[Qemu-devel] [PATCH 1/6] Make fw_cfg interface 32-bit aware

[Alexander Graf]

The fw_cfg interface can only handle up to 16 bits of data for its streams.
While that isn't too much of a problem when handling integers, we would
like to stream full kernel images over that interface!

So let's extend it to 32 bit length variables.

Signed-off-by: Alexander Graf <ag...@suse.de>

---

v1 -> v2:

  - add savevm compat code (untested!)
---
 hw/fw_cfg.c |   30 ++++++++++++++++++++++++------
 hw/fw_cfg.h |    2 +-
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/hw/fw_cfg.c b/hw/fw_cfg.c
index a6d811b..0cd6f68 100644
--- a/hw/fw_cfg.c
+++ b/hw/fw_cfg.c
@@ -39,7 +39,7 @@
 #define FW_CFG_SIZE 2
 
 typedef struct _FWCfgEntry {
-    uint16_t len;
+    uint32_t len;
     uint8_t *data;
     void *callback_opaque;
     FWCfgCallback callback;
@@ -48,7 +48,7 @@ typedef struct _FWCfgEntry {
 typedef struct _FWCfgState {
     FWCfgEntry entries[2][FW_CFG_MAX_ENTRY];
     uint16_t cur_entry;
-    uint16_t cur_offset;
+    uint32_t cur_offset;
 } FWCfgState;
 
 static void fw_cfg_write(FWCfgState *s, uint8_t value)
@@ -164,19 +164,37 @@ static void fw_cfg_reset(void *opaque)
     fw_cfg_select(s, 0);
 }
 
+static int fw_cfg_load_old(QEMUFile *f, void *opaque, int version_id)
+{
+    FWCfgState *s = opaque;
+    uint16_t cur_offset;
+
+    if (version_id != 1)
+        return -EINVAL;
+
+    qemu_get_be16s(f, &s->cur_entry);
+
+    /* Convert old 16 bit value to new 32 bit width */
+    qemu_get_be16s(f, &cur_offset);
+    s->cur_offset = cur_offset;
+
+    return 0;
+}
+
 static const VMStateDescription vmstate_fw_cfg = {
     .name = "fw_cfg",
-    .version_id = 1,
-    .minimum_version_id = 1,
+    .version_id = 2,
+    .minimum_version_id = 2,
     .minimum_version_id_old = 1,
+    .load_state_old = fw_cfg_load_old,
     .fields      = (VMStateField []) {
         VMSTATE_UINT16(cur_entry, FWCfgState),
-        VMSTATE_UINT16(cur_offset, FWCfgState),
+        VMSTATE_UINT32(cur_offset, FWCfgState),
         VMSTATE_END_OF_LIST()
     }
 };
 
-int fw_cfg_add_bytes(void *opaque, uint16_t key, uint8_t *data, uint16_t len)
+int fw_cfg_add_bytes(void *opaque, uint16_t key, uint8_t *data, uint32_t len)
 {
     FWCfgState *s = opaque;
     int arch = !!(key & FW_CFG_ARCH_LOCAL);
diff --git a/hw/fw_cfg.h b/hw/fw_cfg.h
index 30dfec7..359d45a 100644
--- a/hw/fw_cfg.h
+++ b/hw/fw_cfg.h
@@ -28,7 +28,7 @@
 #ifndef NO_QEMU_PROTOS
 typedef void (*FWCfgCallback)(void *opaque, uint8_t *data);
 
-int fw_cfg_add_bytes(void *opaque, uint16_t key, uint8_t *data, uint16_t len);
+int fw_cfg_add_bytes(void *opaque, uint16_t key, uint8_t *data, uint32_t len);
 int fw_cfg_add_i16(void *opaque, uint16_t key, uint16_t value);
 int fw_cfg_add_i32(void *opaque, uint16_t key, uint32_t value);
 int fw_cfg_add_i64(void *opaque, uint16_t key, uint64_t value);
-- 
1.6.0.2