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UefiCpuPkg:Wake up APs after power-up or RESET through SIPI.

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The implementation of this new behavior aligns with the guidelines
outlined in the Intel SDM.

Following a power-up or RESET of an MP system, system hardware
dynamically selects one of the processors on the system bus as the BSP.
The remaining processors are designated as APs. The APs complete a
minimal self-configuration, then wait for a startup signal (a SIPI
message) from the BSP processor.

Additionally, the MP protocol is executed only after
a power-up or RESET. If the MP protocol has completed and a
BSP is chosen, subsequent INITs (either to a specific processor or
system wide) do not cause the MP protocol to be repeated. Instead, each
logical processor examines its BSP flag (in the IA32_APIC_BASE MSR) to
determine whether it should execute the BIOS boot-strap code (if it is
the BSP) or enter a wait-for-SIPI state (if it is an AP).

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Ray Ni <ray.ni@intel.com>
Signed-off-by: Yuanhao Xie <yuanhao.xie@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
This commit is contained in:
YuanhaoXie
2023-07-18 17:59:30 +08:00
committed by mergify[bot]
parent 1d76560146
commit eaffa1d7ff
1 changed files with 8 additions and 1 deletions
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7
UefiCpuPkg/Library/MpInitLib/MpLib.c
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@@ -1293,10 +1293,17 @@ WakeUpAP (
// //
if (CpuMpData->SevSnpIsEnabled && (CpuMpData->InitFlag != ApInitConfig)) { if (CpuMpData->SevSnpIsEnabled && (CpuMpData->InitFlag != ApInitConfig)) {
SevSnpCreateAP (CpuMpData, -1); SevSnpCreateAP (CpuMpData, -1);
} else {
if ((CpuMpData->InitFlag == ApInitConfig) && FixedPcdGetBool (PcdFirstTimeWakeUpAPsBySipi)) {
//
// SIPI can be used for the first time wake up after reset to reduce boot time.
//
SendStartupIpiAllExcludingSelf ((UINT32)ExchangeInfo->BufferStart);
} else { } else {
SendInitSipiSipiAllExcludingSelf ((UINT32)ExchangeInfo->BufferStart); SendInitSipiSipiAllExcludingSelf ((UINT32)ExchangeInfo->BufferStart);
} }
} }
}
if (CpuMpData->InitFlag == ApInitConfig) { if (CpuMpData->InitFlag == ApInitConfig) {
if (PcdGet32 (PcdCpuBootLogicalProcessorNumber) > 0) { if (PcdGet32 (PcdCpuBootLogicalProcessorNumber) > 0) {