virtio-9p: Add a virtio 9p device to qemu
[qemu.git] / hw / virtio-balloon.c
blob152af803ee7c796527c38ec437b04adf6e1be8c8
1 /*
2 * Virtio Block Device
4 * Copyright IBM, Corp. 2008
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
14 #include "iov.h"
15 #include "qemu-common.h"
16 #include "virtio.h"
17 #include "pc.h"
18 #include "sysemu.h"
19 #include "cpu.h"
20 #include "monitor.h"
21 #include "balloon.h"
22 #include "virtio-balloon.h"
23 #include "kvm.h"
24 #include "qlist.h"
25 #include "qint.h"
26 #include "qstring.h"
28 #if defined(__linux__)
29 #include <sys/mman.h>
30 #endif
32 typedef struct VirtIOBalloon
34 VirtIODevice vdev;
35 VirtQueue *ivq, *dvq, *svq;
36 uint32_t num_pages;
37 uint32_t actual;
38 uint64_t stats[VIRTIO_BALLOON_S_NR];
39 VirtQueueElement stats_vq_elem;
40 size_t stats_vq_offset;
41 MonitorCompletion *stats_callback;
42 void *stats_opaque_callback_data;
43 } VirtIOBalloon;
45 static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
47 return (VirtIOBalloon *)vdev;
50 static void balloon_page(void *addr, int deflate)
52 #if defined(__linux__)
53 if (!kvm_enabled() || kvm_has_sync_mmu())
54 madvise(addr, TARGET_PAGE_SIZE,
55 deflate ? MADV_WILLNEED : MADV_DONTNEED);
56 #endif
60 * reset_stats - Mark all items in the stats array as unset
62 * This function needs to be called at device intialization and before
63 * before updating to a set of newly-generated stats. This will ensure that no
64 * stale values stick around in case the guest reports a subset of the supported
65 * statistics.
67 static inline void reset_stats(VirtIOBalloon *dev)
69 int i;
70 for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
73 static void stat_put(QDict *dict, const char *label, uint64_t val)
75 if (val != -1)
76 qdict_put(dict, label, qint_from_int(val));
79 static QObject *get_stats_qobject(VirtIOBalloon *dev)
81 QDict *dict = qdict_new();
82 uint64_t actual = ram_size - ((uint64_t) dev->actual <<
83 VIRTIO_BALLOON_PFN_SHIFT);
85 stat_put(dict, "actual", actual);
86 stat_put(dict, "mem_swapped_in", dev->stats[VIRTIO_BALLOON_S_SWAP_IN]);
87 stat_put(dict, "mem_swapped_out", dev->stats[VIRTIO_BALLOON_S_SWAP_OUT]);
88 stat_put(dict, "major_page_faults", dev->stats[VIRTIO_BALLOON_S_MAJFLT]);
89 stat_put(dict, "minor_page_faults", dev->stats[VIRTIO_BALLOON_S_MINFLT]);
90 stat_put(dict, "free_mem", dev->stats[VIRTIO_BALLOON_S_MEMFREE]);
91 stat_put(dict, "total_mem", dev->stats[VIRTIO_BALLOON_S_MEMTOT]);
93 return QOBJECT(dict);
96 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
98 VirtIOBalloon *s = to_virtio_balloon(vdev);
99 VirtQueueElement elem;
101 while (virtqueue_pop(vq, &elem)) {
102 size_t offset = 0;
103 uint32_t pfn;
105 while (iov_to_buf(elem.out_sg, elem.out_num, &pfn, offset, 4) == 4) {
106 ram_addr_t pa;
107 ram_addr_t addr;
109 pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
110 offset += 4;
112 addr = cpu_get_physical_page_desc(pa);
113 if ((addr & ~TARGET_PAGE_MASK) != IO_MEM_RAM)
114 continue;
116 /* Using qemu_get_ram_ptr is bending the rules a bit, but
117 should be OK because we only want a single page. */
118 balloon_page(qemu_get_ram_ptr(addr), !!(vq == s->dvq));
121 virtqueue_push(vq, &elem, offset);
122 virtio_notify(vdev, vq);
126 static void complete_stats_request(VirtIOBalloon *vb)
128 QObject *stats;
130 if (!vb->stats_opaque_callback_data)
131 return;
133 stats = get_stats_qobject(vb);
134 vb->stats_callback(vb->stats_opaque_callback_data, stats);
135 qobject_decref(stats);
136 vb->stats_opaque_callback_data = NULL;
137 vb->stats_callback = NULL;
140 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
142 VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev);
143 VirtQueueElement *elem = &s->stats_vq_elem;
144 VirtIOBalloonStat stat;
145 size_t offset = 0;
147 if (!virtqueue_pop(vq, elem)) {
148 return;
151 /* Initialize the stats to get rid of any stale values. This is only
152 * needed to handle the case where a guest supports fewer stats than it
153 * used to (ie. it has booted into an old kernel).
