mirror of https://github.com/xemu-project/xemu.git
libvduse: Add support for reconnecting
To support reconnecting after restart or crash, VDUSE backend might need to resubmit inflight I/Os. This stores the metadata such as the index of inflight I/O's descriptors to a shm file so that VDUSE backend can restore them during reconnecting. Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Message-Id: <20220523084611.91-9-xieyongji@bytedance.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Xie Yongji
Kevin Wolf
parent
9e4dea6727
commit
d043e2db87
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@ -30,6 +30,7 @@ typedef struct VduseBlkExport {
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VirtioBlkHandler handler;
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VduseDev *dev;
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uint16_t num_queues;
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char *recon_file;
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unsigned int inflight;
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} VduseBlkExport;
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@ -125,6 +126,8 @@ static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq)
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aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
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true, on_vduse_vq_kick, NULL, NULL, NULL, vq);
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/* Make sure we don't miss any kick afer reconnecting */
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eventfd_write(vduse_queue_get_fd(vq), 1);
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}
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static void vduse_blk_disable_queue(VduseDev *dev, VduseVirtq *vq)
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@ -306,6 +309,15 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
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return -ENOMEM;
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}
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vblk_exp->recon_file = g_strdup_printf("%s/vduse-blk-%s",
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g_get_tmp_dir(), exp->id);
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if (vduse_set_reconnect_log_file(vblk_exp->dev, vblk_exp->recon_file)) {
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error_setg(errp, "failed to set reconnect log file");
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vduse_dev_destroy(vblk_exp->dev);
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g_free(vblk_exp->recon_file);
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return -EINVAL;
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}
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for (i = 0; i < num_queues; i++) {
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vduse_dev_setup_queue(vblk_exp->dev, i, queue_size);
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}
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@ -324,11 +336,16 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
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static void vduse_blk_exp_delete(BlockExport *exp)
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{
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VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
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int ret;
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blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
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vblk_exp);
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blk_set_dev_ops(exp->blk, NULL, NULL);
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vduse_dev_destroy(vblk_exp->dev);
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ret = vduse_dev_destroy(vblk_exp->dev);
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if (ret != -EBUSY) {
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unlink(vblk_exp->recon_file);
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}
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g_free(vblk_exp->recon_file);
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}
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static void vduse_blk_exp_request_shutdown(BlockExport *exp)
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@ -42,6 +42,8 @@
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#define VDUSE_VQ_ALIGN 4096
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#define MAX_IOVA_REGIONS 256
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#define LOG_ALIGNMENT 64
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/* Round number down to multiple */
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#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
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@ -52,6 +54,31 @@
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#define unlikely(x) __builtin_expect(!!(x), 0)
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#endif
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typedef struct VduseDescStateSplit {
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uint8_t inflight;
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uint8_t padding[5];
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uint16_t next;
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uint64_t counter;
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} VduseDescStateSplit;
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typedef struct VduseVirtqLogInflight {
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uint64_t features;
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uint16_t version;
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uint16_t desc_num;
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uint16_t last_batch_head;
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uint16_t used_idx;
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VduseDescStateSplit desc[];
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} VduseVirtqLogInflight;
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typedef struct VduseVirtqLog {
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VduseVirtqLogInflight inflight;
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} VduseVirtqLog;
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typedef struct VduseVirtqInflightDesc {
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uint16_t index;
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uint64_t counter;
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} VduseVirtqInflightDesc;
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typedef struct VduseRing {
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unsigned int num;
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uint64_t desc_addr;
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@ -74,6 +101,10 @@ struct VduseVirtq {
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bool ready;
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int fd;
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VduseDev *dev;
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VduseVirtqInflightDesc *resubmit_list;
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uint16_t resubmit_num;
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uint64_t counter;
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VduseVirtqLog *log;
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};
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typedef struct VduseIovaRegion {
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@ -97,8 +128,36 @@ struct VduseDev {
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int fd;
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int ctrl_fd;
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void *priv;
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void *log;
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};
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static inline size_t vduse_vq_log_size(uint16_t queue_size)
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{
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return ALIGN_UP(sizeof(VduseDescStateSplit) * queue_size +
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sizeof(VduseVirtqLogInflight), LOG_ALIGNMENT);
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}
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static void *vduse_log_get(const char *filename, size_t size)
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{
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void *ptr = MAP_FAILED;
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int fd;
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fd = open(filename, O_RDWR | O_CREAT, 0600);
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if (fd == -1) {
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return MAP_FAILED;
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}
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if (ftruncate(fd, size) == -1) {
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goto out;
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}
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ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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out:
