On 7/31/20 8:36 AM, Tom Lendacky wrote:
> On 7/31/20 7:43 AM, Laszlo Ersek wrote:
>> Hi Tom,
>
> Hi Laszlo,
Hi Laszlo,
Can you try this incremental patch to see if it fixes the issue you're
seeing? If it does, I'll merge it into patch #45 and send out a v14.
Thanks,
Tom
diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
index 7165bcf3124a..2c00d72ddefe 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
@@ -365,9 +365,9 @@ RelocateApLoop (
MwaitSupport,
CpuMpData->ApTargetCState,
CpuMpData->PmCodeSegment,
- CpuMpData->Pm16CodeSegment,
StackStart - ProcessorNumber * AP_SAFE_STACK_SIZE,
(UINTN) &mNumberToFinish,
+ CpuMpData->Pm16CodeSegment,
CpuMpData->SevEsAPBuffer,
CpuMpData->WakeupBuffer
);
diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
index 309d53bf3b37..7e81d24aa60f 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
@@ -226,7 +226,10 @@ SwitchToRealProcStart:
SwitchToRealProcEnd:
;-------------------------------------------------------------------------------------
-; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
TopOfApStack, CountTofinish);
+; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
TopOfApStack, CountTofinish, Pm16CodeSegment, SevEsAPJumpTable, WakeupBuffer);
+;
+; The last three parameters (Pm16CodeSegment, SevEsAPJumpTable and
WakeupBuffer) are
+; specific to SEV-ES support and are not applicable on IA32.
;-------------------------------------------------------------------------------------
global ASM_PFX(AsmRelocateApLoop)
ASM_PFX(AsmRelocateApLoop):
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h
b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 267aa5201c50..02652eaae126 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -350,9 +350,9 @@ VOID
IN BOOLEAN MwaitSupport,
IN UINTN ApTargetCState,
IN UINTN PmCodeSegment,
- IN UINTN Pm16CodeSegment,
IN UINTN TopOfApStack,
IN UINTN NumberToFinish,
+ IN UINTN Pm16CodeSegment,
IN UINTN SevEsAPJumpTable,
IN UINTN WakeupBuffer
);
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
index 3b8ec477b8b3..5d30f35b201c 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
@@ -491,13 +491,13 @@ PM16Mode:
SwitchToRealProcEnd:
;-------------------------------------------------------------------------------------
-; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
Pm16CodeSegment, TopOfApStack, CountTofinish, SevEsAPJumpTable, WakeupBuffer);
+; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
TopOfApStack, CountTofinish, Pm16CodeSegment, SevEsAPJumpTable, WakeupBuffer);
;-------------------------------------------------------------------------------------
global ASM_PFX(AsmRelocateApLoop)
ASM_PFX(AsmRelocateApLoop):
AsmRelocateApLoopStart:
BITS 64
- cmp qword [rsp + 56], 0
+ cmp qword [rsp + 56], 0 ; SevEsAPJumpTable
je NoSevEs
;
@@ -539,16 +539,17 @@ BITS 64
NoSevEs:
cli ; Disable interrupt before switching to
32-bit mode
- mov rax, [rsp + 48] ; CountTofinish
+ mov rax, [rsp + 40] ; CountTofinish
lock dec dword [rax] ; (*CountTofinish)--
+ mov r10, [rsp + 48] ; Pm16CodeSegment
mov rax, [rsp + 56] ; SevEsAPJumpTable
mov rbx, [rsp + 64] ; WakeupBuffer
- mov rsp, [rsp + 40] ; TopOfApStack
+ mov rsp, r9 ; TopOfApStack
push rax ; Save SevEsAPJumpTable
push rbx ; Save WakeupBuffer
- push r9 ; Save Pm16CodeSegment
+ push r10 ; Save Pm16CodeSegment
push rcx ; Save MwaitSupport
push rdx ; Save ApTargetCState
>
>>
>> On 07/30/20 20:43, Tom Lendacky wrote:
>>> From: Tom Lendacky <thomas.lenda...@amd.com>
>>>
>>> BZ:
>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D2198&data=02%7C01%7Cthomas.lendacky%40amd.com%7Cb8c77cf296c949d2bbd808d8354f542b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637317962138028351&sdata=HISHZmLjOc%2FfgVrBm8MlNeDAk453NJ64%2B51bETZj4rk%3D&reserved=0
>>>
>>>
>>>
>>> Before UEFI transfers control to the OS, it must park the AP. This is
>>> done using the AsmRelocateApLoop function to transition into 32-bit
>>> non-paging mode. For an SEV-ES guest, a few additional things must be
>>> done:
>>> - AsmRelocateApLoop must be updated to support SEV-ES. This means
>>> performing a VMGEXIT AP Reset Hold instead of an MWAIT or HLT loop.
