X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=arch%2Fx86%2Fkvm%2Fvmx.c;h=064d0be67ecc23734aa465541138d9b5be295277;hb=d757380c11018e7921324af094aee8dc979f223a;hp=a7e18551c9689b5192d528ccae10ee9dbb20e84a;hpb=23e3a1d971f6658de5aa423011c153765f28fe26;p=~andy%2Flinux

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a7e18551c96..064d0be67ec 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3404,15 +3404,22 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
 	var->limit = vmx_read_guest_seg_limit(vmx, seg);
 	var->selector = vmx_read_guest_seg_selector(vmx, seg);
 	ar = vmx_read_guest_seg_ar(vmx, seg);
+	var->unusable = (ar >> 16) & 1;
 	var->type = ar & 15;
 	var->s = (ar >> 4) & 1;
 	var->dpl = (ar >> 5) & 3;
-	var->present = (ar >> 7) & 1;
+	/*
+	 * Some userspaces do not preserve unusable property. Since usable
+	 * segment has to be present according to VMX spec we can use present
+	 * property to amend userspace bug by making unusable segment always
+	 * nonpresent. vmx_segment_access_rights() already marks nonpresent
+	 * segment as unusable.
+	 */
+	var->present = !var->unusable;
 	var->avl = (ar >> 12) & 1;
 	var->l = (ar >> 13) & 1;
 	var->db = (ar >> 14) & 1;
 	var->g = (ar >> 15) & 1;
-	var->unusable = (ar >> 16) & 1;
 }
 
 static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)