Hi Sean, I love your patch! Perhaps something to improve: [auto build test WARNING on 26291c54e111ff6ba87a164d85d4a4e134b7315c] url: https://github.com/0day-ci/linux/commits/Sean-Christopherson/x86-uaccess-CMPXCHG-KVM-bug-fixes/20220201-091001 base: 26291c54e111ff6ba87a164d85d4a4e134b7315c config: x86_64-rhel-8.3-kselftests (https://download.01.org/0day-ci/archive/20220201/202202012104.eSvVUhWh-lkp@xxxxxxxxx/config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/0day-ci/linux/commit/c880d7a9df876f20dc3acdd893c5c71f3cda5029 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Sean-Christopherson/x86-uaccess-CMPXCHG-KVM-bug-fixes/20220201-091001 git checkout c880d7a9df876f20dc3acdd893c5c71f3cda5029 # save the config file to linux build tree mkdir build_dir make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> sparse warnings: (new ones prefixed by >>) arch/x86/kvm/mmu/mmu.c:695:9: sparse: sparse: context imbalance in 'walk_shadow_page_lockless_begin' - different lock contexts for basic block arch/x86/kvm/mmu/mmu.c: note: in included file (through include/linux/rbtree.h, include/linux/mm_types.h, arch/x86/kvm/irq.h): include/linux/rcupdate.h:725:9: sparse: sparse: context imbalance in 'walk_shadow_page_lockless_end' - unexpected unlock arch/x86/kvm/mmu/mmu.c:2595:9: sparse: sparse: context imbalance in 'mmu_try_to_unsync_pages' - different lock contexts for basic block arch/x86/kvm/mmu/mmu.c: note: in included file: >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression arch/x86/kvm/mmu/mmu.c: note: in included file: >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression arch/x86/kvm/mmu/mmu.c: note: in included file: >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression >> arch/x86/kvm/mmu/paging_tmpl.h:244:23: sparse: sparse: dereference of noderef expression arch/x86/kvm/mmu/mmu.c:4549:57: sparse: sparse: cast truncates bits from constant value (ffffff33 becomes 33) arch/x86/kvm/mmu/mmu.c:4551:56: sparse: sparse: cast truncates bits from constant value (ffffff0f becomes f) arch/x86/kvm/mmu/mmu.c:4553:57: sparse: sparse: cast truncates bits from constant value (ffffff55 becomes 55) vim +244 arch/x86/kvm/mmu/paging_tmpl.h 191 192 static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu, 193 struct kvm_mmu *mmu, 194 struct guest_walker *walker, 195 gpa_t addr, int write_fault) 196 { 197 unsigned level, index; 198 pt_element_t pte, orig_pte; 199 pt_element_t __user *ptep_user; 200 gfn_t table_gfn; 201 int ret; 202 203 /* dirty/accessed bits are not supported, so no need to update them */ 204 if (!PT_HAVE_ACCESSED_DIRTY(mmu)) 205 return 0; 206 207 for (level = walker->max_level; level >= walker->level; --level) { 208 pte = orig_pte = walker->ptes[level - 1]; 209 table_gfn = walker->table_gfn[level - 1]; 210 ptep_user = walker->ptep_user[level - 1]; 211 index = offset_in_page(ptep_user) / sizeof(pt_element_t); 212 if (!(pte & PT_GUEST_ACCESSED_MASK)) { 213 trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte)); 214 pte |= PT_GUEST_ACCESSED_MASK; 215 } 216 if (level == walker->level && write_fault && 217 !(pte & PT_GUEST_DIRTY_MASK)) { 218 trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte)); 219 #if PTTYPE == PTTYPE_EPT 220 if (kvm_x86_ops.nested_ops->write_log_dirty(vcpu, addr)) 221 return -EINVAL; 222 #endif 223 pte |= PT_GUEST_DIRTY_MASK; 224 } 225 if (pte == orig_pte) 226 continue; 227 228 /* 229 * If the slot is read-only, simply do not process the accessed 230 * and dirty bits. This is the correct thing to do if the slot 231 * is ROM, and page tables in read-as-ROM/write-as-MMIO slots 232 * are only supported if the accessed and dirty bits are already 233 * set in the ROM (so that MMIO writes are never needed). 234 * 235 * Note that NPT does not allow this at all and faults, since 236 * it always wants nested page table entries for the guest 237 * page tables to be writable. And EPT works but will simply 238 * overwrite the read-only memory to set the accessed and dirty 239 * bits. 240 */ 241 if (unlikely(!walker->pte_writable[level - 1])) 242 continue; 243 > 244 ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault); 245 if (ret) 246 return ret; 247 248 kvm_vcpu_mark_page_dirty(vcpu, table_gfn); 249 walker->ptes[level - 1] = pte; 250 } 251 return 0; 252 } 253 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
