[edk2-devel] [PATCH v6 1/9] OvmfPkg/CpuHotplugSmm: refactor hotplug logic
Laszlo Ersek
lersek at redhat.com
Sat Jan 30 01:15:25 UTC 2021
On 01/29/21 01:59, Ankur Arora wrote:
> Refactor CpuHotplugMmi() to pull out the CPU hotplug logic into
> ProcessHotAddedCpus(). This is in preparation for supporting CPU
> hot-unplug.
>
> 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>
> ---
>
> Notes:
> > + if (EFI_ERROR(Status)) {
> > + goto Fatal;
> > }
>
> (13) Without having seen the rest of the patches, I think this error
> check should be nested under the same (PluggedCount > 0) condition; in
> other words, I think it only makes sense to check Status after we
> actually call ProcessHotAddedCpus().
>
> Addresses all comments from v5, except for this one, since the (lack) of
> nesting makes more sense after patch 4, "OvmfPkg/CpuHotplugSmm: introduce
> UnplugCpus()".
>
> OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 214 ++++++++++++++++++++++---------------
> 1 file changed, 129 insertions(+), 85 deletions(-)
>
> diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> index cfe698ed2b5e..05b1f8cb63a6 100644
> --- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> +++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> @@ -62,6 +62,130 @@ STATIC UINT32 mPostSmmPenAddress;
> //
> STATIC EFI_HANDLE mDispatchHandle;
>
> +/**
> + Process CPUs that have been hot-added, per QemuCpuhpCollectApicIds().
> +
> + For each such CPU, relocate the SMBASE, and report the CPU to PiSmmCpuDxeSmm
> + via EFI_SMM_CPU_SERVICE_PROTOCOL. If the supposedly hot-added CPU is already
> + known, skip it silently.
> +
> + @param[in] PluggedApicIds The APIC IDs of the CPUs that have been
> + hot-plugged.
> +
> + @param[in] PluggedCount The number of filled-in APIC IDs in
> + PluggedApicIds.
> +
> + @retval EFI_SUCCESS CPUs corresponding to all the APIC IDs are
> + populated.
> +
> + @retval EFI_OUT_OF_RESOURCES Out of APIC ID space in "mCpuHotPlugData".
> +
> + @return Error codes propagated from SmbaseRelocate()
> + and mMmCpuService->AddProcessor().
> +
> +**/
> +STATIC
> +EFI_STATUS
> +ProcessHotAddedCpus (
> + IN APIC_ID *PluggedApicIds,
> + IN UINT32 PluggedCount
> + )
> +{
> + EFI_STATUS Status;
> + UINT32 PluggedIdx;
> + UINT32 NewSlot;
> +
> + //
> + // The Post-SMM Pen need not be reinstalled multiple times within a single
> + // root MMI handling. Even reinstalling once per root MMI is only prudence;
> + // in theory installing the pen in the driver's entry point function should
> + // suffice.
> + //
> + SmbaseReinstallPostSmmPen (mPostSmmPenAddress);
> +
> + PluggedIdx = 0;
> + NewSlot = 0;
> + while (PluggedIdx < PluggedCount) {
> + APIC_ID NewApicId;
> + UINT32 CheckSlot;
> + UINTN NewProcessorNumberByProtocol;
> +
> + NewApicId = PluggedApicIds[PluggedIdx];
> +
> + //
> + // Check if the supposedly hot-added CPU is already known to us.
> + //
> + for (CheckSlot = 0;
> + CheckSlot < mCpuHotPlugData->ArrayLength;
> + CheckSlot++) {
> + if (mCpuHotPlugData->ApicId[CheckSlot] == NewApicId) {
> + break;
> + }
> + }
> + if (CheckSlot < mCpuHotPlugData->ArrayLength) {
> + DEBUG ((DEBUG_VERBOSE, "%a: APIC ID " FMT_APIC_ID " was hot-plugged "
> + "before; ignoring it\n", __FUNCTION__, NewApicId));
> + PluggedIdx++;
> + continue;
> + }
> +
> + //
> + // Find the first empty slot in CPU_HOT_PLUG_DATA.
> + //
> + while (NewSlot < mCpuHotPlugData->ArrayLength &&
> + mCpuHotPlugData->ApicId[NewSlot] != MAX_UINT64) {
> + NewSlot++;
> + }
> + if (NewSlot == mCpuHotPlugData->ArrayLength) {
> + DEBUG ((DEBUG_ERROR, "%a: no room for APIC ID " FMT_APIC_ID "\n",
> + __FUNCTION__, NewApicId));
> + return EFI_OUT_OF_RESOURCES;
> + }
> +
> + //
> + // Store the APIC ID of the new processor to the slot.
> + //
> + mCpuHotPlugData->ApicId[NewSlot] = NewApicId;
> +
> + //
> + // Relocate the SMBASE of the new CPU.
> + //
> + Status = SmbaseRelocate (NewApicId, mCpuHotPlugData->SmBase[NewSlot],
> + mPostSmmPenAddress);
> + if (EFI_ERROR (Status)) {
> + goto RevokeNewSlot;
> + }
> +
> + //
> + // Add the new CPU with EFI_SMM_CPU_SERVICE_PROTOCOL.
