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[PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplu
From: |
Babu Moger |
Subject: |
[PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug |
Date: |
Mon, 08 Jun 2020 15:18:50 -0500 |
User-agent: |
StGit/unknown-version |
Noticed the following command failure while testing CPU hotplug.
$ qemu-system-x86_64 -machine q35,accel=kvm -smp 1,maxcpus=2,
cores=1, threads=1,sockets=2 -cpu EPYC -device EPYC-x86_64-
cpu,core-id=0,socket-id=1,thread-id=0
qemu-system-x86_64: -device EPYC-x86_64-cpu,core-id=0,socket-id=1,
thread-id=0: Invalid CPU [socket: 21855, die: 0, core: 0, thread: 0]
with APIC ID 21855, valid index range 0:1
This happens because APIC ID is calculated using uninitialized memory.
This is happening after the addition of new field node_id in X86CPUTopoIDs
structure. The node_id field is uninitialized while calling
apicid_from_topo_ids. The problem is discussed in the thread below.
20200602171838.GG577771@habkost.net/">https://lore.kernel.org/qemu-devel/20200602171838.GG577771@habkost.net/
Fix the problem by initializing the node_id properly.
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
hw/i386/pc.c | 2 ++
include/hw/i386/topology.h | 11 +++++++++++
2 files changed, 13 insertions(+)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 2128f3d6fe..974cc30891 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1585,6 +1585,8 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev,
topo_ids.die_id = cpu->die_id;
topo_ids.core_id = cpu->core_id;
topo_ids.smt_id = cpu->thread_id;
+ topo_ids.node_id = cpu_x86_use_epyc_apic_id_encoding(ms->cpu_type) ?
+ x86_node_id_for_epyc(&topo_info, &topo_ids) : 0;
cpu->apic_id = x86ms->apicid_from_topo_ids(&topo_info, &topo_ids);
}
diff --git a/include/hw/i386/topology.h b/include/hw/i386/topology.h
index 07239f95f4..ee4deb84c4 100644
--- a/include/hw/i386/topology.h
+++ b/include/hw/i386/topology.h
@@ -140,6 +140,17 @@ static inline unsigned
apicid_pkg_offset_epyc(X86CPUTopoInfo *topo_info)
apicid_node_width_epyc(topo_info);
}
+static inline unsigned x86_node_id_for_epyc(X86CPUTopoInfo *topo_info,
+ const X86CPUTopoIDs *topo_ids)
+{
+ unsigned nr_nodes = MAX(topo_info->nodes_per_pkg, 1);
+ unsigned cores_per_node = DIV_ROUND_UP((topo_info->dies_per_pkg *
+ topo_info->cores_per_die *
+ topo_info->threads_per_core),
+ nr_nodes);
+
+ return (topo_ids->core_id / cores_per_node) % nr_nodes;
+}
/*
* Make APIC ID for the CPU based on Pkg_ID, Core_ID, SMT_ID
*
- [PATCH 0/2] Fix couple of issues with AMD topology, Babu Moger, 2020/06/08
- [PATCH 2/2] i386: Simplify CPUID_8000_001E for AMD, Babu Moger, 2020/06/08
- [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug,
Babu Moger <=
- Re: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Igor Mammedov, 2020/06/16
- RE: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Babu Moger, 2020/06/16
- Re: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Igor Mammedov, 2020/06/24
- RE: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Babu Moger, 2020/06/24
- Re: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Igor Mammedov, 2020/06/25
- RE: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Babu Moger, 2020/06/25
- Re: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Igor Mammedov, 2020/06/25
- Re: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Babu Moger, 2020/06/25
- RE: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Babu Moger, 2020/06/26
- RE: [PATCH 1/2] hw/386: Fix uninitialized memory with -device and CPU hotplug, Babu Moger, 2020/06/29