qemu/include/hw/virtio/virtio-mem.h
David Hildenbrand 3b95a71b22 virtio-mem: Migrate immutable properties early
The bitmap and the size are immutable while migration is active: see
virtio_mem_is_busy(). We can migrate this information early, before
migrating any actual RAM content. Further, all information we need for
sanity checks is immutable as well.

Having this information in place early will, for example, allow for
properly preallocating memory before touching these memory locations
during RAM migration: this way, we can make sure that all memory was
actually preallocated and that any user errors (e.g., insufficient
hugetlb pages) can be handled gracefully.

In contrast, usable_region_size and requested_size can theoretically
still be modified on the source while the VM is running. Keep migrating
these properties the usual, late, way.

Use a new device property to keep behavior of compat machines
unmodified.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>S
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-02-06 19:22:56 +01:00

104 lines
2.8 KiB
C

/*
* Virtio MEM device
*
* Copyright (C) 2020 Red Hat, Inc.
*
* Authors:
* David Hildenbrand <david@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2.
* See the COPYING file in the top-level directory.
*/
#ifndef HW_VIRTIO_MEM_H
#define HW_VIRTIO_MEM_H
#include "standard-headers/linux/virtio_mem.h"
#include "hw/virtio/virtio.h"
#include "qapi/qapi-types-misc.h"
#include "sysemu/hostmem.h"
#include "qom/object.h"
#define TYPE_VIRTIO_MEM "virtio-mem"
OBJECT_DECLARE_TYPE(VirtIOMEM, VirtIOMEMClass,
VIRTIO_MEM)
#define VIRTIO_MEM_MEMDEV_PROP "memdev"
#define VIRTIO_MEM_NODE_PROP "node"
#define VIRTIO_MEM_SIZE_PROP "size"
#define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size"
#define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size"
#define VIRTIO_MEM_ADDR_PROP "memaddr"
#define VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP "unplugged-inaccessible"
#define VIRTIO_MEM_EARLY_MIGRATION_PROP "x-early-migration"
#define VIRTIO_MEM_PREALLOC_PROP "prealloc"
struct VirtIOMEM {
VirtIODevice parent_obj;
/* guest -> host request queue */
VirtQueue *vq;
/* bitmap used to track unplugged memory */
int32_t bitmap_size;
unsigned long *bitmap;
/* assigned memory backend and memory region */
HostMemoryBackend *memdev;
/* NUMA node */
uint32_t node;
/* assigned address of the region in guest physical memory */
uint64_t addr;
/* usable region size (<= region_size) */
uint64_t usable_region_size;
/* actual size (how much the guest plugged) */
uint64_t size;
/* requested size */
uint64_t requested_size;
/* block size and alignment */
uint64_t block_size;
/*
* Whether we indicate VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE to the guest.
* For !x86 targets this will always be "on" and consequently indicate
* VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE.
*/
OnOffAuto unplugged_inaccessible;
/* whether to prealloc memory when plugging new blocks */
bool prealloc;
/*
* Whether we migrate properties that are immutable while migration is
* active early, before state of other devices and especially, before
* migrating any RAM content.
*/
bool early_migration;
/* notifiers to notify when "size" changes */
NotifierList size_change_notifiers;
/* listeners to notify on plug/unplug activity. */
QLIST_HEAD(, RamDiscardListener) rdl_list;
};
struct VirtIOMEMClass {
/* private */
VirtIODevice parent;
/* public */
void (*fill_device_info)(const VirtIOMEM *vmen, VirtioMEMDeviceInfo *vi);
MemoryRegion *(*get_memory_region)(VirtIOMEM *vmem, Error **errp);
void (*add_size_change_notifier)(VirtIOMEM *vmem, Notifier *notifier);
void (*remove_size_change_notifier)(VirtIOMEM *vmem, Notifier *notifier);
};
#endif