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audk/OvmfPkg/Library/SmmCpuPlatformHookLibQemu/SmmCpuPlatformHookLibQemu.inf

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OvmfPkg: clone SmmCpuPlatformHookLib from UefiCpuPkg Clone the Null instance of SmmCpuPlatformHookLib from UefiCpuPkg to OvmfPkg. In this patch, customize the lib instance only with the following no-op steps: - Replace Null/NULL references in filenames and comments with Qemu/QEMU references. - Update copyright notices. - Clean up and rewrap comment blocks. - Update INF_VERSION to the latest INF spec version (1.29). - Update FILE_GUID. - Drop the UNI file. This patch is best reviewed with: $ git show --find-copies=43 --find-copies-harder Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Michael Kinney <michael.d.kinney@intel.com> Cc: Philippe Mathieu-Daudé <philmd@redhat.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20200226221156.29589-4-lersek@redhat.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2020-02-26 23:11:43 +01:00
## @file
# SMM CPU Platform Hook library instance for QEMU.
#
# Copyright (c) 2020, Red Hat, Inc.
# Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
# SPDX-License-Identifier: BSD-2-Clause-Patent
##
[Defines]
INF_VERSION = 1.29
BASE_NAME = SmmCpuPlatformHookLibQemu
FILE_GUID = 154D6D26-54B8-45BC-BA3A-CBAA20C02A6A
MODULE_TYPE = DXE_DRIVER
VERSION_STRING = 1.0
LIBRARY_CLASS = SmmCpuPlatformHookLib
#
# The following information is for reference only and not required by the build
# tools.
#
# VALID_ARCHITECTURES = IA32 X64
#
[Sources]
SmmCpuPlatformHookLibQemu.c
[Packages]
MdePkg/MdePkg.dec
UefiCpuPkg/UefiCpuPkg.dec
OvmfPkg: enable SMM Monarch Election in PiSmmCpuDxeSmm With "PcdCpuSmmEnableBspElection" set to FALSE, PiSmmCpuDxeSmm always considers the processor with index 0 to be the SMM Monarch (a.k.a. the SMM BSP). The SMM Monarch handles the SMI for real, while the other CPUs wait in their SMM loops. In a subsequent patch, we want to set "PcdCpuHotPlugSupport" to TRUE. For that, PiCpuSmmEntry() [UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c] forces us with an ASSERT() to set "PcdCpuSmmEnableBspElection" to TRUE as well. To satisfy that expectation, we can simply remove our current "PcdCpuSmmEnableBspElection|FALSE" setting, and inherit the default TRUE value from "UefiCpuPkg.dec". This causes "mSmmMpSyncData->BspIndex" in PiSmmCpuDxeSmm to lose its static zero value (standing for CPU#0); instead it becomes (-1) in general, and the SMM Monarch is elected anew on every SMI. The default SMM Monarch Election is basically a race -- whichever CPU can flip "mSmmMpSyncData->BspIndex" from (-1) to its own index, becomes king, for handling that SMI. Refer to SmiRendezvous() [UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c]. I consider this non-determinism less than ideal on QEMU/KVM; it would be nice to stick with a "mostly permanent" SMM Monarch even with the Election enabled. We can do that by implementing the PlatformSmmBspElection() API in the SmmCpuPlatformHookLibQemu instance: The IA32 APIC Base MSR can be read on each CPU concurrently, and it will report the BSP bit as set only on the current Boot Service Processor. QEMU marks CPU#0 as the BSP, by default. Elect the current BSP, as reported by QEMU, for the SMM Monarch role. (Note that the QEMU commit history is not entirely consistent on whether QEMU/KVM may mark a CPU with nonzero index as the BSP: - At tag v4.2.0, "target/i386/cpu.c" has a comment saying "We hard-wire the BSP to the first CPU". This comment goes back to commit 6cb2996cef5e ("x86: Extend validity of bsp_to_cpu", 2010-03-04). - Compare commit 9cb11fd7539b ("target-i386: clear bsp bit when designating bsp", 2015-04-02) though, especially considering KVM. Either way, this OvmfPkg patch is *not* dependent on CPU index 0; it just takes the race on every SMI out of the game.) One benefit of using a "mostly permanent" SMM Monarch / BSP is that we can continue testing the SMM CPU synchronization by deterministically entering the firmware on the BSP, vs. on an AP, from Linux guests: $ time taskset -c 0 efibootmgr $ time taskset -c 1 efibootmgr (See <https://github.com/tianocore/tianocore.github.io/wiki/Testing-SMM-with-QEMU,-KVM-and-libvirt#uefi-variable-access-test>.) Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Michael Kinney <michael.d.kinney@intel.com> Cc: Philippe Mathieu-Daudé <philmd@redhat.com> Suggested-by: Igor Mammedov <imammedo@redhat.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512#c5 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20200226221156.29589-5-lersek@redhat.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2020-02-26 23:11:44 +01:00
[LibraryClasses]
BaseLib