Re: [PATCH v5 3/9] target/s390x: add zpci-interp to cpu models

From: Thomas Huth <thuth@redhat.com>
To: Matthew Rosato <mjrosato@linux.ibm.com>,
	qemu-s390x@nongnu.org, david@redhat.com
Cc: alex.williamson@redhat.com, schnelle@linux.ibm.com,
	cohuck@redhat.com, farman@linux.ibm.com, pmorel@linux.ibm.com,
	richard.henderson@linaro.org, pasic@linux.ibm.com,
	borntraeger@linux.ibm.com, mst@redhat.com, pbonzini@redhat.com,
	qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [PATCH v5 3/9] target/s390x: add zpci-interp to cpu models
Date: Wed, 18 May 2022 10:01:32 +0200	[thread overview]
Message-ID: <f7ca365a-1e7e-d0a8-8a0e-5cf744cd1d20@redhat.com> (raw)
In-Reply-To: <20220404181726.60291-4-mjrosato@linux.ibm.com>

On 04/04/2022 20.17, Matthew Rosato wrote:
> The zpci-interp feature is used to specify whether zPCI interpretation is
> to be used for this guest.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>   hw/s390x/s390-virtio-ccw.c          | 1 +
>   target/s390x/cpu_features_def.h.inc | 1 +
>   target/s390x/gen-features.c         | 2 ++
>   target/s390x/kvm/kvm.c              | 1 +
>   4 files changed, 5 insertions(+)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 90480e7cf9..b190234308 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -805,6 +805,7 @@ static void ccw_machine_6_2_instance_options(MachineState *machine)
>       static const S390FeatInit qemu_cpu_feat = { S390_FEAT_LIST_QEMU_V6_2 };
>   
>       ccw_machine_7_0_instance_options(machine);
> +    s390_cpudef_featoff_greater(14, 1, S390_FEAT_ZPCI_INTERP);
>       s390_set_qemu_cpu_model(0x3906, 14, 2, qemu_cpu_feat);
>   }
>   
> diff --git a/target/s390x/cpu_features_def.h.inc b/target/s390x/cpu_features_def.h.inc
> index e86662bb3b..4ade3182aa 100644
> --- a/target/s390x/cpu_features_def.h.inc
> +++ b/target/s390x/cpu_features_def.h.inc
> @@ -146,6 +146,7 @@ DEF_FEAT(SIE_CEI, "cei", SCLP_CPU, 43, "SIE: Conditional-external-interception f
>   DEF_FEAT(DAT_ENH_2, "dateh2", MISC, 0, "DAT-enhancement facility 2")
>   DEF_FEAT(CMM, "cmm", MISC, 0, "Collaborative-memory-management facility")
>   DEF_FEAT(AP, "ap", MISC, 0, "AP instructions installed")
> +DEF_FEAT(ZPCI_INTERP, "zpci-interp", MISC, 0, "zPCI interpretation")
>   
>   /* Features exposed via the PLO instruction. */
>   DEF_FEAT(PLO_CL, "plo-cl", PLO, 0, "PLO Compare and load (32 bit in general registers)")
> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
> index 22846121c4..9db6bd545e 100644
> --- a/target/s390x/gen-features.c
> +++ b/target/s390x/gen-features.c
> @@ -554,6 +554,7 @@ static uint16_t full_GEN14_GA1[] = {
>       S390_FEAT_HPMA2,
>       S390_FEAT_SIE_KSS,
>       S390_FEAT_GROUP_MULTIPLE_EPOCH_PTFF,
> +    S390_FEAT_ZPCI_INTERP,
>   };
>   
>   #define full_GEN14_GA2 EmptyFeat
> @@ -650,6 +651,7 @@ static uint16_t default_GEN14_GA1[] = {
>       S390_FEAT_GROUP_MSA_EXT_8,
>       S390_FEAT_MULTIPLE_EPOCH,
>       S390_FEAT_GROUP_MULTIPLE_EPOCH_PTFF,
> +    S390_FEAT_ZPCI_INTERP,
>   };

If you add something to the default model, I think you also need to add some 
compatibility handling to the machine types. See e.g. commit 84176c7906f as 
an example.

  Thomas