155 reset_stats(s);
157 while (iov_to_buf(elem->out_sg, elem->out_num, &stat, offset, sizeof(stat))
158 == sizeof(stat)) {
159 uint16_t tag = tswap16(stat.tag);
160 uint64_t val = tswap64(stat.val);
162 offset += sizeof(stat);
163 if (tag < VIRTIO_BALLOON_S_NR)
164 s->stats[tag] = val;
166 s->stats_vq_offset = offset;
168 complete_stats_request(s);
171 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
173 VirtIOBalloon *dev = to_virtio_balloon(vdev);
174 struct virtio_balloon_config config;
176 config.num_pages = cpu_to_le32(dev->num_pages);
177 config.actual = cpu_to_le32(dev->actual);
179 memcpy(config_data, &config, 8);
182 static void virtio_balloon_set_config(VirtIODevice *vdev,
183 const uint8_t *config_data)
185 VirtIOBalloon *dev = to_virtio_balloon(vdev);
186 struct virtio_balloon_config config;
187 memcpy(&config, config_data, 8);
188 dev->actual = config.actual;
191 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
193 f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
194 return f;
197 static void virtio_balloon_to_target(void *opaque, ram_addr_t target,
198 MonitorCompletion cb, void *cb_data)
200 VirtIOBalloon *dev = opaque;
202 if (target > ram_size)
203 target = ram_size;
205 if (target) {
206 dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
207 virtio_notify_config(&dev->vdev);
208 } else {
209 /* For now, only allow one request at a time. This restriction can be
210 * removed later by queueing callback and data pairs.
212 if (dev->stats_callback != NULL) {
213 return;
215 dev->stats_callback = cb;
216 dev->stats_opaque_callback_data = cb_data;
217 if (dev->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ)) {
218 virtqueue_push(dev->svq, &dev->stats_vq_elem, dev->stats_vq_offset);
219 virtio_notify(&dev->vdev, dev->svq);
220 } else {
221 /* Stats are not supported. Clear out any stale values that might
222 * have been set by a more featureful guest kernel.
224 reset_stats(dev);
225 complete_stats_request(dev);
230 static void virtio_balloon_save(QEMUFile *f, void *opaque)
232 VirtIOBalloon *s = opaque;
234 virtio_save(&s->vdev, f);
236 qemu_put_be32(f, s->num_pages);
237 qemu_put_be32(f, s->actual);
240 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
242 VirtIOBalloon *s = opaque;
244 if (version_id != 1)
245 return -EINVAL;
247 virtio_load(&s->vdev, f);
249 s->num_pages = qemu_get_be32(f);
250 s->actual = qemu_get_be32(f);
251 return 0;
254 VirtIODevice *virtio_balloon_init(DeviceState *dev)
256 VirtIOBalloon *s;
258 s = (VirtIOBalloon *)virtio_common_init("virtio-balloon",
259 VIRTIO_ID_BALLOON,
260 8, sizeof(VirtIOBalloon));
262 s->vdev.get_config = virtio_balloon_get_config;
263 s->vdev.set_config = virtio_balloon_set_config;
264 s->vdev.get_features = virtio_balloon_get_features;
266 s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
267 s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
268 s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats);
270 reset_stats(s);
271 qemu_add_balloon_handler(virtio_balloon_to_target, s);
273 register_savevm("virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s);
275 return &s->vdev;