re-work access handling (#220)

Various cleanups and fixes to handling of region accesses, including:

- there should be no reason for us to split accesses into 1/2/4/8 byte accesses:
in general, the client will have already be doing that, and if not, there's no
particular reason we should be the ones to split up such larger accesses.

- use a callback for PCI config space reads and writes if one is provided (needs
more work for capabilities)

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

1 files changed, 10 insertions, 9 deletions

diff --git a/lib/migration.c b/lib/migration.c
index 29c667b..91fd09f 100644
--- a/lib/migration.c
+++ b/lib/migration.c
@@ -36,6 +36,7 @@
 
 #include "common.h"
 #include "migration.h"
+#include "private.h"
 
 enum migr_iter_state {
     VFIO_USER_MIGR_ITER_STATE_INITIAL,
@@ -380,10 +381,10 @@ handle_data_size(vfu_ctx_t *vfu_ctx, struct migration *migr,
 }
 
 static ssize_t
-handle_region_access_registers(vfu_ctx_t *vfu_ctx, struct migration *migr,
-                               char *buf, size_t count,
-                               loff_t pos, bool is_write)
+migration_region_access_registers(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
+                                  loff_t pos, bool is_write)
 {
+    struct migration *migr = vfu_ctx->migration;
     int ret;
 
     assert(migr != NULL);
@@ -430,18 +431,18 @@ handle_region_access_registers(vfu_ctx_t *vfu_ctx, struct migration *migr,
 }
 
 ssize_t
-handle_migration_region_access(vfu_ctx_t *vfu_ctx, struct migration *migr,
-                               char *buf, size_t count,
-                               loff_t pos, bool is_write)
+migration_region_access(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
+                        loff_t pos, bool is_write)
 {
-    int ret = -EINVAL;
+    struct migration *migr = vfu_ctx->migration;
+    ssize_t ret = -EINVAL;
 
     assert(migr != NULL);
     assert(buf != NULL);
 
     if (pos + count <= sizeof(struct vfio_device_migration_info)) {
-        ret = handle_region_access_registers(vfu_ctx, migr, buf,
-                                             count, pos, is_write);
+        ret = migration_region_access_registers(vfu_ctx, buf, count,
+                                                pos, is_write);
     } else {
         pos -= sizeof(struct vfio_device_migration_info);
         if (is_write) {