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close(fd);
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return ptr;
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}
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static inline bool has_feature(uint64_t features, unsigned int fbit)
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{
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assert(fbit < 64);
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@ -149,6 +208,105 @@ static int vduse_inject_irq(VduseDev *dev, int index)
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return ioctl(dev->fd, VDUSE_VQ_INJECT_IRQ, &index);
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}
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static int inflight_desc_compare(const void *a, const void *b)
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{
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VduseVirtqInflightDesc *desc0 = (VduseVirtqInflightDesc *)a,
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*desc1 = (VduseVirtqInflightDesc *)b;
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if (desc1->counter > desc0->counter &&
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(desc1->counter - desc0->counter) < VIRTQUEUE_MAX_SIZE * 2) {
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return 1;
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}
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return -1;
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}
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static int vduse_queue_check_inflights(VduseVirtq *vq)
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{
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int i = 0;
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VduseDev *dev = vq->dev;
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vq->used_idx = le16toh(vq->vring.used->idx);
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vq->resubmit_num = 0;
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vq->resubmit_list = NULL;
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vq->counter = 0;
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if (unlikely(vq->log->inflight.used_idx != vq->used_idx)) {
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if (vq->log->inflight.last_batch_head > VIRTQUEUE_MAX_SIZE) {
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return -1;
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}
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vq->log->inflight.desc[vq->log->inflight.last_batch_head].inflight = 0;
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barrier();
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vq->log->inflight.used_idx = vq->used_idx;
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}
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for (i = 0; i < vq->log->inflight.desc_num; i++) {
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if (vq->log->inflight.desc[i].inflight == 1) {
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vq->inuse++;
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}
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}
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vq->shadow_avail_idx = vq->last_avail_idx = vq->inuse + vq->used_idx;
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if (vq->inuse) {
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vq->resubmit_list = calloc(vq->inuse, sizeof(VduseVirtqInflightDesc));
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if (!vq->resubmit_list) {
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return -1;
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}
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for (i = 0; i < vq->log->inflight.desc_num; i++) {
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if (vq->log->inflight.desc[i].inflight) {
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vq->resubmit_list[vq->resubmit_num].index = i;
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vq->resubmit_list[vq->resubmit_num].counter =
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vq->log->inflight.desc[i].counter;
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vq->resubmit_num++;
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}
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}
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if (vq->resubmit_num > 1) {
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qsort(vq->resubmit_list, vq->resubmit_num,
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sizeof(VduseVirtqInflightDesc), inflight_desc_compare);
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}
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vq->counter = vq->resubmit_list[0].counter + 1;
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}
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vduse_inject_irq(dev, vq->index);
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return 0;
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}
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static int vduse_queue_inflight_get(VduseVirtq *vq, int desc_idx)
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{
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vq->log->inflight.desc[desc_idx].counter = vq->counter++;
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barrier();
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vq->log->inflight.desc[desc_idx].inflight = 1;
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return 0;
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}
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static int vduse_queue_inflight_pre_put(VduseVirtq *vq, int desc_idx)
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{
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vq->log->inflight.last_batch_head = desc_idx;
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return 0;
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}
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static int vduse_queue_inflight_post_put(VduseVirtq *vq, int desc_idx)
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{
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vq->log->inflight.desc[desc_idx].inflight = 0;
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barrier();
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vq->log->inflight.used_idx = vq->used_idx;
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return 0;
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}
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static void vduse_iova_remove_region(VduseDev *dev, uint64_t start,
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uint64_t last)
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{
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@ -579,11 +737,24 @@ void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
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unsigned int head;
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VduseVirtqElement *elem;
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VduseDev *dev = vq->dev;
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int i;
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if (unlikely(!vq->vring.avail)) {
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return NULL;
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}
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if (unlikely(vq->resubmit_list && vq->resubmit_num > 0)) {
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i = (--vq->resubmit_num);
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elem = vduse_queue_map_desc(vq, vq->resubmit_list[i].index, sz);
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if (!vq->resubmit_num) {
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free(vq->resubmit_list);
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vq->resubmit_list = NULL;
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}
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return elem;
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}
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if (vduse_queue_empty(vq)) {
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return NULL;
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}
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@ -611,6 +782,8 @@ void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
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vq->inuse++;
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vduse_queue_inflight_get(vq, head);
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return elem;
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}
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@ -668,7 +841,9 @@ void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
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unsigned int len)
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{
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vduse_queue_fill(vq, elem, len, 0);
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vduse_queue_inflight_pre_put(vq, elem->index);
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vduse_queue_flush(vq, 1);
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vduse_queue_inflight_post_put(vq, elem->index);
