diag.c

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/*
 * handling diagnose instructions
 *
 * Copyright IBM Corp. 2008, 2011
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): Carsten Otte <[email protected]>
 *               Christian Borntraeger <[email protected]>
 */

#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include "kvm-s390.h"
#include "trace.h"
#include "trace-s390.h"

static int diag_release_pages(struct kvm_vcpu *vcpu)
{
    unsigned long start, end;
    unsigned long prefix  = vcpu->arch.sie_block->prefix;

    start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
    end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;

    if (start & ~PAGE_MASK || end & ~PAGE_MASK || start > end
        || start < 2 * PAGE_SIZE)
        return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

    VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
    vcpu->stat.diagnose_10++;

    /* we checked for start > end above */
    if (end < prefix || start >= prefix + 2 * PAGE_SIZE) {
        gmap_discard(start, end, vcpu->arch.gmap);
    } else {
        if (start < prefix)
            gmap_discard(start, prefix, vcpu->arch.gmap);
        if (end >= prefix)
            gmap_discard(prefix + 2 * PAGE_SIZE,
                     end, vcpu->arch.gmap);
    }
    return 0;
}

static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
{
    VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
    vcpu->stat.diagnose_44++;
    kvm_vcpu_on_spin(vcpu);
    return 0;
}

static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
{
    struct kvm *kvm = vcpu->kvm;
    struct kvm_vcpu *tcpu;
    int tid;
    int i;

    tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
    vcpu->stat.diagnose_9c++;
    VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);

    if (tid == vcpu->vcpu_id)
        return 0;

    kvm_for_each_vcpu(i, tcpu, kvm)
        if (tcpu->vcpu_id == tid) {
            kvm_vcpu_yield_to(tcpu);
            break;
        }

    return 0;
}

static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
{
    unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
    unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;

    VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
    switch (subcode) {
    case 3:
        vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
        break;
    case 4:
        vcpu->run->s390_reset_flags = 0;
        break;
    default:
        return -EOPNOTSUPP;
    }

    atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
    vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
    vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
    vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
    vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
    VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
      vcpu->run->s390_reset_flags);
    trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
    return -EREMOTE;
}

int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
{
    int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;

    trace_kvm_s390_handle_diag(vcpu, code);
    switch (code) {
    case 0x10:
        return diag_release_pages(vcpu);
    case 0x44:
        return __diag_time_slice_end(vcpu);
    case 0x9c:
        return __diag_time_slice_end_directed(vcpu);
    case 0x308:
        return __diag_ipl_functions(vcpu);
    default:
        return -EOPNOTSUPP;
    }
}