* [Qemu-devel] [PATCH] hw/ppc/spapr: Use POWER8 by default for the pseries-2.8 machine
@ 2016-10-04 12:55 Thomas Huth
2016-10-05 0:07 ` David Gibson
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Huth @ 2016-10-04 12:55 UTC (permalink / raw)
To: David Gibson, qemu-ppc; +Cc: Alexander Graf, qemu-devel
A couple of distributors are compiling their distributions
with "-mcpu=power8" for ppc64le these days, so the user sooner
or later runs into a crash there when not explicitely specifying
the "-cpu POWER8" option to QEMU. Due to this reason, the linux-user
target already switched to POWER8 by default a while ago (see commit
de3f1b98410e0d5b406a0df3a48547b559d18602). Since the softmmu target
of course has the same problem, we should switch there to POWER8
by default for the newer machine types, too.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1357808
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
Note: This patch should be applied on top of David's ppc-for-2.8
tree, since the pseries-2.8 machine has just been added there
recently.
hw/ppc/spapr.c | 11 ++++++++++-
include/hw/ppc/spapr.h | 1 +
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 63b6a0d..799bcff 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1775,7 +1775,13 @@ static void ppc_spapr_init(MachineState *machine)
/* init CPUs */
if (machine->cpu_model == NULL) {
- machine->cpu_model = kvm_enabled() ? "host" : "POWER7";
+ if (kvm_enabled()) {
+ machine->cpu_model = "host";
+ } else if (smc->tcg_default_cpu) {
+ machine->cpu_model = smc->tcg_default_cpu;
+ } else {
+ machine->cpu_model = "POWER8";
+ }
}
ppc_cpu_parse_features(machine->cpu_model);
@@ -2478,7 +2484,10 @@ static void spapr_machine_2_7_instance_options(MachineState *machine)
static void spapr_machine_2_7_class_options(MachineClass *mc)
{
+ sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
+
spapr_machine_2_8_class_options(mc);
+ smc->tcg_default_cpu = "POWER7";
SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_7);
}
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 6289d50..39dadaa 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -39,6 +39,7 @@ struct sPAPRMachineClass {
/*< public >*/
bool dr_lmb_enabled; /* enable dynamic-reconfig/hotplug of LMBs */
bool use_ohci_by_default; /* use USB-OHCI instead of XHCI */
+ const char *tcg_default_cpu; /* which (TCG) CPU to simulate by default */
};
/**
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH] hw/ppc/spapr: Use POWER8 by default for the pseries-2.8 machine
2016-10-04 12:55 [Qemu-devel] [PATCH] hw/ppc/spapr: Use POWER8 by default for the pseries-2.8 machine Thomas Huth
@ 2016-10-05 0:07 ` David Gibson
2016-10-05 7:36 ` Thomas Huth
0 siblings, 1 reply; 3+ messages in thread
From: David Gibson @ 2016-10-05 0:07 UTC (permalink / raw)
To: Thomas Huth; +Cc: qemu-ppc, Alexander Graf, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 2887 bytes --]
On Tue, Oct 04, 2016 at 02:55:44PM +0200, Thomas Huth wrote:
> A couple of distributors are compiling their distributions
> with "-mcpu=power8" for ppc64le these days, so the user sooner
> or later runs into a crash there when not explicitely specifying
> the "-cpu POWER8" option to QEMU. Due to this reason, the linux-user
> target already switched to POWER8 by default a while ago (see commit
> de3f1b98410e0d5b406a0df3a48547b559d18602). Since the softmmu target
> of course has the same problem, we should switch there to POWER8
> by default for the newer machine types, too.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1357808
> Signed-off-by: Thomas Huth <thuth@redhat.com>
Sounds good, one detail..
> ---
> Note: This patch should be applied on top of David's ppc-for-2.8
> tree, since the pseries-2.8 machine has just been added there
> recently.
