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Re: [Qemu-devel] [PATCH v1 08/11] s390x: allow only 1 CPU with TCG
From: |
David Hildenbrand |
Subject: |
Re: [Qemu-devel] [PATCH v1 08/11] s390x: allow only 1 CPU with TCG |
Date: |
Thu, 31 Aug 2017 17:33:13 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
On 31.08.2017 17:07, Cornelia Huck wrote:
> On Thu, 31 Aug 2017 17:03:21 +0200
> David Hildenbrand <address@hidden> wrote:
>
>> On 31.08.2017 16:41, Cornelia Huck wrote:
>>> On Wed, 30 Aug 2017 19:05:58 +0200
>>> David Hildenbrand <address@hidden> wrote:
>>>
>>>> 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 are specified, so we don't raise people's
>>>> hope.
>>>>
>>>> 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 7754e3eaf9..eff96808c4 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"
>>>> @@ -56,6 +57,11 @@ 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);
>>>
>>> Make this a #define, so we can just flip the switch when smp support is
>>> ready?
>>
>> As an alternative: yield a warning?
>
> If we know that this can't work, it makes sense to stop immediately, no?
Hmm, like that than?
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 18ed0c57e3..dae848fa5f 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"
@@ -56,6 +57,12 @@ 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 > S390_TCG_MAX_CPUS) {
+ error_report("Number of SMP CPUs requested (%d) exceeds max CPUs "
+ "supported by TCG (%d) on s390x", max_cpus,
+ S390_TCG_MAX_CPUS);
+ exit(1);
+ }
ms->cpus = g_new0(S390CPU *, max_cpus);
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 7ed9103b33..4e1de2102d 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -210,6 +210,8 @@ static inline S390CPU
*s390_env_get_cpu(CPUS390XState *env)
#define ENV_OFFSET offsetof(S390CPU, env)
+#define S390_TCG_MAX_CPUS 1
+
#ifndef CONFIG_USER_ONLY
extern const struct VMStateDescription vmstate_s390_cpu;
#endif
--
Thanks,
David
- Re: [Qemu-devel] [PATCH v1 05/11] s390x: rename s390-virtio.h to s390-virtio-hcall.h, (continued)
[Qemu-devel] [PATCH v1 07/11] target/s390x: rename next_cpu_id to next_cpu_addr, David Hildenbrand, 2017/08/30
[Qemu-devel] [PATCH v1 08/11] s390x: allow only 1 CPU with TCG, David Hildenbrand, 2017/08/30
[Qemu-devel] [PATCH v1 09/11] target/s390x: tcg_s390_program_interrupt() will never return, David Hildenbrand, 2017/08/30
[Qemu-devel] [PATCH v1 10/11] target/s390x: use trigger_pgm_exception() in s390_cpu_handle_mmu_fault(), David Hildenbrand, 2017/08/30
[Qemu-devel] [PATCH v1 11/11] target/s390x: use program_interrupt() in per_check_exception(), David Hildenbrand, 2017/08/30
Re: [Qemu-devel] [PATCH v1 00/11] next round of s390x cleanups, Cornelia Huck, 2017/08/31