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SubjectRe: [PATCH v2 08/15] KVM: s390: interface to enable AP execution mode
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On 27.02.2018 15:28, Tony Krowiak wrote:
> Introduces a new interface to enable AP interpretive
> execution (IE) mode for the KVM guest. When running
> with IE mode enabled, AP instructions executed on the
> KVM guest will be interpreted by the firmware and
> passed directly through to an AP device installed on
> the system. The CPU model feature for AP must
> be enabled for the KVM guest in order to enable
> interpretive execution mode.
>
> This interface will be used in a subsequent patch
> by the VFIO AP device driver.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
> ---
> arch/s390/include/asm/kvm-ap.h | 2 ++
> arch/s390/include/asm/kvm_host.h | 1 +
> arch/s390/kvm/kvm-ap.c | 27 +++++++++++++++++++++++++++
> arch/s390/kvm/kvm-s390.h | 1 +
> 4 files changed, 31 insertions(+), 0 deletions(-)
>
> diff --git a/arch/s390/include/asm/kvm-ap.h b/arch/s390/include/asm/kvm-ap.h
> index 46e7c5b..6bd6bfb 100644
> --- a/arch/s390/include/asm/kvm-ap.h
> +++ b/arch/s390/include/asm/kvm-ap.h
> @@ -51,4 +51,6 @@ struct kvm_ap_matrix {
>
> void kvm_ap_deconfigure_matrix(struct kvm *kvm);
>
> +int kvm_ap_enable_ie_mode(struct kvm *kvm);
> +
> #endif /* _ASM_KVM_AP */
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index a4c77d3..1eebdd6 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -186,6 +186,7 @@ struct kvm_s390_sie_block {
> #define ECA_AIV 0x00200000
> #define ECA_VX 0x00020000
> #define ECA_PROTEXCI 0x00002000
> +#define ECA_APIE 0x00000008
> #define ECA_SII 0x00000001
> __u32 eca; /* 0x004c */
> #define ICPT_INST 0x04
> diff --git a/arch/s390/kvm/kvm-ap.c b/arch/s390/kvm/kvm-ap.c
> index bb29045..862e54b 100644
> --- a/arch/s390/kvm/kvm-ap.c
> +++ b/arch/s390/kvm/kvm-ap.c
> @@ -307,3 +307,30 @@ void kvm_ap_deconfigure_matrix(struct kvm *kvm)
> kvm_ap_clear_crycb_masks(kvm);
> }
> EXPORT_SYMBOL(kvm_ap_deconfigure_matrix);
> +
> +/**
> + * kvm_ap_enable_ie_mode
> + *
> + * Enable interpretrive execution of AP instructions for the guest. When
> + * enabled, AP instructions executed on the guest will be interpreted and
> + * passed through to an AP installed on the host system.
> + *
> + * Returns 0 if interpretrive execution is enabled. Returns -EOPNOTSUPP
> + * if AP facilities are not installed for the guest.
> + *
> + * @kvm: the guest's kvm structure
> + */
> +int kvm_ap_enable_ie_mode(struct kvm *kvm)
> +{
> + int i;
> + struct kvm_vcpu *vcpu;
> +
> + if (!test_kvm_cpu_feat(kvm, KVM_S390_VM_CPU_FEAT_AP))
> + return -EOPNOTSUPP;
> +
> + kvm_for_each_vcpu(i, vcpu, kvm)
> + vcpu->arch.sie_block->eca |= ECA_APIE;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(kvm_ap_enable_ie_mode);
> diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
> index 1b5621f..3142541 100644
> --- a/arch/s390/kvm/kvm-s390.h
> +++ b/arch/s390/kvm/kvm-s390.h
> @@ -18,6 +18,7 @@
> #include <asm/facility.h>
> #include <asm/processor.h>
> #include <asm/sclp.h>
> +#include <asm/ap.h>
>
> /* Transactional Memory Execution related macros */
> #define IS_TE_ENABLED(vcpu) ((vcpu->arch.sie_block->ecb & ECB_TE))
>

And also, what about hot-plugged CPUs?

--

Thanks,

David / dhildenb

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