David Vrabel
2013-Feb-21 17:48 UTC
[PATCH 2/8] xen: make GUEST_HANDLE_64() and uint64_aligned_t available everywhere
From: David Vrabel <david.vrabel@citrix.com>
GUEST_HANDLE_64() and uint64_aligned_t allow hypercall ABI structures
to be identical (binary compatible) for 32 and 64-bit guests. They
are currently limited to only being available for use in sysctls and
domctls. Relax this limit so it may be used by any new structures.
There is a minimal cost for 32-bit guests on 64-but hypervisors as
set_guest_handle() needs to 0 the whole field on GUEST_HANDLE_64()
handles, but this is expected to be less than the overhead of having
to translate compat structures.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
xen/include/public/arch-x86/xen-x86_32.h | 4 +---
xen/include/public/xen.h | 13 ++++++++-----
2 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/xen/include/public/arch-x86/xen-x86_32.h
b/xen/include/public/arch-x86/xen-x86_32.h
index 906e74a..08fac7a 100644
--- a/xen/include/public/arch-x86/xen-x86_32.h
+++ b/xen/include/public/arch-x86/xen-x86_32.h
@@ -91,8 +91,7 @@
#define machine_to_phys_mapping ((unsigned long *)MACH2PHYS_VIRT_START)
#endif
-/* 32-/64-bit invariability for control interfaces (domctl/sysctl). */
-#if defined(__XEN__) || defined(__XEN_TOOLS__)
+/* 32-/64-bit invariability. */
#undef ___DEFINE_XEN_GUEST_HANDLE
#define ___DEFINE_XEN_GUEST_HANDLE(name, type) \
typedef struct { type *p; } \
@@ -107,7 +106,6 @@
#define uint64_aligned_t uint64_t __attribute__((aligned(8)))
#define __XEN_GUEST_HANDLE_64(name) __guest_handle_64_ ## name
#define XEN_GUEST_HANDLE_64(name) __XEN_GUEST_HANDLE_64(name)
-#endif
#ifndef __ASSEMBLY__
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 5593066..c18e7ce 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -840,9 +840,14 @@ __DEFINE_XEN_GUEST_HANDLE(uint64, uint64_t);
#endif /* !__ASSEMBLY__ */
-/* Default definitions for macros used by domctl/sysctl. */
-#if defined(__XEN__) || defined(__XEN_TOOLS__)
-
+/*
+ * Default definitions for 32/64-bit invariant macros.
+ *
+ * Use these in ABI structures that should be identical for 32 and
+ * 64-bit guests. There is some (very small) overhead in using
+ * XEN_GUEST_HANDLE_64() instead of XEN_GUEST_HANDLE() so avoid for
+ * very hot paths.
+ */
#ifndef uint64_aligned_t
#define uint64_aligned_t uint64_t
#endif
@@ -857,8 +862,6 @@ struct xenctl_cpumap {
};
#endif
-#endif /* defined(__XEN__) || defined(__XEN_TOOLS__) */
-
#endif /* __XEN_PUBLIC_XEN_H__ */
/*
--
1.7.2.5