![Eduardo Habkost](/assets/img/avatar_default.png)
The addition of memory stats reporting to the virtio balloon causes the 'info balloon' command to become asynchronous. This is a regression because in some cases it can hang the user monitor. This is an alternative to Adam Litke's patch. Adam's patch disabled the corresponding (guest-visible) virtio feature bit, causing issues for migration. Original discussion is available at: http://marc.info/?l=qemu-devel&m=128448124328314&w=2 Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Acked-by: Adam Litke <agl@us.ibm.com Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
284 lines
8 KiB
C
284 lines
8 KiB
C
/*
|
|
* Virtio Block Device
|
|
*
|
|
* Copyright IBM, Corp. 2008
|
|
*
|
|
* Authors:
|
|
* Anthony Liguori <aliguori@us.ibm.com>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*
|
|
*/
|
|
|
|
#include "iov.h"
|
|
#include "qemu-common.h"
|
|
#include "virtio.h"
|
|
#include "pc.h"
|
|
#include "sysemu.h"
|
|
#include "cpu.h"
|
|
#include "monitor.h"
|
|
#include "balloon.h"
|
|
#include "virtio-balloon.h"
|
|
#include "kvm.h"
|
|
#include "qlist.h"
|
|
#include "qint.h"
|
|
#include "qstring.h"
|
|
|
|
#if defined(__linux__)
|
|
#include <sys/mman.h>
|
|
#endif
|
|
|
|
/* Disable guest-provided stats by now (https://bugzilla.redhat.com/show_bug.cgi?id=623903) */
|
|
#define ENABLE_GUEST_STATS 0
|
|
|
|
|
|
typedef struct VirtIOBalloon
|
|
{
|
|
VirtIODevice vdev;
|
|
VirtQueue *ivq, *dvq, *svq;
|
|
uint32_t num_pages;
|
|
uint32_t actual;
|
|
uint64_t stats[VIRTIO_BALLOON_S_NR];
|
|
VirtQueueElement stats_vq_elem;
|
|
size_t stats_vq_offset;
|
|
MonitorCompletion *stats_callback;
|
|
void *stats_opaque_callback_data;
|
|
} VirtIOBalloon;
|
|
|
|
static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
|
|
{
|
|
return (VirtIOBalloon *)vdev;
|
|
}
|
|
|
|
static void balloon_page(void *addr, int deflate)
|
|
{
|
|
#if defined(__linux__)
|
|
if (!kvm_enabled() || kvm_has_sync_mmu())
|
|
qemu_madvise(addr, TARGET_PAGE_SIZE,
|
|
deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* reset_stats - Mark all items in the stats array as unset
|
|
*
|
|
* This function needs to be called at device intialization and before
|
|
* before updating to a set of newly-generated stats. This will ensure that no
|
|
* stale values stick around in case the guest reports a subset of the supported
|
|
* statistics.
|
|
*/
|
|
static inline void reset_stats(VirtIOBalloon *dev)
|
|
{
|
|
int i;
|
|
for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
|
|
}
|
|
|
|
static void stat_put(QDict *dict, const char *label, uint64_t val)
|
|
{
|
|
if (val != -1)
|
|
qdict_put(dict, label, qint_from_int(val));
|
|
}
|
|
|
|
static QObject *get_stats_qobject(VirtIOBalloon *dev)
|
|
{
|
|
QDict *dict = qdict_new();
|
|
uint64_t actual = ram_size - ((uint64_t) dev->actual <<
|
|
VIRTIO_BALLOON_PFN_SHIFT);
|
|
|
|
stat_put(dict, "actual", actual);
|
|
#if ENABLE_GUEST_STATS
|
|
stat_put(dict, "mem_swapped_in", dev->stats[VIRTIO_BALLOON_S_SWAP_IN]);
|
|
stat_put(dict, "mem_swapped_out", dev->stats[VIRTIO_BALLOON_S_SWAP_OUT]);
|
|
stat_put(dict, "major_page_faults", dev->stats[VIRTIO_BALLOON_S_MAJFLT]);
|
|
stat_put(dict, "minor_page_faults", dev->stats[VIRTIO_BALLOON_S_MINFLT]);
|
|
stat_put(dict, "free_mem", dev->stats[VIRTIO_BALLOON_S_MEMFREE]);
|
|
stat_put(dict, "total_mem", dev->stats[VIRTIO_BALLOON_S_MEMTOT]);
|
|
#endif
|
|
|
|
return QOBJECT(dict);
|
|
}
|
|
|
|
static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
|
|
{
|
|
VirtIOBalloon *s = to_virtio_balloon(vdev);
|
|
VirtQueueElement elem;
|
|
|
|
while (virtqueue_pop(vq, &elem)) {
|
|
size_t offset = 0;
|
|
uint32_t pfn;
|
|
|
|
while (iov_to_buf(elem.out_sg, elem.out_num, &pfn, offset, 4) == 4) {
|
|
ram_addr_t pa;
|
|
ram_addr_t addr;
|
|
|
|
pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
|
|
offset += 4;
|
|
|
|
addr = cpu_get_physical_page_desc(pa);
|
|
if ((addr & ~TARGET_PAGE_MASK) != IO_MEM_RAM)
|
|
continue;
|
|
|
|
/* Using qemu_get_ram_ptr is bending the rules a bit, but
|
|
should be OK because we only want a single page. */
|
|
balloon_page(qemu_get_ram_ptr(addr), !!(vq == s->dvq));
|
|
}
|
|
|
|
virtqueue_push(vq, &elem, offset);
|
|
virtio_notify(vdev, vq);
|
|
}
|
|
}
|
|
|
|
static void complete_stats_request(VirtIOBalloon *vb)
|
|
{
|
|
QObject *stats;
|
|
|
|
if (!vb->stats_opaque_callback_data)
|
|
return;
|
|
|
|
stats = get_stats_qobject(vb);
|
|
vb->stats_callback(vb->stats_opaque_callback_data, stats);
|
|
qobject_decref(stats);
|
|
vb->stats_opaque_callback_data = NULL;
|
|
vb->stats_callback = NULL;
|
|
}
|
|
|
|
static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
|
|
{
|
|
VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev);
|
|
VirtQueueElement *elem = &s->stats_vq_elem;
|
|
VirtIOBalloonStat stat;
|
|
size_t offset = 0;
|
|
|
|
if (!virtqueue_pop(vq, elem)) {
|
|
return;
|
|
}
|
|
|
|
/* Initialize the stats to get rid of any stale values. This is only
|
|
* needed to handle the case where a guest supports fewer stats than it
|
|
* used to (ie. it has booted into an old kernel).
