return EfiLibInstallDriverBindingComponentName2 (
ImageHandle,
SystemTable,
&gDriverBinding,
ImageHandle,
&gComponentName,
&gComponentName2
);
}
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