On Wed, 26 Feb 2020 at 23:12, Laszlo Ersek <ler...@redhat.com> wrote:
>
> Call QemuCpuhpCollectApicIds() in the root MMI handler. The APIC IDs of
> the hotplugged CPUs will be used for several purposes in subsequent
> patches.
>
> For calling QemuCpuhpCollectApicIds(), pre-allocate both of its output
> arrays "PluggedApicIds" and "ToUnplugApicIds" in the driver's entry point
> function. The allocation size is dictated by the possible CPU count, which
> we fetch from "CPU_HOT_PLUG_DATA.ArrayLength".
>
> The CPU_HOT_PLUG_DATA structure in SMRAM is an out-of-band information
> channel between this driver and PiSmmCpuDxeSmm, underlying
> EFI_SMM_CPU_SERVICE_PROTOCOL.
>
> In order to consume "CPU_HOT_PLUG_DATA.ArrayLength", extend the driver's
> DEPEX to EFI_SMM_CPU_SERVICE_PROTOCOL. PiSmmCpuDxeSmm stores the address
> of CPU_HOT_PLUG_DATA to "PcdCpuHotPlugDataAddress", before it produces
> EFI_SMM_CPU_SERVICE_PROTOCOL.
>
> Stash the protocol at once, as it will be needed later.
>
> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>
> 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>
> 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>
Reviewed-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.)
>
> OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf | 7 +-
> OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 111 +++++++++++++++++++-
> 2 files changed, 115 insertions(+), 3 deletions(-)
>
> diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
> b/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
> index ab690a9e5e20..31c1ee1c9f6d 100644
> --- a/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
> +++ b/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
> @@ -11,41 +11,46 @@ [Defines]
> PI_SPECIFICATION_VERSION = 0x00010046 #
> PI-1.7.0
> BASE_NAME = CpuHotplugSmm
> FILE_GUID = 84EEA114-C6BE-4445-8F90-51D97863E363
> MODULE_TYPE = DXE_SMM_DRIVER
> ENTRY_POINT = CpuHotplugEntry
>
> #
> # The following information is for reference only and not required by the
> build
> # tools.
> #
> # VALID_ARCHITECTURES = IA32 X64
> #
>
> [Sources]
> ApicId.h
> CpuHotplug.c
> QemuCpuhp.c
> QemuCpuhp.h
>
> [Packages]
> MdePkg/MdePkg.dec
> OvmfPkg/OvmfPkg.dec
> + UefiCpuPkg/UefiCpuPkg.dec
>
> [LibraryClasses]
> BaseLib
> DebugLib
> MmServicesTableLib
> PcdLib
> + SafeIntLib
> UefiDriverEntryPoint
>
> [Protocols]
> gEfiMmCpuIoProtocolGuid ##
> CONSUMES
> + gEfiSmmCpuServiceProtocolGuid ##
> CONSUMES
>
> [Pcd]
> + gUefiCpuPkgTokenSpaceGuid.PcdCpuHotPlugDataAddress ##
> CONSUMES
> gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase ##
> CONSUMES
>
> [FeaturePcd]
> gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire ##
> CONSUMES
>
> [Depex]
> - gEfiMmCpuIoProtocolGuid
> + gEfiMmCpuIoProtocolGuid AND
> + gEfiSmmCpuServiceProtocolGuid
> diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> index 5df8c689c63a..42e023cb85c0 100644
> --- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> +++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
> @@ -1,46 +1,76 @@
> /** @file
> Root SMI handler for VCPU hotplug SMIs.
>
> Copyright (c) 2020, Red Hat, Inc.
