KVM: MMU: Add EPT support

Enable kvm_set_spte() to generate EPT entries.
Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/mmu.c

@@ -152,6 +152,12 @@ static struct kmem_cache *mmu_page_header_cache;
 
 static u64 __read_mostly shadow_trap_nonpresent_pte;
 static u64 __read_mostly shadow_notrap_nonpresent_pte;
+static u64 __read_mostly shadow_base_present_pte;
+static u64 __read_mostly shadow_nx_mask;
+static u64 __read_mostly shadow_x_mask;	/* mutual exclusive with nx_mask */
+static u64 __read_mostly shadow_user_mask;
+static u64 __read_mostly shadow_accessed_mask;
+static u64 __read_mostly shadow_dirty_mask;
 
 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
 {
@@ -160,6 +166,23 @@ void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
 
+void kvm_mmu_set_base_ptes(u64 base_pte)
+{
+	shadow_base_present_pte = base_pte;
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
+
+void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
+		u64 dirty_mask, u64 nx_mask, u64 x_mask)
+{
+	shadow_user_mask = user_mask;
+	shadow_accessed_mask = accessed_mask;
+	shadow_dirty_mask = dirty_mask;
+	shadow_nx_mask = nx_mask;
+	shadow_x_mask = x_mask;
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
+
 static int is_write_protection(struct kvm_vcpu *vcpu)
 {
 	return vcpu->arch.cr0 & X86_CR0_WP;
@@ -198,7 +221,7 @@ static int is_writeble_pte(unsigned long pte)
 
 static int is_dirty_pte(unsigned long pte)
 {
-	return pte & PT_DIRTY_MASK;
+	return pte & shadow_dirty_mask;
 }
 
 static int is_rmap_pte(u64 pte)
@@ -513,7 +536,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
 		return;
 	sp = page_header(__pa(spte));
 	pfn = spte_to_pfn(*spte);
-	if (*spte & PT_ACCESSED_MASK)
+	if (*spte & shadow_accessed_mask)
 		kvm_set_pfn_accessed(pfn);
 	if (is_writeble_pte(*spte))
 		kvm_release_pfn_dirty(pfn);
@@ -1039,17 +1062,17 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
 	 * whether the guest actually used the pte (in order to detect
 	 * demand paging).
 	 */
-	spte = PT_PRESENT_MASK | PT_DIRTY_MASK;
+	spte = shadow_base_present_pte | shadow_dirty_mask;
 	if (!speculative)
 		pte_access |= PT_ACCESSED_MASK;
 	if (!dirty)
 		pte_access &= ~ACC_WRITE_MASK;
-	if (!(pte_access & ACC_EXEC_MASK))
-		spte |= PT64_NX_MASK;
-
-	spte |= PT_PRESENT_MASK;
+	if (pte_access & ACC_EXEC_MASK)
+		spte |= shadow_x_mask;
+	else
+		spte |= shadow_nx_mask;
 	if (pte_access & ACC_USER_MASK)
-		spte |= PT_USER_MASK;
+		spte |= shadow_user_mask;
 	if (largepage)
 		spte |= PT_PAGE_SIZE_MASK;
 
@@ -1155,7 +1178,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
 			}
 
 			table[index] = __pa(new_table->spt) | PT_PRESENT_MASK
-				| PT_WRITABLE_MASK | PT_USER_MASK;
+				| PT_WRITABLE_MASK | shadow_user_mask;
 		}
 		table_addr = table[index] & PT64_BASE_ADDR_MASK;
 	}
@@ -1599,7 +1622,7 @@ static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
 {
 	u64 *spte = vcpu->arch.last_pte_updated;
 
-	return !!(spte && (*spte & PT_ACCESSED_MASK));
+	return !!(spte && (*spte & shadow_accessed_mask));
 }
 
 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,

arch/x86/kvm/x86.c

@@ -2417,6 +2417,9 @@ int kvm_arch_init(void *opaque)
 
 	kvm_x86_ops = ops;
 	kvm_mmu_set_nonpresent_ptes(0ull, 0ull);
+	kvm_mmu_set_base_ptes(PT_PRESENT_MASK);
+	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
+			PT_DIRTY_MASK, PT64_NX_MASK, 0);
 	return 0;
 
 out:

include/asm-x86/kvm_host.h

@@ -434,6 +434,9 @@ void kvm_mmu_destroy(struct kvm_vcpu *vcpu);
 int kvm_mmu_create(struct kvm_vcpu *vcpu);
 int kvm_mmu_setup(struct kvm_vcpu *vcpu);
 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte);
+void kvm_mmu_set_base_ptes(u64 base_pte);
+void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
+		u64 dirty_mask, u64 nx_mask, u64 x_mask);
 
 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);