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.
+
+ @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;
+}
