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[Qemu-devel] [PULL 6/7] s390x: Limit s390-ccw machines to 248 CPUs
From: |
Cornelia Huck |
Subject: |
[Qemu-devel] [PULL 6/7] s390x: Limit s390-ccw machines to 248 CPUs |
Date: |
Tue, 14 Jun 2016 14:13:54 +0200 |
From: Christian Borntraeger <address@hidden>
The sclp scp read info call fills in a buffer with information about the
system. With more than 248 CPUs we overflow the 4k buffer of the SCCB,
leading to random data corruption. Basically ALL guest operating systems
call scp read info, so let's limit the machines to 248 CPUs to make it
obvious that >=249 does not work.
As KVM also limits itself to 248 and TCG on s390 does not support
SMP, this should cause no regression for any user as no VMs with more
than 248 VCPUs were ever possible.
Signed-off-by: Christian Borntraeger <address@hidden>
Reviewed-by: David Hildenbrand <address@hidden>
Reviewed-by: Boris Fiuczynski <address@hidden>
Signed-off-by: Cornelia Huck <address@hidden>
---
hw/s390x/s390-virtio-ccw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 95ff5e3..e257ca5 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -204,7 +204,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void
*data)
mc->no_parallel = 1;
mc->no_sdcard = 1;
mc->use_sclp = 1;
- mc->max_cpus = 255;
+ mc->max_cpus = 248;
mc->get_hotplug_handler = s390_get_hotplug_handler;
hc->plug = s390_machine_device_plug;
nc->nmi_monitor_handler = s390_nmi;
--
2.9.0
- [Qemu-devel] [PULL 0/7] s390x: next batch of patches, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 3/7] s390x/css: clear IO irqs when generating IPI CRW, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 1/7] linux-headers: update, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 7/7] s390x/kvm: Fixup interrupt type for non-adapter I/O interrupts, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 5/7] virtio-ccw: Provide traces for indicator changes, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 2/7] s390x/kvm: add interface for clearing IO irqs, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 4/7] s390x/css: introduce property type for device ids, Cornelia Huck, 2016/06/14
- [Qemu-devel] [PULL 6/7] s390x: Limit s390-ccw machines to 248 CPUs,
Cornelia Huck <=
- Re: [Qemu-devel] [PULL 0/7] s390x: next batch of patches, Peter Maydell, 2016/06/14