/*
   * Things the lguest guest needs to know.  Note: like all lguest interfaces,
   * this is subject to wild and random change between versions.
   */
  #ifndef _LINUX_LGUEST_H
  #define _LINUX_LGUEST_H
  
  #ifndef __ASSEMBLY__
  #include <linux/time.h>
  #include <asm/irq.h>
  #include <asm/lguest_hcall.h>
  
  #define LG_CLOCK_MIN_DELTA	100UL
  #define LG_CLOCK_MAX_DELTA	ULONG_MAX
  
  /*G:031
   * The second method of communicating with the Host is to via "struct
   * lguest_data".  Once the Guest's initialization hypercall tells the Host where
   * this is, the Guest and Host both publish information in it.
  :*/
  struct lguest_data {
  	/*
  	 * 512 == enabled (same as eflags in normal hardware).  The Guest
  	 * changes interrupts so often that a hypercall is too slow.
  	 */
  	unsigned int irq_enabled;
  	/* Fine-grained interrupt disabling by the Guest */
  	DECLARE_BITMAP(blocked_interrupts, LGUEST_IRQS);
  
  	/*
  	 * The Host writes the virtual address of the last page fault here,
  	 * which saves the Guest a hypercall.  CR2 is the native register where
  	 * this address would normally be found.
  	 */
  	unsigned long cr2;
  
  	/* Wallclock time set by the Host. */
  	struct timespec time;
  
  	/*
  	 * Interrupt pending set by the Host.  The Guest should do a hypercall
  	 * if it re-enables interrupts and sees this set (to X86_EFLAGS_IF).
  	 */
  	int irq_pending;
  
  	/*
  	 * Async hypercall ring.  Instead of directly making hypercalls, we can
  	 * place them in here for processing the next time the Host wants.
  	 * This batching can be quite efficient.
  	 */
  
  	/* 0xFF == done (set by Host), 0 == pending (set by Guest). */
  	u8 hcall_status[LHCALL_RING_SIZE];
  	/* The actual registers for the hypercalls. */
  	struct hcall_args hcalls[LHCALL_RING_SIZE];
  
  /* Fields initialized by the Host at boot: */
  	/* Memory not to try to access */
  	unsigned long reserve_mem;
  	/* KHz for the TSC clock. */
  	u32 tsc_khz;
  
  /* Fields initialized by the Guest at boot: */
  	/* Instruction range to suppress interrupts even if enabled */
  	unsigned long noirq_start, noirq_end;
  	/* Address above which page tables are all identical. */
  	unsigned long kernel_address;
  	/* The vector to try to use for system calls (0x40 or 0x80). */
  	unsigned int syscall_vec;
  };
  extern struct lguest_data lguest_data;
  #endif /* __ASSEMBLY__ */
  #endif	/* _LINUX_LGUEST_H */