arch/s390/kvm/diag.c

   1 /*
   2  * handling diagnose instructions
   3  *
   4  * Copyright IBM Corp. 2008, 2011
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License (version 2 only)
   8  * as published by the Free Software Foundation.
   9  *
  10  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  11  *               Christian Borntraeger <borntraeger@de.ibm.com>
  12  */
  13
  14 #include <linux/kvm.h>
  15 #include <linux/kvm_host.h>
  16 #include <asm/virtio-ccw.h>
  17 #include "kvm-s390.h"
  18 #include "trace.h"
  19 #include "trace-s390.h"
  20
  21 static int diag_release_pages(struct kvm_vcpu *vcpu)
  22 {
  23         unsigned long start, end;
  24         unsigned long prefix  = vcpu->arch.sie_block->prefix;
  25
  26         start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  27         end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
  28
  29         if (start & ~PAGE_MASK || end & ~PAGE_MASK || start > end
  30             || start < 2 * PAGE_SIZE)
  31                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  32
  33         VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
  34         vcpu->stat.diagnose_10++;
  35
  36         /* we checked for start > end above */
  37         if (end < prefix || start >= prefix + 2 * PAGE_SIZE) {
  38                 gmap_discard(start, end, vcpu->arch.gmap);
  39         } else {
  40                 if (start < prefix)
  41                         gmap_discard(start, prefix, vcpu->arch.gmap);
  42                 if (end >= prefix)
  43                         gmap_discard(prefix + 2 * PAGE_SIZE,
  44                                      end, vcpu->arch.gmap);
  45         }
  46         return 0;
  47 }
  48
  49 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
  50 {
  51         VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
  52         vcpu->stat.diagnose_44++;
  53         kvm_vcpu_on_spin(vcpu);
  54         return 0;
  55 }
  56
  57 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
  58 {
  59         struct kvm *kvm = vcpu->kvm;
  60         struct kvm_vcpu *tcpu;
  61         int tid;
  62         int i;
  63
  64         tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  65         vcpu->stat.diagnose_9c++;
  66         VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
  67
  68         if (tid == vcpu->vcpu_id)
  69                 return 0;
  70
  71         kvm_for_each_vcpu(i, tcpu, kvm)
  72                 if (tcpu->vcpu_id == tid) {
  73                         kvm_vcpu_yield_to(tcpu);
  74                         break;
  75                 }
  76
  77         return 0;
  78 }
  79
  80 static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
  81 {
  82         unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
  83         unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;
  84
  85         VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
  86         switch (subcode) {
  87         case 3:
  88                 vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
  89                 break;
  90         case 4:
  91                 vcpu->run->s390_reset_flags = 0;
  92                 break;
  93         default:
  94                 return -EOPNOTSUPP;
  95         }
  96
  97         atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
  98         vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
  99         vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
 100         vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
 101         vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
 102         VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
 103           vcpu->run->s390_reset_flags);
 104         trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
 105         return -EREMOTE;
 106 }
 107
 108 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 109 {
 110         int ret, idx;
 111
 112         /* No virtio-ccw notification? Get out quickly. */
 113         if (!vcpu->kvm->arch.css_support ||
 114             (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
 115                 return -EOPNOTSUPP;
 116
 117         idx = srcu_read_lock(&vcpu->kvm->srcu);
 118         /*
 119          * The layout is as follows:
 120          * - gpr 2 contains the subchannel id (passed as addr)
 121          * - gpr 3 contains the virtqueue index (passed as datamatch)
 122          * - gpr 4 contains the index on the bus (optionally)
 123          */
 124         ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
 125                                       vcpu->run->s.regs.gprs[2] & 0xffffffff,
 126                                       8, &vcpu->run->s.regs.gprs[3],
 127                                       vcpu->run->s.regs.gprs[4]);
 128         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 129
 130         /*
 131          * Return cookie in gpr 2, but don't overwrite the register if the
 132          * diagnose will be handled by userspace.
 133          */
 134         if (ret != -EOPNOTSUPP)
 135                 vcpu->run->s.regs.gprs[2] = ret;
 136         /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
 137         return ret < 0 ? ret : 0;
 138 }
 139
 140 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 141 {
 142         int code = kvm_s390_get_base_disp_rs(vcpu) & 0xffff;
 143
 144         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 145                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
 146
 147         trace_kvm_s390_handle_diag(vcpu, code);
 148         switch (code) {
 149         case 0x10:
 150                 return diag_release_pages(vcpu);
 151         case 0x44:
 152                 return __diag_time_slice_end(vcpu);
 153         case 0x9c:
 154                 return __diag_time_slice_end_directed(vcpu);
 155         case 0x308:
 156                 return __diag_ipl_functions(vcpu);
 157         case 0x500:
 158                 return __diag_virtio_hypercall(vcpu);
 159         default:
 160                 return -EOPNOTSUPP;
 161         }
 162 }