From c1e03baa430b9b5fc61a846d59e5bb21bb266ee6 Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Mon, 1 Aug 2016 08:12:20 +0200 Subject: [PATCH 80/99] pc: Init CPUState->cpu_index with index in possible_cpus[] RH-Author: Igor Mammedov Message-id: <1470039143-24450-76-git-send-email-imammedo@redhat.com> Patchwork-id: 71691 O-Subject: [RHEV-7.3 qemu-kvm-rhev PATCH 75/78] pc: Init CPUState->cpu_index with index in possible_cpus[] Bugzilla: 1087672 RH-Acked-by: Marcel Apfelbaum RH-Acked-by: David Gibson RH-Acked-by: Eduardo Habkost It will enshure that cpu_index for a given cpu stays the same regardless of the order cpus has been created/deleted. No compat code is needed as for initial cpus index in possible_cpus[] matches cpu_index that's been auto-allocated in cpu_exec_init(). Tha same applies for hotplug with cpu-add command if cpus are added sequentially in increasing order as 'id' matches cpu_index. If cpu-add had been used for creating out-of-order cpus, that created unmigratable instance since it were not possible to start target with the same cpu_index using old way of migrating instance with hotplugged cpus: * source QEMU with CLI (-smp 1,maxcpus=3 and cpu-add id=2) following set of cpu_index is allocated [0, 1] with apics set [0, 2] respectivelly * target QEMU is started with CLI -smp 2,maxcpus=3 resulting in set of cpu_index [0, 1] but with set of apics [0, 1] wich doesn't match source. So we don't need compat code in this case as it's never worked and newelly added device_add support would use stable cpu_index set by machine to begin with, so it won't have above limitation and source QEMU could be migrated to destination regardless of the order cpus were created. Signed-off-by: Igor Mammedov Reviewed-by: David Gibson Reviewed-by: Michael S. Tsirkin Signed-off-by: Eduardo Habkost (cherry picked from commit a15d2728a9aadeb801370adf5bf0b411a774a2d2) Signed-off-by: Miroslav Rezanina --- hw/i386/pc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index e25a740..0a6bf0b 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1800,6 +1800,7 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, Error **errp) { int idx; + CPUState *cs; CPUArchId *cpu_slot; X86CPUTopoInfo topo; X86CPU *cpu = X86_CPU(dev); @@ -1900,6 +1901,9 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev, return; } cpu->thread_id = topo.smt_id; + + cs = CPU(cpu); + cs->cpu_index = idx; } static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev, -- 1.8.3.1