esp: recreate ESPState current_req after migration

Since PDMA reads/writes are driven by the guest, it is possible that migration
can occur whilst a SCSIRequest is still active. Fortunately active SCSIRequests
are already included in the migration stream and restarted post migration but
this still leaves the reference in ESPState uninitialised.

Implement the SCSIBusInfo .load_request callback to obtain a reference to the
currently active SCSIRequest and use it to recreate ESPState current_req
after migration.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220305155530.9265-11-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 3f7cf30fa798e741f3b548fb6fc3ab5722aa6cd8..2d3c649567afdbad45d34c44e578ebf877ed44b6 100644 (file)
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -1349,6 +1349,15 @@ static uint64_t sysbus_esp_pdma_read(void *opaque, hwaddr addr,
     return val;
 }
 
+static void *esp_load_request(QEMUFile *f, SCSIRequest *req)
+{
+    ESPState *s = container_of(req->bus, ESPState, bus);
+
+    scsi_req_ref(req);
+    s->current_req = req;
+    return s;
+}
+
 static const MemoryRegionOps sysbus_esp_pdma_ops = {
     .read = sysbus_esp_pdma_read,
     .write = sysbus_esp_pdma_write,
@@ -1364,6 +1373,7 @@ static const struct SCSIBusInfo esp_scsi_info = {
     .max_target = ESP_MAX_DEVS,
     .max_lun = 7,
 
+    .load_request = esp_load_request,
     .transfer_data = esp_transfer_data,
     .complete = esp_command_complete,
     .cancel = esp_request_cancelled