On 2/20/24 18:49, Gerd Hoffmann wrote:
> Add support for splitting Hand-Off data into multiple HOBs. This is
> required for VMs with thousands of CPUs. The actual CPU count per HOB
> is much smaller (128) for better test coverage.
(1) The mention of the count 128 now seems stale for the code.
>
> Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
> ---
> UefiCpuPkg/Library/MpInitLib/PeiMpLib.c | 44 +++++++++++++++----------
> 1 file changed, 27 insertions(+), 17 deletions(-)
>
> diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> index f80e00edcff3..8a916a218016 100644
> --- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
> @@ -126,35 +126,45 @@ SaveCpuMpData (
> IN CPU_MP_DATA *CpuMpData
> )
> {
> + UINT32 MaxCpusPerHob, CpusInHob;
> UINT64 Data64;
> - UINTN Index;
> + UINT32 Index, HobBase;
> CPU_INFO_IN_HOB *CpuInfoInHob;
> MP_HAND_OFF *MpHandOff;
> UINTN MpHandOffSize;
>
> + MaxCpusPerHob = (MAX_UINT16 - sizeof (EFI_HOB_GUID_TYPE) - sizeof
> (MP_HAND_OFF)) / sizeof (PROCESSOR_HAND_OFF);
(2) MAX_UINT16 should be 0xFFF8 instead; see subthread.
> +
> //
> // When APs are in a state that can be waken up by a store operation to a
> memory address,
> // report the MP_HAND_OFF data for DXE to use.
> //
> - CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
> - MpHandOffSize = sizeof (MP_HAND_OFF) + sizeof (PROCESSOR_HAND_OFF) *
> CpuMpData->CpuCount;
> - MpHandOff = (MP_HAND_OFF *)BuildGuidHob (&mMpHandOffGuid,
> MpHandOffSize);
> - ASSERT (MpHandOff != NULL);
> - ZeroMem (MpHandOff, MpHandOffSize);
> - MpHandOff->ProcessorIndex = 0;
> + CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
>
> - MpHandOff->CpuCount = CpuMpData->CpuCount;
> - if (CpuMpData->ApLoopMode != ApInHltLoop) {
> - MpHandOff->StartupSignalValue = MP_HAND_OFF_SIGNAL;
> - MpHandOff->WaitLoopExecutionMode = sizeof (VOID *);
> - }
> + for (Index = 0; Index < CpuMpData->CpuCount; Index++) {
> + if (Index % MaxCpusPerHob == 0) {
> + HobBase = Index;
> + CpusInHob = MIN (CpuMpData->CpuCount - HobBase, MaxCpusPerHob);
>
> - for (Index = 0; Index < MpHandOff->CpuCount; Index++) {
> - MpHandOff->Info[Index].ApicId = CpuInfoInHob[Index].ApicId;
> - MpHandOff->Info[Index].Health = CpuInfoInHob[Index].Health;
> + MpHandOffSize = sizeof (MP_HAND_OFF) + sizeof (PROCESSOR_HAND_OFF) *
> CpusInHob;
> + MpHandOff = (MP_HAND_OFF *)BuildGuidHob (&mMpHandOffGuid,
> MpHandOffSize);
> + ASSERT (MpHandOff != NULL);
> + ZeroMem (MpHandOff, MpHandOffSize);
> +
> + MpHandOff->ProcessorIndex = HobBase;
> + MpHandOff->CpuCount = CpusInHob;
> +
> + if (CpuMpData->ApLoopMode != ApInHltLoop) {
> + MpHandOff->StartupSignalValue = MP_HAND_OFF_SIGNAL;
> + MpHandOff->WaitLoopExecutionMode = sizeof (VOID *);
> + }
> + }
> +
> + MpHandOff->Info[Index-HobBase].ApicId = CpuInfoInHob[Index].ApicId;
> + MpHandOff->Info[Index-HobBase].Health = CpuInfoInHob[Index].Health;
> if (CpuMpData->ApLoopMode != ApInHltLoop) {
> - MpHandOff->Info[Index].StartupSignalAddress =
> (UINT64)(UINTN)CpuMpData->CpuData[Index].StartupApSignal;
> - MpHandOff->Info[Index].StartupProcedureAddress =
> (UINT64)(UINTN)&CpuMpData->CpuData[Index].ApFunction;
> + MpHandOff->Info[Index-HobBase].StartupSignalAddress =
> (UINT64)(UINTN)CpuMpData->CpuData[Index].StartupApSignal;
> + MpHandOff->Info[Index-HobBase].StartupProcedureAddress =
> (UINT64)(UINTN)&CpuMpData->CpuData[Index].ApFunction;
> }
> }
>
(3) The conversion looks good otherwise, but I dislike that
StartupSignalValue and WaitLoopExecutionMode get uselessly replicated
over all HOBs. Again, it *increases* technical debt. It's fine to ignore
existent debt (if you can), but adding to it is not right.
Can you file a new TianoCore BZ, for moving these fields to separate
dynamic PCDs, or to a new singleton GUID HOB (containing both fields)?
If you assign that BZ to yourself, and reference it in patches #4 and
#5, I'll be happy to R-b version 3 of the series. (Which is something
I'd like to do.)
Version 3 may be mergeable regardless, of course, if Ray accepts it.
Thanks,
Laszlo
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#115770): https://edk2.groups.io/g/devel/message/115770
Mute This Topic: https://groups.io/mt/104472313/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-
