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edk2/SOURCES/edk2-OvmfPkg-CpuHotplugSmm-...

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1.6 KiB

From 33ebaa6f0d476008ca6ba264657ac37faf63b723 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Thu, 29 Aug 2024 09:20:29 +0200
Subject: [PATCH 1/2] OvmfPkg/CpuHotplugSmm: delay SMM exit
RH-Author: Gerd Hoffmann <None>
RH-MergeRequest: 74: OvmfPkg/CpuHotplugSmm: delay SMM exit
RH-Jira: RHEL-56974
RH-Acked-by: Oliver Steffen <osteffen@redhat.com>
RH-Commit: [1/1] e1fb3f4db68457ec9f59ca5db47606bf4c34e6c5 (kraxel.rh/centos-src-edk2)
Let APs wait until the BSP has completed the register updates to remove
the CPU. This makes sure all APs stay in SMM mode until the CPU
hot-unplug operation is complete, which in turn makes sure the ACPI lock
is released only after the CPU hot-unplug operation is complete.
Some background: The CPU hotplug SMI is triggered from an ACPI function
which is protected by an ACPI lock. The ACPI function is in the ACPI
tables generated by qemu.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
upstream: submitted (https://github.com/tianocore/edk2/pull/6138)
---
OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
index d504163026..5af78211d3 100644
--- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
+++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
@@ -355,6 +355,11 @@ EjectCpu (
//
QemuSelector = mCpuHotEjectData->QemuSelectorMap[ProcessorNum];
if (QemuSelector == CPU_EJECT_QEMU_SELECTOR_INVALID) {
+ /* wait until BSP is done */
+ while (mCpuHotEjectData->Handler != NULL) {
+ CpuPause ();
+ }
+
return;
}
--
2.39.3