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    Subject[PATCH v4 04/15] KVM: s390: CPU model support for AP virtualization
    Date
    Introduces a new CPU model feature and two CPU model
    facilities to support AP virtualization for KVM guests.

    CPU model feature:

    The KVM_S390_VM_CPU_FEAT_AP feature indicates that
    AP instructions are available on the guest. This
    feature will be enabled by the kernel only if the AP
    instructions are installed on the linux host. This feature
    must be specifically turned on for the KVM guest from
    userspace to use the VFIO AP device driver for guest
    access to AP devices.

    CPU model facilities:

    1. AP Query Configuration Information (QCI) facility is installed.

    This is indicated by setting facilities bit 12 for
    the guest. The kernel will not enable this facility
    for the guest if it is not set on the host. This facility
    must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP
    feature is not installed.

    2. AP Facilities Test facility (APFT) is installed.

    This is indicated by setting facilities bit 15 for
    the guest. The kernel will not enable this facility for
    the guest if it is not set on the host. This facility
    must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP
    feature is not installed.

    Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
    Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
    Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
    ---
    arch/s390/include/asm/kvm_host.h | 1 +
    arch/s390/include/uapi/asm/kvm.h | 1 +
    arch/s390/kvm/kvm-s390.c | 5 +++++
    arch/s390/tools/gen_facilities.c | 2 ++
    4 files changed, 9 insertions(+), 0 deletions(-)

    diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
    index c990a1d..3162783 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/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
    index 4cdaa55..a580dec 100644
    --- a/arch/s390/include/uapi/asm/kvm.h
    +++ b/arch/s390/include/uapi/asm/kvm.h
    @@ -130,6 +130,7 @@ struct kvm_s390_vm_cpu_machine {
    #define KVM_S390_VM_CPU_FEAT_PFMFI 11
    #define KVM_S390_VM_CPU_FEAT_SIGPIF 12
    #define KVM_S390_VM_CPU_FEAT_KSS 13
    +#define KVM_S390_VM_CPU_FEAT_AP 14
    struct kvm_s390_vm_cpu_feat {
    __u64 feat[16];
    };
    diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
    index b47ff11..55cd897 100644
    --- a/arch/s390/kvm/kvm-s390.c
    +++ b/arch/s390/kvm/kvm-s390.c
    @@ -367,6 +367,11 @@ static void kvm_s390_cpu_feat_init(void)

    if (MACHINE_HAS_ESOP)
    allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP);
    +
    + /* Check if AP instructions installed on host */
    + if (kvm_ap_instructions_installed())
    + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP);
    +
    /*
    * We need SIE support, ESOP (PROT_READ protection for gmap_shadow),
    * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing).
    diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c
    index 90a8c9e..a52290b 100644
    --- a/arch/s390/tools/gen_facilities.c
    +++ b/arch/s390/tools/gen_facilities.c
    @@ -106,6 +106,8 @@ struct facility_def {

    .name = "FACILITIES_KVM_CPUMODEL",
    .bits = (int[]){
    + 12, /* AP Query Configuration Information */
    + 15, /* AP Facilities Test */
    -1 /* END */
    }
    },
    --
    1.7.1
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