From 22be5a133169e855097936438417ab1b672ad43f Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 21 Jan 2016 13:22:54 +0100 Subject: [PATCH] KVM: s390: forward ESOP if available ESOP guarantees that during a protection exception, bit 61 of real location 168-175 will only be set to 1 if it was because of ALCP or DATP. If the exception is due to LAP or KCP, the bit will always be set to 0. The old SOP definition allowed bit 61 to be unpredictable in case of LAP or KCP in some conditions. So ESOP replaces this unpredictability by a guarantee. Therefore, we can directly forward ESOP if it is available on our machine. We don't have to do anything when ESOP is disabled - the guest will simply expect unpredictable values. Our guest access functions are already handling ESOP properly. Please note that future functionality in KVM will require knowledge about ESOP being enabled for a guest or not. Reviewed-by: Christian Borntraeger Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/include/uapi/asm/kvm.h | 1 + arch/s390/kvm/kvm-s390.c | 13 +++++++++++++ 2 files changed, 14 insertions(+) diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h index a8559f265e26..789c4e27e294 100644 --- a/arch/s390/include/uapi/asm/kvm.h +++ b/arch/s390/include/uapi/asm/kvm.h @@ -97,6 +97,7 @@ struct kvm_s390_vm_cpu_machine { #define KVM_S390_VM_CPU_MACHINE_FEAT 3 #define KVM_S390_VM_CPU_FEAT_NR_BITS 1024 +#define KVM_S390_VM_CPU_FEAT_ESOP 0 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 6960468f28ad..2b5c14da3227 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -193,6 +193,17 @@ void kvm_arch_hardware_unsetup(void) &kvm_clock_notifier); } +static void allow_cpu_feat(unsigned long nr) +{ + set_bit_inv(nr, kvm_s390_available_cpu_feat); +} + +static void kvm_s390_cpu_feat_init(void) +{ + if (MACHINE_HAS_ESOP) + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); +} + int kvm_arch_init(void *opaque) { kvm_s390_dbf = debug_register("kvm-trace", 32, 1, 7 * sizeof(long)); @@ -204,6 +215,8 @@ int kvm_arch_init(void *opaque) return -ENOMEM; } + kvm_s390_cpu_feat_init(); + /* Register floating interrupt controller interface. */ return kvm_register_device_ops(&kvm_flic_ops, KVM_DEV_TYPE_FLIC); } -- 2.20.1