Re: [edk2-devel] [PATCH v2 13/31] OvmfPkg/Library/XenPlatformLib: New library

["Laszlo Ersek" <lersek@redhat.com>]

On 04/09/19 13:08, Anthony PERARD wrote:
> The purpose of XenPlatformPei is to regroup the few functions that are

(1) did you mean XenPlatformLib here?

> used in several places to detect if Xen is detected, and to get the
> XenInfo HOB.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> ---
>  OvmfPkg/XenOvmf.dsc                                                                                       |  1 +
>  MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf => OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf | 27 +++----
>  OvmfPkg/Include/Library/XenPlatformLib.h                                                                  | 59 +++++++++++++++
>  OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c                                                           | 75 ++++++++++++++++++++
>  4 files changed, 150 insertions(+), 12 deletions(-)
> 
> diff --git a/OvmfPkg/XenOvmf.dsc b/OvmfPkg/XenOvmf.dsc
> index cc51bac3be..9529b4834f 100644
> --- a/OvmfPkg/XenOvmf.dsc
> +++ b/OvmfPkg/XenOvmf.dsc
> @@ -198,6 +198,7 @@ [LibraryClasses]
>    SmbusLib|MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf
>    OrderedCollectionLib|MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.inf
>    XenHypercallLib|OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
> +  XenPlatformLib|OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
>  
>    Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.inf
>  
> diff --git a/MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
> similarity index 56%
> copy from MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf
> copy to OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
> index 4fd4874595..ca078f7263 100644
> --- a/MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf
> +++ b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf

obviously this is a false positive for git's "--find-copies-harder", but
I can look at the file in isolation using your git branch...

(3) Please use "SPDX-License-Identifier: BSD-2-Clause-Patent", rather
than the open-coded 2-clause BSDL.

(This applies to other new files in this patch as well.)

[...]

> diff --git a/OvmfPkg/Include/Library/XenPlatformLib.h b/OvmfPkg/Include/Library/XenPlatformLib.h
> new file mode 100644
> index 0000000000..8f57450575
> --- /dev/null
> +++ b/OvmfPkg/Include/Library/XenPlatformLib.h
> @@ -0,0 +1,59 @@
> +/** @file
> +*  Get information about Xen
> +*
> +*  This library simply allow to find out if OVMF is running under Xen and
> +*  allow to get more information when it is the case.
> +*
> +*  Copyright (c) 2019, Citrix Systems, 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.
> +*
> +**/
> +
> +#ifndef _XEN_PLATFORM_LIB_H_
> +#define _XEN_PLATFORM_LIB_H_
> +
> +#include <Guid/XenInfo.h>
> +
> +/**
> +  This function detects if OVMF is running on Xen.
> +
> +  @retval TRUE    OVMF is running on Xen
> +  @retval FALSE   Xen as not been detected

(4) "has" not been detected

... same for the function definition as well, in the .c file below.

(5) At the introduction of a new library class, we should update the
[LibraryClasses] section in the "OvmfPkg/OvmfPkg.dec" file. I think you
can add this new class under XenHypercallLib and XenIoMmioLib there.

(To confirm, I'm not speaking about the .dsc file, but the .dec file.)

Thanks
Laszlo

> +**/
> +BOOLEAN
> +EFIAPI
> +XenDetected (
> +  VOID
> +  );
> +
> +/**
> +  This function detect if OVMF have started via the PVH entry point.
> +
> +  @retval TRUE  PVH entry point as been used
> +  @retval FALSE OVMF have started via the HVM route
> +**/
> +BOOLEAN
> +EFIAPI
> +XenPvhDetected (
> +  VOID
> +  );
> +
> +/**
> +  This function return a pointer to the XenInfo HOB.
> +
> +  @return  XenInfo pointer or NULL if not available
> +**/
> +EFI_XEN_INFO *
> +EFIAPI
> +XenGetInfoHOB (
> +  VOID
> +  );
> +
> +#endif
> diff --git a/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c
> new file mode 100644
> index 0000000000..274ddfc9ad
> --- /dev/null
> +++ b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c
> @@ -0,0 +1,75 @@
> +/** @file
> +*  Get information about Xen
> +*
> +*  This library simply allow to find out if OVMF is running under Xen and
> +*  allow to get more information when it is the case.
> +*
> +*  Copyright (c) 2019, Citrix Systems, 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 <PiDxe.h>
> +#include <Library/HobLib.h>
> +#include <Library/XenPlatformLib.h>
> +
> +/**
> +  This function return a pointer to the XenInfo HOB.
> +
> +  @return  XenInfo pointer or NULL if not available
> +**/
> +EFI_XEN_INFO *
> +EFIAPI
> +XenGetInfoHOB (
> +  VOID
> +  )
> +{
> +  EFI_HOB_GUID_TYPE  *GuidHob;
> +
> +  GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);
> +  if (GuidHob == NULL) {
> +    return NULL;
> +  }
> +
> +  return (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob);
> +}
> +
> +/**
> +  This function detects if OVMF is running on Xen.
> +
> +  @retval TRUE    OVMF is running on Xen
> +  @retval FALSE   Xen as not been detected
> +**/
> +BOOLEAN
> +EFIAPI
> +XenDetected (
> +  VOID
> +  )
> +{
> +  return (XenGetInfoHOB () != NULL);
> +}
> +
> +/**
> +  This function detect if OVMF have started via the PVH entry point.
> +
> +  @retval TRUE  PVH entry point as been used
> +  @retval FALSE OVMF have started via the HVM route
> +**/
> +BOOLEAN
> +EFIAPI
> +XenPvhDetected (
> +  VOID
> +  )
> +{
> +  EFI_XEN_INFO        *XenInfo;
> +
> +  XenInfo = XenGetInfoHOB ();
> +  return (XenInfo != NULL && XenInfo->RsdpPvh != NULL);
> +}
>