On 03/02/20 21:34, Philippe Mathieu-Daudé wrote:
> On 2/26/20 11:11 PM, Laszlo Ersek wrote:
>> Add a function that collects the APIC IDs of CPUs that have just been
>> hot-plugged, or are about to be hot-unplugged.
>>
>> Pending events are only located and never cleared; QEMU's AML needs the
>> firmware to leave the status bits intact in the hotplug register block.
>>
>> 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>
>> ---
>>
>> 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/Include/IndustryStandard/QemuCpuHotplug.h | 2 +
>> OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf | 1 +
>> OvmfPkg/CpuHotplugSmm/ApicId.h | 23 +++
>> OvmfPkg/CpuHotplugSmm/QemuCpuhp.h | 20 ++-
>> OvmfPkg/CpuHotplugSmm/QemuCpuhp.c | 171
>> +++++++++++++++++++-
>> 5 files changed, 211 insertions(+), 6 deletions(-)
>>
>> diff --git a/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
>> b/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
>> index 3d013633501b..a34a6d3fae61 100644
>> --- a/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
>> +++ b/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
>> @@ -13,32 +13,34 @@
>> The new ("modern") hotplug interface appeared in QEMU v2.7.0.
>> The macros in this header file map to the minimal subset of
>> the modern
>> interface that OVMF needs.
>> **/
>> #ifndef QEMU_CPU_HOTPLUG_H_
>> #define QEMU_CPU_HOTPLUG_H_
>> #include <Base.h>
>> //
>> // Each register offset is:
>> // - relative to the board-dependent IO base address of the register
>> block,
>> // - named QEMU_CPUHP_(R|W|RW)_*, according to the possible access
>> modes of the
>> // register,
>> // - followed by distinguished bitmasks or values in the register.
>> //
>> #define QEMU_CPUHP_R_CMD_DATA2 0x0
>> #define QEMU_CPUHP_R_CPU_STAT 0x4
>> #define QEMU_CPUHP_STAT_ENABLED BIT0
>> +#define QEMU_CPUHP_STAT_INSERT BIT1
>> +#define QEMU_CPUHP_STAT_REMOVE BIT2
>> #define QEMU_CPUHP_RW_CMD_DATA 0x8
>> #define QEMU_CPUHP_W_CPU_SEL 0x0
>> #define QEMU_CPUHP_W_CMD 0x5
>> #define QEMU_CPUHP_CMD_GET_PENDING 0x0
>> #define QEMU_CPUHP_CMD_GET_ARCH_ID 0x3
>> #endif // QEMU_CPU_HOTPLUG_H_
>> diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
>> b/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
>> index ac4ca4c1f4f2..ab690a9e5e20 100644
>> --- a/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
>> +++ b/OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf
>> @@ -3,44 +3,45 @@
>> #
>> # Copyright (c) 2020, Red Hat, Inc.
>> #
>> # SPDX-License-Identifier: BSD-2-Clause-Patent
>> ##
>> [Defines]
>> INF_VERSION = 1.29
>> 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
>> [LibraryClasses]
>> BaseLib
>> DebugLib
>> MmServicesTableLib
>> PcdLib
>> UefiDriverEntryPoint
>> [Protocols]
>> gEfiMmCpuIoProtocolGuid
>> ## CONSUMES
>> [Pcd]
>> gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase
>> ## CONSUMES
>> [FeaturePcd]
>> diff --git a/OvmfPkg/CpuHotplugSmm/ApicId.h
>> b/OvmfPkg/CpuHotplugSmm/ApicId.h
>> new file mode 100644
>> index 000000000000..3c365148ed02
>> --- /dev/null
>> +++ b/OvmfPkg/CpuHotplugSmm/ApicId.h
>> @@ -0,0 +1,23 @@
>> +/** @file
>> + Type and macro definitions for representing and printing APIC IDs,
>> compatibly
>> + with the LocalApicLib and PrintLib classes, respectively.
>> +
>> + Copyright (c) 2020, Red Hat, Inc.
>> +
>> + SPDX-License-Identifier: BSD-2-Clause-Patent
>> +**/
>> +
>> +#ifndef APIC_ID_H_
>> +#define APIC_ID_H_
>> +
>> +//
>> +// The type that LocalApicLib represents an APIC ID with.
>> +//
>> +typedef UINT32 APIC_ID;
>> +
>> +//
>> +// The PrintLib conversion specification for formatting an APIC_ID.
