Introduce a new function UnplugCpus() which, for each unplugged CPU:
* finds the slot for APIC ID in CPU_HOT_PLUG_DATA
* informs PiSmmCpuDxeSmm by calling
EFI_SMM_CPU_SERVICE_PROTOCOL.RemoveProcessor()
* caches the APIC ID, such that it can be ejected at SMI exit
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Aaron Young <aaron.young@oracle.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3132
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 135 ++++++++++++++++++++++++++++++++++++-
1 file changed, 134 insertions(+), 1 deletion(-)
diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
index 0f8f210d0ecf..20d92a35da39 100644
--- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
+++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
@@ -53,6 +53,14 @@ STATIC CPU_HOT_PLUG_DATA *mCpuHotPlugData;
STATIC APIC_ID *mPluggedApicIds;
STATIC APIC_ID *mToUnplugApicIds;
//
+// Similar to the SMRAM arrays above mHotunplugWork stores APIC IDs of
+// processors with pending unplugs for the duration of the MMI.
+//
+// This array maps ProcessorNum -> APIC ID and so has room for possible
+// CPU count.
+//
+STATIC APIC_ID *mHotUnplugWork;
+//
// Address of the non-SMRAM reserved memory page that contains the Post-SMM Pen
// for hot-added CPUs.
//
@@ -182,6 +190,100 @@ Fatal:
}
/**
+ CPU Hot-unplug handler function.
+
+ @param[in] mUnplugApicIds List of APIC IDs to be unplugged.
+
+ @param[in] ToUnplugCount Count of APIC IDs to be unplugged.
+
+ @param[out] mHotUnplugWork List mapping ProcessorNum -> APIC ID for later unplug.
+ Invalid entries are specified as MAX_UINT32.
+
+ @retval EFI_SUCCESS Some of the requested APIC IDs will be hot-unplugged.
+
+ @retval EFI_INTERRUPT_PENDING Fatal error while hot-plugging.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+UnplugCpus(
+ IN APIC_ID *mUnplugApicIds,
+ IN UINT32 ToUnplugCount,
+ OUT APIC_ID *mHotUnplugWork
+ )
+{
+ EFI_STATUS Status = EFI_SUCCESS;
+ UINT32 ToUnplugIdx;
+
+ //
+ // Remove the CPU with EFI_SMM_CPU_SERVICE_PROTOCOL.
+ //
+
+ ToUnplugIdx = 0;
+ while (ToUnplugIdx < ToUnplugCount) {
+ APIC_ID RemoveApicId;
+ UINT32 ProcessorNum;
+
+ RemoveApicId = mUnplugApicIds[ToUnplugIdx];
+
+ for (ProcessorNum = 0;
+ ProcessorNum < mCpuHotPlugData->ArrayLength;
+ ProcessorNum++) {
+ if (mCpuHotPlugData->ApicId[ProcessorNum] == RemoveApicId) {
+ break;
+ }
+ }
+
+ //
+ // Ignore the unplug if APIC ID is not found
+ //
+ if (ProcessorNum == mCpuHotPlugData->ArrayLength) {
+ DEBUG ((DEBUG_VERBOSE, "%a: did not find APIC ID " FMT_APIC_ID " to unplug\n",
+ __FUNCTION__, RemoveApicId));
+ ToUnplugIdx++;
+ continue;
+ }
+
+ Status = mMmCpuService->RemoveProcessor (mMmCpuService, ProcessorNum);
+
+ if (EFI_ERROR(Status)) {
+ DEBUG ((DEBUG_ERROR, "%a: RemoveProcessor(" FMT_APIC_ID "): %r\n",
+ __FUNCTION__, RemoveApicId, Status));
+ goto Fatal;
+ } else {
+ //
+ // Stash the APIC IDs so we can do the actual unplug later.
+ //
+
+ if (mHotUnplugWork[ProcessorNum] != MAX_UINT32) {
+ //
+ // Since ProcessorNum and APIC-ID are a 1-1 mapping, so an already
+ // filled mHotUnplugWork[ProcessorNum] is a fatal error.
+ //
+ DEBUG ((DEBUG_ERROR, "%a: ProcessorNum %u maps to " FMT_APIC_ID ", cannot map to " FMT_APIC_ID "\n",
+ __FUNCTION__, ProcessorNum, mHotUnplugWork[ProcessorNum], RemoveApicId));
+ goto Fatal;
+ }
+
+ DEBUG ((DEBUG_INFO, "%a: Caching ProcessorNum %u -> " FMT_APIC_ID " for unplugging\n",
+ __FUNCTION__, ProcessorNum, RemoveApicId));
+ mHotUnplugWork[ProcessorNum] = RemoveApicId;
+ }
+
+ ToUnplugIdx++;
+ }
+
+ //
+ // We've handled this unplug.
+ //
+ return EFI_SUCCESS;
+
+Fatal:
+ return EFI_INTERRUPT_PENDING;
+}
+
+/**
CPU Hotplug MMI handler function.
This is a root MMI handler.
@@ -297,6 +399,8 @@ CpuHotplugMmi (
if (PluggedCount > 0) {
Status = PlugCpus(mPluggedApicIds, PluggedCount);
+ } else if (ToUnplugCount > 0) {
+ Status = UnplugCpus(mToUnplugApicIds, ToUnplugCount, mHotUnplugWork);
}
if (EFI_ERROR(Status)) {
@@ -330,6 +434,7 @@ CpuHotplugEntry (
{
EFI_STATUS Status;
UINTN Size;
+ UINTN Idx;
//
// This module should only be included when SMM support is required.
@@ -403,12 +508,36 @@ CpuHotplugEntry (
}
//
+ // Allocate for the full CPU count. We index to-be-unplugged APIC IDs
+ // with ProcessorNum.
+ //
+ if (RETURN_ERROR (SafeUintnMult (sizeof (APIC_ID), mCpuHotPlugData->ArrayLength, &Size))) {
+ Status = EFI_ABORTED;
+ DEBUG ((DEBUG_ERROR, "%a: invalid CPU_HOT_PLUG_DATA\n", __FUNCTION__));
+ goto ReleaseToUnplugApicIds;
+ }
+ Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,
+ (VOID **)&mHotUnplugWork);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__, Status));
+ goto ReleaseToUnplugApicIds;
+ }
+
+ //
+ // We will use mHotUnplugWork to map from ProcessorNum -> APIC_ID.
+ // Initialize to known invalid values.
+ //
+ for (Idx = 0; Idx < mCpuHotPlugData->ArrayLength; Idx++) {
+ mHotUnplugWork[Idx] = MAX_UINT32;
+ }
+
+ //
// Allocate the Post-SMM Pen for hot-added CPUs.
//
Status = SmbaseAllocatePostSmmPen (&mPostSmmPenAddress,
SystemTable->BootServices);
if (EFI_ERROR (Status)) {
- goto ReleaseToUnplugApicIds;
+ goto ReleaseToHotUnplugWork;
}
//
@@ -468,6 +597,10 @@ ReleasePostSmmPen:
SmbaseReleasePostSmmPen (mPostSmmPenAddress, SystemTable->BootServices);
mPostSmmPenAddress = 0;
+ReleaseToHotUnplugWork:
+ gMmst->MmFreePool (mHotUnplugWork);
+ mHotUnplugWork = NULL;
+
ReleaseToUnplugApicIds:
gMmst->MmFreePool (mToUnplugApicIds);
mToUnplugApicIds = NULL;
--
2.9.3
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