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
> **/
>
> +#include <CpuHotPlugData.h> // CPU_HOT_PLUG_DATA
> #include <IndustryStandard/Q35MchIch9.h> // ICH9_APM_CNT
> #include <IndustryStandard/QemuCpuHotplug.h> // QEMU_CPUHP_CMD_GET_PENDING
> #include <Library/BaseLib.h> // CpuDeadLoop()
> #include <Library/DebugLib.h> // ASSERT()
> #include <Library/MmServicesTableLib.h> // gMmst
> #include <Library/PcdLib.h> // PcdGetBool()
> +#include <Library/SafeIntLib.h> // SafeUintnSub()
> #include <Protocol/MmCpuIo.h> // EFI_MM_CPU_IO_PROTOCOL
> +#include <Protocol/SmmCpuService.h> // EFI_SMM_CPU_SERVICE_PROTOCOL
> #include <Uefi/UefiBaseType.h> // EFI_STATUS
>
> +#include "ApicId.h" // APIC_ID
> #include "QemuCpuhp.h" // QemuCpuhpWriteCpuSelector()
>
> //
> // We use this protocol for accessing IO Ports.
> //
> STATIC EFI_MM_CPU_IO_PROTOCOL *mMmCpuIo;
> //
> +// The following protocol is used to report the addition or removal of a CPU
> to
> +// the SMM CPU driver (PiSmmCpuDxeSmm).
> +//
> +STATIC EFI_SMM_CPU_SERVICE_PROTOCOL *mMmCpuService;
> +//
> +// This structure is a communication side-channel between the
> +// EFI_SMM_CPU_SERVICE_PROTOCOL consumer (i.e., this driver) and provider
> +// (i.e., PiSmmCpuDxeSmm).
> +//
> +STATIC CPU_HOT_PLUG_DATA *mCpuHotPlugData;
> +//
> +// SMRAM arrays for fetching the APIC IDs of processors with pending events
> (of
> +// known event types), for the time of just one MMI.
> +//
> +// The lifetimes of these arrays match that of this driver only because we
> +// don't want to allocate SMRAM at OS runtime, and potentially fail (or
> +// fragment the SMRAM map).
> +//
> +// These arrays provide room for ("possible CPU count" minus one) APIC IDs
> +// each, as we don't expect every possible CPU to appear, or disappear, in a
> +// single MMI. The numbers of used (populated) elements in the arrays are
> +// determined on every MMI separately.
> +//
> +STATIC APIC_ID *mPluggedApicIds;
> +STATIC APIC_ID *mToUnplugApicIds;
> +//
> // Represents the registration of the CPU Hotplug MMI handler.
> //
> STATIC EFI_HANDLE mDispatchHandle;
>
>
> /**
> CPU Hotplug MMI handler function.
>
> This is a root MMI handler.
>
> @param[in] DispatchHandle The unique handle assigned to this handler
> by
> EFI_MM_SYSTEM_TABLE.MmiHandlerRegister().
>
> @param[in] Context Context passed in by
> EFI_MM_SYSTEM_TABLE.MmiManage(). Due to
> CpuHotplugMmi() being a root MMI handler,
> Context is ASSERT()ed to be NULL.
>
> @param[in,out] CommBuffer Ignored, due to CpuHotplugMmi() being a root
> MMI handler.
>
> @param[in,out] CommBufferSize Ignored, due to CpuHotplugMmi() being a root
> @@ -65,162 +95,239 @@ STATIC EFI_HANDLE mDispatchHandle;
> but other handlers should still
> be called.
>
> @retval EFI_WARN_INTERRUPT_SOURCE_PENDING The MMI source is still
> pending,
> and other handlers should still
> be called.
>
> @retval EFI_INTERRUPT_PENDING The MMI source could not be
> quiesced.
> **/
> STATIC
> EFI_STATUS
> EFIAPI
> CpuHotplugMmi (
> IN EFI_HANDLE DispatchHandle,
> IN CONST VOID *Context OPTIONAL,
> IN OUT VOID *CommBuffer OPTIONAL,
> IN OUT UINTN *CommBufferSize OPTIONAL
> )
> {
> EFI_STATUS Status;
> UINT8 ApmControl;
> + UINT32 PluggedCount;
> + UINT32 ToUnplugCount;
>
> //
> // Assert that we are entering this function due to our root MMI handler
> // registration.
> //
> ASSERT (DispatchHandle == mDispatchHandle);
> //
> // When MmiManage() is invoked to process root MMI handlers, the caller
> (the
> // MM Core) is expected to pass in a NULL Context. MmiManage() then passes
> // the same NULL Context to individual handlers.
