RFC: vaddr_t and vsize_t

["Christoph Egger" <Christoph.Egger@amd.com>]

Hi!

*BSD uses two types for virtual addresses and the virtual address space:
vaddr_t and vsize_t.

vaddr_t is used when a virtual address is meant. It is an unsigned integer and 
its size always matches sizeof(void *).
vsize_t is used when the virtual address space is meant. It is an unsigned 
integer and its size always matches the whole size of the virtual address 
space.

The difference to the pointer is that the pointer is only used to point to
something specific, e.g. a structure in the kernel.

That way mixing up virtual addresses, virtual address spaces and pointers
is hardly possible. What do you think about adding those types to Xen?


The type definition for x86_32 and x86_64 would be this:

diff -r fd2667419c53 xen/include/asm-x86/types.h
--- a/xen/include/asm-x86/types.h       Tue Jan 16 14:04:12 2007 -0500
+++ b/xen/include/asm-x86/types.h       Thu Nov 09 10:23:14 2006 +0100
@@ -36,6 +36,9 @@ typedef unsigned int u32;
 #if defined(__i386__)
 typedef signed long long s64;
 typedef unsigned long long u64;
+/* datatype to store virtual addresses. */
+typedef unsigned long vaddr_t;
+typedef unsigned long vsize_t;
 #if defined(CONFIG_X86_PAE)
 typedef u64 paddr_t;
 #define PRIpaddr "016llx"
@@ -47,6 +50,8 @@ typedef signed long s64;
 typedef signed long s64;
 typedef unsigned long u64;
 typedef unsigned long paddr_t;
+typedef unsigned long vaddr_t;
+typedef unsigned long vsize_t;
 #define PRIpaddr "016lx"
 #endif