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virtio-blk: use BDRV_REQ_REGISTERED_BUF optimization hint
Register guest RAM using BlockRAMRegistrar and set the BDRV_REQ_REGISTERED_BUF flag so block drivers can optimize memory accesses in I/O requests. This is for vdpa-blk, vhost-user-blk, and other I/O interfaces that rely on DMA mapping/unmapping. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20221013185908.1297568-14-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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parent
c5640b3e2f
commit
baf422684d
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@ -21,6 +21,7 @@
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#include "hw/block/block.h"
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#include "hw/block/block.h"
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#include "hw/qdev-properties.h"
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#include "hw/qdev-properties.h"
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#include "sysemu/blockdev.h"
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#include "sysemu/blockdev.h"
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#include "sysemu/block-ram-registrar.h"
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#include "sysemu/sysemu.h"
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#include "sysemu/sysemu.h"
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#include "sysemu/runstate.h"
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#include "sysemu/runstate.h"
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#include "hw/virtio/virtio-blk.h"
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#include "hw/virtio/virtio-blk.h"
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@ -362,12 +363,14 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
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}
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}
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}
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}
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static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
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static inline void submit_requests(VirtIOBlock *s, MultiReqBuffer *mrb,
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int start, int num_reqs, int niov)
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int start, int num_reqs, int niov)
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{
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{
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BlockBackend *blk = s->blk;
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QEMUIOVector *qiov = &mrb->reqs[start]->qiov;
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QEMUIOVector *qiov = &mrb->reqs[start]->qiov;
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int64_t sector_num = mrb->reqs[start]->sector_num;
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int64_t sector_num = mrb->reqs[start]->sector_num;
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bool is_write = mrb->is_write;
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bool is_write = mrb->is_write;
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BdrvRequestFlags flags = 0;
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if (num_reqs > 1) {
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if (num_reqs > 1) {
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int i;
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int i;
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@ -398,12 +401,18 @@ static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
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num_reqs - 1);
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num_reqs - 1);
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}
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}
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if (blk_ram_registrar_ok(&s->blk_ram_registrar)) {
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flags |= BDRV_REQ_REGISTERED_BUF;
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}
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if (is_write) {
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if (is_write) {
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blk_aio_pwritev(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0,
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blk_aio_pwritev(blk, sector_num << BDRV_SECTOR_BITS, qiov,
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virtio_blk_rw_complete, mrb->reqs[start]);
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flags, virtio_blk_rw_complete,
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mrb->reqs[start]);
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} else {
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} else {
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blk_aio_preadv(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0,
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blk_aio_preadv(blk, sector_num << BDRV_SECTOR_BITS, qiov,
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virtio_blk_rw_complete, mrb->reqs[start]);
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flags, virtio_blk_rw_complete,
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mrb->reqs[start]);
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}
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}
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}
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}
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@ -425,14 +434,14 @@ static int multireq_compare(const void *a, const void *b)
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}
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}
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}
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}
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static void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
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static void virtio_blk_submit_multireq(VirtIOBlock *s, MultiReqBuffer *mrb)
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{
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{
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int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0;
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int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0;
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uint32_t max_transfer;
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uint32_t max_transfer;
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int64_t sector_num = 0;
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int64_t sector_num = 0;
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if (mrb->num_reqs == 1) {
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if (mrb->num_reqs == 1) {
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submit_requests(blk, mrb, 0, 1, -1);
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submit_requests(s, mrb, 0, 1, -1);
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mrb->num_reqs = 0;
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mrb->num_reqs = 0;
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return;
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return;
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}
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}
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@ -452,11 +461,11 @@ static void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
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* 3. merge would exceed maximum transfer length of backend device
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* 3. merge would exceed maximum transfer length of backend device
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*/
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*/
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if (sector_num + nb_sectors != req->sector_num ||
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if (sector_num + nb_sectors != req->sector_num ||
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niov > blk_get_max_iov(blk) - req->qiov.niov ||
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niov > blk_get_max_iov(s->blk) - req->qiov.niov ||
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req->qiov.size > max_transfer ||
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req->qiov.size > max_transfer ||
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nb_sectors > (max_transfer -
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nb_sectors > (max_transfer -
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req->qiov.size) / BDRV_SECTOR_SIZE) {
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req->qiov.size) / BDRV_SECTOR_SIZE) {
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submit_requests(blk, mrb, start, num_reqs, niov);
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submit_requests(s, mrb, start, num_reqs, niov);
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num_reqs = 0;
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num_reqs = 0;
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}
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}
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}
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}
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@ -472,7 +481,7 @@ static void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
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num_reqs++;
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num_reqs++;
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}
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}
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submit_requests(blk, mrb, start, num_reqs, niov);
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submit_requests(s, mrb, start, num_reqs, niov);
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mrb->num_reqs = 0;
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mrb->num_reqs = 0;
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}
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}
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@ -487,7 +496,7 @@ static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
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* Make sure all outstanding writes are posted to the backing device.
