Hi Ben, Thank you for the patch! Yet something to improve: [auto build test ERROR on next-20210331] [cannot apply to kvm/queue tip/master linux/master linus/master v5.12-rc5 v5.12-rc4 v5.12-rc3 v5.12-rc5] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Ben-Gardon/More-parallel-operations-for-the-TDP-MMU/20210401-051137 base: 7a43c78d0573e0bbbb0456b033e2b9a895b89464 config: x86_64-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/2b2c6d3bdc35269df5f9293a02da5b71c74095f3 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ben-Gardon/More-parallel-operations-for-the-TDP-MMU/20210401-051137 git checkout 2b2c6d3bdc35269df5f9293a02da5b71c74095f3 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): In file included from include/linux/rculist.h:11, from include/linux/pid.h:5, from include/linux/sched.h:14, from include/linux/hardirq.h:9, from include/linux/kvm_host.h:7, from arch/x86/kvm/mmu.h:5, from arch/x86/kvm/mmu/tdp_mmu.c:3: arch/x86/kvm/mmu/tdp_mmu.c: In function 'kvm_tdp_mmu_get_vcpu_root_hpa': >> arch/x86/kvm/mmu/tdp_mmu.c:139:5: error: implicit declaration of function 'lockdep_is_held_write'; did you mean 'lockdep_is_held_type'? [-Werror=implicit-function-declaration] 139 | lockdep_is_held_write(&kvm->mmu_lock)) | ^~~~~~~~~~~~~~~~~~~~~ include/linux/rcupdate.h:318:52: note: in definition of macro 'RCU_LOCKDEP_WARN' 318 | if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \ | ^ include/linux/rculist.h:391:7: note: in expansion of macro '__list_check_rcu' 391 | for (__list_check_rcu(dummy, ## cond, 0), \ | ^~~~~~~~~~~~~~~~ arch/x86/kvm/mmu/tdp_mmu.c:138:2: note: in expansion of macro 'list_for_each_entry_rcu' 138 | list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link, \ | ^~~~~~~~~~~~~~~~~~~~~~~ arch/x86/kvm/mmu/tdp_mmu.c:184:2: note: in expansion of macro 'for_each_tdp_mmu_root' 184 | for_each_tdp_mmu_root(kvm, root) { | ^~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +139 arch/x86/kvm/mmu/tdp_mmu.c 2 > 3 #include "mmu.h" 4 #include "mmu_internal.h" 5 #include "mmutrace.h" 6 #include "tdp_iter.h" 7 #include "tdp_mmu.h" 8 #include "spte.h" 9 10 #include <asm/cmpxchg.h> 11 #include <trace/events/kvm.h> 12 13 static bool __read_mostly tdp_mmu_enabled = false; 14 module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644); 15 16 /* Initializes the TDP MMU for the VM, if enabled. */ 17 void kvm_mmu_init_tdp_mmu(struct kvm *kvm) 18 { 19 if (!tdp_enabled || !READ_ONCE(tdp_mmu_enabled)) 20 return; 21 22 /* This should not be changed for the lifetime of the VM. */ 23 kvm->arch.tdp_mmu_enabled = true; 24 25 INIT_LIST_HEAD(&kvm->arch.tdp_mmu_roots); 26 spin_lock_init(&kvm->arch.tdp_mmu_pages_lock); 27 INIT_LIST_HEAD(&kvm->arch.tdp_mmu_pages); 28 } 29 30 void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) 31 { 32 if (!kvm->arch.tdp_mmu_enabled) 33 return; 34 35 WARN_ON(!list_empty(&kvm->arch.tdp_mmu_roots)); 36 37 /* 38 * Ensure that all the outstanding RCU callbacks to free shadow pages 39 * can run before the VM is torn down. 40 */ 41 rcu_barrier(); 42 } 43 44 static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, 45 gfn_t start, gfn_t end, bool can_yield); 46 47 static void tdp_mmu_free_sp(struct kvm_mmu_page *sp) 48 { 49 free_page((unsigned long)sp->spt); 50 kmem_cache_free(mmu_page_header_cache, sp); 51 } 52 53 /* 54 * This is called through call_rcu in order to free TDP page table memory 55 * safely with respect to other kernel threads that may be operating on 56 * the memory. 57 * By only accessing TDP MMU page table memory in an RCU read critical 58 * section, and freeing it after a grace period, lockless access to that 59 * memory won't use it after it is freed. 60 */ 61 static void tdp_mmu_free_sp_rcu_callback(struct rcu_head *head) 62 { 63 struct kvm_mmu_page *sp = container_of(head, struct kvm_mmu_page, 64 rcu_head); 65 66 tdp_mmu_free_sp(sp); 67 } 68 69 void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root) 70 { 71 gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT); 72 73 lockdep_assert_held_write(&kvm->mmu_lock); 74 75 if (!refcount_dec_and_test(&root->tdp_mmu_root_count)) 76 return; 77 78 WARN_ON(!root->tdp_mmu_page); 79 80 spin_lock(&kvm->arch.tdp_mmu_pages_lock); 81 list_del_rcu(&root->link); 82 spin_unlock(&kvm->arch.tdp_mmu_pages_lock); 83 84 zap_gfn_range(kvm, root, 0, max_gfn, false); 85 86 call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback); 87 } 88 89 /* 90 * Finds the next valid root after root (or the first valid root if root 91 * is NULL), takes a reference on it, and returns that next root. If root 92 * is not NULL, this thread should have already taken a reference on it, and 93 * that reference will be dropped. If no valid root is found, this 94 * function will return NULL. 95 */ 96 static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, 97 struct kvm_mmu_page *prev_root) 98 { 99 struct kvm_mmu_page *next_root; 100 101 lockdep_assert_held_write(&kvm->mmu_lock); 102 103 rcu_read_lock(); 104 105 if (prev_root) 106 next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, 107 &prev_root->link, 108 typeof(*prev_root), link); 109 else 110 next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots, 111 typeof(*next_root), link); 112 113 while (next_root && !kvm_tdp_mmu_get_root(kvm, next_root)) 114 next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, 115 &next_root->link, typeof(*next_root), link); 116 117 rcu_read_unlock(); 118 119 if (prev_root) 120 kvm_tdp_mmu_put_root(kvm, prev_root); 121 122 return next_root; 123 } 124 125 /* 126 * Note: this iterator gets and puts references to the roots it iterates over. 127 * This makes it safe to release the MMU lock and yield within the loop, but 128 * if exiting the loop early, the caller must drop the reference to the most 129 * recent root. (Unless keeping a live reference is desirable.) 130 */ 131 #define for_each_tdp_mmu_root_yield_safe(_kvm, _root) \ 132 for (_root = tdp_mmu_next_root(_kvm, NULL); \ 133 _root; \ 134 _root = tdp_mmu_next_root(_kvm, _root)) 135 136 /* Only safe under the MMU lock in write mode, without yielding. */ 137 #define for_each_tdp_mmu_root(_kvm, _root) \ 138 list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link, \ > 139 lockdep_is_held_write(&kvm->mmu_lock)) 140 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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