On Fri, Apr 26, 2024, Rick P Edgecombe wrote: > On Fri, 2024-04-26 at 08:28 -0700, Sean Christopherson wrote: > > If the choice is between an enum and exclude_*, I would strongly prefer the > > enum. Using exclude_* results in inverted polarity for the code that > > triggers invalidations. > > Right, the awkwardness lands in that code. > > The processing code looks nice though: > https://lore.kernel.org/kvm/5210e6e6e2eb73b04cb7039084015612479ae2fe.camel@xxxxxxxxx/ Heh, where's your bitmask abuse spirit? It's a little evil (and by "evil" I mean awesome), but the need to process different roots is another good argument for an enum+bitmask. enum tdp_mmu_root_types { KVM_SHARED_ROOTS = KVM_PROCESS_SHARED, KVM_PRIVATE_ROOTS = KVM_PROCESS_PRIVATE, KVM_VALID_ROOTS = BIT(2), KVM_ANY_VALID_ROOT = KVM_SHARED_ROOT | KVM_PRIVATE_ROOT | KVM_VALID_ROOT, KVM_ANY_ROOT = KVM_SHARED_ROOT | KVM_PRIVATE_ROOT, } static_assert(!(KVM_SHARED_ROOTS & KVM_VALID_ROOTS)); static_assert(!(KVM_PRIVATE_ROOTS & KVM_VALID_ROOTS)); static_assert(KVM_PRIVATE_ROOTS == (KVM_SHARED_ROOTS << 1)); /* * Returns the next root after @prev_root (or the first root if @prev_root is * NULL). A reference to the returned root is acquired, and the reference to * @prev_root is released (the caller obviously must hold a reference to * @prev_root if it's non-NULL). * * Returns NULL if the end of tdp_mmu_roots was reached. */ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, struct kvm_mmu_page *prev_root, enum tdp_mmu_root_types types) { bool only_valid = types & KVM_VALID_ROOTS; struct kvm_mmu_page *next_root; /* * While the roots themselves are RCU-protected, fields such as * role.invalid are protected by mmu_lock. */ lockdep_assert_held(&kvm->mmu_lock); rcu_read_lock(); if (prev_root) next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, &prev_root->link, typeof(*prev_root), link); else next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots, typeof(*next_root), link); while (next_root) { if ((!only_valid || !next_root->role.invalid) && (types & (KVM_SHARED_ROOTS << is_private_sp(root))) && kvm_tdp_mmu_get_root(next_root)) break; next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, &next_root->link, typeof(*next_root), link); } rcu_read_unlock(); if (prev_root) kvm_tdp_mmu_put_root(kvm, prev_root); return next_root; } #define __for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _types) \ for (_root = tdp_mmu_next_root(_kvm, NULL, _types); \ ({ lockdep_assert_held(&(_kvm)->mmu_lock); }), _root; \ _root = tdp_mmu_next_root(_kvm, _root, _types)) \ if (_as_id >= 0 && kvm_mmu_page_as_id(_root) != _as_id) { \ } else #define for_each_valid_tdp_mmu_root_yield_safe(_kvm, _root, _as_id) \ __for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, KVM_ANY_VALID_ROOT) #define for_each_tdp_mmu_root_yield_safe(_kvm, _root) \ for (_root = tdp_mmu_next_root(_kvm, NULL, KVM_ANY_ROOT); \ ({ lockdep_assert_held(&(_kvm)->mmu_lock); }), _root; \ _root = tdp_mmu_next_root(_kvm, _root, KVM_ANY_ROOT))