>
> hw/ppc/spapr.c | 11 ++++++++++-
> include/hw/ppc/spapr.h | 1 +
> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 63b6a0d..799bcff 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1775,7 +1775,13 @@ static void ppc_spapr_init(MachineState *machine)
>
> /* init CPUs */
> if (machine->cpu_model == NULL) {
> - machine->cpu_model = kvm_enabled() ? "host" : "POWER7";
> + if (kvm_enabled()) {
> + machine->cpu_model = "host";
> + } else if (smc->tcg_default_cpu) {
> + machine->cpu_model = smc->tcg_default_cpu;
> + } else {
> + machine->cpu_model = "POWER8";
> + }
You can avoid the last if branch if you initialize tcg_default_cpu to
POWER8 in spapr_machine_class_init().
> }
>
> ppc_cpu_parse_features(machine->cpu_model);
> @@ -2478,7 +2484,10 @@ static void spapr_machine_2_7_instance_options(MachineState *machine)
>
> static void spapr_machine_2_7_class_options(MachineClass *mc)
> {
> + sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
> +
> spapr_machine_2_8_class_options(mc);
> + smc->tcg_default_cpu = "POWER7";
> SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_7);
> }
>
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 6289d50..39dadaa 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -39,6 +39,7 @@ struct sPAPRMachineClass {
> /*< public >*/
> bool dr_lmb_enabled; /* enable dynamic-reconfig/hotplug of LMBs */
> bool use_ohci_by_default; /* use USB-OHCI instead of XHCI */
> + const char *tcg_default_cpu; /* which (TCG) CPU to simulate by default */
> };
>
> /**
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH] hw/ppc/spapr: Use POWER8 by default for the pseries-2.8 machine
2016-10-05 0:07 ` David Gibson
@ 2016-10-05 7:36 ` Thomas Huth
0 siblings, 0 replies; 3+ messages in thread
From: Thomas Huth @ 2016-10-05 7:36 UTC (permalink / raw)
To: David Gibson; +Cc: qemu-ppc, Alexander Graf, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 1914 bytes --]
On 05.10.2016 02:07, David Gibson wrote:
> On Tue, Oct 04, 2016 at 02:55:44PM +0200, Thomas Huth wrote:
>> A couple of distributors are compiling their distributions
>> with "-mcpu=power8" for ppc64le these days, so the user sooner
>> or later runs into a crash there when not explicitely specifying
>> the "-cpu POWER8" option to QEMU. Due to this reason, the linux-user
>> target already switched to POWER8 by default a while ago (see commit
>> de3f1b98410e0d5b406a0df3a48547b559d18602). Since the softmmu target
>> of course has the same problem, we should switch there to POWER8
>> by default for the newer machine types, too.
>>
>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1357808
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>
> Sounds good, one detail..
>
>> ---
>> Note: This patch should be applied on top of David's ppc-for-2.8
>> tree, since the pseries-2.8 machine has just been added there
>> recently.
>>
>> hw/ppc/spapr.c | 11 ++++++++++-
>> include/hw/ppc/spapr.h | 1 +
>> 2 files changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index 63b6a0d..799bcff 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -1775,7 +1775,13 @@ static void ppc_spapr_init(MachineState *machine)
>>
>> /* init CPUs */
>> if (machine->cpu_model == NULL) {
>> - machine->cpu_model = kvm_enabled() ? "host" : "POWER7";
>> + if (kvm_enabled()) {
>> + machine->cpu_model = "host";
>> + } else if (smc->tcg_default_cpu) {
>> + machine->cpu_model = smc->tcg_default_cpu;
>> + } else {
>> + machine->cpu_model = "POWER8";
>> + }
>
> You can avoid the last if branch if you initialize tcg_default_cpu to
> POWER8 in spapr_machine_class_init().
You're right, that sounds better. I'll send a v2 ...
Thomas
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2016-10-04 12:55 [Qemu-devel] [PATCH] hw/ppc/spapr: Use POWER8 by default for the pseries-2.8 machine Thomas Huth
2016-10-05 0:07 ` David Gibson
2016-10-05 7:36 ` Thomas Huth
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