>> +//
>> +#define FMT_APIC_ID "0x%08x"
>> +
>> +#endif // APIC_ID_H_
>> diff --git a/OvmfPkg/CpuHotplugSmm/QemuCpuhp.h
>> b/OvmfPkg/CpuHotplugSmm/QemuCpuhp.h
>> index 82f88f0b73bb..8adaa0ad91f0 100644
>> --- a/OvmfPkg/CpuHotplugSmm/QemuCpuhp.h
>> +++ b/OvmfPkg/CpuHotplugSmm/QemuCpuhp.h
>> @@ -1,47 +1,61 @@
>> /** @file
>> - Simple wrapper functions that access QEMU's modern CPU hotplug
>> register
>> - block.
>> + Simple wrapper functions and utility functions that access QEMU's
>> modern CPU
>> + hotplug register block.
>> - These functions thinly wrap some of the registers described in
>> + These functions manipulate some of the registers described in
>> "docs/specs/acpi_cpu_hotplug.txt" in the QEMU source. IO Ports are
>> accessed
>> via EFI_MM_CPU_IO_PROTOCOL. If a protocol call fails, these
>> functions don't
>> return.
>> Copyright (c) 2020, Red Hat, Inc.
>> SPDX-License-Identifier: BSD-2-Clause-Patent
>> **/
>> #ifndef QEMU_CPUHP_H_
>> #define QEMU_CPUHP_H_
>> #include <Protocol/MmCpuIo.h> // EFI_MM_CPU_IO_PROTOCOL
>> +#include <Uefi/UefiBaseType.h> // EFI_STATUS
>> +
>> +#include "ApicId.h" // APIC_ID
>> UINT32
>> QemuCpuhpReadCommandData2 (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo
>> );
>> UINT8
>> QemuCpuhpReadCpuStatus (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo
>> );
>> UINT32
>> QemuCpuhpReadCommandData (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo
>> );
>> VOID
>> QemuCpuhpWriteCpuSelector (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo,
>> IN UINT32 Selector
>> );
>> VOID
>> QemuCpuhpWriteCommand (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo,
>> IN UINT8 Command
>> );
>> +EFI_STATUS
>> +QemuCpuhpCollectApicIds (
>> + IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo,
>> + IN UINT32 PossibleCpuCount,
>> + IN UINT32 ApicIdCount,
>> + OUT APIC_ID *PluggedApicIds,
>> + OUT UINT32 *PluggedCount,
>> + OUT APIC_ID *ToUnplugApicIds,
>> + OUT UINT32 *ToUnplugCount
>> + );
>> +
>> #endif // QEMU_CPUHP_H_
>> diff --git a/OvmfPkg/CpuHotplugSmm/QemuCpuhp.c
>> b/OvmfPkg/CpuHotplugSmm/QemuCpuhp.c
>> index 31e46f51934a..8d4a6693c8d6 100644
>> --- a/OvmfPkg/CpuHotplugSmm/QemuCpuhp.c
>> +++ b/OvmfPkg/CpuHotplugSmm/QemuCpuhp.c
>> @@ -1,27 +1,27 @@
>> /** @file
>> - Simple wrapper functions that access QEMU's modern CPU hotplug
>> register
>> - block.
>> + Simple wrapper functions and utility functions that access QEMU's
>> modern CPU
>> + hotplug register block.
>> - These functions thinly wrap some of the registers described in
>> + These functions manipulate some of the registers described in
>> "docs/specs/acpi_cpu_hotplug.txt" in the QEMU source. IO Ports are
>> accessed
>> via EFI_MM_CPU_IO_PROTOCOL. If a protocol call fails, these
>> functions don't
>> return.
>> Copyright (c) 2020, Red Hat, Inc.
