[PATCH v4 07/13] nEPT: Redefine EPT-specific link_shadow_page()

[Gleb Natapov <gleb@redhat.com>]

From: Yang Zhang <yang.z.zhang@Intel.com>

Since nEPT doesn't support A/D bit, so we should not set those bit
when build shadow page table.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 arch/x86/kvm/mmu.c         |   12 +++++++++---
 arch/x86/kvm/paging_tmpl.h |    4 ++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b5273c3..9e0f467 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2047,12 +2047,18 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
 	return __shadow_walk_next(iterator, *iterator->sptep);
 }
 
-static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
+static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp, bool accessed)
 {
 	u64 spte;
 
+	BUILD_BUG_ON(VMX_EPT_READABLE_MASK != PT_PRESENT_MASK ||
+			VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
+
 	spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK |
-	       shadow_user_mask | shadow_x_mask | shadow_accessed_mask;
+	       shadow_user_mask | shadow_x_mask;
+
+	if (accessed)
+		spte |= shadow_accessed_mask;
 
 	mmu_spte_set(sptep, spte);
 }
@@ -2677,7 +2683,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
 					      iterator.level - 1,
 					      1, ACC_ALL, iterator.sptep);
 
-			link_shadow_page(iterator.sptep, sp);
+			link_shadow_page(iterator.sptep, sp, true);
 		}
 	}
 	return emulate;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index e38b3c0..23a19a5 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -545,7 +545,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 			goto out_gpte_changed;
 
 		if (sp)
-			link_shadow_page(it.sptep, sp);
+			link_shadow_page(it.sptep, sp, PTTYPE != PTTYPE_EPT);
 	}
 
 	for (;
@@ -565,7 +565,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 
 		sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
 				      true, direct_access, it.sptep);
-		link_shadow_page(it.sptep, sp);
+		link_shadow_page(it.sptep, sp, PTTYPE != PTTYPE_EPT);
 	}
 
 	clear_sp_write_flooding_count(it.sptep);
-- 
1.7.10.4