>>> - Since the AP must transition to real mode, a small routine is copied
>>> to the WakeupBuffer area. Since the WakeupBuffer will be used by
>>> the AP during OS booting, it must be placed in reserved memory.
>>> Additionally, the AP stack must be located where it can be accessed
>>> in real mode.
>>> - Once the AP is in real mode it will transfer control to the
>>> destination specified by the OS in the SEV-ES AP Jump Table. The
>>> SEV-ES AP Jump Table address is saved by the hypervisor for the OS
>>> using the GHCB VMGEXIT AP Jump Table exit code.
>>>
>>> Cc: Eric Dong <eric.d...@intel.com>
>>> Cc: Ray Ni <ray...@intel.com>
>>> Cc: Laszlo Ersek <ler...@redhat.com>
>>> Reviewed-by: Eric Dong <eric.d...@intel.com>
>>> Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
>>> ---
>>> UefiCpuPkg/Library/MpInitLib/MpLib.h | 8 +-
>>> UefiCpuPkg/Library/MpInitLib/DxeMpLib.c | 54 +++++++-
>>> UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 131 ++++++++++++++++--
>>> 3 files changed, 175 insertions(+), 18 deletions(-)
>>
>> Now that this series is almost ready to merge, I've done a bit of
>> regression-testing.
>>
>> Unfortunately, this patch breaks booting with IA32 OVMF.
>>
>> More precisely, it breaks the IA32 version of DxeMpInitLib.
>
> Yeah, that's not good. I will look into this based on your input below.
> What's strange is that my system doesn't hang and successfully boots all
> APs (up to 64 is what I've tested with).
>
> But, yes, both call sites should be the same and I will make that change.
>
>>
>> The symptom is that just when the OS would be launched, the
>> multiprocessor guest hangs. This is how the log terminates:
>>
>>> FSOpen: Open
>>> '\370ac550dcaa48b88f1ca75ad903b0e7\4.16.7-100.fc26.i686\linux'
>>> Success
>>> [Security] 3rd party image[0] can be loaded after EndOfDxe:
>>> PciRoot(0x0)/Pci(0x2,0x1)/Pci(0x0,0x0)/Scsi(0x0,0x0)/HD(1,GPT,D9F1FBA5-E5D3-440A-B6A7-87B593E4FAB1,0x800,0x100000)/\370ac550dcaa48b88f1ca75ad903b0e7\4.16.7-100.fc26.i686\linux.
>>>
>>>
>>> InstallProtocolInterface: [EfiLoadedImageProtocol] 853A03A8
>>> Loading driver at 0x00083E72000 EntryPoint=0x00083E76680
>>> InstallProtocolInterface: [EfiLoadedImageDevicePathProtocol] 853A0510
>>> ProtectUefiImageCommon - 0x853A03A8
>>> - 0x0000000083E72000 - 0x0000000000E75000
>>> FSOpen: Open
>>> '370ac550dcaa48b88f1ca75ad903b0e7\4.16.7-100.fc26.i686\initrd'
>>> Success
>>> PixelBlueGreenRedReserved8BitPerColor
>>> ConvertPages: range 400000 - 1274FFF covers multiple entries
>>> SmmInstallProtocolInterface: [EdkiiSmmExitBootServicesProtocol] 0
>>> CpuDxe: 5-Level Paging = 0
>>> [HANG]
>>
>> Meanwhile some guest CPUs are pegged.
