On Tue, Sep 08, 2020 at 08:13:28AM +0000, Haibo Xu wrote:
> Turn on the spe cpu property by default if host cpu
> support it, i.e. we can now do '-cpu max|host' to add
> the vSPE, and '-cpu max|host,spe=off' to remove it.
>
> Signed-off-by: Haibo Xu <haibo...@linaro.org>
> ---
> target/arm/cpu.c | 3 +++
> target/arm/cpu.h | 2 ++
> target/arm/cpu64.c | 7 ++++++-
> target/arm/kvm64.c | 12 ++++++++++++
> 4 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 786cc6134c..58f12d6eb5 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -2271,6 +2271,9 @@ static void arm_host_initfn(Object *obj)
> kvm_arm_set_cpu_features_from_host(cpu);
> if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
> aarch64_add_sve_properties(obj);
> +
> + cpu->has_spe = ON_OFF_AUTO_AUTO;
> + aarch64_add_spe_properties(obj);
Why not put the assignment of has_spe into aarch64_add_spe_properties()?
> }
> arm_cpu_post_init(obj);
> }
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index 395a1e5df8..5a3ea876c8 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -1040,6 +1040,7 @@ void aarch64_sve_narrow_vq(CPUARMState *env, unsigned
> vq);
> void aarch64_sve_change_el(CPUARMState *env, int old_el,
> int new_el, bool el0_a64);
> void aarch64_add_sve_properties(Object *obj);
> +void aarch64_add_spe_properties(Object *obj);
>
> /*
> * SVE registers are encoded in KVM's memory in an endianness-invariant
> format.
> @@ -1071,6 +1072,7 @@ static inline void aarch64_sve_change_el(CPUARMState
> *env, int o,
> int n, bool a)
> { }
> static inline void aarch64_add_sve_properties(Object *obj) { }
> +static inline void aarch64_add_spe_properties(Object *obj) { }
> #endif
>
> #if !defined(CONFIG_TCG)
> diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> index 4997c4a3c0..d38c55e2ca 100644
> --- a/target/arm/cpu64.c
> +++ b/target/arm/cpu64.c
> @@ -621,6 +621,11 @@ static void arm_spe_set(Object *obj, bool value, Error
> **errp)
> ARM_CPU(obj)->has_spe = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
> }
>
> +void aarch64_add_spe_properties(Object *obj)
> +{
> + object_property_add_bool(obj, "spe", arm_spe_get, arm_spe_set);
> +}
> +
> /* -cpu max: if KVM is enabled, like -cpu host (best possible with this
> host);
> * otherwise, a CPU with as many features enabled as our emulation supports.
> * The version of '-cpu max' for qemu-system-arm is defined in cpu.c;
> @@ -772,7 +777,7 @@ static void aarch64_max_initfn(Object *obj)
> cpu_max_set_sve_max_vq, NULL, NULL);
>
> cpu->has_spe = ON_OFF_AUTO_AUTO;
> - object_property_add_bool(obj, "spe", arm_spe_get, arm_spe_set);
> + aarch64_add_spe_properties(obj);
If TCG doesn't support this cpu feature then this should be in the
kvm_enabled() part of this function.
> }
>
> static const ARMCPUInfo aarch64_cpus[] = {
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index 5a2032fc9e..3f0a09c05b 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -515,6 +515,7 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures
> *ahcf)
> */
> int fdarray[3];
> bool sve_supported;
> + bool spe_supported;
> uint64_t features = 0;
> uint64_t t;
> int err;
> @@ -655,6 +656,8 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures
> *ahcf)
> }
>
> sve_supported = ioctl(fdarray[0], KVM_CHECK_EXTENSION, KVM_CAP_ARM_SVE)
> > 0;
> + spe_supported = ioctl(fdarray[0], KVM_CHECK_EXTENSION,
> + KVM_CAP_ARM_SPE_V1) > 0;
>
> kvm_arm_destroy_scratch_host_vcpu(fdarray);
>
> @@ -668,6 +671,11 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures
> *ahcf)
> t = FIELD_DP64(t, ID_AA64PFR0, SVE, 1);
> ahcf->isar.id_aa64pfr0 = t;
> }
> + if (!spe_supported) {
> + t = ahcf->isar.id_aa64dfr0;
> + t = FIELD_DP64(t, ID_AA64DFR0, PMSVER, 0);
> + ahcf->isar.id_aa64dfr0 = t;
> + }
>
If this works then there's a bug with the KVM implementation. get-one-reg
shouldn't expose SPE unless userspace has enabled it, which we're not
doing on the scratch vcpu. That's why we set, not clear, the ID bits for
SVE.
> /*
> * We can assume any KVM supporting CPU is at least a v8
> @@ -830,6 +838,10 @@ int kvm_arch_init_vcpu(CPUState *cs)
> assert(kvm_arm_sve_supported());
> cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_SVE;
> }
> + if (cpu_isar_feature(aa64_spe, cpu)) {
> + assert(kvm_arm_spe_supported());
> + cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_SPE_V1;
> + }
>
> /* Do KVM_ARM_VCPU_INIT ioctl */
> ret = kvm_arm_vcpu_init(cs);
> --
> 2.17.1
>
Thanks,
drew
