Yuanhao, Zhihao,
Can you kindly explain a bit more about this sentence in commit message " SMM
read save state requires AP must be present."?
Thanks,
Ray
> -----Original Message-----
> From: Xie, Yuanhao <yuanhao....@intel.com>
> Sent: Friday, December 15, 2023 5:30 PM
> To: devel@edk2.groups.io
> Cc: Xie, Yuanhao <yuanhao....@intel.com>; Li, Zhihao <zhihao...@intel.com>;
> Ni, Ray <ray...@intel.com>; Kumar, Rahul R <rahul.r.ku...@intel.com>; Gerd
> Hoffmann <kra...@redhat.com>; Wu, Jiaxin <jiaxin...@intel.com>
> Subject: [Patch V3] UefiCpuPkg/PiSmmCpuDxeSmm: SmmCpuRendezvous
> ensure all Aps in Present.
>
> SMM read save state requires AP must be present.
> This patch aim to avoid the AP not ready for save state check.
> Furthermore, SmmWaitForApArrival has two callers: SmmCpuRendezvous and
> BSPHandler, the behavior of the two callers can be consistent by add
> the while loop to check the present of the APs to SmmCpuRendezvous.
>
> Signed-off-by: Zhihao Li <zhihao...@intel.com>
> Cc: Ray Ni <ray...@intel.com>
> Cc: Rahul Kumar <rahul1.ku...@intel.com>
> Cc: Gerd Hoffmann <kra...@redhat.com>
> Cc: Jiaxin Wu <jiaxin...@intel.com>
> ---
> UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c | 27
> +++++++++++++++++++++++++++
> UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h | 13 +++++++++++++
> 2 files changed, 40 insertions(+)
>
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> index c0485b0519..3e98955319 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> @@ -416,8 +416,15 @@ SmmCpuRendezvous (
> IN BOOLEAN BlockingMode
> )
> {
> + UINTN Index;
> + UINTN PresentCount;
> + UINT32 BlockedCount;
> + UINT32 DisabledCount;
> EFI_STATUS Status;
>
> + BlockedCount = 0;
> + DisabledCount = 0;
> +
> //
> // Return success immediately if all CPUs are already synchronized.
> //
> @@ -436,6 +443,26 @@ SmmCpuRendezvous (
> // There are some APs outside SMM, Wait for all avaiable APs to arrive.
> //
> SmmWaitForApArrival ();
> +
> + //
> + // Make sure all APs have their Present flag set
> + //
> + while (TRUE) {
> + PresentCount = 0;
> + for (Index = 0; Index < mMaxNumberOfCpus; Index++) {
> + if (*(mSmmMpSyncData->CpuData[Index].Present)) {
> + PresentCount++;
> + }
> + }
> +
> + GetSmmDelayedBlockedDisabledCount (NULL, &BlockedCount,
> &DisabledCount);
> + if (PresentCount == mMaxNumberOfCpus - BlockedCount -
> DisabledCount ) {
> + break;
> + }
> +
> + CpuPause ();
> + }
> +
> Status = mSmmMpSyncData->AllApArrivedWithException ?
> EFI_SUCCESS : EFI_TIMEOUT;
> } else {
> //
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
> b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
> index f18345881b..e3538957fb 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
> @@ -1552,6 +1552,19 @@ SmmWaitForApArrival (
> VOID
> );
>
> +/**
> + Returns the Number of SMM Delayed & Blocked & Disabled Thread Count.
> + @param[in,out] DelayedCount The Number of SMM Delayed Thread
> Count.
> + @param[in,out] BlockedCount The Number of SMM Blocked Thread
> Count.
> + @param[in,out] DisabledCount The Number of SMM Disabled Thread
> Count.
> +**/
> +VOID
> +GetSmmDelayedBlockedDisabledCount (
> + IN OUT UINT32 *DelayedCount,
> + IN OUT UINT32 *BlockedCount,
> + IN OUT UINT32 *DisabledCount
> + );
> +
> /**
> Write unprotect read-only pages if Cr0.Bits.WP is 1.
>
> --
> 2.39.1.windows.1
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