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/pgalloc.h>
  17 #include <asm/virtio-ccw.h>
  18 #include "kvm-s390.h"
  19 #include "trace.h"
  20 #include "trace-s390.h"
  21
  22 static int diag_release_pages(struct kvm_vcpu *vcpu)
  23 {
  24         unsigned long start, end;
  25         unsigned long prefix  = vcpu->arch.sie_block->prefix;
  26
  27         start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  28         end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
  29
  30         if (start & ~PAGE_MASK || end & ~PAGE_MASK || start > end
  31             || start < 2 * PAGE_SIZE)
  32                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  33
  34         VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
  35         vcpu->stat.diagnose_10++;
  36
  37         /* we checked for start > end above */
  38         if (end < prefix || start >= prefix + 2 * PAGE_SIZE) {
  39                 gmap_discard(start, end, vcpu->arch.gmap);
  40         } else {
  41                 if (start < prefix)
  42                         gmap_discard(start, prefix, vcpu->arch.gmap);
  43                 if (end >= prefix)
  44                         gmap_discard(prefix + 2 * PAGE_SIZE,
  45                                      end, vcpu->arch.gmap);
  46         }
  47         return 0;
  48 }
  49
  50 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
  51 {
  52         VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
  53         vcpu->stat.diagnose_44++;
  54         kvm_vcpu_on_spin(vcpu);
  55         return 0;
  56 }
  57
  58 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
  59 {
  60         struct kvm *kvm = vcpu->kvm;
  61         struct kvm_vcpu *tcpu;
  62         int tid;
  63         int i;
  64
  65         tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  66         vcpu->stat.diagnose_9c++;
  67         VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
  68
  69         if (tid == vcpu->vcpu_id)
  70                 return 0;
  71
  72         kvm_for_each_vcpu(i, tcpu, kvm)
  73                 if (tcpu->vcpu_id == tid) {
  74                         kvm_vcpu_yield_to(tcpu);
  75                         break;
  76                 }
  77
  78         return 0;
  79 }
  80
  81 static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
  82 {
  83         unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
  84         unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;
  85
  86         VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
  87         switch (subcode) {
  88         case 3:
  89                 vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
  90                 page_table_reset_pgste(current->mm, 0, TASK_SIZE);
  91                 break;
  92         case 4:
  93                 vcpu->run->s390_reset_flags = 0;
  94                 page_table_reset_pgste(current->mm, 0, TASK_SIZE);
  95                 break;
  96         default:
  97                 return -EOPNOTSUPP;
  98         }
  99
 100         atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
 101         vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
 102         vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
 103         vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
 104         vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
 105         VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
 106           vcpu->run->s390_reset_flags);
 107         trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
 108         return -EREMOTE;
 109 }
 110
 111 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 112 {
 113         int ret;
 114
 115         /* No virtio-ccw notification? Get out quickly. */
 116         if (!vcpu->kvm->arch.css_support ||
 117             (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
 118                 return -EOPNOTSUPP;
 119
 120         /*
 121          * The layout is as follows:
 122          * - gpr 2 contains the subchannel id (passed as addr)
 123          * - gpr 3 contains the virtqueue index (passed as datamatch)
 124          * - gpr 4 contains the index on the bus (optionally)
 125          */
 126         ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
 127                                       vcpu->run->s.regs.gprs[2] & 0xffffffff,
 128                                       8, &vcpu->run->s.regs.gprs[3],
 129                                       vcpu->run->s.regs.gprs[4]);
 130
 131         /*
 132          * Return cookie in gpr 2, but don't overwrite the register if the
 133          * diagnose will be handled by userspace.
 134          */
 135         if (ret != -EOPNOTSUPP)
 136                 vcpu->run->s.regs.gprs[2] = ret;
 137         /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
 138         return ret < 0 ? ret : 0;
 139 }
 140
 141 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 142 {
 143         int code = kvm_s390_get_base_disp_rs(vcpu) & 0xffff;
 144
 145         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 146                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
 147
 148         trace_kvm_s390_handle_diag(vcpu, code);
 149         switch (code) {
 150         case 0x10:
 151                 return diag_release_pages(vcpu);
 152         case 0x44:
 153                 return __diag_time_slice_end(vcpu);
 154         case 0x9c:
 155                 return __diag_time_slice_end_directed(vcpu);
 156         case 0x308:
 157                 return __diag_ipl_functions(vcpu);
 158         case 0x500:
 159                 return __diag_virtio_hypercall(vcpu);
 160         default:
 161                 return -EOPNOTSUPP;
 162         }
 163 }