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Re: [Qemu-devel] [PATCH v5 11/22] s390x: allow only 1 CPU with TCG
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v5 11/22] s390x: allow only 1 CPU with TCG |
Date: |
Wed, 13 Sep 2017 17:13:50 +0100 |
User-agent: |
mu4e 0.9.19; emacs 25.2.50.3 |
David Hildenbrand <address@hidden> writes:
> Specifying more than 1 CPU (e.g. -smp 5) leads to SIGP errors (the
> guest tries to bring these CPUs up but fails), because we don't support
> multiple CPUs on s390x under TCG.
>
> Let's bail out if more than 1 is specified, so we don't raise people's
> hope.
Why does this restriction exist? Without MTTCG enabled -smp > 1 should
be safe from any races.
>
> Tested-by: Matthew Rosato <address@hidden>
> Signed-off-by: David Hildenbrand <address@hidden>
> ---
> hw/s390x/s390-virtio-ccw.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index f67b4b5d58..417998ec28 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -23,6 +23,7 @@
> #include "hw/s390x/css.h"
> #include "virtio-ccw.h"
> #include "qemu/config-file.h"
> +#include "qemu/error-report.h"
> #include "s390-pci-bus.h"
> #include "hw/s390x/storage-keys.h"
> #include "hw/s390x/storage-attributes.h"
> @@ -55,6 +56,11 @@ static void s390_init_cpus(MachineState *machine)
> if (machine->cpu_model == NULL) {
> machine->cpu_model = s390_default_cpu_model_name();
> }
> + if (tcg_enabled() && max_cpus > 1) {
> + error_report("Number of SMP CPUs requested (%d) exceeds max CPUs "
> + "supported by TCG (1) on s390x", max_cpus);
> + exit(1);
> + }
>
> cpu_states = g_new0(S390CPU *, max_cpus);
--
Alex Bennée
- Re: [Qemu-devel] [PATCH v5 08/22] s390x: move sclp_service_call() to sclp.h, (continued)
[Qemu-devel] [PATCH v5 07/22] target/s390x: move some s390x typedefs to cpu-qom.h, David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 10/22] target/s390x: use program_interrupt() in per_check_exception(), David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 11/22] s390x: allow only 1 CPU with TCG, David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 12/22] target/s390x: set cpu->id for linux user when realizing, David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 14/22] target/s390x: rename next_cpu_id to next_core_id, David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 13/22] target/s390x: use "core-id" for cpu number/address/id handling, David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 15/22] s390x: print CPU definitions in sorted order, David Hildenbrand, 2017/09/13
[Qemu-devel] [PATCH v5 16/22] s390x: allow cpu hotplug via device_add, David Hildenbrand, 2017/09/13