qemu/include/hw/virtio/virtio-balloon.h
Alexander Duyck 91b867191d virtio-balloon: Provide an interface for free page reporting
Add support for free page reporting. The idea is to function very similar
to how the balloon works in that we basically end up madvising the page as
not being used. However we don't really need to bother with any deflate
type logic since the page will be faulted back into the guest when it is
read or written to.

This provides a new way of letting the guest proactively report free
pages to the hypervisor, so the hypervisor can reuse them. In contrast to
inflate/deflate that is triggered via the hypervisor explicitly.

Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Message-Id: <20200527041407.12700.73735.stgit@localhost.localdomain>
2020-06-09 14:18:04 -04:00

77 lines
2.0 KiB
C

/*
* Virtio Support
*
* Copyright IBM, Corp. 2007-2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Rusty Russell <rusty@rustcorp.com.au>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#ifndef QEMU_VIRTIO_BALLOON_H
#define QEMU_VIRTIO_BALLOON_H
#include "standard-headers/linux/virtio_balloon.h"
#include "hw/virtio/virtio.h"
#include "sysemu/iothread.h"
#define TYPE_VIRTIO_BALLOON "virtio-balloon-device"
#define VIRTIO_BALLOON(obj) \
OBJECT_CHECK(VirtIOBalloon, (obj), TYPE_VIRTIO_BALLOON)
#define VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN 0x80000000
typedef struct virtio_balloon_stat VirtIOBalloonStat;
typedef struct virtio_balloon_stat_modern {
uint16_t tag;
uint8_t reserved[6];
uint64_t val;
} VirtIOBalloonStatModern;
enum virtio_balloon_free_page_report_status {
FREE_PAGE_REPORT_S_STOP = 0,
FREE_PAGE_REPORT_S_REQUESTED = 1,
FREE_PAGE_REPORT_S_START = 2,
FREE_PAGE_REPORT_S_DONE = 3,
};
typedef struct VirtIOBalloon {
VirtIODevice parent_obj;
VirtQueue *ivq, *dvq, *svq, *free_page_vq, *reporting_vq;
uint32_t free_page_report_status;
uint32_t num_pages;
uint32_t actual;
uint32_t free_page_report_cmd_id;
uint64_t stats[VIRTIO_BALLOON_S_NR];
VirtQueueElement *stats_vq_elem;
size_t stats_vq_offset;
QEMUTimer *stats_timer;
IOThread *iothread;
QEMUBH *free_page_bh;
/*
* Lock to synchronize threads to access the free page reporting related
* fields (e.g. free_page_report_status).
*/
QemuMutex free_page_lock;
QemuCond free_page_cond;
/*
* Set to block iothread to continue reading free page hints as the VM is
* stopped.
*/
bool block_iothread;
NotifierWithReturn free_page_report_notify;
int64_t stats_last_update;
int64_t stats_poll_interval;
uint32_t host_features;
bool qemu_4_0_config_size;
uint32_t poison_val;
} VirtIOBalloon;
#endif