rework DMA callbacks (#396)

This fixes a number of issues with how DMA is handled, based on some changes by
Thanos Makatos:

- rename callbacks to register/unregister, as there is not necessarily
any mapping
- provide the (large) page-aligned mapped start and size, the page size used,
as well as the protection flags: some API users need these
- for convenience, provide the virtual address separately that corresponds to
the mapped region
- we should only require a DMA controller to use vfu_addr_to_sg(),
not an unregister callback
- the callbacks should return errno not -errno
- region removal was incorrectly updating the region array
- various other cleanups and clarifications

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

1 files changed, 5 insertions, 7 deletions

diff --git a/test/mocks.h b/test/mocks.h
index 4ffe047..496cc54 100644
--- a/test/mocks.h
+++ b/test/mocks.h
@@ -28,16 +28,14 @@
  *
  */
 
-#include <stdbool.h>
-#include <sys/socket.h>
-
 #include "private.h"
 
-void patch(const char *func);
-
 void unpatch_all(void);
 
-int
-mock_unmap_dma(vfu_ctx_t *vfu_ctx, uint64_t iova, uint64_t len);
+void patch(const char *name);
+
+void mock_dma_register(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info);
+
+int mock_dma_unregister(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info);
 
 /* ex: set tabstop=4 shiftwidth=4 softtabstop=4 expandtab: */