>> SPDX-License-Identifier: BSD-2-Clause-Patent
>> **/
>> #include <IndustryStandard/Q35MchIch9.h> // ICH9_CPU_HOTPLUG_BASE
>> #include <IndustryStandard/QemuCpuHotplug.h> // QEMU_CPUHP_R_CMD_DATA2
>> #include <Library/BaseLib.h> // CpuDeadLoop()
>> #include <Library/DebugLib.h> // DEBUG()
>> #include "QemuCpuhp.h"
>> UINT32
>> QemuCpuhpReadCommandData2 (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo
>> )
>> {
>> UINT32 CommandData2;
>> @@ -115,22 +115,187 @@ QemuCpuhpWriteCpuSelector (
>> VOID
>> QemuCpuhpWriteCommand (
>> IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo,
>> IN UINT8 Command
>> )
>> {
>> EFI_STATUS Status;
>> Status = MmCpuIo->Io.Write (
>> MmCpuIo,
>> MM_IO_UINT8,
>> ICH9_CPU_HOTPLUG_BASE + QEMU_CPUHP_W_CMD,
>> 1,
>> &Command
>> );
>> if (EFI_ERROR (Status)) {
>> DEBUG ((DEBUG_ERROR, "%a: %r\n", __FUNCTION__, Status));
>> ASSERT (FALSE);
>> CpuDeadLoop ();
>> }
>> }
>> +
>> +/**
>> + Collect the APIC IDs of
>> + - the CPUs that have been hot-plugged,
>> + - the CPUs that are about to be hot-unplugged.
>> +
>> + This function only scans for events -- it does not modify them --
>> in the
>> + hotplug registers.
>> +
>> + On error, the contents of the output parameters are undefined.
>> +
>> + @param[in] MmCpuIo The EFI_MM_CPU_IO_PROTOCOL instance for
>> + accessing IO Ports.
>> +
>> + @param[in] PossibleCpuCount The number of possible CPUs in the
>> system. Must
>> + be positive.
>
> Maybe nitpicking: "positive (non zero)"?
Zero is not positive, zero is zero. Positive implies nonzero. :)
Thanks
Laszlo
>
>> +
>> + @param[in] ApicIdCount The number of elements each one of the
>> + PluggedApicIds and ToUnplugApicIds
>> arrays can
>> + accommodate. Must be positive.
>> +
>> + @param[out] PluggedApicIds The APIC IDs of the CPUs that have been
>> + hot-plugged.
>> +
>> + @param[out] PluggedCount The number of filled-in APIC IDs in
>> + PluggedApicIds.
>> +
>> + @param[out] ToUnplugApicIds The APIC IDs of the CPUs that are
>> about to be
>> + hot-unplugged.
>> +
>> + @param[out] ToUnplugCount The number of filled-in APIC IDs in
>> + ToUnplugApicIds.
>> +
>> + @retval EFI_INVALID_PARAMETER PossibleCpuCount is zero, or
>> ApicIdCount is
>> + zero.
>> +
>> + @retval EFI_PROTOCOL_ERROR Invalid bitmap detected in the
>> + QEMU_CPUHP_R_CPU_STAT register.
>> +
>> + @retval EFI_BUFFER_TOO_SMALL There was an attempt to place more than
>> + ApicIdCount APIC IDs into one of the
>> + PluggedApicIds and ToUnplugApicIds
>> arrays.
>> +
>> + @retval EFI_SUCCESS Output parameters have been set
>> successfully.
>> +**/
>> +EFI_STATUS
>> +QemuCpuhpCollectApicIds (
>> + IN CONST EFI_MM_CPU_IO_PROTOCOL *MmCpuIo,
>> + IN UINT32 PossibleCpuCount,
>> + IN UINT32 ApicIdCount,
>> + OUT APIC_ID *PluggedApicIds,
>> + OUT UINT32 *PluggedCount,
>> + OUT APIC_ID *ToUnplugApicIds,
>> + OUT UINT32 *ToUnplugCount
>> + )
>> +{
>> + UINT32 CurrentSelector;
>> +
>> + if (PossibleCpuCount == 0 || ApicIdCount == 0) {
>> + return EFI_INVALID_PARAMETER;
>> + }
>> +
>> + *PluggedCount = 0;
>> + *ToUnplugCount = 0;
>> +
>> + CurrentSelector = 0;
>> + do {
>> + UINT32 PendingSelector;
>> + UINT8 CpuStatus;
>> + APIC_ID *ExtendIds;
>> + UINT32 *ExtendCount;
>> + APIC_ID NewApicId;
>> +
>> + //
>> + // Write CurrentSelector (which is valid) to the CPU selector
>> register.
>> + // Consequences:
>> + //
>> + // - Other register accesses will be permitted.
>> + //
>> + // - The QEMU_CPUHP_CMD_GET_PENDING command will start scanning
>> for a CPU
>> + // with pending events at CurrentSelector (inclusive).
>> + //
>> + QemuCpuhpWriteCpuSelector (MmCpuIo, CurrentSelector);
>> + //
>> + // Write the QEMU_CPUHP_CMD_GET_PENDING command. Consequences
>> + // (independently of each other):
>> + //
>> + // - If there is a CPU with pending events, starting at
>> CurrentSelector
>> + // (inclusive), the CPU selector will be updated to that CPU.
