[RFC PATCH 1/4] mmu: add a boolean to indicate host ept execute only support

[Bandan Das <bsd@redhat.com>]

This is passed as the last argument with the call to
kvm_mmu_set_mask_ptes. This is an easier alternative to
FNAMing is_shadow_pte_present().

Signed-off-by: Bandan Das <bsd@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 arch/x86/kvm/mmu.c              | 6 +++++-
 arch/x86/kvm/vmx.c              | 3 ++-
 arch/x86/kvm/x86.c              | 2 +-
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 69e62862..791f7e2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1026,7 +1026,7 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu);
 void kvm_mmu_init_vm(struct kvm *kvm);
 void kvm_mmu_uninit_vm(struct kvm *kvm);
 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
-		u64 dirty_mask, u64 nx_mask, u64 x_mask);
+		u64 dirty_mask, u64 nx_mask, u64 x_mask, bool xonly);
 
 void kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
 void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index def97b3..37b01b1 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -175,6 +175,8 @@ static u64 __read_mostly shadow_user_mask;
 static u64 __read_mostly shadow_accessed_mask;
 static u64 __read_mostly shadow_dirty_mask;
 static u64 __read_mostly shadow_mmio_mask;
+/* true if processor supports execute only ept mappings */
+static bool __read_mostly shadow_xonly_valid;
 
 static void mmu_spte_set(u64 *sptep, u64 spte);
 static void mmu_free_roots(struct kvm_vcpu *vcpu);
@@ -282,13 +284,15 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
 }
 
 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
-		u64 dirty_mask, u64 nx_mask, u64 x_mask)
+		u64 dirty_mask, u64 nx_mask, u64 x_mask,
+		bool xonly_valid)
 {
 	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;
+	shadow_xonly_valid = xonly_valid;
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 003618e..dbfc000 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6369,7 +6369,8 @@ static __init int hardware_setup(void)
 		kvm_mmu_set_mask_ptes(0ull,
 			(enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
 			(enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull,
-			0ull, VMX_EPT_EXECUTABLE_MASK);
+			0ull, VMX_EPT_EXECUTABLE_MASK,
+			cpu_has_vmx_ept_execute_only() ? true : false);
 		ept_set_mmio_spte_mask();
 		kvm_enable_tdp();
 	} else
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 902d9da..a098d11 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5873,7 +5873,7 @@ int kvm_arch_init(void *opaque)
 	kvm_x86_ops = ops;
 
 	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
-			PT_DIRTY_MASK, PT64_NX_MASK, 0);
+			PT_DIRTY_MASK, PT64_NX_MASK, 0, false);
 
 	kvm_timer_init();
 
-- 
2.5.5