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 

    23 #if defined(__linux__)

    24 #include <sys/mman.h>

    25 #endif

    26 

    27 typedef struct VirtIOBalloon

    28 {

    29     VirtIODevice vdev;

    30     VirtQueue *ivq, *dvq;

    31     uint32_t num_pages;

    32     uint32_t actual;

    33 } VirtIOBalloon;

    34 

    35 static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)

    36 {

    37     return (VirtIOBalloon *)vdev;

    38 }

    39 

    40 static void balloon_page(void *addr, int deflate)

    41 {

    42 #if defined(__linux__)

    43     if (!kvm_enabled() || kvm_has_sync_mmu())

    44         madvise(addr, TARGET_PAGE_SIZE,

    45                 deflate ? MADV_WILLNEED : MADV_DONTNEED);

    46 #endif

    47 }

    48 

    49 /* FIXME: once we do a virtio refactoring, this will get subsumed into common

    50  * code */

    51 static size_t memcpy_from_iovector(void *data, size_t offset, size_t size,

    52                                    struct iovec *iov, int iovlen)

    53 {

    54     int i;

    55     uint8_t *ptr = data;

    56     size_t iov_off = 0;

    57     size_t data_off = 0;

    58 

    59     for (i = 0; i < iovlen && size; i++) {

    60         if (offset < (iov_off + iov[i].iov_len)) {

    61             size_t len = MIN((iov_off + iov[i].iov_len) - offset , size);

    62 

    63             memcpy(ptr + data_off, iov[i].iov_base + (offset - iov_off), len);

    64 

    65             data_off += len;

    66             offset += len;

    67             size -= len;

    68         }

    69 

    70         iov_off += iov[i].iov_len;

    71     }

    72 

    73     return data_off;

    74 }

    75 

    76 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)

    77 {

    78     VirtIOBalloon *s = to_virtio_balloon(vdev);

    79     VirtQueueElement elem;

    80 

    81     while (virtqueue_pop(vq, &elem)) {

    82         size_t offset = 0;

    83         uint32_t pfn;

    84 

    85         while (memcpy_from_iovector(&pfn, offset, 4,

    86                                     elem.out_sg, elem.out_num) == 4) {

    87             ram_addr_t pa;

    88             ram_addr_t addr;

    89 

    90             pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;

    91             offset += 4;

    92 

    93             addr = cpu_get_physical_page_desc(pa);

    94             if ((addr & ~TARGET_PAGE_MASK) != IO_MEM_RAM)

    95                 continue;

    96 

    97             balloon_page(host_ram_addr(addr), !!(vq == s->dvq));

    98         }

    99 

   100         virtqueue_push(vq, &elem, offset);

   101         virtio_notify(vdev, vq);

   102     }

   103 }

   104 

   105 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)

   106 {

   107     VirtIOBalloon *dev = to_virtio_balloon(vdev);

   108     struct virtio_balloon_config config;

   109 

   110     config.num_pages = cpu_to_le32(dev->num_pages);

   111     config.actual = cpu_to_le32(dev->actual);

   112 

   113     memcpy(config_data, &config, 8);

   114 }

   115 

   116 static void virtio_balloon_set_config(VirtIODevice *vdev,

   117                                       const uint8_t *config_data)

   118 {

   119     VirtIOBalloon *dev = to_virtio_balloon(vdev);

   120     struct virtio_balloon_config config;

   121     memcpy(&config, config_data, 8);

   122     dev->actual = config.actual;

   123 }

   124 

   125 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev)

   126 {

   127     return 0;

   128 }

   129 

   130 static ram_addr_t virtio_balloon_to_target(void *opaque, ram_addr_t target)

   131 {

   132     VirtIOBalloon *dev = opaque;

   133 

   134     if (target > ram_size)

   135         target = ram_size;

   136 

   137     if (target) {

   138         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;

   139         virtio_notify_config(&dev->vdev);

   140     }

   141 

   142     return ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT);

   143 }

   144 

   145 static void virtio_balloon_save(QEMUFile *f, void *opaque)

   146 {

   147     VirtIOBalloon *s = opaque;

   148 

   149     virtio_save(&s->vdev, f);

   150 

   151     qemu_put_be32(f, s->num_pages);

   152     qemu_put_be32(f, s->actual);

   153 }

   154 

   155 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)

   156 {

   157     VirtIOBalloon *s = opaque;

   158 

   159     if (version_id != 1)

   160         return -EINVAL;

   161 

   162     virtio_load(&s->vdev, f);

   163 

   164     s->num_pages = qemu_get_be32(f);

   165     s->actual = qemu_get_be32(f);

   166 

   167     return 0;

   168 }

   169 

   170 void virtio_balloon_init(VirtIOBindFn bind, void *bind_arg)

   171 {

   172     VirtIOBalloon *s;

   173 

   174     s = (VirtIOBalloon *)bind(bind_arg, "virtio-balloon",

   175                               0, VIRTIO_ID_BALLOON,

   176                               8, sizeof(VirtIOBalloon));

   177     if (s == NULL)

   178         return;

   179 

   180     s->vdev.get_config = virtio_balloon_get_config;

   181     s->vdev.set_config = virtio_balloon_set_config;

   182     s->vdev.get_features = virtio_balloon_get_features;

   183 

   184     s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);

   185     s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);

   186 

   187     qemu_add_balloon_handler(virtio_balloon_to_target, s);

   188 

   189     register_savevm("virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s);

   190 }