[PULL,17/35] scsi: esp: Defer command completion until previous interrupts have been handled

diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c
index d956909186..6b0bbb9b7f 100644
--- a/hw/scsi/esp-pci.c
+++ b/hw/scsi/esp-pci.c
@@ -313,8 +313,8 @@  static void esp_pci_hard_reset(DeviceState *dev)
 
 static const VMStateDescription vmstate_esp_pci_scsi = {
     .name = "pciespscsi",
-    .version_id = 0,
-    .minimum_version_id = 0,
+    .version_id = 1,
+    .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(parent_obj, PCIESPState),
         VMSTATE_BUFFER_UNSAFE(dma_regs, PCIESPState, 0, 8 * sizeof(uint32_t)),
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 630d923623..ca8b36c0c5 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -286,11 +286,8 @@  static void esp_do_dma(ESPState *s)
     esp_dma_done(s);
 }
 
-void esp_command_complete(SCSIRequest *req, uint32_t status,
-                                 size_t resid)
+static void esp_report_command_complete(ESPState *s, uint32_t status)
 {
-    ESPState *s = req->hba_private;
-
     trace_esp_command_complete();
     if (s->ti_size != 0) {
         trace_esp_command_complete_unexpected();
@@ -311,6 +308,23 @@  void esp_command_complete(SCSIRequest *req, uint32_t status,
     }
 }
 
+void esp_command_complete(SCSIRequest *req, uint32_t status,
+                          size_t resid)
+{
+    ESPState *s = req->hba_private;
+
+    if (s->rregs[ESP_RSTAT] & STAT_INT) {
+        /* Defer handling command complete until the previous
+         * interrupt has been handled.
+         */
+        trace_esp_command_complete_deferred();
+        s->deferred_status = status;
+        s->deferred_complete = true;
+        return;
+    }
+    esp_report_command_complete(s, status);
+}
+
 void esp_transfer_data(SCSIRequest *req, uint32_t len)
 {
     ESPState *s = req->hba_private;
@@ -422,7 +436,10 @@  uint64_t esp_reg_read(ESPState *s, uint32_t saddr)
         s->rregs[ESP_RSTAT] &= ~STAT_TC;
         s->rregs[ESP_RSEQ] = SEQ_CD;
         esp_lower_irq(s);
-
+        if (s->deferred_complete) {
+            esp_report_command_complete(s, s->deferred_status);
+            s->deferred_complete = false;
+        }
         return old_val;
     case ESP_TCHI:
         /* Return the unique id if the value has never been written */
@@ -582,6 +599,8 @@  const VMStateDescription vmstate_esp = {
         VMSTATE_UINT32(ti_wptr, ESPState),
         VMSTATE_BUFFER(ti_buf, ESPState),
         VMSTATE_UINT32(status, ESPState),
+        VMSTATE_UINT32(deferred_status, ESPState),
+        VMSTATE_BOOL(deferred_complete, ESPState),
         VMSTATE_UINT32(dma, ESPState),
         VMSTATE_PARTIAL_BUFFER(cmdbuf, ESPState, 16),
         VMSTATE_BUFFER_START_MIDDLE_V(cmdbuf, ESPState, 16, 4),
@@ -671,8 +690,8 @@  static void sysbus_esp_hard_reset(DeviceState *dev)
 
 static const VMStateDescription vmstate_sysbus_esp_scsi = {
     .name = "sysbusespscsi",
-    .version_id = 0,
-    .minimum_version_id = 0,
+    .version_id = 1,
+    .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_STRUCT(esp, SysBusESPState, 0, vmstate_esp, ESPState),
         VMSTATE_END_OF_LIST()
diff --git a/hw/scsi/trace-events b/hw/scsi/trace-events
index 0fb6a99616..2fe8a7c062 100644
--- a/hw/scsi/trace-events
+++ b/hw/scsi/trace-events
@@ -167,6 +167,7 @@  esp_handle_satn_stop(uint32_t cmdlen) "cmdlen %d"
 esp_write_response(uint32_t status) "Transfer status (status=%d)"
 esp_do_dma(uint32_t cmdlen, uint32_t len) "command len %d + %d"
 esp_command_complete(void) "SCSI Command complete"
+esp_command_complete_deferred(void) "SCSI Command complete deferred"
 esp_command_complete_unexpected(void) "SCSI command completed unexpectedly"
 esp_command_complete_fail(void) "Command failed"
 esp_transfer_data(uint32_t dma_left, int32_t ti_size) "transfer %d/%d"
diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h
index 682a0d2de0..adab63d1c9 100644
--- a/include/hw/scsi/esp.h
+++ b/include/hw/scsi/esp.h
@@ -23,6 +23,8 @@  struct ESPState {
     int32_t ti_size;
     uint32_t ti_rptr, ti_wptr;
     uint32_t status;
+    uint32_t deferred_status;
+    bool deferred_complete;
     uint32_t dma;
     uint8_t ti_buf[TI_BUFSZ];
     SCSIBus bus;