[edk2-devel] [PATCH v8 04/10] OvmfPkg/CpuHotplugSmm: introduce UnplugCpus()
Laszlo Ersek
lersek at redhat.com
Mon Feb 22 12:39:23 UTC 2021
On 02/22/21 08:19, Ankur Arora wrote:
> 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>
> ---
>
> Notes:
> Addresses these review comments from v6:
> (1) Drop the empty line in the comment block around UnplugCpus().
> (2) Make the "did not find APIC ID" DEBUG_VERBOSE instead of DEBUG_INFO.
> (3) Un-Indented ("Outdented") the line following the comment "Ignore the
> unplug if APIC ID.
> (4) Remove the empty line between Status assignment and check.
> (5) Drop the "goto Fatal" logic and just return Status directly.
> (6) Handle both Plugging and Unplugging of CPUs in one go.
> (7) Also nest the EFI_STATUS check.
>
> OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 84 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 84 insertions(+)
>
> diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> index 3192bfea1f15..f07b5072749a 100644
> --- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> +++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> @@ -188,6 +188,83 @@ 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_VERBOSE, "%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));
> + return Status;
> + }
> +
> + ToUnplugIdx++;
> + }
> +
> + //
> + // We've removed this set of APIC IDs from SMM data structures.
> + //
> + return EFI_SUCCESS;
> +}
> +
> +/**
> CPU Hotplug MMI handler function.
>
> This is a root MMI handler.
> @@ -309,6 +386,13 @@ CpuHotplugMmi (
> }
> }
>
> + if (ToUnplugCount > 0) {
> + Status = UnplugCpus (mToUnplugApicIds, ToUnplugCount);
> + if (EFI_ERROR (Status)) {
> + goto Fatal;
> + }
> + }
> +
> //
> // We've handled this MMI.
> //
>
Reviewed-by: Laszlo Ersek <lersek at redhat.com>
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