> + //
> + Status = mMmCpuService->AddProcessor (mMmCpuService, NewApicId,
> + &NewProcessorNumberByProtocol);
> + if (EFI_ERROR (Status)) {
> + DEBUG ((DEBUG_ERROR, "%a: AddProcessor(" FMT_APIC_ID "): %r\n",
> + __FUNCTION__, NewApicId, Status));
> + goto RevokeNewSlot;
> + }
> +
> + DEBUG ((DEBUG_INFO, "%a: hot-added APIC ID " FMT_APIC_ID ", SMBASE 0x%Lx, "
> + "EFI_SMM_CPU_SERVICE_PROTOCOL assigned number %Lu\n", __FUNCTION__,
> + NewApicId, (UINT64)mCpuHotPlugData->SmBase[NewSlot],
> + (UINT64)NewProcessorNumberByProtocol));
> +
> + NewSlot++;
> + PluggedIdx++;
> + }
> +
> + //
> + // We've processed this batch of hot-added CPUs.
> + //
> + return EFI_SUCCESS;
> +
> +RevokeNewSlot:
> + mCpuHotPlugData->ApicId[NewSlot] = MAX_UINT64;
> +
> + return Status;
> +}
>
> /**
> CPU Hotplug MMI handler function.
> @@ -122,8 +246,6 @@ CpuHotplugMmi (
> UINT8 ApmControl;
> UINT32 PluggedCount;
> UINT32 ToUnplugCount;
> - UINT32 PluggedIdx;
> - UINT32 NewSlot;
>
> //
> // Assert that we are entering this function due to our root MMI handler
> @@ -179,87 +301,12 @@ CpuHotplugMmi (
> goto Fatal;
> }
>
> - //
> - // Process hot-added CPUs.
> - //
> - // The Post-SMM Pen need not be reinstalled multiple times within a single
> - // root MMI handling. Even reinstalling once per root MMI is only prudence;
> - // in theory installing the pen in the driver's entry point function should
> - // suffice.
> - //
> - SmbaseReinstallPostSmmPen (mPostSmmPenAddress);
> + if (PluggedCount > 0) {
> + Status = ProcessHotAddedCpus (mPluggedApicIds, PluggedCount);
> + }
>
> - PluggedIdx = 0;
> - NewSlot = 0;
> - while (PluggedIdx < PluggedCount) {
> - APIC_ID NewApicId;
> - UINT32 CheckSlot;
> - UINTN NewProcessorNumberByProtocol;
> -
> - NewApicId = mPluggedApicIds[PluggedIdx];
> -
> - //
> - // Check if the supposedly hot-added CPU is already known to us.
> - //
> - for (CheckSlot = 0;
> - CheckSlot < mCpuHotPlugData->ArrayLength;
> - CheckSlot++) {
> - if (mCpuHotPlugData->ApicId[CheckSlot] == NewApicId) {
> - break;
> - }
> - }
> - if (CheckSlot < mCpuHotPlugData->ArrayLength) {
> - DEBUG ((DEBUG_VERBOSE, "%a: APIC ID " FMT_APIC_ID " was hot-plugged "
> - "before; ignoring it\n", __FUNCTION__, NewApicId));
> - PluggedIdx++;
> - continue;
> - }
> -
> - //
> - // Find the first empty slot in CPU_HOT_PLUG_DATA.
> - //
> - while (NewSlot < mCpuHotPlugData->ArrayLength &&
> - mCpuHotPlugData->ApicId[NewSlot] != MAX_UINT64) {
> - NewSlot++;
> - }
> - if (NewSlot == mCpuHotPlugData->ArrayLength) {
> - DEBUG ((DEBUG_ERROR, "%a: no room for APIC ID " FMT_APIC_ID "\n",
> - __FUNCTION__, NewApicId));
> - goto Fatal;
> - }
> -
> - //
> - // Store the APIC ID of the new processor to the slot.
> - //
> - mCpuHotPlugData->ApicId[NewSlot] = NewApicId;
> -
> - //
> - // Relocate the SMBASE of the new CPU.
> - //
> - Status = SmbaseRelocate (NewApicId, mCpuHotPlugData->SmBase[NewSlot],
> - mPostSmmPenAddress);
> - if (EFI_ERROR (Status)) {
> - goto RevokeNewSlot;
> - }
> -
> - //
> - // Add the new CPU with EFI_SMM_CPU_SERVICE_PROTOCOL.
> - //
> - Status = mMmCpuService->AddProcessor (mMmCpuService, NewApicId,
> - &NewProcessorNumberByProtocol);
> - if (EFI_ERROR (Status)) {
> - DEBUG ((DEBUG_ERROR, "%a: AddProcessor(" FMT_APIC_ID "): %r\n",
> - __FUNCTION__, NewApicId, Status));
> - goto RevokeNewSlot;
> - }
> -
> - DEBUG ((DEBUG_INFO, "%a: hot-added APIC ID " FMT_APIC_ID ", SMBASE 0x%Lx, "
> - "EFI_SMM_CPU_SERVICE_PROTOCOL assigned number %Lu\n", __FUNCTION__,
> - NewApicId, (UINT64)mCpuHotPlugData->SmBase[NewSlot],
> - (UINT64)NewProcessorNumberByProtocol));
> -
> - NewSlot++;
> - PluggedIdx++;
> + if (EFI_ERROR(Status)) {
(1) I understand why you skipped point (13) from the previous review,
but you missed point (14) as well -- space character missing after
"EFI_ERROR":
https://edk2.groups.io/g/devel/message/70785
Anyway, in case v7 will not be necessary, I can fix this up myself.
With the space character added:
Reviewed-by: Laszlo Ersek <lersek at redhat.com>
Thanks
Laszlo
> + goto Fatal;
> }
>
> //
> @@ -267,9 +314,6 @@ CpuHotplugMmi (
> //
> return EFI_SUCCESS;
>
> -RevokeNewSlot:
> - mCpuHotPlugData->ApicId[NewSlot] = MAX_UINT64;
> -
> Fatal:
> ASSERT (FALSE);
> CpuDeadLoop ();
>
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