1 files changed, 116 insertions, 0 deletions
diff --git a/include/linux/lguest.h b/include/linux/lguest.h
new file mode 100644
index 00000000000..157ad64aa7c
--- /dev/null
+++ b/include/linux/lguest.h
@@ -0,0 +1,116 @@
+/* Things the lguest guest needs to know.  Note: like all lguest interfaces,
+ * this is subject to wild and random change between versions. */
+#ifndef _ASM_LGUEST_H
+#define _ASM_LGUEST_H
+
+#ifndef __ASSEMBLY__
+#include <asm/irq.h>
+
+#define LHCALL_FLUSH_ASYNC	0
+#define LHCALL_LGUEST_INIT	1
+#define LHCALL_CRASH		2
+#define LHCALL_LOAD_GDT		3
+#define LHCALL_NEW_PGTABLE	4
+#define LHCALL_FLUSH_TLB	5
+#define LHCALL_LOAD_IDT_ENTRY	6
+#define LHCALL_SET_STACK	7
+#define LHCALL_TS		8
+#define LHCALL_SET_CLOCKEVENT	9
+#define LHCALL_HALT		10
+#define LHCALL_BIND_DMA		12
+#define LHCALL_SEND_DMA		13
+#define LHCALL_SET_PTE		14
+#define LHCALL_SET_PMD		15
+#define LHCALL_LOAD_TLS		16
+
+#define LG_CLOCK_MIN_DELTA	100UL
+#define LG_CLOCK_MAX_DELTA	ULONG_MAX
+
+/*G:031 First, how does our Guest contact the Host to ask for privileged
+ * operations?  There are two ways: the direct way is to make a "hypercall",
+ * to make requests of the Host Itself.
+ *
+ * Our hypercall mechanism uses the highest unused trap code (traps 32 and
+ * above are used by real hardware interrupts).  Seventeen hypercalls are
+ * available: the hypercall number is put in the %eax register, and the
+ * arguments (when required) are placed in %edx, %ebx and %ecx.  If a return
+ * value makes sense, it's returned in %eax.
+ *
+ * Grossly invalid calls result in Sudden Death at the hands of the vengeful
+ * Host, rather than returning failure.  This reflects Winston Churchill's
+ * definition of a gentleman: "someone who is only rude intentionally". */
+#define LGUEST_TRAP_ENTRY 0x1F
+
+static inline unsigned long
+hcall(unsigned long call,
+      unsigned long arg1, unsigned long arg2, unsigned long arg3)
+{
+	/* "int" is the Intel instruction to trigger a trap. */
+	asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
+		       /* The call is in %eax (aka "a"), and can be replaced */
+		     : "=a"(call)
+		       /* The other arguments are in %eax, %edx, %ebx & %ecx */
+		     : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3)
+		       /* "memory" means this might write somewhere in memory.
+			* This isn't true for all calls, but it's safe to tell
+			* gcc that it might happen so it doesn't get clever. */
+		     : "memory");
+	return call;
+}
+/*:*/
+
+void async_hcall(unsigned long call,
+		 unsigned long arg1, unsigned long arg2, unsigned long arg3);
+
+/* Can't use our min() macro here: needs to be a constant */
+#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32)
+
+#define LHCALL_RING_SIZE 64
+struct hcall_ring
+{
+	u32 eax, edx, ebx, ecx;
+};
+
+/*G:032 The second method of communicating with the Host is to via "struct
+ * lguest_data".  The Guest's very first hypercall is to tell the Host where
+ * this is, and then 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;
+
+	/* 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_ring hcalls[LHCALL_RING_SIZE];
+
+/* Fields initialized by the Host at boot: */
+	/* Memory not to try to access */
+	unsigned long reserve_mem;
+	/* ID of this Guest (used by network driver to set ethernet address) */
+	u16 guestid;
+	/* 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;
+};
+extern struct lguest_data lguest_data;
+#endif /* __ASSEMBLY__ */
+#endif	/* _ASM_LGUEST_H */