_PageModifyPermissions

#include <vmm.h>

ULONG EXTERNAL _PageModifyPermissions(ULONG page, ULONG npages,
    ULONG permand, ULONG permor);

Modifies the permissions for pages in the specified range. Uses EAX, ECX, EDX and Flags.

• Returns the previous permissions of the first page in the range if successful, –1 otherwise. If an error occurs, the service returns without modifying any permissions.

page and npages

Linear page number if the first page in the range, and the number of pages in the range. All of the specified pages must be committed. None of the pages may be static unless the permor parameter specifies the PC_STATIC flag.

permand

AND mask to combine with the existing permissions for each page. Can be PC_USER, PC_WRITEABLE, or both. To withhold a permission, do not specify the corresponding flag.

permor

OR mask to combine with the existing permissions for each page. Can be PC_USER, PC_WRITEABLE, or both. To grant a permission, specify the corresponding flag. To change the permissions of static pages, this parameter must also include the PC_STATIC flag.

For more information about permission flags, see the description of the _PageCommit service.

See also _pagecommit