KVM: get_tss_base_addr() should return a gpa_t

If TSS we are switching to resides in high memory task switch will fail
since address will be truncated. Windows2k3 does this sometimes when
running with more then 4G

Cc: [e-mail]
Signed-off-by: Gleb Natapov <[e-mail]>
Signed-off-by: Avi Kivity <[e-mail]>

arch/x86/kvm/x86.c

···
 	return kvm_write_guest_virt(dtable.base + index*8, seg_desc, sizeof(*seg_desc), vcpu);
 }
 
-static u32 get_tss_base_addr(struct kvm_vcpu *vcpu,
+static gpa_t get_tss_base_addr(struct kvm_vcpu *vcpu,
 			     struct desc_struct *seg_desc)
 {
 	u32 base_addr = get_desc_base(seg_desc);