KVM: Add ioctl to tss address from userspace,

Currently kvm has a wart in that it requires three extra pages for use
as a tss when emulating real mode on Intel.  This patch moves the allocation
internally, only requiring userspace to tell us where in the physical address
space we can place the tss.

Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 82c3b13..3d07d9b 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -382,6 +382,7 @@
 	struct kvm_pic *vpic;
 	struct kvm_ioapic *vioapic;
 	int round_robin_prev_vcpu;
+	unsigned int tss_addr;
 };
 
 static inline struct kvm_pic *pic_irqchip(struct kvm *kvm)
@@ -467,6 +468,8 @@
 	void (*inject_pending_irq)(struct kvm_vcpu *vcpu);
 	void (*inject_pending_vectors)(struct kvm_vcpu *vcpu,
 				       struct kvm_run *run);
+
+	int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
 };
 
 extern struct kvm_x86_ops *kvm_x86_ops;