KVM: x86/tdp_mmu: Take root types for kvm_tdp_mmu_invalidate_all_roots()

Rename kvm_tdp_mmu_invalidate_all_roots() to
kvm_tdp_mmu_invalidate_roots(), and make it enum kvm_tdp_mmu_root_types
as an argument.

kvm_tdp_mmu_invalidate_roots() is called with different root types. For
kvm_mmu_zap_all_fast() it only operates on shared roots. But when tearing
down a VM it needs to invalidate all roots. Have the callers only
invalidate the required roots instead of all roots.

Within kvm_tdp_mmu_invalidate_roots(), respect the root type
passed by checking the root type in root iterator.

Suggested-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-17-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 7a71e607709424d122fd65c23860bfbe135e9a5d..1fac5971604f0636c4d8ef836a4dc9e21dcb1c59 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6454,8 +6454,13 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
         * write and in the same critical section as making the reload request,
         * e.g. before kvm_zap_obsolete_pages() could drop mmu_lock and yield.
         */
-       if (tdp_mmu_enabled)
-               kvm_tdp_mmu_invalidate_all_roots(kvm);
+       if (tdp_mmu_enabled) {
+               /*
+                * External page tables don't support fast zapping, therefore
+                * their mirrors must be invalidated separately by the caller.
+                */
+               kvm_tdp_mmu_invalidate_roots(kvm, KVM_DIRECT_ROOTS);
+       }
 
        /*
         * Notify all vcpus to reload its shadow page table and flush TLB.

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 7ebadc7f2640cc195da6857227568d4fe2a1d5dc..ca2b95b75ca4f32d9df6c4a779f807e1c801e5cf 100644 (file)
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -37,7 +37,7 @@ void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm)
         * for zapping and thus puts the TDP MMU's reference to each root, i.e.
         * ultimately frees all roots.
         */
-       kvm_tdp_mmu_invalidate_all_roots(kvm);
+       kvm_tdp_mmu_invalidate_roots(kvm, KVM_VALID_ROOTS);
        kvm_tdp_mmu_zap_invalidated_roots(kvm, false);
 
        WARN_ON(atomic64_read(&kvm->arch.tdp_mmu_pages));
@@ -1070,10 +1070,18 @@ void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm, bool shared)
  * Note, kvm_tdp_mmu_zap_invalidated_roots() is gifted the TDP MMU's reference.
  * See kvm_tdp_mmu_alloc_root().
  */
-void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm)
+void kvm_tdp_mmu_invalidate_roots(struct kvm *kvm,
+                                 enum kvm_tdp_mmu_root_types root_types)
 {
        struct kvm_mmu_page *root;
 
+       /*
+        * Invalidating invalid roots doesn't make sense, prevent developers from
+        * having to think about it.
+        */
+       if (WARN_ON_ONCE(root_types & KVM_INVALID_ROOTS))
+               root_types &= ~KVM_INVALID_ROOTS;
+
        /*
         * mmu_lock must be held for write to ensure that a root doesn't become
         * invalid while there are active readers (invalidating a root while
@@ -1095,6 +1103,9 @@ void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm)
         * or get/put references to roots.
         */
        list_for_each_entry(root, &kvm->arch.tdp_mmu_roots, link) {
+               if (!tdp_mmu_root_match(root, root_types))
+                       continue;
+
                /*
                 * Note, invalid roots can outlive a memslot update!  Invalid
                 * roots must be *zapped* before the memslot update completes,

diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index 9887441cd7034312c7d99247cec7547c0f60e0ce..52acf99d40a0052354bad2f4f245010f42be46dc 100644 (file)
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -66,7 +66,8 @@ static inline struct kvm_mmu_page *tdp_mmu_get_root(struct kvm_vcpu *vcpu,
 bool kvm_tdp_mmu_zap_leafs(struct kvm *kvm, gfn_t start, gfn_t end, bool flush);
 bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp);
 void kvm_tdp_mmu_zap_all(struct kvm *kvm);
-void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm);
+void kvm_tdp_mmu_invalidate_roots(struct kvm *kvm,
+                                 enum kvm_tdp_mmu_root_types root_types);
 void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm, bool shared);
 
 int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);