From fea374e7c8079563bca7c8fac895c6a880f76adc Mon Sep 17 00:00:00 2001 From: Eduardo Habkost Date: Fri, 16 Aug 2019 14:07:50 -0300 Subject: pc: Don't make die-id mandatory unless necessary We have this issue reported when using libvirt to hotplug CPUs: https://bugzilla.redhat.com/show_bug.cgi?id=1741451 Basically, libvirt is not copying die-id from query-hotpluggable-cpus, but die-id is now mandatory. We could blame libvirt and say it is not following the documented interface, because we have this buried in the QAPI schema documentation: > Note: currently there are 5 properties that could be present > but management should be prepared to pass through other > properties with device_add command to allow for future > interface extension. This also requires the filed names to be kept in > sync with the properties passed to -device/device_add. But I don't think this would be reasonable from us. We can just make QEMU more flexible and let die-id to be omitted when there's no ambiguity. This will allow us to keep compatibility with existing libvirt versions. Test case included to ensure we don't break this again. Fixes: commit 176d2cda0dee ("i386/cpu: Consolidate die-id validity in smp context") Signed-off-by: Eduardo Habkost Message-Id: <20190816170750.23910-1-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost --- hw/i386/pc.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'hw/i386') diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 3494423d63..c7200b0b54 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -2421,6 +2421,14 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev, int max_socket = (ms->smp.max_cpus - 1) / smp_threads / smp_cores / pcms->smp_dies; + /* + * die-id was optional in QEMU 4.0 and older, so keep it optional + * if there's only one die per socket. + */ + if (cpu->die_id < 0 && pcms->smp_dies == 1) { + cpu->die_id = 0; + } + if (cpu->socket_id < 0) { error_setg(errp, "CPU socket-id is not set"); return; -- cgit v1.2.3