[RESEND PATCH V8 03/11] KVM: X86: Add helper function to convert SPTE to GFN

[Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>]

Signed-off-by: Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>
---
 arch/x86/kvm/mmu.c | 7 +++++++
 arch/x86/kvm/mmu.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 098df7d135..bbfe3f2863 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1053,6 +1053,13 @@ static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
 
 	return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
 }
+gfn_t spte_to_gfn(u64 *spte)
+{
+	struct kvm_mmu_page *sp;
+
+	sp = page_header(__pa(spte));
+	return kvm_mmu_page_get_gfn(sp, spte - sp->spt);
+}
 
 static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
 {
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index c7b333147c..49d7f2f002 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -211,4 +211,5 @@ void kvm_mmu_gfn_allow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);
 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
 				    struct kvm_memory_slot *slot, u64 gfn);
 int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
+gfn_t spte_to_gfn(u64 *sptep);
 #endif
-- 
2.19.2