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authorAl Viro <viro@zeniv.linux.org.uk>2008-08-17 21:05:42 -0400
committerH. Peter Anvin <hpa@zytor.com>2008-10-22 22:55:20 -0700
commitbb8985586b7a906e116db835c64773b7a7d51663 (patch)
treede93ae58e88cc563d95cc124a73f3930594c6100 /arch/x86/include/asm/lguest_hcall.h
parent8ede0bdb63305d3353efd97e9af6210afb05734e (diff)
x86, um: ... and asm-x86 move
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/lguest_hcall.h')
-rw-r--r--arch/x86/include/asm/lguest_hcall.h71
1 files changed, 71 insertions, 0 deletions
diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
new file mode 100644
index 00000000000..8f034ba4b53
--- /dev/null
+++ b/arch/x86/include/asm/lguest_hcall.h
@@ -0,0 +1,71 @@
+/* Architecture specific portion of the lguest hypercalls */
+#ifndef ASM_X86__LGUEST_HCALL_H
+#define ASM_X86__LGUEST_HCALL_H
+
+#define LHCALL_FLUSH_ASYNC 0
+#define LHCALL_LGUEST_INIT 1
+#define LHCALL_SHUTDOWN 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_SET_PTE 14
+#define LHCALL_SET_PMD 15
+#define LHCALL_LOAD_TLS 16
+#define LHCALL_NOTIFY 17
+
+#define LGUEST_TRAP_ENTRY 0x1F
+
+/* Argument number 3 to LHCALL_LGUEST_SHUTDOWN */
+#define LGUEST_SHUTDOWN_POWEROFF 1
+#define LGUEST_SHUTDOWN_RESTART 2
+
+#ifndef __ASSEMBLY__
+#include <asm/hw_irq.h>
+
+/*G:031 But 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). Fifteen 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". */
+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 in %eax (aka "a") might be overwritten */
+ : "=a"(call)
+ /* The 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;
+}
+/*:*/
+
+/* 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_args {
+ /* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */
+ unsigned long arg0, arg2, arg3, arg1;
+};
+
+#endif /* !__ASSEMBLY__ */
+#endif /* ASM_X86__LGUEST_HCALL_H */