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From: "Zeng, Star" <star.zeng@intel.com>
To: "Ni, Ruiyu" <ruiyu.ni@intel.com>,
	"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Cc: "Dong, Eric" <eric.dong@intel.com>, "Zeng, Star" <star.zeng@intel.com>
Subject: Re: [PATCH] MdeModulePkg/BdsDxe: Don't delete "BootNext" until booting it
Date: Thu, 28 Sep 2017 05:59:52 +0000	[thread overview]
Message-ID: <0C09AFA07DD0434D9E2A0C6AEB0483103B97C214@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <20170928055021.111952-1-ruiyu.ni@intel.com>

I am ok with the code logic change, but a little confused by the new comment. It seems not match with the commit log.

" This could avoid the "BootNext" set by PlatformBootManagerLib be consumed in this boot. "


Thanks,
Star
-----Original Message-----
From: Ni, Ruiyu 
Sent: Thursday, September 28, 2017 1:50 PM
To: edk2-devel@lists.01.org
Cc: Dong, Eric <eric.dong@intel.com>; Zeng, Star <star.zeng@intel.com>
Subject: [PATCH] MdeModulePkg/BdsDxe: Don't delete "BootNext" until booting it

Current implementation deletes the "BootNext" before calling any PlatformBootManagerLib APIs, but if system resets in PlatformBootManagerLib APIs, "BootNext" is not consumed but lost.

The patch defers the deletion of "BootNext" to before booting it.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
---
 MdeModulePkg/Universal/BdsDxe/BdsEntry.c | 35 ++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/MdeModulePkg/Universal/BdsDxe/BdsEntry.c b/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
index ac5f9088dd..a6fe617b56 100644
--- a/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
+++ b/MdeModulePkg/Universal/BdsDxe/BdsEntry.c
@@ -808,7 +808,8 @@ BdsEntry (
   ASSERT_EFI_ERROR (Status);
 
   //
-  // Cache and remove the "BootNext" NV variable.
+  // 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)) {
@@ -817,17 +818,6 @@ BdsEntry (
     }
     BootNext = NULL;
   }
-  Status = gRT->SetVariable (
-                  EFI_BOOT_NEXT_VARIABLE_NAME,
-                  &gEfiGlobalVariableGuid,
-                  0,
-                  0,
-                  NULL
-                  );
-  //
-  // Deleting NV variable shouldn't fail unless it doesn't exist.
-  //
-  ASSERT (Status == EFI_SUCCESS || Status == EFI_NOT_FOUND);
 
   //
   // Initialize the platform language variables @@ -1052,10 +1042,25 @@ BdsEntry (
 
     EfiBootManagerHotkeyBoot ();
 
-    //
-    // Boot to "BootNext"
-    //
     if (BootNext != NULL) {
+      //
+      // Delete "BootNext" NV variable before transferring control to it to prevent loops.
+      //
+      Status = gRT->SetVariable (
+                      EFI_BOOT_NEXT_VARIABLE_NAME,
+                      &gEfiGlobalVariableGuid,
+                      0,
+                      0,
+                      NULL
+                      );
+      //
+      // Deleting NV variable shouldn't fail unless it doesn't exist.
+      //
+      ASSERT (Status == EFI_SUCCESS || Status == EFI_NOT_FOUND);
+
+      //
+      // Boot to "BootNext"
+      //
       UnicodeSPrint (BootNextVariableName, sizeof (BootNextVariableName), L"Boot%04x", *BootNext);
       Status = EfiBootManagerVariableToLoadOption (BootNextVariableName, &LoadOption);
       if (!EFI_ERROR (Status)) {
--
2.12.2.windows.2



  reply	other threads:[~2017-09-28  5:56 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-28  5:50 [PATCH] MdeModulePkg/BdsDxe: Don't delete "BootNext" until booting it Ruiyu Ni
2017-09-28  5:59 ` Zeng, Star [this message]
2017-09-28  6:01   ` Ni, Ruiyu
2017-09-28  6:13     ` Zeng, Star
2017-09-28  6:18       ` Ni, Ruiyu
2017-09-28  6:22         ` Zeng, Star
2017-09-28  6:46 ` Wang, Sunny (HPS SW)

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