KVM: x86/mmu: Don't rely on page-track mechanism to flush on memslot change

Call kvm_mmu_zap_all_fast() directly when flushing a memslot instead of
bouncing through the page-track mechanism.  KVM (unfortunately) needs to
zap and flush all page tables on memslot DELETE/MOVE irrespective of
whether KVM is shadowing guest page tables.

This will allow changing KVM to register a page-track notifier on the
first shadow root allocation, and will also allow deleting the misguided
kvm_page_track_flush_slot() hook itself once KVM-GT also moves to a
different method for reacting to memslot changes.

No functional change intended.

Cc: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20221110014821.1548347-2-seanjc@google.com
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.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 acb99a9..eabd5b1 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6159,13 +6159,6 @@ static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
        return unlikely(!list_empty_careful(&kvm->arch.zapped_obsolete_pages));
 }
 
-static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
-                       struct kvm_memory_slot *slot,
-                       struct kvm_page_track_notifier_node *node)
-{
-       kvm_mmu_zap_all_fast(kvm);
-}
-
 int kvm_mmu_init_vm(struct kvm *kvm)
 {
        struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker;
@@ -6183,7 +6176,6 @@ int kvm_mmu_init_vm(struct kvm *kvm)
        }
 
        node->track_write = kvm_mmu_pte_write;
-       node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
        kvm_page_track_register_notifier(kvm, node);
 
        kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
@@ -6711,6 +6703,8 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
                                   struct kvm_memory_slot *slot)
 {
+       kvm_mmu_zap_all_fast(kvm);
+
        kvm_page_track_flush_slot(kvm, slot);
 }