Re: [edk2-devel] [PATCH v2 01/12] MdeModulePkg: Define the VariablePolicy protocol interface

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

On 05/12/20 08:46, Michael Kubacki wrote:
> From: Bret Barkelew <brbarkel@microsoft.com>
> 
> https://bugzilla.tianocore.org/show_bug.cgi?id=2522
> 
> VariablePolicy is an updated interface to
> replace VarLock and VarCheckProtocol.
> 
> Add the VariablePolicy protocol interface
> header and add to the MdeModulePkg.dec file.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
> ---
>  MdeModulePkg/Include/Protocol/VariablePolicy.h | 157 ++++++++++++++++++++
>  MdeModulePkg/MdeModulePkg.dec                  |  14 +-
>  2 files changed, 170 insertions(+), 1 deletion(-)
> 
> diff --git a/MdeModulePkg/Include/Protocol/VariablePolicy.h b/MdeModulePkg/Include/Protocol/VariablePolicy.h
> new file mode 100644
> index 000000000000..2cd025860554
> --- /dev/null
> +++ b/MdeModulePkg/Include/Protocol/VariablePolicy.h
> @@ -0,0 +1,157 @@
> +/** @file -- VariablePolicy.h
> +
> +This protocol allows communication with Variable Policy Engine.
> +
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +**/
> +
> +#ifndef __VARIABLE_POLICY_PROTOCOL__
> +#define __VARIABLE_POLICY_PROTOCOL__
> +
> +#define VARIABLE_POLICY_PROTOCOL_REVISION   0x0000000000010000
> +
> +#define VARIABLE_POLICY_PROTOCOL_GUID \
> +  { \
> +    0x81D1675C, 0x86F6, 0x48DF, { 0xBD, 0x95, 0x9A, 0x6E, 0x4F, 0x09, 0x25, 0xC3 } \
> +  }
> +
> +#define VARIABLE_POLICY_ENTRY_REVISION      0x00010000
> +
> +#pragma pack(push, 1)
> +typedef struct {
> +  UINT32   Version;
> +  UINT16   Size;
> +  UINT16   OffsetToName;
> +  EFI_GUID Namespace;
> +  UINT32   MinSize;
> +  UINT32   MaxSize;
> +  UINT32   AttributesMustHave;
> +  UINT32   AttributesCantHave;
> +  UINT8    LockPolicyType;
> +  UINT8    Padding[3];
> +  // UINT8    LockPolicy[];     // Variable Length Field
> +  // CHAR16   Name[]            // Variable Length Field
> +} VARIABLE_POLICY_ENTRY;
> +
> +#define     VARIABLE_POLICY_NO_MIN_SIZE             0
> +#define     VARIABLE_POLICY_NO_MAX_SIZE             MAX_UINT32
> +#define     VARIABLE_POLICY_NO_MUST_ATTR            0
> +#define     VARIABLE_POLICY_NO_CANT_ATTR            0
> +
> +#define     VARIABLE_POLICY_TYPE_NO_LOCK            0
> +#define     VARIABLE_POLICY_TYPE_LOCK_NOW           1
> +#define     VARIABLE_POLICY_TYPE_LOCK_ON_CREATE     2
> +#define     VARIABLE_POLICY_TYPE_LOCK_ON_VAR_STATE  3
> +
> +typedef struct {
> +  EFI_GUID Namespace;
> +  UINT8    Value;
> +  UINT8    Padding;
> +  // CHAR16   Name[];           // Variable Length Field
> +} VARIABLE_LOCK_ON_VAR_STATE_POLICY;
> +#pragma pack(pop)
> +
> +/**
> +  This API function disables the variable policy enforcement. If it's
> +  already been called once, will return EFI_ALREADY_STARTED.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     EFI_ALREADY_STARTED   Has already been called once this boot.
> +  @retval     EFI_WRITE_PROTECTED   Interface has been locked until reboot.
> +  @retval     EFI_WRITE_PROTECTED   Interface option is disabled by platform PCD.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *DISABLE_VARIABLE_POLICY)(
> +  VOID
> +  );
> +
> +/**
> +  This API function returns whether or not the policy engine is
> +  currently being enforced.
> +
> +  @param[out]   State       Pointer to a return value for whether the policy enforcement
> +                            is currently enabled.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     Others        An error has prevented this command from completing.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *IS_VARIABLE_POLICY_ENABLED)(
> +  OUT BOOLEAN *State
> +  );
> +
> +/**
> +  This API function validates and registers a new policy with
> +  the policy enforcement engine.
> +
> +  @param[in]  NewPolicy     Pointer to the incoming policy structure.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     EFI_INVALID_PARAMETER   NewPolicy is NULL or is internally inconsistent.
> +  @retval     EFI_ALREADY_STARTED     An identical matching policy already exists.
> +  @retval     EFI_WRITE_PROTECTED     The interface has been locked until the next reboot.
> +  @retval     EFI_ABORTED             A calculation error has prevented this function from completing.
> +  @retval     EFI_OUT_OF_RESOURCES    Cannot grow the table to hold any more policies.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *REGISTER_VARIABLE_POLICY)(
> +  IN VARIABLE_POLICY_ENTRY *PolicyEntry
> +  );
> +
> +/**
> +  This API function will dump the entire contents of the variable policy table.
> +
> +  Similar to GetVariable, the first call can be made with a 0 size and it will return
> +  the size of the buffer required to hold the entire table.
> +
> +  @param[out]     Policy  Pointer to the policy buffer. Can be NULL if Size is 0.
> +  @param[in,out]  Size    On input, the size of the output buffer. On output, the size
> +                          of the data returned.
> +
> +  @retval     EFI_SUCCESS             Policy data is in the output buffer and Size has been updated.
> +  @retval     EFI_INVALID_PARAMETER   Size is NULL, or Size is non-zero and Policy is NULL.
> +  @retval     EFI_BUFFER_TOO_SMALL    Size is insufficient to hold policy. Size updated with required size.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *DUMP_VARIABLE_POLICY)(
> +  IN OUT UINT8  *Policy,
> +  IN OUT UINT32 *Size
> +  );
> +
> +/**
> +  This API function locks the interface so that no more policy updates
> +  can be performed or changes made to the enforcement until the next boot.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     Others        An error has prevented this command from completing.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *LOCK_VARIABLE_POLICY)(
> +  VOID
> +  );
> +
> +typedef struct {
> +  UINT64                     Revision;
> +  DISABLE_VARIABLE_POLICY    DisableVariablePolicy;
> +  IS_VARIABLE_POLICY_ENABLED IsVariablePolicyEnabled;
> +  REGISTER_VARIABLE_POLICY   RegisterVariablePolicy;
> +  DUMP_VARIABLE_POLICY       DumpVariablePolicy;
> +  LOCK_VARIABLE_POLICY       LockVariablePolicy;
> +} _VARIABLE_POLICY_PROTOCOL;
> +
> +typedef _VARIABLE_POLICY_PROTOCOL VARIABLE_POLICY_PROTOCOL;
> +
> +extern EFI_GUID gVariablePolicyProtocolGuid;
> +
> +#endif
> diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
> index 4f44af694862..f74fea00b6e7 100644
> --- a/MdeModulePkg/MdeModulePkg.dec
> +++ b/MdeModulePkg/MdeModulePkg.dec
> @@ -8,7 +8,7 @@
>  # Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
>  # (C) Copyright 2016 - 2019 Hewlett Packard Enterprise Development LP<BR>
>  # Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
> -# Copyright (c) 2016, Microsoft Corporation<BR>
> +# Copyright (c) Microsoft Corporation.<BR>
>  # SPDX-License-Identifier: BSD-2-Clause-Patent
>  #
>  ##
> @@ -624,6 +624,9 @@
>  #   0x80000006 | Incorrect error code provided.
>  #
>  
> +  ## Include/Protocol/VariablePolicy.h
> +  gVariablePolicyProtocolGuid = { 0x81D1675C, 0x86F6, 0x48DF, { 0xBD, 0x95, 0x9A, 0x6E, 0x4F, 0x09, 0x25, 0xC3 } }
> +

