include/xen/interface/memory.h

Source file repositories/reference/linux-study-clean/include/xen/interface/memory.h

File Facts

System
Linux kernel
Corpus path
include/xen/interface/memory.h
Extension
.h
Size
10923 bytes
Lines
329
Domain
Repository Root And Misc
Bucket
include
Inferred role
Repository Root And Misc: implementation source
Status
source implementation candidate

Why This File Exists

Top-level or miscellaneous repository surface. Use this as map coverage unless a later manual pass promotes the file into a deeper subsystem dossier.

Dependency Surface

Detected Declarations

Annotated Snippet

struct xen_memory_reservation {

    /*
     * XENMEM_increase_reservation:
     *   OUT: MFN (*not* GMFN) bases of extents that were allocated
     * XENMEM_decrease_reservation:
     *   IN:  GMFN bases of extents to free
     * XENMEM_populate_physmap:
     *   IN:  GPFN bases of extents to populate with memory
     *   OUT: GMFN bases of extents that were allocated
     *   (NB. This command also updates the mach_to_phys translation table)
     */
    GUEST_HANDLE(xen_pfn_t) extent_start;

    /* Number of extents, and size/alignment of each (2^extent_order pages). */
    xen_ulong_t  nr_extents;
    unsigned int   extent_order;

    /*
     * Maximum # bits addressable by the user of the allocated region (e.g.,
     * I/O devices often have a 32-bit limitation even in 64-bit systems). If
     * zero then the user has no addressing restriction.
     * This field is not used by XENMEM_decrease_reservation.
     */
    unsigned int   address_bits;

    /*
     * Domain whose reservation is being changed.
     * Unprivileged domains can specify only DOMID_SELF.
     */
    domid_t        domid;

};
DEFINE_GUEST_HANDLE_STRUCT(xen_memory_reservation);

/*
 * An atomic exchange of memory pages. If return code is zero then
 * @out.extent_list provides GMFNs of the newly-allocated memory.
 * Returns zero on complete success, otherwise a negative error code.
 * On complete success then always @nr_exchanged == @in.nr_extents.
 * On partial success @nr_exchanged indicates how much work was done.
 */
#define XENMEM_exchange             11
struct xen_memory_exchange {
    /*
     * [IN] Details of memory extents to be exchanged (GMFN bases).
     * Note that @in.address_bits is ignored and unused.
     */
    struct xen_memory_reservation in;

    /*
     * [IN/OUT] Details of new memory extents.
     * We require that:
     *  1. @in.domid == @out.domid
     *  2. @in.nr_extents  << @in.extent_order ==
     *     @out.nr_extents << @out.extent_order
     *  3. @in.extent_start and @out.extent_start lists must not overlap
     *  4. @out.extent_start lists GPFN bases to be populated
     *  5. @out.extent_start is overwritten with allocated GMFN bases
     */
    struct xen_memory_reservation out;

    /*
     * [OUT] Number of input extents that were successfully exchanged:
     *  1. The first @nr_exchanged input extents were successfully
     *     deallocated.
     *  2. The corresponding first entries in the output extent list correctly
     *     indicate the GMFNs that were successfully exchanged.
     *  3. All other input and output extents are untouched.
     *  4. If not all input exents are exchanged then the return code of this
     *     command will be non-zero.
     *  5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER!
     */
    xen_ulong_t nr_exchanged;
};

DEFINE_GUEST_HANDLE_STRUCT(xen_memory_exchange);
/*
 * Returns the maximum machine frame number of mapped RAM in this system.
 * This command always succeeds (it never returns an error code).
 * arg == NULL.
 */
#define XENMEM_maximum_ram_page     2

/*
 * Returns the current or maximum memory reservation, in pages, of the
 * specified domain (may be DOMID_SELF). Returns -ve errcode on failure.
 * arg == addr of domid_t.
 */
#define XENMEM_current_reservation  3

Annotation

Implementation Notes