[kbuild-all] [intel-tdx:kvm-upstream 132/152] arch/x86/kvm/mmu/tdp_mmu.c:1258:43: warning: variable 'shared' is uninitialized when used here

tree: https://github.com/intel/tdx.git kvm-upstream head: bdfe06c17daab60c196ff80c1d98467a1d3734fa commit: 81d423a001d35c498d0c024fa49bba248a916c55 [132/152] KVM, x86/mmu: Support TDX private mapping for TDP MMU config: x86_64-randconfig-a013-20211216 (https://download.01.org/0day-ci/archive/20211217/202112172122.1aS4OBuJ-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project dd245bab9fbb364faa1581e4f92ba3119a872fba) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel/tdx/commit/81d423a001d35c498d0c024fa49bba248a916c55 git remote add intel-tdx https://github.com/intel/tdx.git git fetch --no-tags intel-tdx kvm-upstream git checkout 81d423a001d35c498d0c024fa49bba248a916c55 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/kvm/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): tdp_mmu_zap_alias_spte(vcpu, gfn_alias, shared); ^~~~~~ arch/x86/kvm/mmu/tdp_mmu.c:1233:13: note: initialize the variable 'shared' to silence this warning bool shared; ^ = 0 is_large_pte(iter->old_spte) ? PT_PAGE_SIZE_MASK : 0; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ arch/x86/kvm/mmu/tdp_mmu.c:1409:32: note: place parentheses around the '|' expression to silence this warning is_large_pte(iter->old_spte) ? PT_PAGE_SIZE_MASK : 0; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ arch/x86/kvm/mmu/tdp_mmu.c:1409:32: note: place parentheses around the '?:' expression to evaluate it first is_large_pte(iter->old_spte) ? PT_PAGE_SIZE_MASK : 0; ^ ( ) 2 warnings generated. vim +/shared +1258 arch/x86/kvm/mmu/tdp_mmu.c 1219 1220 /* 1221 * Handle a TDP page fault (NPT/EPT violation/misconfiguration) by installing 1222 * page tables and SPTEs to translate the faulting guest physical address. 1223 */ 1224 int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) 1225 { 1226 struct kvm_mmu *mmu = vcpu->arch.mmu; 1227 struct tdp_iter iter; 1228 struct kvm_mmu_page *sp; 1229 u64 *child_pt; 1230 u64 new_spte; 1231 gfn_t raw_gfn; 1232 bool is_private; 1233 bool shared; 1234 int ret; 1235 1236 kvm_mmu_hugepage_adjust(vcpu, fault); 1237 1238 trace_kvm_mmu_spte_requested(fault); 1239 1240 rcu_read_lock(); 1241 1242 raw_gfn = fault->addr >> PAGE_SHIFT; 1243 is_private = kvm_is_private_gfn(vcpu->kvm, raw_gfn); 1244 1245 if (is_error_noslot_pfn(fault->pfn) || 1246 kvm_is_reserved_pfn(fault->pfn)) { 1247 if (is_private) { 1248 rcu_read_unlock(); 1249 return -EFAULT; 1250 } 1251 } else if (vcpu->kvm->arch.gfn_shared_mask) { 1252 gfn_t gfn_alias = raw_gfn ^ vcpu->kvm->arch.gfn_shared_mask; 1253 /* 1254 * At given time, for one GPA, only one mapping can be valid 1255 * (either private, or shared). Zap aliasing mapping to make 1256 * sure of it. Also see comment in direct_page_fault(). 1257 */ 1259 } 1260 1261 tdp_mmu_for_each_pte(iter, mmu, is_private, raw_gfn, raw_gfn + 1) { 1262 if (fault->nx_huge_page_workaround_enabled) 1263 disallowed_hugepage_adjust(fault, iter.old_spte, iter.level); 1264 1265 if (iter.level == fault->goal_level) 1266 break; 1267 1268 /* 1269 * If there is an SPTE mapping a large page at a higher level 1270 * than the target, that SPTE must be cleared and replaced 1271 * with a non-leaf SPTE. 1272 */ 1273 if (is_shadow_present_pte(iter.old_spte) && 1274 is_large_pte(iter.old_spte)) { 1275 if (!tdp_mmu_zap_spte_flush_excl_or_shared(vcpu->kvm, 1276 &iter, shared)) 1277 break; 1278 /* 1279 * TODO: large page support. 1280 * Doesn't support large page for TDX now 1281 */ 1282 WARN_ON(is_private_spte(&iter.old_spte)); 1283 1284 1285 /* 1286 * The iter must explicitly re-read the spte here 1287 * because the new value informs the !present 1288 * path below. 