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OvmfPkg: introduce IOMMU-like member functions to VIRTIO_DEVICE_PROTOCOL 

The patch extends VIRTIO_DEVICE_PROTOCOL to provide the following new
member functions:

- AllocateSharedPages : allocate a memory region suitable for sharing
   between guest and hypervisor (e.g ring buffer).

- FreeSharedPages: free the memory allocated using AllocateSharedPages ().

- MapSharedBuffer: map a host address to device address suitable to share
   with device for bus master operations.

- UnmapSharedBuffer: unmap the device address obtained through the
   MapSharedBuffer().

We're free to extend the protocol structure without changing the protocol
GUID, or bumping any protocol version fields (of which we currently have
none), because VIRTIO_DEVICE_PROTOCOL is internal to edk2 by design --
see the disclaimers in "VirtioDevice.h".

The patch implements Laszlo's recommendation [1].

[1] http://mid.mail-archive.com/841bec5f-6f6e-8b1f-25ba-0fd37a915b72@redhat.com

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Brijesh Singh 2017-08-23 06:57:15 -04:00 committed by Laszlo Ersek
parent c69071bd7e
commit 878115261a
1 changed files with 143 additions and 0 deletions
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143
OvmfPkg/Include/Protocol/VirtioDevice.h
View File

@ -5,6 +5,7 @@
and should not be used outside of the EDK II tree.
Copyright (c) 2013, ARM Ltd. All rights reserved.<BR>
Copyright (c) 2017, AMD Inc, 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
@ -33,6 +34,25 @@
typedef struct _VIRTIO_DEVICE_PROTOCOL VIRTIO_DEVICE_PROTOCOL;
//
// VIRTIO Operation for VIRTIO_MAP_SHARED
//
typedef enum {
//
// A read operation from system memory by a bus master
//
VirtioOperationBusMasterRead,
//
// A write operation to system memory by a bus master
//
VirtioOperationBusMasterWrite,
//
// Provides both read and write access to system memory by both the
// processor and a bus master
//
VirtioOperationBusMasterCommonBuffer,
} VIRTIO_MAP_OPERATION;
/**
Read a word from the device-specific I/O region of the Virtio Header.
@ -321,6 +341,121 @@ EFI_STATUS
IN UINT8 DeviceStatus
);
/**
Allocates pages that are suitable for an VirtioOperationBusMasterCommonBuffer
mapping. This means that the buffer allocated by this function supports
simultaneous access by both the processor and the bus master. The device
address that the bus master uses to access the buffer must be retrieved with
a call to VIRTIO_MAP_SHARED.
@param[in] This The protocol instance pointer.
@param[in] Pages The number of pages to allocate.
@param[in,out] HostAddress A pointer to store the system memory base
address of the allocated range.
@retval EFI_SUCCESS The requested memory pages were allocated.
@retval EFI_OUT_OF_RESOURCES The memory pages could not be allocated.
**/
typedef
EFI_STATUS
(EFIAPI *VIRTIO_ALLOCATE_SHARED)(
IN VIRTIO_DEVICE_PROTOCOL *This,
IN UINTN Pages,
IN OUT VOID **HostAddress
);
/**
Frees memory that was allocated with VIRTIO_ALLOCATE_SHARED.
@param[in] This The protocol instance pointer.
@param[in] Pages The number of pages to free.
@param[in] HostAddress The system memory base address of the allocated
range.
**/
typedef
VOID
(EFIAPI *VIRTIO_FREE_SHARED)(
IN VIRTIO_DEVICE_PROTOCOL *This,
IN UINTN Pages,
IN VOID *HostAddress
);
/**
Provides the virtio device address required to access system memory from a
DMA bus master.
The interface follows the same usage pattern as defined in UEFI spec 2.6
(Section 13.2 PCI Root Bridge I/O Protocol)
@param[in] This The protocol instance pointer.
@param[in] Operation Indicates if the bus master is going to
read or write to system memory.
@param[in] HostAddress The system memory address to map to shared
buffer address.
@param[in,out] NumberOfBytes On input the number of bytes to map.
On output the number of bytes that were
mapped.
@param[out] DeviceAddress The resulting shared map address for the
bus master to access the hosts HostAddress.
@param[out] Mapping A resulting token to pass to
VIRTIO_UNMAP_SHARED.
@retval EFI_SUCCESS The range was mapped for the returned
NumberOfBytes.
@retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a
common buffer.
@retval EFI_INVALID_PARAMETER One or more parameters are invalid.
@retval EFI_OUT_OF_RESOURCES The request could not be completed due to
a lack of resources.
@retval EFI_DEVICE_ERROR The system hardware could not map the
requested address.
**/
typedef
EFI_STATUS
(EFIAPI *VIRTIO_MAP_SHARED) (
IN VIRTIO_DEVICE_PROTOCOL *This,
IN VIRTIO_MAP_OPERATION Operation,
IN VOID *HostAddress,
IN OUT UINTN *NumberOfBytes,
OUT EFI_PHYSICAL_ADDRESS *DeviceAddress,
OUT VOID **Mapping
);
/**
Completes the VIRTIO_MAP_SHARED operation and releases any corresponding
resources.
@param[in] This The protocol instance pointer.
@param[in] Mapping The mapping token returned from
VIRTIO_MAP_SHARED.
@retval EFI_SUCCESS The range was unmapped.
@retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
VIRTIO_MAP_SHARED. Passing an invalid Mapping
token can cause undefined behavior.
@retval EFI_DEVICE_ERROR The data was not committed to the target
system memory.
**/
typedef
EFI_STATUS
(EFIAPI *VIRTIO_UNMAP_SHARED)(
IN VIRTIO_DEVICE_PROTOCOL *This,
IN VOID *Mapping
);
///
/// This protocol provides an abstraction over the VirtIo transport layer
@ -361,6 +496,14 @@ struct _VIRTIO_DEVICE_PROTOCOL {
//
VIRTIO_DEVICE_WRITE WriteDevice;
VIRTIO_DEVICE_READ ReadDevice;
//
// Functions to allocate, free, map and unmap shared buffer
//
VIRTIO_ALLOCATE_SHARED AllocateSharedPages;
VIRTIO_FREE_SHARED FreeSharedPages;
VIRTIO_MAP_SHARED MapSharedBuffer;
VIRTIO_UNMAP_SHARED UnmapSharedBuffer;
};
extern EFI_GUID gVirtioDeviceProtocolGuid;