4 files changed, 36 insertions, 4 deletions

diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c
index 82795e6..00b7297 100644
--- a/hw/scsi/esp-pci.c
+++ b/hw/scsi/esp-pci.c
@@ -268,6 +268,9 @@ static void esp_pci_dma_memory_rw(PCIESPState *pci, uint8_t *buf, int len,
     /* update status registers */
     pci->dma_regs[DMA_WBC] -= len;
     pci->dma_regs[DMA_WAC] += len;
+    if (pci->dma_regs[DMA_WBC] == 0) {
+        pci->dma_regs[DMA_STAT] |= DMA_STAT_DONE;
+    }
 }
 
 static void esp_pci_dma_memory_read(void *opaque, uint8_t *buf, int len)
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 5ab44d8..272d13d 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -364,7 +364,7 @@ void esp_hard_reset(ESPState *s)
 {
     memset(s->rregs, 0, ESP_REGS);
     memset(s->wregs, 0, ESP_REGS);
-    s->rregs[ESP_TCHI] = s->chip_id;
+    s->tchi_written = 0;
     s->ti_size = 0;
     s->ti_rptr = 0;
     s->ti_wptr = 0;
@@ -422,6 +422,11 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr)
         esp_lower_irq(s);
 
         return old_val;
+    case ESP_TCHI:
+        /* Return the unique id if the value has never been written */
+        if (!s->tchi_written) {
+            return s->chip_id;
+        }
     default:
         break;
     }
@@ -432,9 +437,11 @@ void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
 {
     trace_esp_mem_writeb(saddr, s->wregs[saddr], val);
     switch (saddr) {
+    case ESP_TCHI:
+        s->tchi_written = true;
+        /* fall through */
     case ESP_TCLO:
     case ESP_TCMID:
-    case ESP_TCHI:
         s->rregs[ESP_RSTAT] &= ~STAT_TC;
         break;
     case ESP_FIFO:
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index 9651e6f..03a1e8c 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -92,9 +92,14 @@ VirtIOSCSIReq *virtio_scsi_pop_req_vring(VirtIOSCSI *s,
 
 void virtio_scsi_vring_push_notify(VirtIOSCSIReq *req)
 {
+    VirtIODevice *vdev = VIRTIO_DEVICE(req->vring->parent);
+
     vring_push(&req->vring->vring, &req->elem,
                req->qsgl.size + req->resp_iov.size);
-    event_notifier_set(&req->vring->guest_notifier);
+
+    if (vring_should_notify(vdev, &req->vring->vring)) {
+        event_notifier_set(&req->vring->guest_notifier);
+    }
 }
 
 static void virtio_scsi_iothread_handle_ctrl(EventNotifier *notifier)
@@ -230,7 +235,7 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
     if (!s->event_vring) {
         goto fail_vrings;
     }
-    s->cmd_vrings = g_malloc0(sizeof(VirtIOSCSIVring) * vs->conf.num_queues);
+    s->cmd_vrings = g_new(VirtIOSCSIVring *, vs->conf.num_queues);
     for (i = 0; i < vs->conf.num_queues; i++) {
         s->cmd_vrings[i] =
             virtio_scsi_vring_init(s, vs->cmd_vqs[i],
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index fdcacfd..ef48550 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -118,6 +118,7 @@ static size_t qemu_sgl_concat(VirtIOSCSIReq *req, struct iovec *iov,
 static int virtio_scsi_parse_req(VirtIOSCSIReq *req,
                                  unsigned req_size, unsigned resp_size)
 {
+    VirtIODevice *vdev = (VirtIODevice *) req->dev;
     size_t in_size, out_size;
 
     if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
@@ -130,8 +131,24 @@ static int virtio_scsi_parse_req(VirtIOSCSIReq *req,
                               resp_size) < resp_size) {
         return -EINVAL;
     }
+
     req->resp_size = resp_size;
 
+    /* Old BIOSes left some padding by mistake after the req_size/resp_size.
+     * As a workaround, always consider the first buffer as the virtio-scsi
+     * request/response, making the payload start at the second element
+     * of the iovec.
+     *
+     * The actual length of the response header, stored in req->resp_size,
+     * does not change.
+     *
+     * TODO: always disable this workaround for virtio 1.0 devices.
+     */
+    if ((vdev->guest_features & VIRTIO_F_ANY_LAYOUT) == 0) {
+        req_size = req->elem.out_sg[0].iov_len;
+        resp_size = req->elem.in_sg[0].iov_len;
+    }
+
     out_size = qemu_sgl_concat(req, req->elem.out_sg,
                                &req->elem.out_addr[0], req->elem.out_num,
                                req_size);