>>
>> Normally, when this series is not applied, the next log entry is (in
>> place of [HANG]):
>>
>>> MpInitChangeApLoopCallback() done!
>>
>> I've identified this patch by bisection, after applying the series on
>> current master (137c2c6eff67, "Revert "BaseTools/PatchCheck.py: Add
>> LicenseCheck"", 2020-07-31).
>>
>> Here's the bisection log:
>>
>>> git bisect start
>>> # good: [137c2c6eff67f4750d77e8e40af6683c412d3ed0] Revert
>>> "BaseTools/PatchCheck.py: Add LicenseCheck"
>>> git bisect good 137c2c6eff67f4750d77e8e40af6683c412d3ed0
>>> # bad: [d3f7971f4f70c9f39170b42af837e58e59435ad3] Maintainers.txt: Add
>>> reviewers for the OvmfPkg SEV-related files
>>> git bisect bad d3f7971f4f70c9f39170b42af837e58e59435ad3
>>> # good: [9551e3fc61ba0c0ddf8e79b425a22aa7dd61cb8b] OvmfPkg/VmgExitLib:
>>> Add support for RDTSCP NAE events
>>> git bisect good 9551e3fc61ba0c0ddf8e79b425a22aa7dd61cb8b
>>> # good: [10acf16b38522d8a1b538b3aa432daaa72c0e97b] OvmfPkg: Reserve a
>>> page in memory for the SEV-ES usage
>>> git bisect good 10acf16b38522d8a1b538b3aa432daaa72c0e97b
>>> # good: [ccb4267e76b6474657c41bef7e76a980930c22ea] UefiCpuPkg: Add a
>>> 16-bit protected mode code segment descriptor
>>> git bisect good ccb4267e76b6474657c41bef7e76a980930c22ea
>>> # good: [94e238ae37505cfb081f3b9b4632067e4a113cf9] OvmfPkg: Use the
>>> SEV-ES work area for the SEV-ES AP reset vector
>>> git bisect good 94e238ae37505cfb081f3b9b4632067e4a113cf9
>>> # bad: [16c21b9d10b032d66d4105dd4693fd9dc6e6ec18] UefiCpuPkg/MpInitLib:
>>> Prepare SEV-ES guest APs for OS use
>>> git bisect bad 16c21b9d10b032d66d4105dd4693fd9dc6e6ec18
>>> # good: [49855596e383ab2aa6410fa060e22d4817d8e64e] OvmfPkg: Move the
>>> GHCB allocations into reserved memory
>>> git bisect good 49855596e383ab2aa6410fa060e22d4817d8e64e
>>> # first bad commit: [16c21b9d10b032d66d4105dd4693fd9dc6e6ec18]
>>> UefiCpuPkg/MpInitLib: Prepare SEV-ES guest APs for OS use
>>
>> So clearly we should be looking for an IA32-specific change, or
>> IA32-specific *omission*, in this patch, that could cause the problem.
>>
>> The bug is the following:
>>
>> On 07/30/20 20:43, Tom Lendacky wrote:
>>>
>>> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h
>>> b/UefiCpuPkg/Library/MpInitLib/MpLib.h
>>> index b1a9d99cb3eb..267aa5201c50 100644
>>> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
>>> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
>>> @@ -349,8 +350,11 @@ VOID
>>> IN BOOLEAN MwaitSupport,
>>> IN UINTN ApTargetCState,
>>> IN UINTN PmCodeSegment,
>>> + IN UINTN Pm16CodeSegment,
>>> IN UINTN TopOfApStack,
>>> - IN UINTN NumberToFinish
>>> + IN UINTN NumberToFinish,
>>> + IN UINTN SevEsAPJumpTable,
>>> + IN UINTN WakeupBuffer
>>> );
>>>
>>> /**
>>
>> (1) This hunk modifies the parameter list of functions pointed-to by
>> ASM_RELOCATE_AP_LOOP.
