The routine ar_translation() is called by get_vcpu_asce(), which is called by both the instruction intercept path (where the access registers had been loaded with the guest's values), and the MEM_OP ioctl (which hadn't). This means that any ALET the guest expects to be used would be ignored.
Furthermore, the logic in ar_translation() will store the contents of the access registers back to the KVM_RUN struct. This unexpected change of AR values can lead to problems after invoking the MEM_OP, for example an ALET Specification Exception. Fix this by swapping the host/guest access registers around the MEM_OP ioctl, in the same way that the KVM_RUN ioctl does with sync_regs()/store_regs(). The full register swap isn't needed here, since only the access registers are used in this interface. Suggested-by: Christian Borntraeger <[email protected]> Signed-off-by: Eric Farman <[email protected]> --- arch/s390/kvm/kvm-s390.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ea63ac769889..c2dfeea55dcf 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5391,6 +5391,10 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu, return -ENOMEM; } + /* Swap host/guest access registers in the event of a MEM_OP with AR specified */ + save_access_regs(vcpu->arch.host_acrs); + restore_access_regs(vcpu->run->s.regs.acrs); + acc_mode = mop->op == KVM_S390_MEMOP_LOGICAL_READ ? GACC_FETCH : GACC_STORE; if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) { r = check_gva_range(vcpu, mop->gaddr, mop->ar, mop->size, @@ -5420,6 +5424,8 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu, kvm_s390_inject_prog_irq(vcpu, &vcpu->arch.pgm); out_free: + save_access_regs(vcpu->run->s.regs.acrs); + restore_access_regs(vcpu->arch.host_acrs); vfree(tmpbuf); return r; } -- 2.40.1