> //
> ASSERT (Context == NULL);
> //
> // Read the MMI command value from the APM Control Port, to see if this is
> an
> // MMI we should care about.
> //
> Status = mMmCpuIo->Io.Read (mMmCpuIo, MM_IO_UINT8, ICH9_APM_CNT, 1,
> &ApmControl);
> if (EFI_ERROR (Status)) {
> DEBUG ((DEBUG_ERROR, "%a: failed to read ICH9_APM_CNT: %r\n",
> __FUNCTION__,
> Status));
> //
> // We couldn't even determine if the MMI was for us or not.
> //
> goto Fatal;
> }
>
> if (ApmControl != ICH9_APM_CNT_CPU_HOTPLUG) {
> //
> // The MMI is not for us.
> //
> return EFI_WARN_INTERRUPT_SOURCE_QUIESCED;
> }
>
> + //
> + // Collect the CPUs with pending events.
> + //
> + Status = QemuCpuhpCollectApicIds (
> + mMmCpuIo,
> + mCpuHotPlugData->ArrayLength, // PossibleCpuCount
> + mCpuHotPlugData->ArrayLength - 1, // ApicIdCount
> + mPluggedApicIds,
> + &PluggedCount,
> + mToUnplugApicIds,
> + &ToUnplugCount
> + );
> + if (EFI_ERROR (Status)) {
> + goto Fatal;
> + }
> + if (ToUnplugCount > 0) {
> + DEBUG ((DEBUG_ERROR, "%a: hot-unplug is not supported yet\n",
> + __FUNCTION__));
> + goto Fatal;
> + }
> +
> //
> // We've handled this MMI.
> //
> return EFI_SUCCESS;
>
> Fatal:
> ASSERT (FALSE);
> CpuDeadLoop ();
> //
> // We couldn't handle this MMI.
> //
> return EFI_INTERRUPT_PENDING;
> }
>
>
> //
> // Entry point function of this driver.
> //
> EFI_STATUS
> EFIAPI
> CpuHotplugEntry (
> IN EFI_HANDLE ImageHandle,
> IN EFI_SYSTEM_TABLE *SystemTable
> )
> {
> EFI_STATUS Status;
> + UINTN Size;
>
> //
> // This module should only be included when SMM support is required.
> //
> ASSERT (FeaturePcdGet (PcdSmmSmramRequire));
> //
> // This driver depends on the dynamically detected "SMRAM at default
> SMBASE"
> // feature.
> //
> if (!PcdGetBool (PcdQ35SmramAtDefaultSmbase)) {
> return EFI_UNSUPPORTED;
> }
>
> //
> // Errors from here on are fatal; we cannot allow the boot to proceed if we
> // can't set up this driver to handle CPU hotplug.
> //
> // First, collect the protocols needed later. All of these protocols are
> // listed in our module DEPEX.
> //
> Status = gMmst->MmLocateProtocol (&gEfiMmCpuIoProtocolGuid,
> NULL /* Registration */, (VOID **)&mMmCpuIo);
> if (EFI_ERROR (Status)) {
> DEBUG ((DEBUG_ERROR, "%a: locate MmCpuIo: %r\n", __FUNCTION__, Status));
> goto Fatal;
> }
> + Status = gMmst->MmLocateProtocol (&gEfiSmmCpuServiceProtocolGuid,
> + NULL /* Registration */, (VOID **)&mMmCpuService);
> + if (EFI_ERROR (Status)) {
> + DEBUG ((DEBUG_ERROR, "%a: locate MmCpuService: %r\n", __FUNCTION__,
> + Status));
> + goto Fatal;
> + }
> +
> + //
> + // Our DEPEX on EFI_SMM_CPU_SERVICE_PROTOCOL guarantees that PiSmmCpuDxeSmm
> + // has pointed PcdCpuHotPlugDataAddress to CPU_HOT_PLUG_DATA in SMRAM.