(1) Should be called gEdkiiVariablePolicyProtocolGuid, IMO.

Similarly, all VARIABLE_POLICY_PROTOCOL substrings should be
EDKII_VARIABLE_POLICY_PROTOCOL, in the protocol header file, I believe.

>  [PcdsFeatureFlag]
>    ## Indicates if the platform can support update capsule across a system reset.<BR><BR>
>    #   TRUE  - Supports update capsule across a system reset.<BR>
> @@ -1129,6 +1132,15 @@
>    # @Prompt Variable storage size.
>    gEfiMdeModulePkgTokenSpaceGuid.PcdVariableStoreSize|0x10000|UINT32|0x30000005
>  
> +  ## Toggle for whether the VariablePolicy engine should allow disabling.
> +  # The engine is enabled at power-on, but the interface allows the platform to
> +  # disable enforcement for servicing flexibility. If this PCD is disabled, it will block the ability to
> +  # disable the enforcement and VariablePolicy enforcement will always be ON.
> +  #   TRUE - VariablePolicy can be disabled by request through the interface (until interface is locked)
> +  #   FALSE - VariablePolicy interface will not accept requests to disable and is ALWAYS ON
> +  # @Prompt Allow VariablePolicy enforcement to be disabled.
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdAllowVariablePolicyEnforcementDisable|FALSE|BOOLEAN|0x30000020
> +
>    ## FFS filename to find the ACPI tables.
>    # @Prompt FFS name of ACPI tables storage.
>    gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiTableStorageFile|{ 0x25, 0x4e, 0x37, 0x7e, 0x01, 0x8e, 0xee, 0x4f, 0x87, 0xf2, 0x39, 0xc, 0x23, 0xc6, 0x6, 0xcd }|VOID*|0x30000016
> 

(2) This patch should update "MdeModulePkg.uni" in tandem with
"MdeModulePkg.dec", I think.

Thanks
Laszlo