[Xen-devel] [PATCH] Allow direct hypercalls

[john.levon@xxxxxxx]

# HG changeset patch
# User john.levon@xxxxxxx
# Date 1209521783 25200
# Node ID 9a5c6e3620d83f9354e3eedbc4ef24a7a5ad752e
# Parent  f477f895f78752bb9fa2e6ee6c1d09b6a8cd3230
Allow direct hypercalls

For PV guests, there's no reason to force use of the indirect hypercall
mechanism. Allow it. Also allow TRAP_INSTR to be used from assembly.

Signed-off-by: John Levon <john.levon@xxxxxxx>

diff --git a/xen/include/public/arch-x86/xen-x86_32.h 
b/xen/include/public/arch-x86/xen-x86_32.h
--- a/xen/include/public/arch-x86/xen-x86_32.h
+++ b/xen/include/public/arch-x86/xen-x86_32.h
@@ -36,13 +36,15 @@
  * Clobbered: Argument registers (e.g., 2-arg hypercall clobbers %ebx,%ecx)
  */
 
-#if __XEN_INTERFACE_VERSION__ < 0x00030203
 /*
- * Legacy hypercall interface:
+ * Direct hypercall interface:
  * As above, except the entry sequence to the hypervisor is:
  *  mov $hypercall-number*32,%eax ; int $0x82
  */
+#if !defined(_ASM)
 #define TRAP_INSTR "int $0x82"
+#else
+#define TRAP_INSTR int $0x82
 #endif
 
 /*
diff --git a/xen/include/public/arch-x86/xen-x86_64.h 
b/xen/include/public/arch-x86/xen-x86_64.h
--- a/xen/include/public/arch-x86/xen-x86_64.h
+++ b/xen/include/public/arch-x86/xen-x86_64.h
@@ -36,16 +36,18 @@
  * Clobbered: argument registers (e.g., 2-arg hypercall clobbers %rdi,%rsi)
  */
 
-#if __XEN_INTERFACE_VERSION__ < 0x00030203
 /*
- * Legacy hypercall interface:
+ * Direct hypercall interface:
  * As above, except the entry sequence to the hypervisor is:
  *  mov $hypercall-number*32,%eax ; syscall
  * Clobbered: %rcx, %r11, argument registers (as above)
  */
+#if !defined(_ASM)
 #define TRAP_INSTR "syscall"
+#else
+#define TRAP_INSTR syscall
 #endif
-
+  
 /*
  * 64-bit segment selectors
  * These flat segments are in the Xen-private section of every GDT. Since these

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