The "ACPI_CPU_DATA.NumberOfCpus" field is specified as follows, in "UefiCpuPkg/Include/AcpiCpuData.h" (rewrapped for this commit message):
// // The number of CPUs. If a platform does not support hot plug CPUs, // then this is the number of CPUs detected when the platform is booted, // regardless of being enabled or disabled. If a platform does support // hot plug CPUs, then this is the maximum number of CPUs that the // platform supports. // The InitializeCpuBeforeRebase() and InitializeCpuAfterRebase() functions in "UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c" try to restore CPU configuration on the S3 Resume path for *all* CPUs accounted for in "ACPI_CPU_DATA.NumberOfCpus". This is wrong, as with CPU hotplug, not all of the possible CPUs may be present at the time of S3 Suspend / Resume. The symptom is an infinite wait. Instead, the "mNumberOfCpus" variable should be used, which is properly maintained through the EFI_SMM_CPU_SERVICE_PROTOCOL implementation (see SmmAddProcessor(), SmmRemoveProcessor(), SmmCpuUpdate() in "UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c"). When CPU hotplug is disabled, "mNumberOfCpus" is constant, and equals "ACPI_CPU_DATA.NumberOfCpus" at all times. Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> Cc: Eric Dong <eric.d...@intel.com> Cc: Igor Mammedov <imamm...@redhat.com> Cc: Jiewen Yao <jiewen....@intel.com> Cc: Jordan Justen <jordan.l.jus...@intel.com> Cc: Michael Kinney <michael.d.kin...@intel.com> Cc: Philippe Mathieu-Daudé <phi...@redhat.com> Cc: Ray Ni <ray...@intel.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512 Signed-off-by: Laszlo Ersek <ler...@redhat.com> Acked-by: Ard Biesheuvel <ard.biesheu...@linaro.org> --- Notes: v2: - Pick up Ard's Acked-by, which is conditional on approval from Intel reviewers on Cc. (I'd like to save Ard the churn of re-acking unmodified patches.) UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c index ba5cc0194c2d..1e0840119724 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c @@ -597,75 +597,85 @@ PrepareApStartupVector ( } /** The function is invoked before SMBASE relocation in S3 path to restores CPU status. The function is invoked before SMBASE relocation in S3 path. It does first time microcode load and restores MTRRs for both BSP and APs. **/ VOID InitializeCpuBeforeRebase ( VOID ) { LoadMtrrData (mAcpiCpuData.MtrrTable); SetRegister (TRUE); ProgramVirtualWireMode (); PrepareApStartupVector (mAcpiCpuData.StartupVector); - mNumberToFinish = mAcpiCpuData.NumberOfCpus - 1; + if (FeaturePcdGet (PcdCpuHotPlugSupport)) { + ASSERT (mNumberOfCpus <= mAcpiCpuData.NumberOfCpus); + } else { + ASSERT (mNumberOfCpus == mAcpiCpuData.NumberOfCpus); + } + mNumberToFinish = mNumberOfCpus - 1; mExchangeInfo->ApFunction = (VOID *) (UINTN) InitializeAp; // // Execute code for before SmmBaseReloc. Note: This flag is maintained across S3 boots. // mInitApsAfterSmmBaseReloc = FALSE; // // Send INIT IPI - SIPI to all APs // SendInitSipiSipiAllExcludingSelf ((UINT32)mAcpiCpuData.StartupVector); while (mNumberToFinish > 0) { CpuPause (); } } /** The function is invoked after SMBASE relocation in S3 path to restores CPU status. The function is invoked after SMBASE relocation in S3 path. It restores configuration according to data saved by normal boot path for both BSP and APs. **/ VOID InitializeCpuAfterRebase ( VOID ) { - mNumberToFinish = mAcpiCpuData.NumberOfCpus - 1; + if (FeaturePcdGet (PcdCpuHotPlugSupport)) { + ASSERT (mNumberOfCpus <= mAcpiCpuData.NumberOfCpus); + } else { + ASSERT (mNumberOfCpus == mAcpiCpuData.NumberOfCpus); + } + mNumberToFinish = mNumberOfCpus - 1; // // Signal that SMM base relocation is complete and to continue initialization for all APs. // mInitApsAfterSmmBaseReloc = TRUE; // // Must begin set register after all APs have continue their initialization. // This is a requirement to support semaphore mechanism in register table. // Because if semaphore's dependence type is package type, semaphore will wait // for all Aps in one package finishing their tasks before set next register // for all APs. If the Aps not begin its task during BSP doing its task, the // BSP thread will hang because it is waiting for other Aps in the same // package finishing their task. // SetRegister (FALSE); while (mNumberToFinish > 0) { CpuPause (); } } -- 2.19.1.3.g30247aa5d201 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#54946): https://edk2.groups.io/g/devel/message/54946 Mute This Topic: https://groups.io/mt/71575170/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
