virtio-blk: suppress virtqueue kick during processing

[mirror_qemu.git] / hw / block / virtio-blk.c

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 3a6112fbf4c4a94e2708f14d200ab65c6ccc64d0..50bb0cbb9329e9639d10b9cd1669c5c30b41bec2 100644 (file)
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -29,8 +29,8 @@
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"
 
-void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq,
-                             VirtIOBlockReq *req)
+static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq,
+                                    VirtIOBlockReq *req)
 {
     req->dev = s;
     req->vq = vq;
@@ -40,7 +40,7 @@ void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq,
     req->mr_next = NULL;
 }
 
-void virtio_blk_free_request(VirtIOBlockReq *req)
+static void virtio_blk_free_request(VirtIOBlockReq *req)
 {
     if (req) {
         g_free(req);
@@ -381,7 +381,7 @@ static int multireq_compare(const void *a, const void *b)
     }
 }
 
-void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
+static void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
 {
     int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0;
     uint32_t max_transfer;
@@ -468,30 +468,32 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
     return true;
 }
 
-void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
+static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
 {
     uint32_t type;
     struct iovec *in_iov = req->elem.in_sg;
     struct iovec *iov = req->elem.out_sg;
     unsigned in_num = req->elem.in_num;
     unsigned out_num = req->elem.out_num;
+    VirtIOBlock *s = req->dev;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
 
     if (req->elem.out_num < 1 || req->elem.in_num < 1) {
-        error_report("virtio-blk missing headers");
-        exit(1);
+        virtio_error(vdev, "virtio-blk missing headers");
+        return -1;
     }
 
     if (unlikely(iov_to_buf(iov, out_num, 0, &req->out,
                             sizeof(req->out)) != sizeof(req->out))) {
-        error_report("virtio-blk request outhdr too short");
-        exit(1);
+        virtio_error(vdev, "virtio-blk request outhdr too short");
+        return -1;
     }
 
     iov_discard_front(&iov, &out_num, sizeof(req->out));
 
     if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
-        error_report("virtio-blk request inhdr too short");
-        exit(1);
+        virtio_error(vdev, "virtio-blk request inhdr too short");
+        return -1;
     }
 
     /* We always touch the last byte, so just see how big in_iov is.  */
@@ -529,7 +531,7 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
             block_acct_invalid(blk_get_stats(req->dev->blk),
                                is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
             virtio_blk_free_request(req);
-            return;
+            return 0;
         }
 
         block_acct_start(blk_get_stats(req->dev->blk),
@@ -576,6 +578,7 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
         virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
         virtio_blk_free_request(req);
     }
+    return 0;
 }
 
 void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
@@ -585,9 +588,19 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
 
     blk_io_plug(s->blk);
 
-    while ((req = virtio_blk_get_request(s, vq))) {
-        virtio_blk_handle_request(req, &mrb);
-    }
+    do {
+        virtio_queue_set_notification(vq, 0);
+
+        while ((req = virtio_blk_get_request(s, vq))) {
+            if (virtio_blk_handle_request(req, &mrb)) {
+                virtqueue_detach_element(req->vq, &req->elem, 0);
+                virtio_blk_free_request(req);
+                break;
+            }
+        }
+
+        virtio_queue_set_notification(vq, 1);
+    } while (!virtio_queue_empty(vq));
 
     if (mrb.num_reqs) {
         virtio_blk_submit_multireq(s->blk, &mrb);
@@ -604,7 +617,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
         /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
          * dataplane here instead of waiting for .set_status().
          */
-        virtio_blk_data_plane_start(s->dataplane);
+        virtio_device_start_ioeventfd(vdev);
         if (!s->dataplane_disabled) {
             return;
         }
@@ -625,7 +638,18 @@ static void virtio_blk_dma_restart_bh(void *opaque)
 
     while (req) {
         VirtIOBlockReq *next = req->next;
-        virtio_blk_handle_request(req, &mrb);
+        if (virtio_blk_handle_request(req, &mrb)) {
+            /* Device is now broken and won't do any processing until it gets
+             * reset. Already queued requests will be lost: let's purge them.
+             */
+            while (req) {
+                next = req->next;
+                virtqueue_detach_element(req->vq, &req->elem, 0);
+                virtio_blk_free_request(req);
+                req = next;
+            }
+            break;
+        }
         req = next;
     }
 
@@ -665,14 +689,13 @@ static void virtio_blk_reset(VirtIODevice *vdev)
     while (s->rq) {
         req = s->rq;
         s->rq = req->next;
+        virtqueue_detach_element(req->vq, &req->elem, 0);
         virtio_blk_free_request(req);
     }
 
-    if (s->dataplane) {
-        virtio_blk_data_plane_stop(s->dataplane);
-    }
     aio_context_release(ctx);
 
+    assert(!s->dataplane_started);
     blk_set_enable_write_cache(s->blk, s->original_wce);
 }
 
@@ -770,9 +793,8 @@ static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VirtIOBlock *s = VIRTIO_BLK(vdev);
 
-    if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER |
-                                    VIRTIO_CONFIG_S_DRIVER_OK))) {
-        virtio_blk_data_plane_stop(s->dataplane);
+    if (!(status & (VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK))) {
+        assert(!s->dataplane_started);
     }
 
     if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
@@ -803,13 +825,6 @@ static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
     }
 }
 
-static void virtio_blk_save(QEMUFile *f, void *opaque, size_t size)
-{
-    VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
-
-    virtio_save(vdev, f);
-}
-    
 static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f)
 {
     VirtIOBlock *s = VIRTIO_BLK(vdev);
@@ -828,14 +843,6 @@ static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f)
     qemu_put_sbyte(f, 0);
 }
 
-static int virtio_blk_load(QEMUFile *f, void *opaque, size_t size)
-{
-    VirtIOBlock *s = opaque;
-    VirtIODevice *vdev = VIRTIO_DEVICE(s);
-
-    return virtio_load(vdev, f, 2);
-}
-
 static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f,
                                   int version_id)
 {
@@ -915,7 +922,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
     s->sector_mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1;
 
     for (i = 0; i < conf->num_queues; i++) {
-        virtio_add_queue_aio(vdev, 128, virtio_blk_handle_output);
+        virtio_add_queue(vdev, 128, virtio_blk_handle_output);
     }
     virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err);
     if (err != NULL) {
@@ -956,7 +963,15 @@ static void virtio_blk_instance_init(Object *obj)
                                   DEVICE(obj), NULL);
 }
 
-VMSTATE_VIRTIO_DEVICE(blk, 2, virtio_blk_load, virtio_blk_save);
+static const VMStateDescription vmstate_virtio_blk = {
+    .name = "virtio-blk",
+    .minimum_version_id = 2,
+    .version_id = 2,
+    .fields = (VMStateField[]) {
+        VMSTATE_VIRTIO_DEVICE,
+        VMSTATE_END_OF_LIST()
+    },
+};
 
 static Property virtio_blk_properties[] = {
     DEFINE_BLOCK_PROPERTIES(VirtIOBlock, conf.conf),
@@ -990,6 +1005,8 @@ static void virtio_blk_class_init(ObjectClass *klass, void *data)
     vdc->reset = virtio_blk_reset;
     vdc->save = virtio_blk_save_device;
     vdc->load = virtio_blk_load_device;
+    vdc->start_ioeventfd = virtio_blk_data_plane_start;
+    vdc->stop_ioeventfd = virtio_blk_data_plane_stop;
 }
 
 static const TypeInfo virtio_blk_info = {