>> Note that
>> + // the scanning in QEMU may wrap around, because we must never
>> clear the
>> + // event bits.
>> + //
>> + // - The QEMU_CPUHP_RW_CMD_DATA register will return the
>> (possibly updated)
>> + // CPU selector value.
>> + //
>> + QemuCpuhpWriteCommand (MmCpuIo, QEMU_CPUHP_CMD_GET_PENDING);
>> + PendingSelector = QemuCpuhpReadCommandData (MmCpuIo);
>> + if (PendingSelector < CurrentSelector) {
>> + DEBUG ((DEBUG_VERBOSE, "%a: CurrentSelector=%u
>> PendingSelector=%u: "
>> + "wrap-around\n", __FUNCTION__, CurrentSelector,
>> PendingSelector));
>> + break;
>> + }
>> + CurrentSelector = PendingSelector;
>> +
>> + //
>> + // Check the known status / event bits for the currently selected
>> CPU.
>> + //
>> + CpuStatus = QemuCpuhpReadCpuStatus (MmCpuIo);
>> + if ((CpuStatus & QEMU_CPUHP_STAT_INSERT) != 0) {
>> + //
>> + // The "insert" event guarantees the "enabled" status; plus it
>> excludes
>> + // the "remove" event.
>> + //
>> + if ((CpuStatus & QEMU_CPUHP_STAT_ENABLED) == 0 ||
>> + (CpuStatus & QEMU_CPUHP_STAT_REMOVE) != 0) {
>> + DEBUG ((DEBUG_ERROR, "%a: CurrentSelector=%u CpuStatus=0x%x: "
>> + "inconsistent CPU status\n", __FUNCTION__, CurrentSelector,
>> + CpuStatus));
>> + return EFI_PROTOCOL_ERROR;
>> + }
>> +
>> + DEBUG ((DEBUG_VERBOSE, "%a: CurrentSelector=%u: insert\n",
>> __FUNCTION__,
>> + CurrentSelector));
>> +
>> + ExtendIds = PluggedApicIds;
>> + ExtendCount = PluggedCount;
>> + } else if ((CpuStatus & QEMU_CPUHP_STAT_REMOVE) != 0) {
>> + DEBUG ((DEBUG_VERBOSE, "%a: CurrentSelector=%u: remove\n",
>> __FUNCTION__,
>> + CurrentSelector));
>> +
>> + ExtendIds = ToUnplugApicIds;
>> + ExtendCount = ToUnplugCount;
>> + } else {
>> + DEBUG ((DEBUG_VERBOSE, "%a: CurrentSelector=%u: no event\n",
>> + __FUNCTION__, CurrentSelector));
>> + break;
>> + }
>> +
>> + //
>> + // Save the APIC ID of the CPU with the pending event, to the
>> corresponding
>> + // APIC ID array.
>> + //
>> + if (*ExtendCount == ApicIdCount) {
>> + DEBUG ((DEBUG_ERROR, "%a: APIC ID array too small\n",
>> __FUNCTION__));
>> + return EFI_BUFFER_TOO_SMALL;
>> + }
>> + QemuCpuhpWriteCommand (MmCpuIo, QEMU_CPUHP_CMD_GET_ARCH_ID);
>> + NewApicId = QemuCpuhpReadCommandData (MmCpuIo);
>> + DEBUG ((DEBUG_VERBOSE, "%a: ApicId=" FMT_APIC_ID "\n", __FUNCTION__,
>> + NewApicId));
>> + ExtendIds[(*ExtendCount)++] = NewApicId;
>> +
>> + //
>> + // We've processed the CPU with (known) pending events, but we
>> must never
>> + // clear events. Therefore we need to advance past this CPU
>> manually;
>> + // otherwise, QEMU_CPUHP_CMD_GET_PENDING would stick to the
>> currently
>> + // selected CPU.
>> + //
>> + CurrentSelector++;
>> + } while (CurrentSelector < PossibleCpuCount);
>> +
>> + DEBUG ((DEBUG_VERBOSE, "%a: PluggedCount=%u ToUnplugCount=%u\n",
>> + __FUNCTION__, *PluggedCount, *ToUnplugCount));
>> + return EFI_SUCCESS;
>> +}
>>
>
> Reviewed-by: Philippe Mathieu-Daude <phi...@redhat.com>
>
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