cryptospore / rpms / qemu-kvm

Forked from rpms/qemu-kvm 2 years ago
Clone

Blame SOURCES/kvm-apic-Use-32bit-APIC-ID-for-migration-instance-ID.patch

22c213
From 0d5a09173eb75b7e56122c2aefb2646a2be58400 Mon Sep 17 00:00:00 2001
22c213
From: Peter Xu <peterx@redhat.com>
22c213
Date: Fri, 31 Jan 2020 17:12:57 +0000
22c213
Subject: [PATCH 15/15] apic: Use 32bit APIC ID for migration instance ID
22c213
22c213
RH-Author: Peter Xu <peterx@redhat.com>
22c213
Message-id: <20200131171257.1066593-4-peterx@redhat.com>
22c213
Patchwork-id: 93628
22c213
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 3/3] apic: Use 32bit APIC ID for migration instance ID
22c213
Bugzilla: 1529231
22c213
RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
22c213
RH-Acked-by: Juan Quintela <quintela@redhat.com>
22c213
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
22c213
22c213
Migration is silently broken now with x2apic config like this:
22c213
22c213
     -smp 200,maxcpus=288,sockets=2,cores=72,threads=2 \
22c213
     -device intel-iommu,intremap=on,eim=on
22c213
22c213
After migration, the guest kernel could hang at anything, due to
22c213
x2apic bit not migrated correctly in IA32_APIC_BASE on some vcpus, so
22c213
any operations related to x2apic could be broken then (e.g., RDMSR on
22c213
x2apic MSRs could fail because KVM would think that the vcpu hasn't
22c213
enabled x2apic at all).
22c213
22c213
The issue is that the x2apic bit was never applied correctly for vcpus
22c213
whose ID > 255 when migrate completes, and that's because when we
22c213
migrate APIC we use the APICCommonState.id as instance ID of the
22c213
migration stream, while that's too short for x2apic.
22c213
22c213
Let's use the newly introduced initial_apic_id for that.
22c213
22c213
Signed-off-by: Peter Xu <peterx@redhat.com>
22c213
Reviewed-by: Juan Quintela <quintela@redhat.com>
22c213
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
22c213
Signed-off-by: Juan Quintela <quintela@redhat.com>
22c213
(cherry picked from commit 0ab994867c365db21e15f9503922c79234d8e40e)
22c213
Signed-off-by: Peter Xu <peterx@redhat.com>
22c213
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
22c213
---
22c213
 hw/intc/apic_common.c | 5 ++++-
22c213
 1 file changed, 4 insertions(+), 1 deletion(-)
22c213
22c213
diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
22c213
index 54b8731..b5dbeb6 100644
22c213
--- a/hw/intc/apic_common.c
22c213
+++ b/hw/intc/apic_common.c
22c213
@@ -268,7 +268,10 @@ static void apic_common_realize(DeviceState *dev, Error **errp)
22c213
     APICCommonState *s = APIC_COMMON(dev);
22c213
     APICCommonClass *info;
22c213
     static DeviceState *vapic;
22c213
-    uint32_t instance_id = s->id;
22c213
+    uint32_t instance_id = s->initial_apic_id;
22c213
+
22c213
+    /* Normally initial APIC ID should be no more than hundreds */
22c213
+    assert(instance_id != VMSTATE_INSTANCE_ID_ANY);
22c213
 
22c213
     info = APIC_COMMON_GET_CLASS(s);
22c213
     info->realize(dev, errp);
22c213
-- 
22c213
1.8.3.1
22c213