1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * handling diagnose instructions 4 * 5 * Copyright IBM Corp. 2008, 2020 6 * 7 * Author(s): Carsten Otte <cotte@de.ibm.com> 8 * Christian Borntraeger <borntraeger@de.ibm.com> 9 */ 10 11 #include <linux/kvm.h> 12 #include <linux/kvm_host.h> 13 #include <asm/gmap.h> 14 #include <asm/virtio-ccw.h> 15 #include "kvm-s390.h" 16 #include "trace.h" 17 #include "trace-s390.h" 18 #include "gaccess.h" 19 20 static int diag_release_pages(struct kvm_vcpu *vcpu) 21 { 22 unsigned long start, end; 23 unsigned long prefix = kvm_s390_get_prefix(vcpu); 24 25 start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4]; 26 end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + PAGE_SIZE; 27 vcpu->stat.instruction_diagnose_10++; 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 35 /* 36 * We checked for start >= end above, so lets check for the 37 * fast path (no prefix swap page involved) 38 */ 39 if (end <= prefix || start >= prefix + 2 * PAGE_SIZE) { 40 gmap_discard(vcpu->arch.gmap, start, end); 41 } else { 42 /* 43 * This is slow path. gmap_discard will check for start 44 * so lets split this into before prefix, prefix, after 45 * prefix and let gmap_discard make some of these calls 46 * NOPs. 47 */ 48 gmap_discard(vcpu->arch.gmap, start, prefix); 49 if (start <= prefix) 50 gmap_discard(vcpu->arch.gmap, 0, PAGE_SIZE); 51 if (end > prefix + PAGE_SIZE) 52 gmap_discard(vcpu->arch.gmap, PAGE_SIZE, 2 * PAGE_SIZE); 53 gmap_discard(vcpu->arch.gmap, prefix + 2 * PAGE_SIZE, end); 54 } 55 return 0; 56 } 57 58 static int __diag_page_ref_service(struct kvm_vcpu *vcpu) 59 { 60 struct prs_parm { 61 u16 code; 62 u16 subcode; 63 u16 parm_len; 64 u16 parm_version; 65 u64 token_addr; 66 u64 select_mask; 67 u64 compare_mask; 68 u64 zarch; 69 }; 70 struct prs_parm parm; 71 int rc; 72 u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4; 73 u16 ry = (vcpu->arch.sie_block->ipa & 0x0f); 74 75 VCPU_EVENT(vcpu, 3, "diag page reference parameter block at 0x%llx", 76 vcpu->run->s.regs.gprs[rx]); 77 vcpu->stat.instruction_diagnose_258++; 78 if (vcpu->run->s.regs.gprs[rx] & 7) 79 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); 80 rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm)); 81 if (rc) 82 return kvm_s390_inject_prog_cond(vcpu, rc); 83 if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258) 84 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); 85 86 switch (parm.subcode) { 87 case 0: /* TOKEN */ 88 VCPU_EVENT(vcpu, 3, "pageref token addr 0x%llx " 89 "select mask 0x%llx compare mask 0x%llx", 90 parm.token_addr, parm.select_mask, parm.compare_mask); 91 if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) { 92 /* 93 * If the pagefault handshake is already activated, 94 * the token must not be changed. We have to return 95 * decimal 8 instead, as mandated in SC24-6084. 96 */ 97 vcpu->run->s.regs.gprs[ry] = 8; 98 return 0; 99 } 100 101 if ((parm.compare_mask & parm.select_mask) != parm.compare_mask || 102 parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL) 103 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); 104 105 if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr)) 106 return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); 107 108 vcpu->arch.pfault_token = parm.token_addr; 109 vcpu->arch.pfault_select = parm.select_mask; 110 vcpu->arch.pfault_compare = parm.compare_mask; 111 vcpu->run->s.regs.gprs[ry] = 0; 112 rc = 0; 113 break; 114 case 1: /* 115 * CANCEL 116 * Specification allows to let already pending tokens survive 117 * the cancel, therefore to reduce code complexity, we assume 118 * all outstanding tokens are already pending. 119 */ 120 VCPU_EVENT(vcpu, 3, "pageref cancel addr 0x%llx", parm.token_addr); 121 if (parm.token_addr || parm.select_mask || 122 parm.compare_mask || parm.zarch) 123 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); 124 125 vcpu->run->s.regs.gprs[ry] = 0; 126 /* 127 * If the pfault handling was not established or is already 128 * canceled SC24-6084 requests to return decimal 4. 129 */ 130 if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID) 131 vcpu->run->s.regs.gprs[ry] = 4; 132 else 133 vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID; 134 135 rc = 0; 136 break; 137 default: 138 rc = -EOPNOTSUPP; 139 break; 140 } 141 142 return rc; 143 } 144 145 static int __diag_time_slice_end(struct kvm_vcpu *vcpu) 146 { 147 VCPU_EVENT(vcpu, 5, "%s", "diag time slice end"); 148 vcpu->stat.instruction_diagnose_44++; 149 kvm_vcpu_on_spin(vcpu, true); 150 return 0; 151 } 152 153 static int forward_cnt; 154 static unsigned long cur_slice; 155 156 static int diag9c_forwarding_overrun(void) 157 { 158 /* Reset the count on a new slice */ 159 if (time_after(jiffies, cur_slice)) { 160 cur_slice = jiffies; 161 forward_cnt = diag9c_forwarding_hz / HZ; 162 } 163 return forward_cnt-- <= 0 ? 