1289 */ 1290 iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); 1291 } 1292 1293 if (!is_shadow_present_pte(iter.old_spte)) { 1294 1295 /* 1296 * TODO: large page support. 1297 * Not expecting blocked private SPTE points to a 1298 * large page now. 1299 */ 1300 WARN_ON(is_zapped_private_pte(iter.old_spte) && 1301 is_large_pte(iter.old_spte)); 1302 1303 /* 1304 * If SPTE has been frozen by another thread, just 1305 * give up and retry, avoiding unnecessary page table 1306 * allocation and free. 1307 */ 1308 if (is_removed_spte(iter.old_spte)) 1309 break; 1310 1311 sp = alloc_tdp_mmu_page(vcpu, 1312 tdp_iter_gfn_unalias(vcpu->kvm, &iter), 1313 iter.level - 1, is_private); 1314 child_pt = sp->spt; 1315 1316 new_spte = make_nonleaf_spte(child_pt, 1317 !shadow_accessed_mask); 1318 1319 if (tdp_mmu_set_spte_excl_or_shared(vcpu->kvm, &iter, 1320 new_spte, shared)) { 1321 tdp_mmu_link_page(vcpu->kvm, sp, 1322 fault->huge_page_disallowed && 1323 fault->req_level >= iter.level); 1324 1325 trace_kvm_mmu_get_page(sp, true); 1326 } else { 1327 tdp_mmu_free_sp(sp); 1328 break; 1329 } 1330 } 1331 } 1332 1333 if (iter.level != fault->goal_level) { 1334 rcu_read_unlock(); 1335 return RET_PF_RETRY; 1336 } 1337 1338 ret = tdp_mmu_map_handle_target_level(vcpu, fault, &iter, shared); 1339 rcu_read_unlock(); 1340 1341 return ret; 1342 } 1343 1344 static bool block_private_gfn_range(struct kvm *kvm, 1345 struct kvm_gfn_range *range); 1346 1347 bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range, 1348 bool flush) 1349 { 1350 struct kvm_mmu_page *root; 1351 1352 for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, false) { 1353 if (is_private_sp(root)) 1354 flush |= block_private_gfn_range(kvm, range); 1355 else 1356 flush = zap_gfn_range(kvm, root, range->start, range->end, 1357 range->may_block, flush, false); 1358 } 1359 1360 return flush; 1361 } 1362 1363 typedef bool (*tdp_handler_t)(struct kvm *kvm, struct tdp_iter *iter, 1364 struct kvm_gfn_range *range); 1365 1366 static __always_inline bool kvm_tdp_mmu_handle_gfn(struct kvm *kvm, 1367 struct kvm_gfn_range *range, 1368 tdp_handler_t handler) 1369 { 1370 struct kvm_mmu_page *root; 1371 struct tdp_iter iter; 1372 bool ret = false; 1373 1374 rcu_read_lock(); 1375 1376 /* 1377 * Don't support rescheduling, none of the MMU notifiers that funnel 1378 * into this helper allow blocking; it'd be dead, wasteful code. 1379 */ 1380 for_each_tdp_mmu_root(kvm, root, range->slot->as_id) { 1381 /* 1382 * For TDX shared mapping, set GFN shared bit to the range, 1383 * so the handler() doesn't need to set it, to avoid duplicated 1384 * code in multiple handler()s. 1385 */ 1386 if (kvm->arch.gfn_shared_mask && !is_private_sp(root)) { 1387 range->start |= kvm->arch.gfn_shared_mask; 1388 range->end |= kvm->arch.gfn_shared_mask; 1389 } 1390 tdp_root_for_each_leaf_pte(iter, root, range->start, range->end) 1391 ret |= handler(kvm, &iter, range); 1392 } 1393 1394 rcu_read_unlock(); 1395 1396 return ret; 1397 } 1398 1399 static bool block_private_spte(struct kvm *kvm, struct tdp_iter *iter, 1400 struct kvm_gfn_range *range) 1401 { 1402 u64 new_spte; 1403 1404 if (WARN_ON(!is_private_spte(iter->sptep))) 1405 return false; 1406 1407 new_spte = SPTE_PRIVATE_ZAPPED | 1408 (spte_to_pfn(iter->old_spte) << PAGE_SHIFT) | 1410 1411 WRITE_ONCE(*rcu_dereference(iter->sptep), new_spte); 1412 1413 static_call(kvm_x86_zap_private_spte)(kvm, iter->gfn, iter->level); 1414 1415 return true; 1416 } 1417 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org