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* Make sure all outstanding writes are posted to the backing device.
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*/
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*/
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if (mrb->is_write && mrb->num_reqs > 0) {
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if (mrb->is_write && mrb->num_reqs > 0) {
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virtio_blk_submit_multireq(s->blk, mrb);
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virtio_blk_submit_multireq(s, mrb);
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}
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}
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blk_aio_flush(s->blk, virtio_blk_flush_complete, req);
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blk_aio_flush(s->blk, virtio_blk_flush_complete, req);
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}
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}
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@ -667,7 +676,7 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
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if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS ||
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if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS ||
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is_write != mrb->is_write ||
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is_write != mrb->is_write ||
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!s->conf.request_merging)) {
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!s->conf.request_merging)) {
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virtio_blk_submit_multireq(s->blk, mrb);
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virtio_blk_submit_multireq(s, mrb);
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}
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}
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assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS);
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assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS);
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@ -774,7 +783,7 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
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} while (!virtio_queue_empty(vq));
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} while (!virtio_queue_empty(vq));
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if (mrb.num_reqs) {
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if (mrb.num_reqs) {
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virtio_blk_submit_multireq(s->blk, &mrb);
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virtio_blk_submit_multireq(s, &mrb);
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}
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}
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blk_io_unplug(s->blk);
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blk_io_unplug(s->blk);
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@ -823,7 +832,7 @@ void virtio_blk_process_queued_requests(VirtIOBlock *s, bool is_bh)
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}
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}
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if (mrb.num_reqs) {
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if (mrb.num_reqs) {
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virtio_blk_submit_multireq(s->blk, &mrb);
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virtio_blk_submit_multireq(s, &mrb);
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}
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}
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if (is_bh) {
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if (is_bh) {
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blk_dec_in_flight(s->conf.conf.blk);
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blk_dec_in_flight(s->conf.conf.blk);
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@ -1205,6 +1214,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
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}
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}
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s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
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s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
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blk_ram_registrar_init(&s->blk_ram_registrar, s->blk);
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blk_set_dev_ops(s->blk, &virtio_block_ops, s);
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blk_set_dev_ops(s->blk, &virtio_block_ops, s);
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blk_iostatus_enable(s->blk);
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blk_iostatus_enable(s->blk);
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@ -1230,6 +1240,7 @@ static void virtio_blk_device_unrealize(DeviceState *dev)
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virtio_del_queue(vdev, i);
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virtio_del_queue(vdev, i);
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}
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}
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qemu_coroutine_dec_pool_size(conf->num_queues * conf->queue_size / 2);
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qemu_coroutine_dec_pool_size(conf->num_queues * conf->queue_size / 2);
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blk_ram_registrar_destroy(&s->blk_ram_registrar);
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qemu_del_vm_change_state_handler(s->change);
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qemu_del_vm_change_state_handler(s->change);
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blockdev_mark_auto_del(s->blk);
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blockdev_mark_auto_del(s->blk);
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virtio_cleanup(vdev);
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virtio_cleanup(vdev);
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@ -19,6 +19,7 @@
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#include "hw/block/block.h"
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#include "hw/block/block.h"
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#include "sysemu/iothread.h"
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#include "sysemu/iothread.h"
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#include "sysemu/block-backend.h"
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#include "sysemu/block-backend.h"
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#include "sysemu/block-ram-registrar.h"
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#include "qom/object.h"
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#include "qom/object.h"
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#define TYPE_VIRTIO_BLK "virtio-blk-device"
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#define TYPE_VIRTIO_BLK "virtio-blk-device"
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@ -64,6 +65,7 @@ struct VirtIOBlock {
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struct VirtIOBlockDataPlane *dataplane;
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struct VirtIOBlockDataPlane *dataplane;
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uint64_t host_features;
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uint64_t host_features;
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size_t config_size;
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size_t config_size;
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BlockRAMRegistrar blk_ram_registrar;
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};
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};
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typedef struct VirtIOBlockReq {
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typedef struct VirtIOBlockReq {
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