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From: "Ard Biesheuvel" <ard.biesheuvel@arm.com>
To: Sami Mujawar <sami.mujawar@arm.com>, devel@edk2.groups.io
Cc: leif@nuviainc.com, lersek@redhat.com, Alexandru.Elisei@arm.com,
	Andre.Przywara@arm.com, Matteo.Carlini@arm.com,
	Laura.Moretta@arm.com, nd@arm.com
Subject: Re: [PATCH v2 06/11] ArmVirtPkg: Add kvmtool platform driver
Date: Thu, 14 May 2020 11:29:28 +0200	[thread overview]
Message-ID: <fc4c2d78-0c9b-726b-f569-d09bc93bafb0@arm.com> (raw)
In-Reply-To: <20200514084019.71368-7-sami.mujawar@arm.com>

On 5/14/20 10:40 AM, Sami Mujawar wrote:
> Kvmtool is a virtual machine manager that enables
> hosting KVM guests. It essentially provides an
> emulated platform for guest operating systems.
> 
> Kvmtool hands of a device tree containing the
> current hardware configuration to the firmware.
> 
> A standards-based operating system would use
> ACPI to consume the platform hardware
> information, while some operating systems may
> prefer to use Device Tree.
> 
> The KvmtoolPlatformDxe performs the platform
> actions like determining if the firmware should
> expose ACPI or the Device Tree based hardware
> description to the operating system.
> 
> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
> ---
> 
> Notes:
>      v2:
>        - Updated according to review comments.                     [Sami]
>      
>      v1:
>        - Add kvmtool platform driver to support loading platform   [Sami]
>          specific information.
>        - Keep code to initialise the variable storage PCDs in the  [Laszlo]
>          platform-specific FVB driver.
>        - Document code derived from                                [Laszlo]
>          "ArmVirtPkg/PlatformHasAcpiDtDxe"
>          Ref: https://edk2.groups.io/g/devel/topic/30915278#30757
> 
>   ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.c   | 93 ++++++++++++++++++++
>   ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.inf | 47 ++++++++++
>   2 files changed, 140 insertions(+)
> 
> diff --git a/ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.c b/ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..e7568f66f5ebeb0423fc1c10345cd8dad0800d94
> --- /dev/null
> +++ b/ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.c
> @@ -0,0 +1,93 @@
> +/** @file
> +
> +  The KvmtoolPlatformDxe performs the platform specific initialization like:
> +  - It decides if the firmware should expose ACPI or Device Tree-based
> +    hardware description to the operating system.
> +
> +  Copyright (c) 2018 - 2020, ARM Limited. All rights reserved.
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Guid/VariableFormat.h>
> +#include <Library/BaseLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/DxeServicesTableLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiDriverEntryPoint.h>
> +#include <Protocol/FdtClient.h>
> +
> +/** Decide if the firmware should expose ACPI tables or Device Tree and
> +    install the appropriate protocol interface.
> +
> +  Note: This function is derived from "ArmVirtPkg/PlatformHasAcpiDtDxe",
> +        by dropping the word size check, and the fw_cfg check.
> +
> +  @param [in]  ImageHandle  Handle for this image.
> +
> +  @retval EFI_SUCCESS             Success.
> +  @retval EFI_OUT_OF_RESOURCES    There was not enough memory to install the
> +                                  protocols.
> +  @retval EFI_INVALID_PARAMETER   A parameter is invalid.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +PlatformHasAcpiDt (
> +  IN EFI_HANDLE           ImageHandle
> +  )
> +{
> +  if (!PcdGetBool (PcdForceNoAcpi)) {
> +    // Expose ACPI tables
> +    return gBS->InstallProtocolInterface (
> +                  &ImageHandle,
> +                  &gEdkiiPlatformHasAcpiGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  }
> +
> +  // Expose the Device Tree.
> +  return gBS->InstallProtocolInterface (
> +                &ImageHandle,
> +                &gEdkiiPlatformHasDeviceTreeGuid,
> +                EFI_NATIVE_INTERFACE,
> +                NULL
> +                );
> +}
> +
> +/** Entry point for Kvmtool Platform Dxe
> +
> +  @param [in]  ImageHandle  Handle for this image.
> +  @param [in]  SystemTable  Pointer to the EFI system table.
> +
> +  @retval EFI_SUCCESS             Success.
> +  @retval EFI_OUT_OF_RESOURCES    There was not enough memory to install the
> +                                  protocols.
> +  @retval EFI_INVALID_PARAMETER   A parameter is invalid.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +KvmtoolPlatformDxeEntryPoint (
> +  IN EFI_HANDLE           ImageHandle,
> +  IN EFI_SYSTEM_TABLE     *SystemTable
> +  )
> +{
> +  EFI_STATUS                     Status;
> +
> +  Status = PlatformHasAcpiDt (ImageHandle);
> +  if (EFI_ERROR (Status)) {
> +    goto Failed;
> +  }
> +
> +  return Status;
> +
> +Failed:
> +  ASSERT_EFI_ERROR (Status);
> +  CpuDeadLoop ();
> +
> +  return Status;
> +}

Please don't use CpuDeadLoop()s in your drivers.

Installing a protocol on an image handle like this should not ever fail, 
and if it does, it is unlikely to be an issue in the driver itself. So 
just use ASSERT_EFI_ERROR() here, and return EFI_SUCCESS.


