diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index ea49f33fac..e1e2babcf5 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -31,15 +31,15 @@
  * The pos argument can be ignored if the file is only being used for
  * streaming.  The handler should try to write all of the data it can.
  */
-typedef int (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf,
-                                    int64_t pos, int size);
+typedef ssize_t (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf,
+                                        int64_t pos, size_t size);
 
 /* Read a chunk of data from a file at the given position.  The pos argument
  * can be ignored if the file is only be used for streaming.  The number of
  * bytes actually read should be returned.
  */
-typedef int (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
-                                    int64_t pos, int size);
+typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
+                                        int64_t pos, size_t size);
 
 /* Close a file
  *
diff --git a/migration/qemu-file-buf.c b/migration/qemu-file-buf.c
index 2de9330ca5..1d9528e674 100644
--- a/migration/qemu-file-buf.c
+++ b/migration/qemu-file-buf.c
@@ -372,7 +372,8 @@ typedef struct QEMUBuffer {
     bool qsb_allocated;
 } QEMUBuffer;
 
-static int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+static ssize_t buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                              size_t size)
 {
     QEMUBuffer *s = opaque;
     ssize_t len = qsb_get_length(s->qsb) - pos;
@@ -387,8 +388,8 @@ static int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
     return qsb_get_buffer(s->qsb, pos, len, buf);
 }
 
-static int buf_put_buffer(void *opaque, const uint8_t *buf,
-                          int64_t pos, int size)
+static ssize_t buf_put_buffer(void *opaque, const uint8_t *buf,
+                              int64_t pos, size_t size)
 {
     QEMUBuffer *s = opaque;
 
diff --git a/migration/qemu-file-stdio.c b/migration/qemu-file-stdio.c
index 285068b303..dc91137b9c 100644
--- a/migration/qemu-file-stdio.c
+++ b/migration/qemu-file-stdio.c
@@ -37,11 +37,11 @@ static int stdio_get_fd(void *opaque)
     return fileno(s->stdio_file);
 }
 
-static int stdio_put_buffer(void *opaque, const uint8_t *buf, int64_t pos,
-                            int size)
+static ssize_t stdio_put_buffer(void *opaque, const uint8_t *buf, int64_t pos,
+                                size_t size)
 {
     QEMUFileStdio *s = opaque;
-    int res;
+    size_t res;
 
     res = fwrite(buf, 1, size, s->stdio_file);
 
@@ -51,11 +51,12 @@ static int stdio_put_buffer(void *opaque, const uint8_t *buf, int64_t pos,
     return res;
 }
 
-static int stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+static ssize_t stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                                size_t size)
 {
     QEMUFileStdio *s = opaque;
     FILE *fp = s->stdio_file;
-    int bytes;
+    ssize_t bytes;
 
     for (;;) {
         clearerr(fp);
diff --git a/migration/qemu-file-unix.c b/migration/qemu-file-unix.c
index bfbc0861ab..adfe91add1 100644
--- a/migration/qemu-file-unix.c
+++ b/migration/qemu-file-unix.c
@@ -54,7 +54,8 @@ static int socket_get_fd(void *opaque)
     return s->fd;
 }
 
-static int socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+static ssize_t socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                                 size_t size)
 {
     QEMUFileSocket *s = opaque;
     ssize_t len;
@@ -138,7 +139,8 @@ static ssize_t unix_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
     return total;
 }
 
-static int unix_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+static ssize_t unix_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                              size_t size)
 {
     QEMUFileSocket *s = opaque;
     ssize_t len;
diff --git a/migration/rdma.c b/migration/rdma.c
index 9424834501..be7fd922b8 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -2519,8 +2519,8 @@ static void *qemu_rdma_data_init(const char *host_port, Error **errp)
  * SEND messages for control only.
  * VM's ram is handled with regular RDMA messages.
  */
-static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
-                                int64_t pos, int size)
+static ssize_t qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
+                                    int64_t pos, size_t size)
 {
     QEMUFileRDMA *r = opaque;
     QEMUFile *f = r->file;
@@ -2547,7 +2547,8 @@ static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
         r->len = MIN(remaining, RDMA_SEND_INCREMENT);
         remaining -= r->len;
 
-        head.len = r->len;
+        /* Guaranteed to fit due to RDMA_SEND_INCREMENT MIN above */
+        head.len = (uint32_t)r->len;
         head.type = RDMA_CONTROL_QEMU_FILE;
 
         ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL, NULL);
@@ -2564,7 +2565,7 @@ static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
 }
 
 static size_t qemu_rdma_fill(RDMAContext *rdma, uint8_t *buf,
-                             int size, int idx)
+                             size_t size, int idx)
 {
     size_t len = 0;
 
@@ -2585,8 +2586,8 @@ static size_t qemu_rdma_fill(RDMAContext *rdma, uint8_t *buf,
  * RDMA links don't use bytestreams, so we have to
  * return bytes to QEMUFile opportunistically.
  */
-static int qemu_rdma_get_buffer(void *opaque, uint8_t *buf,
-                                int64_t pos, int size)
+static ssize_t qemu_rdma_get_buffer(void *opaque, uint8_t *buf,
+                                    int64_t pos, size_t size)
 {
     QEMUFileRDMA *r = opaque;
     RDMAContext *rdma = r->rdma;
diff --git a/migration/savevm.c b/migration/savevm.c
index 33e55fea09..96b8210cc3 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -138,14 +138,15 @@ static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
     return qiov.size;
 }
 
-static int block_put_buffer(void *opaque, const uint8_t *buf,
-                           int64_t pos, int size)
+static ssize_t block_put_buffer(void *opaque, const uint8_t *buf,
+                                int64_t pos, size_t size)
 {
     bdrv_save_vmstate(opaque, buf, pos, size);
     return size;
 }
 
-static int block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                                size_t size)
 {
     return bdrv_load_vmstate(opaque, buf, pos, size);
 }
diff --git a/trace-events b/trace-events
index 59266e9135..36db793b47 100644
--- a/trace-events
+++ b/trace-events
@@ -1442,7 +1442,7 @@ qemu_rdma_exchange_get_response_none(const char *desc, int type) "Surprise: got
 qemu_rdma_exchange_send_issue_callback(void) ""
 qemu_rdma_exchange_send_waiting(const char *desc) "Waiting for response %s"
 qemu_rdma_exchange_send_received(const char *desc) "Response %s received."
-qemu_rdma_fill(int64_t control_len, int size) "RDMA %" PRId64 " of %d bytes already in buffer"
+qemu_rdma_fill(size_t control_len, size_t size) "RDMA %zd of %zd bytes already in buffer"
 qemu_rdma_init_ram_blocks(int blocks) "Allocated %d local ram block structures"
 qemu_rdma_poll_recv(const char *compstr, int64_t comp, int64_t id, int sent) "completion %s #%" PRId64 " received (%" PRId64 ") left %d"
 qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t block, uint64_t chunk, void *local, void *remote) "completions %s (%" PRId64 ") left %d, block %" PRIu64 ", chunk: %" PRIu64 " %p %p"