Miki, this patch, as well as my queries on the mailing list about this topic
prior to the patch, hasn't received any response on the mailing list. One kind
person did respond privately with some information about my questions.
-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Jeshua Smith via
groups.io
Sent: Thursday, January 19, 2023 10:36 AM
To: devel@edk2.groups.io
Cc: jian.j.w...@intel.com; gaolim...@byosoft.com.cn; zhichao....@intel.com;
ray...@intel.com; Jeshua Smith <jesh...@nvidia.com>
Subject: [edk2-devel] [PATCH] MdeModulePkg: allow PlatformBootManagerLib to use
BootNext
External email: Use caution opening links or attachments
Currently BdsEntry caches BootNext before calling PlatformBootManagerLib APIs,
with the result that:
- If BootNext is already set, a BootNext value written by the APIs will be
ignored and deleted, and the current boot will use the cached BootNext value.
- If BootNext is not present, a BootNext value written by the APIs will have no
effect on the current boot, but will be used by the next boot.
This patch adds PcdAllowBootNextFromPlatformBootManagerLib so that a platform
can enable PlatformBootManagerLib API calls to set BootNext to control the
current boot.
- If the PCD is FALSE (default), there is no change.
- If the PCD is TRUE, then a BootNext value written by the
PlatformBootManagerLib APIs will affect the current boot.
Signed-off-by: Jeshua Smith <jesh...@nvidia.com>
---
MdeModulePkg/MdeModulePkg.dec | 7 +++++
MdeModulePkg/Universal/BdsDxe/BdsDxe.inf | 27 ++++++++++---------
MdeModulePkg/Universal/BdsDxe/BdsEntry.c | 34 ++++++++++++++++++------
3 files changed, 47 insertions(+), 21 deletions(-)
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index 9605c617b7..0e74131712 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -1093,6 +1093,13 @@
# @Prompt Enable UEFI Stack Guard.
gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard|FALSE|BOOLEAN|0x30001055
+ ## Indicates whether PlatformBootManagerLib code can set BootNext for the
current boot.
+ # If enabled, setting BootNext in PlatformBootManagerLib controls the
current boot.<BR><BR>
+ # TRUE - BootNext value from PlatformBootManagerLib will affect the
current boot.<BR>
+ # FALSE - BootNext value from PlatformBootManagerLib will affect the
subsequent boot (or be ignored if already set).<BR>
+ # @Prompt Allow PlatformBootManagerLib to set BootNext for the current boot.
+
+ gEfiMdeModulePkgTokenSpaceGuid.PcdAllowBootNextFromPlatformBootManager
+ Lib|FALSE|BOOLEAN|0x30001056
+
[PcdsFixedAtBuild, PcdsPatchableInModule]
## Dynamic type PCD can be registered callback function for Pcd setting
action.
# PcdMaxPeiPcdCallBackNumberPerPcdEntry indicates the maximum number of
callback function diff --git a/MdeModulePkg/Universal/BdsDxe/BdsDxe.inf
b/MdeModulePkg/Universal/BdsDxe/BdsDxe.inf
index 5bac635def..b7a3560f5f 100644
--- a/MdeModulePkg/Universal/BdsDxe/BdsDxe.inf
+++ b/MdeModulePkg/Universal/BdsDxe/BdsDxe.inf
@@ -85,19 +85,20 @@
gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLangDeprecate ## CONSUMES
[Pcd]
- gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLangCodes ##
CONSUMES
- gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLang ##
SOMETIMES_CONSUMES
- gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultPlatformLangCodes ##
CONSUMES
- gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultPlatformLang ##
CONSUMES
- gEfiMdePkgTokenSpaceGuid.PcdHardwareErrorRecordLevel ##
CONSUMES
- gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut ##
CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdFirmwareVendor ##
CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdFirmwareRevision ##
CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdConInConnectOnDemand ##
CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdErrorCodeSetVariable ##
SOMETIMES_CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdTestKeyUsed ##
CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdCapsuleOnDiskSupport ##
CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdPlatformRecoverySupport ##
CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLangCodes ##
CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLang ##
SOMETIMES_CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultPlatformLangCodes ##
CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultPlatformLang ##
CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdHardwareErrorRecordLevel ##
CONSUMES
+ gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut ##
CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdFirmwareVendor ##
CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdFirmwareRevision ##
CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdConInConnectOnDemand ##
CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdErrorCodeSetVariable ##
SOMETIMES_CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdTestKeyUsed ##
CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdCapsuleOnDiskSupport ##
CONSUMES
+ gEfiMdeModulePkgTokenSpaceGuid.PcdPlatformRecoverySupport ##
CONSUMES
+
+ gEfiMdeModulePkgTokenSpaceGuid.PcdAllowBootNextFromPlatformBootManager
+ Lib ## CONSUMES
[Depex]
TRUE
diff --git a/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
b/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
index 766dde3aae..6450406cce 100644
--- a/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
+++ b/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
@@ -787,15 +787,19 @@ BdsEntry (
//
// Cache the "BootNext" NV variable before calling any
PlatformBootManagerLib APIs
- // This could avoid the "BootNext" set by PlatformBootManagerLib be consumed
in this boot.
- //
- GetEfiGlobalVariable2 (EFI_BOOT_NEXT_VARIABLE_NAME, (VOID **)&BootNext,
&DataSize);
- if (DataSize != sizeof (UINT16)) {
- if (BootNext != NULL) {
- FreePool (BootNext);
- }
+ // if the Platform isn't allowed to override BootNext.
+ // If "BootNext" was already set, a "BootNext" value set in
+ PlatformBootManagerLib APIs // will be ignored; otherwise it will not take
effect until the next boot.
+ //
+ if (!PcdGetBool (PcdAllowBootNextFromPlatformBootManagerLib)) {
+ GetEfiGlobalVariable2 (EFI_BOOT_NEXT_VARIABLE_NAME, (VOID **)&BootNext,
&DataSize);
+ if (DataSize != sizeof (UINT16)) {
+ if (BootNext != NULL) {
+ FreePool (BootNext);
+ }
- BootNext = NULL;
+ BootNext = NULL;
+ }
}
//
@@ -1048,6 +1052,20 @@ BdsEntry (
EfiBootManagerHotkeyBoot ();
+ //
+ // If PlatformBootManagerLib APIs are allowed to override BootNext, read
it just before use
+ //
+ if (PcdGetBool (PcdAllowBootNextFromPlatformBootManagerLib)) {
+ GetEfiGlobalVariable2 (EFI_BOOT_NEXT_VARIABLE_NAME, (VOID **)&BootNext,
&DataSize);
+ if (DataSize != sizeof (UINT16)) {
+ if (BootNext != NULL) {
+ FreePool (BootNext);
+ }
+
+ BootNext = NULL;
+ }
+ }
+
if (BootNext != NULL) {
//
// Delete "BootNext" NV variable before transferring control to it to
prevent loops.
--
2.17.1
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#99929): https://edk2.groups.io/g/devel/message/99929
Mute This Topic: https://groups.io/mt/96861530/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-
