[RFC PATCH 20/28] kvm: mmu: Implement the invalidation MMU notifiers for the direct MMU

[Ben Gardon <bgardon@google.com>]

Implements arch specific handler functions for the invalidation MMU
notifiers, using a paging structure iterator. These handlers are
responsible for zapping paging structure entries to enable the main MM
to safely remap memory that was used to back guest memory.

Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/x86/kvm/mmu.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 32426536723c6..ca9b3f574f401 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2829,6 +2829,22 @@ static bool zap_direct_gfn_range(struct kvm *kvm, int as_id, gfn_t start,
 	return direct_walk_iterator_end_traversal(&iter);
 }
 
+static int zap_direct_gfn_range_handler(struct kvm *kvm,
+					struct kvm_memory_slot *slot,
+					gfn_t start, gfn_t end,
+					unsigned long data)
+{
+	return zap_direct_gfn_range(kvm, slot->as_id, start, end,
+				    MMU_WRITE_LOCK);
+}
+
+static bool zap_direct_hva_range(struct kvm *kvm, unsigned long start,
+		unsigned long end)
+{
+	return kvm_handle_direct_hva_range(kvm, start, end, 0,
+					   zap_direct_gfn_range_handler);
+}
+
 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
 			  unsigned long data,
 			  int (*handler)(struct kvm *kvm,
@@ -2842,7 +2858,13 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
 
 int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
 {
-	return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
+	int r = 0;
+
+	if (kvm->arch.direct_mmu_enabled)
+		r |= zap_direct_hva_range(kvm, start, end);
+	if (!kvm->arch.pure_direct_mmu)
+		r |= kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
+	return r;
 }
 
 int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
-- 
2.23.0.444.g18eeb5a265-goog