[PATCH v4 3/6] KVM: MMU: introduce kvm_clear_all_lpage_info

[Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>]

This function is used to reset the large page info of all guest pages
which will be used in later patch

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
 arch/x86/kvm/x86.c |   25 +++++++++++++++++++++++++
 arch/x86/kvm/x86.h |    2 ++
 2 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 52b4e97..8e4494c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6951,6 +6951,31 @@ static void memslot_set_lpage_disallowed(struct kvm_memory_slot *slot,
 	}
 }
 
+static void clear_memslot_lpage_info(struct kvm_memory_slot *slot)
+{
+	int i;
+
+	for (i = 1; i < KVM_NR_PAGE_SIZES; ++i) {
+		int lpages;
+		int level = i + 1;
+
+		lpages = gfn_to_index(slot->base_gfn + slot->npages - 1,
+				      slot->base_gfn, level) + 1;
+
+		memset(slot->arch.lpage_info[i - 1], 0,
+		       sizeof(*slot->arch.lpage_info[i - 1]));
+		memslot_set_lpage_disallowed(slot, slot->npages, i, lpages);
+	}
+}
+
+void kvm_clear_all_lpage_info(struct kvm *kvm)
+{
+	struct kvm_memory_slot *slot;
+
+	kvm_for_each_memslot(slot, kvm->memslots)
+		clear_memslot_lpage_info(slot);
+}
+
 int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
 {
 	int i;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index e224f7a..beae540 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -108,6 +108,8 @@ static inline bool vcpu_match_mmio_gpa(struct kvm_vcpu *vcpu, gpa_t gpa)
 	return false;
 }
 
+void kvm_clear_all_lpage_info(struct kvm *kvm);
+
 void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
 void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
 int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
-- 
1.7.7.6