[edk2-devel] [PATCH v6 4/9] OvmfPkg/CpuHotplugSmm: introduce UnplugCpus()
Ankur Arora
ankur.a.arora at oracle.com
Fri Jan 29 00:59:45 UTC 2021
Introduce UnplugCpus() which maps each APIC ID being unplugged
onto the hardware ID of the processor and informs PiSmmCpuDxeSmm
of removal by calling EFI_SMM_CPU_SERVICE_PROTOCOL.RemoveProcessor().
With this change we handle the first phase of unplug where we collect
the CPUs that need to be unplugged and mark them for removal in SMM
data structures.
Cc: Laszlo Ersek <lersek at redhat.com>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel at arm.com>
Cc: Igor Mammedov <imammedo at redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky at oracle.com>
Cc: Aaron Young <aaron.young at oracle.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3132
Signed-off-by: Ankur Arora <ankur.a.arora at oracle.com>
---
OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 84 ++++++++++++++++++++++++++++++++++++++
1 file changed, 84 insertions(+)
diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
index 05b1f8cb63a6..70d69f6ed65b 100644
--- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
+++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
@@ -188,6 +188,88 @@ RevokeNewSlot:
}
/**
+ Process to be hot-unplugged CPUs, per QemuCpuhpCollectApicIds().
+
+ For each such CPU, report the CPU to PiSmmCpuDxeSmm via
+ EFI_SMM_CPU_SERVICE_PROTOCOL. If the to be hot-unplugged CPU is
+ unknown, skip it silently.
+
+ @param[in] ToUnplugApicIds The APIC IDs of the CPUs that are about to be
+ hot-unplugged.
+
+ @param[in] ToUnplugCount The number of filled-in APIC IDs in
+ ToUnplugApicIds.
+
+ @retval EFI_SUCCESS Known APIC IDs have been removed from SMM data
+ structures.
+
+ @return Error codes propagated from
+ mMmCpuService->RemoveProcessor().
+
+**/
+STATIC
+EFI_STATUS
+UnplugCpus (
+ IN APIC_ID *ToUnplugApicIds,
+ IN UINT32 ToUnplugCount
+ )
+{
+ EFI_STATUS Status;
+ UINT32 ToUnplugIdx;
+ UINTN ProcessorNum;
+
+ ToUnplugIdx = 0;
+ while (ToUnplugIdx < ToUnplugCount) {
+ APIC_ID RemoveApicId;
+
+ RemoveApicId = ToUnplugApicIds[ToUnplugIdx];
+
+ //
+ // mCpuHotPlugData->ApicId maps ProcessorNum -> ApicId. Use it to find
+ // the ProcessorNum for the APIC ID to be removed.
+ //
+ for (ProcessorNum = 0;
+ ProcessorNum < mCpuHotPlugData->ArrayLength;
+ ProcessorNum++) {
+ if (mCpuHotPlugData->ApicId[ProcessorNum] == RemoveApicId) {
+ break;
+ }
+ }
+
+ //
+ // Ignore the unplug if APIC ID not found
+ //
+ if (ProcessorNum == mCpuHotPlugData->ArrayLength) {
+ DEBUG ((DEBUG_INFO, "%a: did not find APIC ID " FMT_APIC_ID
+ " to unplug\n", __FUNCTION__, RemoveApicId));
+ ToUnplugIdx++;
+ continue;
+ }
+
+ //
+ // Mark ProcessorNum for removal from SMM data structures
+ //
+ Status = mMmCpuService->RemoveProcessor (mMmCpuService, ProcessorNum);
+
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "%a: RemoveProcessor(" FMT_APIC_ID "): %r\n",
+ __FUNCTION__, RemoveApicId, Status));
+ goto Fatal;
+ }
+
+ ToUnplugIdx++;
+ }
+
+ //
+ // We've removed this set of APIC IDs from SMM data structures.
+ //
+ return EFI_SUCCESS;
+
+Fatal:
+ return Status;
+}
+
+/**
CPU Hotplug MMI handler function.
This is a root MMI handler.
@@ -303,6 +385,8 @@ CpuHotplugMmi (
if (PluggedCount > 0) {
Status = ProcessHotAddedCpus (mPluggedApicIds, PluggedCount);
+ } else if (ToUnplugCount > 0) {
+ Status = UnplugCpus (mToUnplugApicIds, ToUnplugCount);
}
if (EFI_ERROR(Status)) {
--
2.9.3
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