hw/virtio-balloon.c

   1 /*
   2  * Virtio Block Device
   3  *
   4  * Copyright IBM, Corp. 2008
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu-common.h"
  15 #include "virtio.h"
  16 #include "pc.h"
  17 #include "sysemu.h"
  18 #include "cpu.h"
  19 #include "balloon.h"
  20 #include "virtio-balloon.h"
  21 #include "kvm.h"
  22 #include "qemu-kvm.h"
  23
  24 #if defined(__linux__)
  25 #include <sys/mman.h>
  26 #endif
  27
  28 typedef struct VirtIOBalloon
  29 {
  30     VirtIODevice vdev;
  31     VirtQueue *ivq, *dvq;
  32     uint32_t num_pages;
  33     uint32_t actual;
  34 } VirtIOBalloon;
  35
  36 static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
  37 {
  38     return (VirtIOBalloon *)vdev;
  39 }
  40
  41 static void balloon_page(void *addr, int deflate)
  42 {
  43 #if defined(__linux__)
  44     if (!kvm_enabled() || kvm_has_sync_mmu())
  45         madvise(addr, TARGET_PAGE_SIZE,
  46                 deflate ? MADV_WILLNEED : MADV_DONTNEED);
  47 #endif
  48 }
  49
  50 /* FIXME: once we do a virtio refactoring, this will get subsumed into common
  51  * code */
  52 static size_t memcpy_from_iovector(void *data, size_t offset, size_t size,
  53                                    struct iovec *iov, int iovlen)
  54 {
  55     int i;
  56     uint8_t *ptr = data;
  57     size_t iov_off = 0;
  58     size_t data_off = 0;
  59
  60     for (i = 0; i < iovlen && size; i++) {
  61         if (offset < (iov_off + iov[i].iov_len)) {
  62             size_t len = MIN((iov_off + iov[i].iov_len) - offset , size);
  63
  64             memcpy(ptr + data_off, iov[i].iov_base + (offset - iov_off), len);
  65
  66             data_off += len;
  67             offset += len;
  68             size -= len;
  69         }
  70
  71         iov_off += iov[i].iov_len;
  72     }
  73
  74     return data_off;
  75 }
  76
  77 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
  78 {
  79     VirtIOBalloon *s = to_virtio_balloon(vdev);
  80     VirtQueueElement elem;
  81
  82     while (virtqueue_pop(vq, &elem)) {
  83         size_t offset = 0;
  84         uint32_t pfn;
  85
  86         while (memcpy_from_iovector(&pfn, offset, 4,
  87                                     elem.out_sg, elem.out_num) == 4) {
  88             ram_addr_t pa;
  89             ram_addr_t addr;
  90
  91             pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
  92             offset += 4;
  93
  94             addr = cpu_get_physical_page_desc(pa);
  95             if ((addr & ~TARGET_PAGE_MASK) != IO_MEM_RAM)
  96                 continue;
  97
  98             balloon_page(phys_ram_base + addr, !!(vq == s->dvq));
  99         }
 100
 101         virtqueue_push(vq, &elem, offset);
 102         virtio_notify(vdev, vq);
 103     }
 104 }
 105
 106 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 107 {
 108     VirtIOBalloon *dev = to_virtio_balloon(vdev);
 109     struct virtio_balloon_config config;
 110
 111     config.num_pages = cpu_to_le32(dev->num_pages);
 112     config.actual = cpu_to_le32(dev->actual);
 113
 114     memcpy(config_data, &config, 8);
 115 }
 116
 117 static void virtio_balloon_set_config(VirtIODevice *vdev,
 118                                       const uint8_t *config_data)
 119 {
 120     VirtIOBalloon *dev = to_virtio_balloon(vdev);
 121     struct virtio_balloon_config config;
 122     memcpy(&config, config_data, 8);
 123     dev->actual = config.actual;
 124 }
 125
 126 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev)
 127 {
 128     return 0;
 129 }
 130
 131 static ram_addr_t virtio_balloon_to_target(void *opaque, ram_addr_t target)
 132 {
 133     VirtIOBalloon *dev = opaque;
 134
 135     if (target > ram_size)
 136         target = ram_size;
 137
 138     if (target) {
 139         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 140         virtio_notify_config(&dev->vdev);
 141     }
 142
 143     return ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT);
 144 }
 145
 146 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 147 {
 148     VirtIOBalloon *s = opaque;
 149
 150     virtio_save(&s->vdev, f);
 151
 152     qemu_put_be32(f, s->num_pages);
 153     qemu_put_be32(f, s->actual);
 154 }
 155
 156 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 157 {
 158     VirtIOBalloon *s = opaque;
 159
 160     if (version_id != 1)
 161         return -EINVAL;
 162
 163     virtio_load(&s->vdev, f);
 164
 165     s->num_pages = qemu_get_be32(f);
 166     s->actual = qemu_get_be32(f);
 167
 168     return 0;
 169 }
 170
 171 void *virtio_balloon_init(PCIBus *bus)
 172 {
 173     VirtIOBalloon *s;
 174
 175     s = (VirtIOBalloon *)virtio_init_pci(bus, "virtio-balloon",
 176                                          PCI_VENDOR_ID_REDHAT_QUMRANET,
 177                                          PCI_DEVICE_ID_VIRTIO_BALLOON,
 178                                          PCI_VENDOR_ID_REDHAT_QUMRANET,
 179                                          VIRTIO_ID_BALLOON,
 180                                          PCI_CLASS_MEMORY_RAM, 0x00,
 181                                          8, sizeof(VirtIOBalloon));
 182     if (s == NULL)
 183         return NULL;
 184
 185     s->vdev.get_config = virtio_balloon_get_config;
 186     s->vdev.set_config = virtio_balloon_set_config;
 187     s->vdev.get_features = virtio_balloon_get_features;
 188
 189     s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
 190     s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
 191
 192     qemu_add_balloon_handler(virtio_balloon_to_target, s);
 193
 194     register_savevm("virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s);
 195
 196     return &s->vdev;
 197 }