Files
system76-edk2/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h
Min Xu 6b27c11690 OvmfPkg: Check Tdx in QemuFwCfgPei to avoid DMA operation
RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

If TDX is enabled then we do not support DMA operation in PEI phase.
This is mainly because DMA in TDX guest requires using bounce buffer
(which need to allocate dynamic memory and allocating a PAGE size'd
buffer can be challenge in PEI phase).

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
2022-04-02 08:15:12 +00:00

74 lines
1.9 KiB
C

/** @file
Internal interfaces specific to the QemuFwCfgLib instances in OvmfPkg.
Copyright (C) 2016, Red Hat, Inc.
Copyright (C) 2017, Advanced Micro Devices. All rights reserved
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#ifndef __QEMU_FW_CFG_LIB_INTERNAL_H__
#define __QEMU_FW_CFG_LIB_INTERNAL_H__
/**
Returns a boolean indicating if the firmware configuration interface is
available for library-internal purposes.
This function never changes fw_cfg state.
@retval TRUE The interface is available internally.
@retval FALSE The interface is not available internally.
**/
BOOLEAN
InternalQemuFwCfgIsAvailable (
VOID
);
/**
Returns a boolean indicating whether QEMU provides the DMA-like access method
for fw_cfg.
@retval TRUE The DMA-like access method is available.
@retval FALSE The DMA-like access method is unavailable.
**/
BOOLEAN
InternalQemuFwCfgDmaIsAvailable (
VOID
);
/**
Transfer an array of bytes, or skip a number of bytes, using the DMA
interface.
@param[in] Size Size in bytes to transfer or skip.
@param[in,out] Buffer Buffer to read data into or write data from. Ignored,
and may be NULL, if Size is zero, or Control is
FW_CFG_DMA_CTL_SKIP.
@param[in] Control One of the following:
FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.
FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.
**/
VOID
InternalQemuFwCfgDmaBytes (
IN UINT32 Size,
IN OUT VOID *Buffer OPTIONAL,
IN UINT32 Control
);
/**
Check if it is Tdx guest
@retval TRUE It is Tdx guest
@retval FALSE It is not Tdx guest
**/
BOOLEAN
QemuFwCfgIsTdxGuest (
VOID
);
#endif