Implement per-task virtual memory limitHEADmaster

  * doc/mach.texi: add a "Memory Limitations" section to document the new interfaces.
  * include/mach/gnumach.defs: (vm_set_size_limit) new routine
    (vm_get_size_limit) likewise
  * kern/task.c: (task_create_kernel) if parent_task is not null copy virtual memory limit
  * tests/test-vm.c: (test_vm_limit) add test for the new routines
  * vm/vm_map.h: (struct vm_map) new fields size_none, size_cur_limit and size_max_limit
    (vm_map_find_entry) add new parameters cur_protection and max_protection
  * vm/vm_map.c: (vm_map_setup) initialize new fields
    (vm_map_enforce_limit) new function
    (vm_map_copy_limits) new function
    (vm_map_find_entry) add protection and max_protection parameters.
    call limit enforcer function
    (vm_map_enter) likewise
    (vm_map_copyout) likewise
    (vm_map_copyout_page_list) likewise
    (vm_map_fork) copy parent limit to the new map and compute and set size_none of the new map
  * vm/vm_user.c: (vm_set_size_limit) new function
    (vm_get_size_limit) likewise
  * xen/grant.c: update call to vm_map_find_entry to pass protection parameters
Message-ID: <0b71f4f89b7cc2b159893a805480d7493d522d60.1758485757.git.dnietoc@gmail.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/doc/mach.texi b/doc/mach.texi
index e2328c1b..1f28cea3 100644
--- a/doc/mach.texi
+++ b/doc/mach.texi
@@ -203,6 +203,7 @@ Virtual Memory Interface
 * Data Transfer::                 Reading, writing and copying memory.
 * Memory Attributes::             Tweaking memory regions.
 * Mapping Memory Objects::        How to map memory objects.
+* Memory Limitations::            Tweaking virtual memory space limts.
 * Memory Statistics::             How to get statistics about memory usage.
 
 External Memory Management
@@ -3029,6 +3030,7 @@ the kernel.
 * Data Transfer::                 Reading, writing and copying memory.
 * Memory Attributes::             Tweaking memory regions.
 * Mapping Memory Objects::        How to map memory objects.
+* Memory Limitations::            Tweaking virtual memory limits.
 * Memory Statistics::             How to get statistics about memory usage.
 * Memory physical addresses::     How to get physical addresses of memory.
 @end menu
@@ -3476,6 +3478,33 @@ found, and @code{KERN_INVALID_ARGUMENT} if an invalid argument was provided.
 @end deftypefun
 
 
+@node Memory Limitations
+@section Memory Limitations
+
+@deftypefun kern_reutrn_t vm_get_size_limit (@w{vm_task_t @var{map}}, @w{vm_size_t *@var{current_limit}}, @w{vm_size_t *@var{max_limit}})
+This function will return the current limit and the maximum limit of the
+virtual memory address space of the task indicated by the @var{map} argument
+in the parameters @var{current_limit} and @var{max_limit}, respectively.
+@end deftypefun
+
+@deftypefun kern_return_t vm_set_size_limit (@w{mach_port_t @var{host_port}}, @w{vm_task_t @var{map}}, @w{vm_size_t @var{current_limit}}, @w{vm_size_t @var{max_limit}})
+This function shall be used to update the virtual address space limits
+of the task given by the @var{map} argument.
+
+If the value of the argument @var{current_limit} is greater than @var{max_limit},
+the function returns @code{KERN_INVALID_ARGUMENT}. The privileged host port
+must be provided in the @var{host_port} argument when the function is used
+to increase the current max limit of the address space. Otherwise the function
+returns @code{KERN_NO_ACCESS}.
+
+The function returns @code{KERN_INVALID_TASK} or @code{KERN_INVALID_HOST} when
+the arguments @var{map} and @var{host_port} are not a vlaid task or host, respectively.
+
+@code{KERN_SUCCESS} is returned when the map limits could be updated
+successfuly.
+@end deftypefun
+
+
 @node Memory Statistics
 @section Memory Statistics