loader: support for unmapped ROM blobs

Support ROM blobs not mapped into guest memory:
same as ROM files really but use caller's buffer.

Support invoking callback on access and
return memory pointer making it easier
for caller to update memory if necessary.

Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 21 insertions, 4 deletions

diff --git a/hw/core/loader.c b/hw/core/loader.c
index 7b3d3ee6a0..449bd4c90a 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -700,10 +700,12 @@ err:
     return -1;
 }
 
-int rom_add_blob(const char *name, const void *blob, size_t len,
-                 hwaddr addr)
+void *rom_add_blob(const char *name, const void *blob, size_t len,
+                   hwaddr addr, const char *fw_file_name,
+                   FWCfgReadCallback fw_callback, void *callback_opaque)
 {
     Rom *rom;
+    void *data = NULL;
 
     rom           = g_malloc0(sizeof(*rom));
     rom->name     = g_strdup(name);
@@ -713,7 +715,22 @@ int rom_add_blob(const char *name, const void *blob, size_t len,
     rom->data     = g_malloc0(rom->datasize);
     memcpy(rom->data, blob, len);
     rom_insert(rom);
-    return 0;
+    if (fw_file_name && fw_cfg) {
+        char devpath[100];
+
+        snprintf(devpath, sizeof(devpath), "/rom@%s", fw_file_name);
+
+        if (rom_file_in_ram) {
+            data = rom_set_mr(rom, OBJECT(fw_cfg), devpath);
+        } else {
+            data = rom->data;
+        }
+
+        fw_cfg_add_file_callback(fw_cfg, fw_file_name,
+                                 fw_callback, callback_opaque,
+                                 data, rom->romsize);
+    }
+    return data;
 }
 
 /* This function is specific for elf program because we don't need to allocate
diff --git a/hw/lm32/lm32_hwsetup.h b/hw/lm32/lm32_hwsetup.h
index 3449bd8dfc..9fd5e697a7 100644
--- a/hw/lm32/lm32_hwsetup.h
+++ b/hw/lm32/lm32_hwsetup.h
@@ -73,7 +73,7 @@ static inline void hwsetup_free(HWSetup *hw)
 static inline void hwsetup_create_rom(HWSetup *hw,
         hwaddr base)
 {
-    rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, base);
+    rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, base, NULL, NULL, NULL);
 }
 
 static inline void hwsetup_add_u8(HWSetup *hw, uint8_t u)