KVM: x86/mmu: Consolidate kvm_mmu_zap_all() and kvm_mmu_zap_mmio_sptes()

...via a new helper, __kvm_mmu_zap_all().  An alternative to passing a
'bool mmio_only' would be to pass a callback function to filter the
shadow page, i.e. to make __kvm_mmu_zap_all() generic and reusable, but
zapping all shadow pages is a last resort, i.e. making the helper less
extensible is a feature of sorts.  And the explicit MMIO parameter makes
it easy to preserve the WARN_ON_ONCE() if a restart is triggered when
zapping MMIO sptes.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8161807..8d43b7c 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5840,7 +5840,7 @@ void kvm_mmu_slot_set_dirty(struct kvm *kvm,
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_slot_set_dirty);
 
-void kvm_mmu_zap_all(struct kvm *kvm)
+static void __kvm_mmu_zap_all(struct kvm *kvm, bool mmio_only)
 {
        struct kvm_mmu_page *sp, *node;
        LIST_HEAD(invalid_list);
@@ -5849,30 +5849,12 @@ void kvm_mmu_zap_all(struct kvm *kvm)
        spin_lock(&kvm->mmu_lock);
 restart:
        list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) {
-               if (sp->role.invalid && sp->root_count)
+               if (mmio_only && !sp->mmio_cached)
                        continue;
-               if (__kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list, &ign) ||
-                   cond_resched_lock(&kvm->mmu_lock))
-                       goto restart;
-       }
-
-       kvm_mmu_commit_zap_page(kvm, &invalid_list);
-       spin_unlock(&kvm->mmu_lock);
-}
-
-static void kvm_mmu_zap_mmio_sptes(struct kvm *kvm)
-{
-       struct kvm_mmu_page *sp, *node;
-       LIST_HEAD(invalid_list);
-       int ign;
-
-       spin_lock(&kvm->mmu_lock);
-restart:
-       list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) {
-               if (!sp->mmio_cached)
+               if (sp->role.invalid && sp->root_count)
                        continue;
                if (__kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list, &ign)) {
-                       WARN_ON_ONCE(1);
+                       WARN_ON_ONCE(mmio_only);
                        goto restart;
                }
                if (cond_resched_lock(&kvm->mmu_lock))
@@ -5883,6 +5865,11 @@ restart:
        spin_unlock(&kvm->mmu_lock);
 }
 
+void kvm_mmu_zap_all(struct kvm *kvm)
+{
+       return __kvm_mmu_zap_all(kvm, false);
+}
+
 void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
 {
        WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
@@ -5904,7 +5891,7 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
         */
        if (unlikely(gen == 0)) {
                kvm_debug_ratelimited("kvm: zapping shadow pages for mmio generation wraparound\n");
-               kvm_mmu_zap_mmio_sptes(kvm);
+               __kvm_mmu_zap_all(kvm, true);
        }
 }