KVM: x86/mmu: Extract zapping of rmaps for gfn range to separate helper

Extract the zapping of rmaps, a.k.a. legacy MMU, for a gfn range to a
separate helper to clean up the unholy mess that kvm_zap_gfn_range() has
become.  In addition to deep nesting, the rmaps zapping spreads out the
declaration of several variables and is generally a mess.  Clean up the
mess now so that future work to improve the memslots implementation
doesn't need to deal with it.

Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-4-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 71165a5d11635ee2cb2b6a8f576ab6f7f370f8b7..354d2ca92df4d15d2f06870be4a67124f37e34c2 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5710,40 +5710,48 @@ void kvm_mmu_uninit_vm(struct kvm *kvm)
        kvm_mmu_uninit_tdp_mmu(kvm);
 }
 
+static bool __kvm_zap_rmaps(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
+{
+       const struct kvm_memory_slot *memslot;
+       struct kvm_memslots *slots;
+       bool flush = false;
+       gfn_t start, end;
+       int i;
+
+       if (!kvm_memslots_have_rmaps(kvm))
+               return flush;
+
+       for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+               slots = __kvm_memslots(kvm, i);
+               kvm_for_each_memslot(memslot, slots) {
+                       start = max(gfn_start, memslot->base_gfn);
+                       end = min(gfn_end, memslot->base_gfn + memslot->npages);
+                       if (start >= end)
+                               continue;
+
+                       flush = slot_handle_level_range(kvm, memslot, kvm_zap_rmapp,
+                                                       PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
+                                                       start, end - 1, true, flush);
+               }
+       }
+
+       return flush;
+}
+
 /*
  * Invalidate (zap) SPTEs that cover GFNs from gfn_start and up to gfn_end
  * (not including it)
  */
 void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 {
-       struct kvm_memslots *slots;
-       struct kvm_memory_slot *memslot;
+       bool flush;
        int i;
-       bool flush = false;
 
        write_lock(&kvm->mmu_lock);
 
        kvm_inc_notifier_count(kvm, gfn_start, gfn_end);
 
-       if (kvm_memslots_have_rmaps(kvm)) {
-               for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
-                       slots = __kvm_memslots(kvm, i);
-                       kvm_for_each_memslot(memslot, slots) {
-                               gfn_t start, end;
-
-                               start = max(gfn_start, memslot->base_gfn);
-                               end = min(gfn_end, memslot->base_gfn + memslot->npages);
-                               if (start >= end)
-                                       continue;
-
-                               flush = slot_handle_level_range(kvm,
-                                               (const struct kvm_memory_slot *) memslot,
-                                               kvm_zap_rmapp, PG_LEVEL_4K,
-                                               KVM_MAX_HUGEPAGE_LEVEL, start,
-                                               end - 1, true, flush);
-                       }
-               }
-       }
+       flush = __kvm_zap_rmaps(kvm, gfn_start, gfn_end);
 
        if (is_tdp_mmu_enabled(kvm)) {
                for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)