KVM: mark segments accessed on HW task switch

On HW task switch newly loaded segments should me marked as accessed.

Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 9 insertions, 13 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3b90298fb980..d47ceda7a928 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4697,18 +4697,6 @@ static u16 get_segment_selector(struct kvm_vcpu *vcpu, int seg)
         return kvm_seg.selector;
 }
 
-static int load_segment_descriptor_to_kvm_desct(struct kvm_vcpu *vcpu,
-                                                u16 selector,
-                                                struct kvm_segment *kvm_seg)
-{
-        struct desc_struct seg_desc;
-
-        if (load_guest_segment_descriptor(vcpu, selector, &seg_desc))
-                return 1;
-        seg_desct_to_kvm_desct(&seg_desc, selector, kvm_seg);
-        return 0;
-}
-
 static int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int seg)
 {
         struct kvm_segment segvar = {
@@ -4749,11 +4737,14 @@ int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
                                 int type_bits, int seg)
 {
         struct kvm_segment kvm_seg;
+        struct desc_struct seg_desc;
 
         if (is_vm86_segment(vcpu, seg) || !is_protmode(vcpu))
                 return kvm_load_realmode_segment(vcpu, selector, seg);
-        if (load_segment_descriptor_to_kvm_desct(vcpu, selector, &kvm_seg))
+
+        if (load_guest_segment_descriptor(vcpu, selector, &seg_desc))
                 return 1;
+        seg_desct_to_kvm_desct(&seg_desc, selector, &kvm_seg);
 
         kvm_check_segment_descriptor(vcpu, seg, selector);
         kvm_seg.type |= type_bits;
@@ -4764,6 +4755,11 @@ int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
                         kvm_seg.unusable = 1;
 
         kvm_set_segment(vcpu, &kvm_seg, seg);
+        if (selector && !kvm_seg.unusable && kvm_seg.s) {
+                /* mark segment as accessed */
+                seg_desc.type |= 1;
+                save_guest_segment_descriptor(vcpu, selector, &seg_desc);
+        }
         return 0;
 }