On 2/26/20 11:11 PM, Laszlo Ersek wrote:
QEMU commit 3a61c8db9d25 ("acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command",
2020-01-22) introduced a new command in the modern CPU hotplug register
block that lets the firmware query the arch-specific IDs (on IA32/X64: the
APIC IDs) of CPUs. Add a macro for this command value, because we'll need
it later.
At the same time, add a sanity check for the modern hotplug interface to
CpuHotplugSmm.
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 | 1 +
OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 35 ++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
b/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
index cf0745610f2c..3d013633501b 100644
--- a/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
+++ b/OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h
@@ -20,24 +20,25 @@
#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_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/CpuHotplug.c
b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
index fd09403eabf3..5df8c689c63a 100644
--- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
+++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
@@ -1,38 +1,41 @@
/** @file
Root SMI handler for VCPU hotplug SMIs.
Copyright (c) 2020, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#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 <Protocol/MmCpuIo.h> // EFI_MM_CPU_IO_PROTOCOL
#include <Uefi/UefiBaseType.h> // EFI_STATUS
+#include "QemuCpuhp.h" // QemuCpuhpWriteCpuSelector()
+
//
// We use this protocol for accessing IO Ports.
//
STATIC EFI_MM_CPU_IO_PROTOCOL *mMmCpuIo;
//
// 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.
@@ -149,43 +152,75 @@ CpuHotplugEntry (
//
// 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;
}
+ //
+ // 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);
Reviewed-by: Philippe Mathieu-Daude <phi...@redhat.com>
+ 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;
+ }
+
//
// 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;
}
return EFI_SUCCESS;
Fatal:
ASSERT (FALSE);
CpuDeadLoop ();
return Status;
}
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