1 : 0; 164 } 165 166 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu) 167 { 168 struct kvm_vcpu *tcpu; 169 int tcpu_cpu; 170 int tid; 171 172 tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4]; 173 vcpu->stat.instruction_diagnose_9c++; 174 175 /* yield to self */ 176 if (tid == vcpu->vcpu_id) 177 goto no_yield; 178 179 /* yield to invalid */ 180 tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid); 181 if (!tcpu) 182 goto no_yield; 183 184 /* target guest VCPU already running */ 185 tcpu_cpu = READ_ONCE(tcpu->cpu); 186 if (tcpu_cpu >= 0) { 187 if (!diag9c_forwarding_hz || diag9c_forwarding_overrun()) 188 goto no_yield; 189 190 /* target host CPU already running */ 191 if (!vcpu_is_preempted(tcpu_cpu)) 192 goto no_yield; 193 smp_yield_cpu(tcpu_cpu); 194 VCPU_EVENT(vcpu, 5, 195 "diag time slice end directed to %d: yield forwarded", 196 tid); 197 vcpu->stat.diag_9c_forward++; 198 return 0; 199 } 200 201 if (kvm_vcpu_yield_to(tcpu) <= 0) 202 goto no_yield; 203 204 VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: done", tid); 205 return 0; 206 no_yield: 207 VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: ignored", tid); 208 vcpu->stat.diag_9c_ignored++; 209 return 0; 210 } 211 212 static int __diag_ipl_functions(struct kvm_vcpu *vcpu) 213 { 214 unsigned int reg = vcpu->arch.sie_block->ipa & 0xf; 215 unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff; 216 217 VCPU_EVENT(vcpu, 3, "diag ipl functions, subcode %lx", subcode); 218 vcpu->stat.instruction_diagnose_308++; 219 switch (subcode) { 220 case 3: 221 vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR; 222 break; 223 case 4: 224 vcpu->run->s390_reset_flags = 0; 225 break; 226 default: 227 return -EOPNOTSUPP; 228 } 229 230 /* 231 * no need to check the return value of vcpu_stop as it can only have 232 * an error for protvirt, but protvirt means user cpu state 233 */ 234 if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) 235 kvm_s390_vcpu_stop(vcpu); 236 vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM; 237 vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL; 238 vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT; 239 vcpu->run->exit_reason = KVM_EXIT_S390_RESET; 240 VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx", 241 vcpu->run->s390_reset_flags); 242 trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags); 243 return -EREMOTE; 244 } 245 246 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) 247 { 248 int ret; 249 250 vcpu->stat.instruction_diagnose_500++; 251 /* No virtio-ccw notification? Get out quickly. */ 252 if (!vcpu->kvm->arch.css_support || 253 (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY)) 254 return -EOPNOTSUPP; 255 256 VCPU_EVENT(vcpu, 4, "diag 0x500 schid 0x%8.8x queue 0x%x cookie 0x%llx", 257 (u32) vcpu->run->s.regs.gprs[2], 258 (u32) vcpu->run->s.regs.gprs[3], 259 vcpu->run->s.regs.gprs[4]); 260 261 /* 262 * The layout is as follows: 263 * - gpr 2 contains the subchannel id (passed as addr) 264 * - gpr 3 contains the virtqueue index (passed as datamatch) 265 * - gpr 4 contains the index on the bus (optionally) 266 */ 267 ret = kvm_io_bus_write_cookie(vcpu, KVM_VIRTIO_CCW_NOTIFY_BUS, 268 vcpu->run->s.regs.gprs[2] & 0xffffffff, 269 8, &vcpu->run->s.regs.gprs[3], 270 vcpu->run->s.regs.gprs[4]); 271 272 /* 273 * Return cookie in gpr 2, but don't overwrite the register if the 274 * diagnose will be handled by userspace. 275 */ 276 if (ret != -EOPNOTSUPP) 277 vcpu->run->s.regs.gprs[2] = ret; 278 /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */ 279 return ret < 0 ? ret : 0; 280 } 281 282 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) 283 { 284 int code = kvm_s390_get_base_disp_rs(vcpu, NULL) & 0xffff; 285 286 if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) 287 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); 288 289 trace_kvm_s390_handle_diag(vcpu, code); 290 switch (code) { 291 case 0x10: 292 return diag_release_pages(vcpu); 293 case 0x44: 294 return __diag_time_slice_end(vcpu); 295 case 0x9c: 296 return __diag_time_slice_end_directed(vcpu); 297 case 0x258: 298 return __diag_page_ref_service(vcpu); 299 case 0x308: 300 return __diag_ipl_functions(vcpu); 301 case 0x500: 302 return __diag_virtio_hypercall(vcpu); 303 default: 304 vcpu->stat.instruction_diagnose_other++; 305 return -EOPNOTSUPP; 306 } 307 } 308