[edk2-devel] [Patch V3] UefiCpuPkg/PiSmmCpuDxeSmm: SmmCpuRendezvous ensure all Aps in Present.

["Yuanhao Xie" <yuanhao.xie@intel.com>]

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.li@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiaxin Wu <jiaxin.wu@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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