On 02/04/21 01:37, Ben Gardon wrote:
+void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
+ bool shared)
{
gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT);
- lockdep_assert_held_write(&kvm->mmu_lock);
+ kvm_lockdep_assert_mmu_lock_held(kvm, shared);
if (!refcount_dec_and_test(&root->tdp_mmu_root_count))
return;
@@ -81,7 +92,7 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root)
list_del_rcu(&root->link);
spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
- zap_gfn_range(kvm, root, 0, max_gfn, false, false);
+ zap_gfn_range(kvm, root, 0, max_gfn, false, false, shared);
call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback);
Instead of patch 13, would it make sense to delay the zap_gfn_range and
call_rcu to a work item (either unconditionally, or only if
shared==false)? Then the zap_gfn_range would be able to yield and take
the mmu_lock for read, similar to kvm_tdp_mmu_zap_invalidated_roots.
If done unconditionally, this would also allow removing the "shared"
argument to kvm_tdp_mmu_put_root, tdp_mmu_next_root and
for_each_tdp_mmu_root_yield_safe, so I would place that change before
this patch.
Paolo