> + //
> + mCpuHotPlugData = (VOID *)(UINTN)PcdGet64 (PcdCpuHotPlugDataAddress);
> + if (mCpuHotPlugData == NULL) {
> + Status = EFI_NOT_FOUND;
> + DEBUG ((DEBUG_ERROR, "%a: CPU_HOT_PLUG_DATA: %r\n", __FUNCTION__,
> Status));
> + goto Fatal;
> + }
> + //
> + // If the possible CPU count is 1, there's nothing for this driver to do.
> + //
> + if (mCpuHotPlugData->ArrayLength == 1) {
> + return EFI_UNSUPPORTED;
> + }
> + //
> + // Allocate the data structures that depend on the possible CPU count.
> + //
> + if (RETURN_ERROR (SafeUintnSub (mCpuHotPlugData->ArrayLength, 1, &Size)) ||
> + RETURN_ERROR (SafeUintnMult (sizeof (APIC_ID), Size, &Size))) {
> + Status = EFI_ABORTED;
> + DEBUG ((DEBUG_ERROR, "%a: invalid CPU_HOT_PLUG_DATA\n", __FUNCTION__));
> + goto Fatal;
> + }
> + Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,
> + (VOID **)&mPluggedApicIds);
> + if (EFI_ERROR (Status)) {
> + DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__,
> Status));
> + goto Fatal;
> + }
> + Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,
> + (VOID **)&mToUnplugApicIds);
> + if (EFI_ERROR (Status)) {
> + DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__,
> Status));
> + goto ReleasePluggedApicIds;
> + }
>
> //
> // Sanity-check the CPU hotplug interface.
> //
> // Both of the following features are part of QEMU 5.0, introduced
> primarily
> // in commit range 3e08b2b9cb64..3a61c8db9d25:
> //
> // (a) the QEMU_CPUHP_CMD_GET_ARCH_ID command of the modern CPU hotplug
> // interface,
> //
> // (b) the "SMRAM at default SMBASE" feature.
> //
> // From these, (b) is restricted to 5.0+ machine type versions, while (a)
> // does not depend on machine type version. Because we ensured the stricter
> // condition (b) through PcdQ35SmramAtDefaultSmbase above, the (a)
> // QEMU_CPUHP_CMD_GET_ARCH_ID command must now be available too. While we
> // can't verify the presence of precisely that command, we can still verify
> // (sanity-check) that the modern interface is active, at least.
> //
> // Consult the "Typical usecases | Detecting and enabling modern CPU
> hotplug
> // interface" section in QEMU's "docs/specs/acpi_cpu_hotplug.txt", on the
> // following.
> //
> QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);
> QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);
> QemuCpuhpWriteCommand (mMmCpuIo, QEMU_CPUHP_CMD_GET_PENDING);
> if (QemuCpuhpReadCommandData2 (mMmCpuIo) != 0) {
> Status = EFI_NOT_FOUND;
> DEBUG ((DEBUG_ERROR, "%a: modern CPU hotplug interface: %r\n",
> __FUNCTION__, Status));
> - goto Fatal;
> + goto ReleaseToUnplugApicIds;
> }
>
> //
> // Register the handler for the CPU Hotplug MMI.
> //
> Status = gMmst->MmiHandlerRegister (
> CpuHotplugMmi,
> NULL, // HandlerType: root MMI handler
> &mDispatchHandle
> );
> if (EFI_ERROR (Status)) {
> DEBUG ((DEBUG_ERROR, "%a: MmiHandlerRegister(): %r\n", __FUNCTION__,
> Status));
> - goto Fatal;
> + goto ReleaseToUnplugApicIds;
> }
>
> return EFI_SUCCESS;
>
> +ReleaseToUnplugApicIds:
> + gMmst->MmFreePool (mToUnplugApicIds);
> + mToUnplugApicIds = NULL;
> +
> +ReleasePluggedApicIds:
> + gMmst->MmFreePool (mPluggedApicIds);
> + mPluggedApicIds = NULL;
> +
> Fatal:
> ASSERT (FALSE);
> CpuDeadLoop ();
> return Status;
> }
> --
> 2.19.1.3.g30247aa5d201
>
>
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