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/*
* 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 "qemu-common.h"
#include "virtio.h"
#include "pc.h"
#include "sysemu.h"
#include "cpu.h"
#include "balloon.h"
#include "virtio-balloon.h"
#include "kvm.h"
#if defined(__linux__)
#include <sys/mman.h>
#endif
typedef struct VirtIOBalloon
{
VirtIODevice vdev;
VirtQueue *ivq, *dvq;
uint32_t num_pages;
uint32_t actual;
} 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())
madvise(addr, TARGET_PAGE_SIZE,
deflate ? MADV_WILLNEED : MADV_DONTNEED);
#endif
}
/* FIXME: once we do a virtio refactoring, this will get subsumed into common
* code */
static size_t memcpy_from_iovector(void *data, size_t offset, size_t size,
struct iovec *iov, int iovlen)
{
int i;
uint8_t *ptr = data;
size_t iov_off = 0;
size_t data_off = 0;
for (i = 0; i < iovlen && size; i++) {
if (offset < (iov_off + iov[i].iov_len)) {
size_t len = MIN((iov_off + iov[i].iov_len) - offset , size);
memcpy(ptr + data_off, iov[i].iov_base + (offset - iov_off), len);
data_off += len;
offset += len;
size -= len;
}
iov_off += iov[i].iov_len;
}
return data_off;
}
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 (memcpy_from_iovector(&pfn, offset, 4,
elem.out_sg, elem.out_num) == 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 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)
{
return 0;
}
static ram_addr_t virtio_balloon_to_target(void *opaque, ram_addr_t target)
{
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);
}
return ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT);
}
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);
qemu_add_balloon_handler(virtio_balloon_to_target, s);
register_savevm("virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s);
return &s->vdev;
}
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