[Qemu-devel] [PATCH] s390/cpumodel: default enable bpb and ppa15 for z196 and later

[Qemu-devel] [PATCH] s390/cpumodel: default enable bpb and ppa15 for z196 and later

[Christian Borntraeger]

Most systems and host kernels provide the necessary building blocks for
bpb and ppa15. We can reverse the logic and default enable those
features, while still allowing to disable it via cpu model.

So let us add bpb and ppa15 to z196 and later default CPU model for the
qemu 3.0 machine. (like -cpu z13).  Older machine types (e.g.
s390-ccw-virtio-2.12) will retain the old value and not provide those
bits in the default model.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c  | 2 ++
 target/s390x/gen-features.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 7ae5fb38dd..f8f58c8acb 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -824,6 +824,8 @@ DEFINE_CCW_MACHINE(3_0, "3.0", true);
 static void ccw_machine_2_12_instance_options(MachineState *machine)
 {
     ccw_machine_3_0_instance_options(machine);
+    s390_cpudef_featoff_greater(11, 1, S390_FEAT_PPA15);
+    s390_cpudef_featoff_greater(11, 1, S390_FEAT_BPB);
 }
 
 static void ccw_machine_2_12_class_options(MachineClass *mc)
diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
index 6c1c636140..5af042c003 100644
--- a/target/s390x/gen-features.c
+++ b/target/s390x/gen-features.c
@@ -513,6 +513,8 @@ static uint16_t default_GEN11_GA1[] = {
     S390_FEAT_IPTE_RANGE,
     S390_FEAT_ACCESS_EXCEPTION_FS_INDICATION,
     S390_FEAT_GROUP_MSA_EXT_4,
+    S390_FEAT_PPA15,
+    S390_FEAT_BPB,
 };
 
 #define default_GEN11_GA2 EmptyFeat
-- 
2.17.0

Re: [Qemu-devel] [PATCH] s390/cpumodel: default enable bpb and ppa15 for z196 and later

[David Hildenbrand]

s/s390/s390x

I can't think of a scenario where this would be harmful. Migration with
compat machines will still work correctly. -cpu qemu is not affected, so
TCG will also continue to work just fine.

Reviewed-by: David Hildenbrand <david@redhat.com>

On 26.06.2018 14:38, Christian Borntraeger wrote:
> Most systems and host kernels provide the necessary building blocks for
> bpb and ppa15. We can reverse the logic and default enable those
> features, while still allowing to disable it via cpu model.
> 
> So let us add bpb and ppa15 to z196 and later default CPU model for the
> qemu 3.0 machine. (like -cpu z13).  Older machine types (e.g.
> s390-ccw-virtio-2.12) will retain the old value and not provide those
> bits in the default model.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  hw/s390x/s390-virtio-ccw.c  | 2 ++
>  target/s390x/gen-features.c | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 7ae5fb38dd..f8f58c8acb 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -824,6 +824,8 @@ DEFINE_CCW_MACHINE(3_0, "3.0", true);
>  static void ccw_machine_2_12_instance_options(MachineState *machine)
>  {
>      ccw_machine_3_0_instance_options(machine);
> +    s390_cpudef_featoff_greater(11, 1, S390_FEAT_PPA15);
> +    s390_cpudef_featoff_greater(11, 1, S390_FEAT_BPB);
>  }
>  
>  static void ccw_machine_2_12_class_options(MachineClass *mc)
> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
> index 6c1c636140..5af042c003 100644
> --- a/target/s390x/gen-features.c
> +++ b/target/s390x/gen-features.c
> @@ -513,6 +513,8 @@ static uint16_t default_GEN11_GA1[] = {
>      S390_FEAT_IPTE_RANGE,
>      S390_FEAT_ACCESS_EXCEPTION_FS_INDICATION,
>      S390_FEAT_GROUP_MSA_EXT_4,
> +    S390_FEAT_PPA15,
> +    S390_FEAT_BPB,
>  };
>  
>  #define default_GEN11_GA2 EmptyFeat
> 


-- 

Thanks,

David / dhildenb

Re: [Qemu-devel] [PATCH] s390/cpumodel: default enable bpb and ppa15 for z196 and later

[Cornelia Huck]

On Tue, 26 Jun 2018 14:38:30 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> Most systems and host kernels provide the necessary building blocks for
> bpb and ppa15. We can reverse the logic and default enable those
> features, while still allowing to disable it via cpu model.
> 
> So let us add bpb and ppa15 to z196 and later default CPU model for the
> qemu 3.0 machine. (like -cpu z13).  Older machine types (e.g.
> s390-ccw-virtio-2.12) will retain the old value and not provide those
> bits in the default model.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  hw/s390x/s390-virtio-ccw.c  | 2 ++
>  target/s390x/gen-features.c | 2 ++
>  2 files changed, 4 insertions(+)

Thanks, applied.