hw/mem/memory-device.h

10  * See the COPYING file in the top-level directory.
16 #include "hw/qdev-core.h"
17 #include "qapi/qapi-types-machine.h"
20 #define TYPE_MEMORY_DEVICE "memory-device"
33  * All memory devices need to implement TYPE_MEMORY_DEVICE as an interface.
44  * Conceptually, memory devices only span one memory region. If multiple
45  * successive memory regions are used, a covering memory region has to
51  * that are RAM memory regions or aliases to RAM memory regions. Other
55  * memory region container, it's supported to dynamically (un)map subregions
71      * no address has been assigned to this memory device yet.
78      * Called when plugging the memory device to configure the determined
87      * Called when calculating the total amount of ram available to the
88      * VM (e.g. to report memory stats to the user).
92      * most devices, this corresponds to the size of the memory region.
100      * Called when (un)plugging the memory device, to (un)map the
101      * memory region in guest physical memory, but also to detect the
108      * Optional: Instruct the memory device to decide how many memory slots
111      * Called exactly once when pre-plugging the memory device, before
124      * Called when (un)plugging the memory device, to check if the requirements
125      * can be satisfied, and to do proper accounting.
134      * Called when plugging the memory device to detect the required alignment
147  * Traditionally, KVM/vhost in many setups supported 509 memslots, whereby
152  * Further, using many memslots can negatively affect performance, so setting
153  * the soft-limit of memslots used by memory devices to the traditional
157  * support automatically deciding how many memslots to use to only use a single
158  * one.
160  * Hotplugging vhost devices with at least 509 memslots is not expected to
161  * cause problems, not even when devices automatically decided how many memslots
162  * to use.