>>
>>> diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
>>> b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
>>> index 9115ff9e3e30..7165bcf3124a 100644
>>> --- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
>>> +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
>>> @@ -330,17 +350,26 @@ RelocateApLoop (
>>> BOOLEAN MwaitSupport;
>>> ASM_RELOCATE_AP_LOOP AsmRelocateApLoopFunc;
>>> UINTN ProcessorNumber;
>>> + UINTN StackStart;
>>>
>>> MpInitLibWhoAmI (&ProcessorNumber);
>>> CpuMpData = GetCpuMpData ();
>>> MwaitSupport = IsMwaitSupport ();
>>> + if (CpuMpData->SevEsIsEnabled) {
>>> + StackStart = CpuMpData->SevEsAPResetStackStart;
>>> + } else {
>>> + StackStart = mReservedTopOfApStack;
>>> + }
>>> AsmRelocateApLoopFunc = (ASM_RELOCATE_AP_LOOP) (UINTN)
>>> mReservedApLoopFunc;
>>> AsmRelocateApLoopFunc (
>>> MwaitSupport,
>>> CpuMpData->ApTargetCState,
>>> CpuMpData->PmCodeSegment,
>>> - mReservedTopOfApStack - ProcessorNumber * AP_SAFE_STACK_SIZE,
>>> - (UINTN) &mNumberToFinish
>>> + CpuMpData->Pm16CodeSegment,
>>> + StackStart - ProcessorNumber * AP_SAFE_STACK_SIZE,
>>> + (UINTN) &mNumberToFinish,
>>> + CpuMpData->SevEsAPBuffer,
>>> + CpuMpData->WakeupBuffer
>>> );
>>> //
>>> // It should never reach here
>>
>> (2) This hunk modifies the call site, in accordance with the prototype
>> change at (1).
>>
>>> diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>> b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>> index 6956b408d004..3b8ec477b8b3 100644
>>> --- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>> +++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>> @@ -465,6 +465,10 @@ BITS 16
>>
>>> ; - IP for Real Mode (two bytes)
>>> ; - CS for Real Mode (two bytes)
>>> ;
>>> + ; This label is also used with AsmRelocateApLoop. During MP
>>> finalization,
>>> + ; the code from PM16Mode to SwitchToRealProcEnd is copied to the
>>> start of
>>> + ; the WakeupBuffer, allowing a parked AP to be booted by an OS.
>>> + ;
>>> PM16Mode:
>>> mov eax, cr0 ; Read CR0
>>> btr eax, 0 ; Set PE=0
>>> @@ -487,32 +491,95 @@ PM16Mode:
>>> SwitchToRealProcEnd:
>>>
>>>
>>> ;-------------------------------------------------------------------------------------
>>>
>>>
>>> -; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
>>> TopOfApStack, CountTofinish);
>>> +; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment,
>>> Pm16CodeSegment, TopOfApStack, CountTofinish, SevEsAPJumpTable,
>>> WakeupBuffer);
>>>
>>> ;-------------------------------------------------------------------------------------
>>>
>>>
>>> global ASM_PFX(AsmRelocateApLoop)
>>> ASM_PFX(AsmRelocateApLoop):
>>> AsmRelocateApLoopStart:
>>> BITS 64
>>
>> (3) Unfortunately, the patch only adapts the X64 implementation of the
>> AsmRelocateApLoopStart() function to the new prototype; the IA32
>> implementation no longer matches the call site.
>>
>> (I'm not sure if the intent was for the IA32 version to simply ignore
>> the new parameters, but even in that case, the "Pm16CodeSegment"
>> parameter is inserted in the middle of the parameter list, likely
>> offsetting the rest.)
>>
>> The problem is foreshadowed even by hunk (2). Namely, in hunk (2), the
>>
>> s/mReservedTopOfApStack/StackStart/
>>
>> replacement is *more difficult* to verify than necessary -- exactly
>> because "CpuMpData->Pm16CodeSegment" is inserted *before* it.
>
> I can do one of two things here and just put the 3 new parameters at the
> end of the function call rather than keeping the code segment parameters
> together or update the IA32 call site. Let me see which looks best. But
> I'll likely update the IA32 call site no matter what with at least
> comments about the parameters that aren't used, either way.
>
> Thanks,
> Tom
>
>>
>> Thanks
>> Laszlo
>>
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