scsi: add scatter/gather functionality

Scatter/gather functionality uses the newly added DMA helpers.  The
device can choose between doing DMA itself, or calling scsi_req_data
as usual, which will use the newly added DMA helpers to copy piecewise
to/from the destination area(s).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/hw/scsi.h b/hw/scsi.h
index 8722ef9..34cdba8 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -49,6 +49,8 @@ struct SCSIRequest {
     size_t            resid;
     SCSICommand       cmd;
     BlockDriverAIOCB  *aiocb;
+    QEMUSGList        *sg;
+    bool              dma_started;
     uint8_t sense[SCSI_SENSE_BUF_SIZE];
     uint32_t sense_len;
     bool enqueued;
@@ -115,6 +117,7 @@ struct SCSIBusInfo {
     void (*transfer_data)(SCSIRequest *req, uint32_t arg);
     void (*complete)(SCSIRequest *req, uint32_t arg, size_t resid);
     void (*cancel)(SCSIRequest *req);
+    QEMUSGList *(*get_sg_list)(SCSIRequest *req);
 };
 
 struct SCSIBus {