root / hw / virtio-balloon.c @ a85d6887
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/*
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* Virtio Block Device
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*
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* Copyright IBM, Corp. 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu-common.h" |
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#include "virtio.h" |
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#include "pc.h" |
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#include "sysemu.h" |
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#include "cpu.h" |
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#include "balloon.h" |
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#include "virtio-balloon.h" |
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#include "kvm.h" |
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#if defined(__linux__)
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#include <sys/mman.h> |
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#endif
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typedef struct VirtIOBalloon |
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{ |
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VirtIODevice vdev; |
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VirtQueue *ivq, *dvq; |
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uint32_t num_pages; |
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uint32_t actual; |
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} VirtIOBalloon; |
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static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
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{ |
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return (VirtIOBalloon *)vdev;
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} |
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static void balloon_page(void *addr, int deflate) |
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{ |
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#if defined(__linux__)
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if (!kvm_enabled() || kvm_has_sync_mmu())
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madvise(addr, TARGET_PAGE_SIZE, |
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deflate ? MADV_WILLNEED : MADV_DONTNEED); |
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#endif
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} |
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/* FIXME: once we do a virtio refactoring, this will get subsumed into common
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* code */
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static size_t memcpy_from_iovector(void *data, size_t offset, size_t size, |
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struct iovec *iov, int iovlen) |
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{ |
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int i;
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uint8_t *ptr = data; |
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size_t iov_off = 0;
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size_t data_off = 0;
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for (i = 0; i < iovlen && size; i++) { |
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if (offset < (iov_off + iov[i].iov_len)) {
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size_t len = MIN((iov_off + iov[i].iov_len) - offset , size); |
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memcpy(ptr + data_off, iov[i].iov_base + (offset - iov_off), len); |
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data_off += len; |
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offset += len; |
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size -= len; |
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} |
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iov_off += iov[i].iov_len; |
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} |
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return data_off;
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} |
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static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) |
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{ |
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VirtIOBalloon *s = to_virtio_balloon(vdev); |
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VirtQueueElement elem; |
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while (virtqueue_pop(vq, &elem)) {
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size_t offset = 0;
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uint32_t pfn; |
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while (memcpy_from_iovector(&pfn, offset, 4, |
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elem.out_sg, elem.out_num) == 4) {
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ram_addr_t pa; |
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ram_addr_t addr; |
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pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT; |
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offset += 4;
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addr = cpu_get_physical_page_desc(pa); |
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if ((addr & ~TARGET_PAGE_MASK) != IO_MEM_RAM)
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continue;
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/* Using qemu_get_ram_ptr is bending the rules a bit, but
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should be OK because we only want a single page. */
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balloon_page(qemu_get_ram_ptr(addr), !!(vq == s->dvq)); |
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} |
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virtqueue_push(vq, &elem, offset); |
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virtio_notify(vdev, vq); |
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} |
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} |
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static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) |
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{ |
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VirtIOBalloon *dev = to_virtio_balloon(vdev); |
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struct virtio_balloon_config config;
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config.num_pages = cpu_to_le32(dev->num_pages); |
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config.actual = cpu_to_le32(dev->actual); |
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memcpy(config_data, &config, 8);
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} |
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static void virtio_balloon_set_config(VirtIODevice *vdev, |
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const uint8_t *config_data)
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{ |
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VirtIOBalloon *dev = to_virtio_balloon(vdev); |
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struct virtio_balloon_config config;
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memcpy(&config, config_data, 8);
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dev->actual = config.actual; |
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} |
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static uint32_t virtio_balloon_get_features(VirtIODevice *vdev)
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{ |
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return 0; |
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} |
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static ram_addr_t virtio_balloon_to_target(void *opaque, ram_addr_t target) |
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{ |
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VirtIOBalloon *dev = opaque; |
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if (target > ram_size)
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target = ram_size; |
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if (target) {
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dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; |
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virtio_notify_config(&dev->vdev); |
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} |
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return ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT);
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} |
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static void virtio_balloon_save(QEMUFile *f, void *opaque) |
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{ |
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VirtIOBalloon *s = opaque; |
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virtio_save(&s->vdev, f); |
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qemu_put_be32(f, s->num_pages); |
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qemu_put_be32(f, s->actual); |
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} |
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static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) |
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{ |
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VirtIOBalloon *s = opaque; |
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if (version_id != 1) |
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return -EINVAL;
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virtio_load(&s->vdev, f); |
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s->num_pages = qemu_get_be32(f); |
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s->actual = qemu_get_be32(f); |
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return 0; |
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} |
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VirtIODevice *virtio_balloon_init(DeviceState *dev) |
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{ |
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VirtIOBalloon *s; |
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s = (VirtIOBalloon *)virtio_common_init("virtio-balloon",
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VIRTIO_ID_BALLOON, |
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8, sizeof(VirtIOBalloon)); |
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s->vdev.get_config = virtio_balloon_get_config; |
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s->vdev.set_config = virtio_balloon_set_config; |
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s->vdev.get_features = virtio_balloon_get_features; |
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s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
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s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
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qemu_add_balloon_handler(virtio_balloon_to_target, s); |
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register_savevm("virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s); |
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return &s->vdev;
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} |