qemu/include/hw/virtio/virtio-mem.h
David Hildenbrand 92a8ee1b59 virtio-mem: Prepare for device unplug support
In many cases, blindly unplugging a virtio-mem device is problematic. We
can only safely remove a device once:
* The guest is not expecting to be able to read unplugged memory
  (unplugged-inaccessible == on)
* The virtio-mem device does not have memory plugged (size == 0)
* The virtio-mem device does not have outstanding requests to the VM to
  plug memory (requested-size == 0)

So let's add a callback to the virtio-mem device class to check for that.
We'll wire-up virtio-mem-pci next.

Message-ID: <20230711153445.514112-7-david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2023-07-12 09:27:31 +02:00

105 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);
void (*unplug_request_check)(VirtIOMEM *vmem, Error **errp);
};
#endif