don't expose -errno in public API (#327)

Regardless of what we do internally, most of our API uses standard mechanisms
for reporting errors. Fix vfu_run_ctx() to do so properly as well, and fix a
couple of other references for user-provided callbacks.

This will require a small fix to SPDK.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/migration.c b/lib/migration.c
index 0e1b2a6..ec07961 100644
--- a/lib/migration.c
+++ b/lib/migration.c
@@ -528,6 +528,9 @@ migration_region_access(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
         pos -= migr->data_offset;
         if (is_write) {
             ret = migr->callbacks.write_data(vfu_ctx, buf, count, pos);
+            if (ret == -1) {
+                ret = -errno;
+            }
         } else {
             /*
              * FIXME <linux/vfio.h> says:
@@ -538,6 +541,9 @@ migration_region_access(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
              * Does this mean that partial reads are not allowed?
              */
             ret = migr->callbacks.read_data(vfu_ctx, buf, count, pos);
+            if (ret == -1) {
+                ret = -errno;
+            }
         }
     }