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}
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static int vduse_queue_update_vring(VduseVirtq *vq, uint64_t desc_addr,
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@ -747,12 +922,15 @@ static void vduse_queue_enable(VduseVirtq *vq)
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}
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vq->fd = fd;
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vq->shadow_avail_idx = vq->last_avail_idx = vq_info.split.avail_index;
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vq->inuse = 0;
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vq->used_idx = 0;
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vq->signalled_used_valid = false;
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vq->ready = true;
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if (vduse_queue_check_inflights(vq)) {
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fprintf(stderr, "Failed to check inflights for vq[%d]\n", vq->index);
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close(fd);
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return;
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}
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dev->ops->enable_queue(dev, vq);
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}
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@ -802,11 +980,15 @@ static void vduse_dev_start_dataplane(VduseDev *dev)
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static void vduse_dev_stop_dataplane(VduseDev *dev)
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{
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size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
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int i;
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for (i = 0; i < dev->num_queues; i++) {
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vduse_queue_disable(&dev->vqs[i]);
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}
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if (dev->log) {
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memset(dev->log, 0, log_size);
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}
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dev->features = 0;
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vduse_iova_remove_region(dev, 0, ULONG_MAX);
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}
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@ -915,6 +1097,30 @@ int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size)
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return -errno;
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}
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vduse_queue_enable(vq);
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return 0;
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}
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int vduse_set_reconnect_log_file(VduseDev *dev, const char *filename)
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{
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size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
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void *log;
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int i;
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dev->log = log = vduse_log_get(filename, log_size);
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if (log == MAP_FAILED) {
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fprintf(stderr, "Failed to get vduse log\n");
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return -EINVAL;
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}
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for (i = 0; i < dev->num_queues; i++) {
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dev->vqs[i].log = log;
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dev->vqs[i].log->inflight.desc_num = VIRTQUEUE_MAX_SIZE;
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log = (void *)((char *)log + vduse_vq_log_size(VIRTQUEUE_MAX_SIZE));
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}
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return 0;
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}
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@ -959,6 +1165,12 @@ static int vduse_dev_init(VduseDev *dev, const char *name,
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return -errno;
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}
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if (ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
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fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
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close(fd);
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return -errno;
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}
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dev_name = strdup(name);
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if (!dev_name) {
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close(fd);
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@ -1003,6 +1215,12 @@ VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
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return NULL;
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}
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if (ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
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fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
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free(dev);
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return NULL;
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}
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ret = vduse_dev_init_vqs(dev, num_queues);
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if (ret) {
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fprintf(stderr, "Failed to init vqs\n");
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@ -1102,7 +1320,7 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
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ret = ioctl(ctrl_fd, VDUSE_CREATE_DEV, dev_config);
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free(dev_config);
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if (ret < 0) {
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if (ret && errno != EEXIST) {
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fprintf(stderr, "Failed to create vduse device %s: %s\n",
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name, strerror(errno));
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goto err_dev;
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@ -1129,8 +1347,15 @@ err_ctrl:
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int vduse_dev_destroy(VduseDev *dev)
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{
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int ret = 0;
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size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
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int i, ret = 0;
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if (dev->log) {
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munmap(dev->log, log_size);
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}
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for (i = 0; i < dev->num_queues; i++) {
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free(dev->vqs[i].resubmit_list);
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}
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free(dev->vqs);
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if (dev->fd >= 0) {
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close(dev->fd);
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@ -173,6 +173,18 @@ int vduse_dev_update_config(VduseDev *dev, uint32_t size,
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*/
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int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size);
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/**
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* vduse_set_reconnect_log_file:
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* @dev: VDUSE device
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* @file: filename of reconnect log
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*
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* Specify the file to store log for reconnecting. It should
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* be called before vduse_dev_setup_queue().
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*
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* Returns: 0 on success, -errno on failure.
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*/
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int vduse_set_reconnect_log_file(VduseDev *dev, const char *filename);
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/**
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* vduse_dev_create_by_fd:
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* @fd: passed file descriptor
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