Merge branch 'master' into for-2.6.35

[safe/jmp/linux-2.6] / arch / x86 / include / asm / lguest_hcall.h

diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
index b14b355..b60f292 100644 (file)
--- a/arch/x86/include/asm/lguest_hcall.h
+++ b/arch/x86/include/asm/lguest_hcall.h
@@ -12,6 +12,7 @@
 #define LHCALL_TS              8
 #define LHCALL_SET_CLOCKEVENT  9
 #define LHCALL_HALT            10
+#define LHCALL_SET_PMD         13
 #define LHCALL_SET_PTE         14
 #define LHCALL_SET_PGD         15
 #define LHCALL_LOAD_TLS                16
@@ -27,29 +28,46 @@
 
 #ifndef __ASSEMBLY__
 #include <asm/hw_irq.h>
-#include <asm/kvm_para.h>
 
-/*G:031 But first, how does our Guest contact the Host to ask for privileged
+/*G:030
+ * 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.
  *
- * We use the KVM hypercall mechanism. Eighteen hypercalls are
+ * 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 %ebx, %ecx, %edx and %esi.
  * 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". */
-/*:*/
+ * 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,
+      unsigned long arg4)
+{
+       /* "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, %ebx, %ecx, %edx & %esi */
+                    : "a"(call), "b"(arg1), "c"(arg2), "d"(arg3), "S"(arg4)
+                      /* "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 and esi
-        * in struct lguest_regs */
+       /* These map directly onto eax/ebx/ecx/edx/esi in struct lguest_regs */
        unsigned long arg0, arg1, arg2, arg3, arg4;
 };