REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4391

FSP should support the scenario that CPU microcode already loaded
before calling LoadMicrocodeDefault(), in this case it should return
directly without spending more time.
Also the LoadMicrocodeDefault() should only attempt to load one version
of the microcode for current CPU and return directly without parsing
rest of the microcode in FV.

Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Chasel Chiu <chasel.chiu@intel.com>
---
 IntelFsp2Pkg/FspSecCore/Ia32/FspApiEntryT.nasm | 26 ++++++++++++++++++++++----
 IntelFsp2Pkg/FspSecCore/X64/FspApiEntryT.nasm  | 26 ++++++++++++++++++++++----
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/IntelFsp2Pkg/FspSecCore/Ia32/FspApiEntryT.nasm b/IntelFsp2Pkg/FspSecCore/Ia32/FspApiEntryT.nasm
index 2cff8b3643..79f2a20a2c 100644
--- a/IntelFsp2Pkg/FspSecCore/Ia32/FspApiEntryT.nasm
+++ b/IntelFsp2Pkg/FspSecCore/Ia32/FspApiEntryT.nasm
@@ -245,6 +245,22 @@ ASM_PFX(LoadMicrocodeDefault):
    cmp    esp, 0
    jz     ParamError
 
+   ;
+   ; If microcode already loaded before this function, exit this function with SUCCESS.
+   ;
+   mov   ecx, MSR_IA32_BIOS_SIGN_ID
+   xor   eax, eax               ; Clear EAX
+   xor   edx, edx               ; Clear EDX
+   wrmsr                        ; Load 0 to MSR at 8Bh
+
+   mov   eax, 1
+   cpuid
+   mov   ecx, MSR_IA32_BIOS_SIGN_ID
+   rdmsr                         ; Get current microcode signature
+   xor   eax, eax
+   test  edx, edx
+   jnz   Exit2
+
    ; skip loading Microcode if the MicrocodeCodeSize is zero
    ; and report error if size is less than 2k
    ; first check UPD header revision
@@ -450,7 +466,7 @@ LoadCheck:
 
    ; Verify this microcode update is not already loaded
    cmp   dword [esi + MicrocodeHdr.MicrocodeHdrRevision], edx
-   je    Continue
+   je    Done ; if already one version microcode loaded, go to done
 
 LoadMicrocode:
    ; EAX contains the linear address of the start of the Update Data
@@ -465,10 +481,12 @@ LoadMicrocode:
    mov   eax, 1
    cpuid
 
-Continue:
-   jmp   NextMicrocode
-
 Done:
+   mov   ecx, MSR_IA32_BIOS_SIGN_ID
+   xor   eax, eax               ; Clear EAX
+   xor   edx, edx               ; Clear EDX
+   wrmsr                        ; Load 0 to MSR at 8Bh
+
    mov   eax, 1
    cpuid
    mov   ecx, MSR_IA32_BIOS_SIGN_ID
diff --git a/IntelFsp2Pkg/FspSecCore/X64/FspApiEntryT.nasm b/IntelFsp2Pkg/FspSecCore/X64/FspApiEntryT.nasm
index b32fa32a89..3e40678f47 100644
--- a/IntelFsp2Pkg/FspSecCore/X64/FspApiEntryT.nasm
+++ b/IntelFsp2Pkg/FspSecCore/X64/FspApiEntryT.nasm
@@ -141,6 +141,22 @@ ASM_PFX(LoadMicrocodeDefault):
    jz     ParamError
    mov    rsp, rcx
 
+   ;
+   ; If microcode already loaded before this function, exit this function with SUCCESS.
+   ;
+   mov   ecx, MSR_IA32_BIOS_SIGN_ID
+   xor   eax, eax               ; Clear EAX
+   xor   edx, edx               ; Clear EDX
+   wrmsr                        ; Load 0 to MSR at 8Bh
+
+   mov   eax, 1
+   cpuid
+   mov   ecx, MSR_IA32_BIOS_SIGN_ID
+   rdmsr                         ; Get current microcode signature
+   xor   rax, rax
+   test  edx, edx
+   jnz   Exit2
+
    ; skip loading Microcode if the MicrocodeCodeSize is zero
    ; and report error if size is less than 2k
    ; first check UPD header revision
@@ -291,7 +307,7 @@ LoadCheck:
 
    ; Verify this microcode update is not already loaded
    cmp   dword [esi + MicrocodeHdr.MicrocodeHdrRevision], edx
-   je    Continue
+   je    Done ; if already one version microcode loaded, go to done
 
 LoadMicrocode:
    ; EAX contains the linear address of the start of the Update Data
@@ -306,10 +322,12 @@ LoadMicrocode:
    mov   eax, 1
    cpuid
 
-Continue:
-   jmp   NextMicrocode
-
 Done:
+   mov   ecx, MSR_IA32_BIOS_SIGN_ID
+   xor   eax, eax               ; Clear EAX
+   xor   edx, edx               ; Clear EDX
+   wrmsr                        ; Load 0 to MSR at 8Bh
+
    mov   eax, 1
    cpuid
    mov   ecx, MSR_IA32_BIOS_SIGN_ID
-- 
2.35.0.windows.1



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#102334): https://edk2.groups.io/g/devel/message/102334
Mute This Topic: https://groups.io/mt/97984449/1787277
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [importer@patchew.org]
-=-=-=-=-=-=-=-=-=-=-=-