hw/core: properly terminate loading .hex on EOF record

The https://makecode.microbit.org/#editor generates slightly weird
.hex files which work fine on a real microbit but causes QEMU to
choke. The reason is extraneous data after the EOF record which causes
the loader to attempt to write a bigger file than it should to the
"rom". According to the HEX file spec an EOF really should be the last
thing we process so lets do that.

Reported-by: Ursula Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200403191150.863-12-alex.bennee@linaro.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/hw/core/loader.c b/hw/core/loader.c
index eeef6da9a1..8bbb1797a4 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -1447,6 +1447,7 @@ typedef struct {
     uint32_t current_rom_index;
     uint32_t rom_start_address;
     AddressSpace *as;
+    bool complete;
 } HexParser;
 
 /* return size or -1 if error */
@@ -1484,6 +1485,7 @@ static int handle_record_type(HexParser *parser)
                                   parser->current_rom_index,
                                   parser->rom_start_address, parser->as);
         }
+        parser->complete = true;
         return parser->total_size;
     case EXT_SEG_ADDR_RECORD:
     case EXT_LINEAR_ADDR_RECORD:
@@ -1548,11 +1550,12 @@ static int parse_hex_blob(const char *filename, hwaddr *addr, uint8_t *hex_blob,
         .bin_buf = g_malloc(hex_blob_size),
         .start_addr = addr,
         .as = as,
+        .complete = false
     };
 
     rom_transaction_begin();
 
-    for (; hex_blob < end; ++hex_blob) {
+    for (; hex_blob < end && !parser.complete; ++hex_blob) {
         switch (*hex_blob) {
         case '\r':
         case '\n':