[PATCH v2 3/7] KVM: x86: introduce kvm_clear_all_gfn_page_info

[Xiao Guangrong]

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

Signed-off-by: Xiao Guangrong <xiaoguangr...@linux.vnet.ibm.com>
---
 arch/x86/kvm/x86.c       |   31 +++++++++++++++++++++++++++++++
 include/linux/kvm_host.h |    1 +
 2 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e0a7f67..87d27a8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6902,6 +6902,37 @@ memslot_set_lpage_disallowed(struct kvm_memory_slot 
*slot,
        }
 }
 
+static void clear_memslot_page_info(struct kvm_memory_slot *slot)
+{
+       int i;
+
+       for (i = 0; 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.rmap[i], 0,
+                      lpages * sizeof(*slot->arch.rmap[i]));
+
+               if (i) {
+                       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_gfn_page_info(struct kvm *kvm)
+{
+       struct kvm_memory_slot *slot;
+
+       kvm_for_each_memslot(slot, kvm->memslots)
+               clear_memslot_page_info(slot);
+}
+
 int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
 {
        int i;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0f4941a..1de9b79 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -491,6 +491,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
                            struct kvm_userspace_memory_region *mem);
 void kvm_arch_free_memslot(struct kvm_memory_slot *free,
                           struct kvm_memory_slot *dont);
+void kvm_clear_all_gfn_page_info(struct kvm *kvm);
 int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long 
npages);
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                struct kvm_memory_slot *memslot,
-- 
1.7.7.6

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