Re: [Patch] UefiCpuPkg/MpInitLib: Keep compatible with former solution.

[Fan Jeff <vanjeff_919@hotmail.com>]

Reviewed-by: Jeff Fan <vanjeff_919@hotmail.com<mailto:vanjeff_919@hotmail.com>>



发自我的小米手机
在 Eric Dong <eric.dong@intel.com>，2017年10月26日 下午1:59写道：

For some special platforms (such as Ovmf), it is possible
that, some APs start up *and finish* before the remaining
APs not start up *at all*. In this case, the enhance
solution by changes 0594ec41 not works as expected.

This change remove check CpuMpData->CpuCount logic to let old
solution still workable if platform owner still set a long
time for PcdCpuApInitTimeOutInMicroSeconds. It's platform
owner's response to decide which solution to use.

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Jeff Fan <vanjeff_919@hotmail.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 48f930b..18060fd 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -936,15 +936,20 @@ WakeUpAP (
     }
     if (CpuMpData->InitFlag == ApInitConfig) {
       //
-      // Wait for one potential AP waken up in one specified period
+      // Here support two methods to collect AP count through adjust
+      // PcdCpuApInitTimeOutInMicroSeconds values.
       //
-      if (CpuMpData->CpuCount == 0) {
-        TimedWaitForApFinish (
-          CpuMpData,
-          PcdGet32 (PcdCpuMaxLogicalProcessorNumber) - 1,
-          PcdGet32 (PcdCpuApInitTimeOutInMicroSeconds)
-          );
-      }
+      // one way is set a value to just let the first AP to start the
+      // initialization, then through the later while loop to wait all Aps
+      // finsh the initialization.
+      // The other way is set a value to let all APs finished the initialzation.
+      // In this case, the later while loop is useless.
+      //
+      TimedWaitForApFinish (
+        CpuMpData,
+        PcdGet32 (PcdCpuMaxLogicalProcessorNumber) - 1,
+        PcdGet32 (PcdCpuApInitTimeOutInMicroSeconds)
+        );

       while (CpuMpData->MpCpuExchangeInfo->NumApsExecuting != 0) {
         CpuPause();
--
2.7.0.windows.1