> diff --git a/ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.inf b/ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.inf
> new file mode 100644
> index 0000000000000000000000000000000000000000..08a0fe5ce14469133479046385bdd48c22698639
> --- /dev/null
> +++ b/ArmVirtPkg/KvmtoolPlatformDxe/KvmtoolPlatformDxe.inf
> @@ -0,0 +1,47 @@
> +#/** @file
> +#
> +#  The KvmtoolPlatformDxe performs the platform specific initialization like:
> +#  - It decides if the firmware should expose ACPI or Device Tree-based
> +#    hardware description to the operating system.
> +#
> +#  Copyright (c) 2018 - 2020, ARM Limited. All rights reserved.
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +#**/
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001B
> +  BASE_NAME                      = KvmtoolPlatformDxe
> +  FILE_GUID                      = 7479CCCD-D721-442A-8C73-A72DBB886669
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = KvmtoolPlatformDxeEntryPoint
> +
> +[Sources]
> +  KvmtoolPlatformDxe.c
> +
> +[Packages]
> +  ArmVirtPkg/ArmVirtPkg.dec
> +  EmbeddedPkg/EmbeddedPkg.dec
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  BaseMemoryLib
> +  DebugLib
> +  DxeServicesTableLib
> +  MemoryAllocationLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +
> +[Guids]
> +  gEdkiiPlatformHasAcpiGuid       ## SOMETIMES_PRODUCES ## PROTOCOL
> +  gEdkiiPlatformHasDeviceTreeGuid ## SOMETIMES_PRODUCES ## PROTOCOL
> +
> +[Pcd]
> +  gArmVirtTokenSpaceGuid.PcdForceNoAcpi
> +
> +[Depex]
> +  TRUE
> 


  reply	other threads:[~2020-05-14  9:29 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-14  8:40 [PATCH v2 00/11] Kvmtool guest firmware support for Arm Sami Mujawar
2020-05-14  8:40 ` [PATCH v2 01/11] PcAtChipsetPkg: Add MMIO Support to RTC driver Sami Mujawar
2020-05-14  9:24   ` Ard Biesheuvel
2020-05-15 10:50   ` André Przywara
2020-05-27  0:37     ` [edk2-devel] " Guomin Jiang
2020-05-14  8:40 ` [PATCH v1 02/11] MdePkg: Add NULL implementation for PCILib Sami Mujawar
2020-05-14  9:23   ` Ard Biesheuvel
2020-05-14 16:21   ` Michael D Kinney
2020-05-14  8:40 ` [PATCH v1 03/11] MdePkg: Base Memory Lib instance using MMIO Sami Mujawar
2020-05-14  9:22   ` Ard Biesheuvel
2020-05-14 17:21     ` Ard Biesheuvel
2020-05-14 16:33   ` [edk2-devel] " Michael D Kinney
2020-05-14  8:40 ` [PATCH v1 04/11] ArmPlatformPkg: Use MMIO to read device memory Sami Mujawar
2020-05-14  8:40 ` [PATCH v1 05/11] ArmPlatformPkg: Dynamic flash variable base Sami Mujawar
2020-05-14  9:24   ` Ard Biesheuvel
2020-05-27 11:48   ` [edk2-devel] " Philippe Mathieu-Daudé
2020-05-14  8:40 ` [PATCH v2 06/11] ArmVirtPkg: Add kvmtool platform driver Sami Mujawar
2020-05-14  9:29   ` Ard Biesheuvel [this message]
2020-05-14 12:12     ` [edk2-devel] " Laszlo Ersek
2020-05-14 12:17       ` Ard Biesheuvel
2020-05-14 16:05         ` Laszlo Ersek
2020-05-14 17:25           ` Ard Biesheuvel
2020-05-15  7:28             ` Laszlo Ersek
2020-05-14 12:20       ` Laszlo Ersek
2020-05-14  8:40 ` [PATCH v1 07/11] ArmVirtPkg: kvmtool platform memory map Sami Mujawar
2020-05-14  9:30   ` Ard Biesheuvel
2020-05-14 12:15   ` [edk2-devel] " Laszlo Ersek
2020-05-14  8:40 ` [PATCH v1 08/11] ArmVirtPkg: Add Kvmtool NOR flash lib Sami Mujawar
2020-05-14  9:32   ` Ard Biesheuvel
2020-05-14 12:17     ` [edk2-devel] " Laszlo Ersek
2020-05-27 11:59   ` Philippe Mathieu-Daudé
2020-06-04  6:30     ` Philippe Mathieu-Daudé
2020-06-04 15:00       ` Sami Mujawar
2020-05-14  8:40 ` [PATCH v2 09/11] ArmVirtPkg: Support for kvmtool emulated platform Sami Mujawar
2020-05-14  9:56   ` Ard Biesheuvel
2020-05-14 12:24   ` [edk2-devel] " Laszlo Ersek
2020-05-14  8:40 ` [PATCH v1 10/11] ArmVirtPkg: Link NorFlashDxe with BaseMemoryLibMmio Sami Mujawar
2020-05-14 12:28   ` [edk2-devel] " Laszlo Ersek
2020-05-14  8:40 ` [PATCH v1 11/11] Maintainer.txt: Add Kvmtool emulated plat maintainer Sami Mujawar
2020-05-14 12:31   ` [edk2-devel] " Laszlo Ersek

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