|
|
*/
|
|
reset_stats(s);
|
|
|
|
while (iov_to_buf(elem->out_sg, elem->out_num, &stat, offset, sizeof(stat))
|
|
== sizeof(stat)) {
|
|
uint16_t tag = tswap16(stat.tag);
|
|
uint64_t val = tswap64(stat.val);
|
|
|
|
offset += sizeof(stat);
|
|
if (tag < VIRTIO_BALLOON_S_NR)
|
|
s->stats[tag] = val;
|
|
}
|
|
s->stats_vq_offset = offset;
|
|
|
|
complete_stats_request(s);
|
|
}
|
|
|
|
static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
|
|
{
|
|
VirtIOBalloon *dev = to_virtio_balloon(vdev);
|
|
struct virtio_balloon_config config;
|
|
|
|
config.num_pages = cpu_to_le32(dev->num_pages);
|
|
config.actual = cpu_to_le32(dev->actual);
|
|
|
|
memcpy(config_data, &config, 8);
|
|
}
|
|
|
|
static void virtio_balloon_set_config(VirtIODevice *vdev,
|
|
const uint8_t *config_data)
|
|
{
|
|
VirtIOBalloon *dev = to_virtio_balloon(vdev);
|
|
struct virtio_balloon_config config;
|
|
memcpy(&config, config_data, 8);
|
|
dev->actual = config.actual;
|
|
}
|
|
|
|
static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
|
|
{
|
|
f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
|
|
return f;
|
|
}
|
|
|
|
static void virtio_balloon_to_target(void *opaque, ram_addr_t target,
|
|
MonitorCompletion cb, void *cb_data)
|
|
{
|
|
VirtIOBalloon *dev = opaque;
|
|
|
|
if (target > ram_size)
|
|
target = ram_size;
|
|
|
|
if (target) {
|
|
dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
|
|
virtio_notify_config(&dev->vdev);
|
|
} else {
|
|
/* For now, only allow one request at a time. This restriction can be
|
|
* removed later by queueing callback and data pairs.
|
|
*/
|
|
if (dev->stats_callback != NULL) {
|
|
return;
|
|
}
|
|
dev->stats_callback = cb;
|
|
dev->stats_opaque_callback_data = cb_data;
|
|
if (ENABLE_GUEST_STATS && (dev->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ))) {
|
|
virtqueue_push(dev->svq, &dev->stats_vq_elem, dev->stats_vq_offset);
|
|
virtio_notify(&dev->vdev, dev->svq);
|
|
} else {
|
|
/* Stats are not supported. Clear out any stale values that might
|
|
* have been set by a more featureful guest kernel.
|
|
*/
|
|
reset_stats(dev);
|
|
complete_stats_request(dev);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void virtio_balloon_save(QEMUFile *f, void *opaque)
|
|
{
|
|
VirtIOBalloon *s = opaque;
|
|
|
|
virtio_save(&s->vdev, f);
|
|
|
|
qemu_put_be32(f, s->num_pages);
|
|
qemu_put_be32(f, s->actual);
|
|
}
|
|
|
|
static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
|
|
{
|
|
VirtIOBalloon *s = opaque;
|
|
|
|
if (version_id != 1)
|
|
return -EINVAL;
|
|
|
|
virtio_load(&s->vdev, f);
|
|
|
|
s->num_pages = qemu_get_be32(f);
|
|
s->actual = qemu_get_be32(f);
|
|
return 0;
|
|
}
|
|
|
|
VirtIODevice *virtio_balloon_init(DeviceState *dev)
|
|
{
|
|
VirtIOBalloon *s;
|
|
|
|
s = (VirtIOBalloon *)virtio_common_init("virtio-balloon",
|
|
VIRTIO_ID_BALLOON,
|
|
8, sizeof(VirtIOBalloon));
|
|
|
|
s->vdev.get_config = virtio_balloon_get_config;
|
|
s->vdev.set_config = virtio_balloon_set_config;
|
|
s->vdev.get_features = virtio_balloon_get_features;
|
|
|
|
s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
|
|
s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
|
|
s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats);
|
|
|
|
reset_stats(s);
|
|
qemu_add_balloon_handler(virtio_balloon_to_target, s);
|
|
|
|
register_savevm(dev, "virtio-balloon", -1, 1,
|
|
virtio_balloon_save, virtio_balloon_load, s);
|
|
|
|
return &s->vdev;
|
|
}
|