[v2,05/12] hw/sd/sdcard: Do not store vendor data on block drive (CMD56)

Commit Message

Philippe Mathieu-Daudé June 25, 2024, 5:53 a.m. UTC

"General command" (GEN_CMD, CMD56) is described as:

  GEN_CMD is the same as the single block read or write
  commands (CMD24 or CMD17). The difference is that [...]
  the data block is not a memory payload data but has a
  vendor specific format and meaning.

Thus this block must not be stored overwriting data block
on underlying storage drive. Keep it in a dedicated
'vendor_data[]' array.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
Tested-by: Cédric Le Goater <[e-mail]>
---
RFC: Is it safe to reuse VMSTATE_UNUSED_V() (which happens
to be the same size)?

Cc: Peter Xu <[e-mail]>
Cc: Fabiano Rosas <[e-mail]>
---
 hw/sd/sd.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Patch

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index e4587a0a37..0f8440efcc 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -143,6 +143,8 @@  struct SDState {
     uint64_t data_start;
     uint32_t data_offset;
     uint8_t data[512];
+    uint8_t vendor_data[512];
+
     qemu_irq readonly_cb;
     qemu_irq inserted_cb;
     QEMUTimer *ocr_power_timer;
@@ -647,6 +649,7 @@  static void sd_reset(DeviceState *dev)
     sd->wp_switch = sd->blk ? !blk_is_writable(sd->blk) : false;
     sd->wp_group_bits = sect;
     sd->wp_group_bmap = bitmap_new(sd->wp_group_bits);
+    memset(sd->vendor_data, 0xec, sizeof(sd->vendor_data));
     memset(sd->function_group, 0, sizeof(sd->function_group));
     sd->erase_start = INVALID_ADDRESS;
     sd->erase_end = INVALID_ADDRESS;
@@ -762,7 +765,7 @@  static const VMStateDescription sd_vmstate = {
         VMSTATE_UINT64(data_start, SDState),
         VMSTATE_UINT32(data_offset, SDState),
         VMSTATE_UINT8_ARRAY(data, SDState, 512),
-        VMSTATE_UNUSED_V(1, 512),
+        VMSTATE_UINT8_ARRAY(vendor_data, SDState, 512),
         VMSTATE_BOOL(enable, SDState),
         VMSTATE_END_OF_LIST()
     },
@@ -2020,9 +2023,8 @@  void sd_write_byte(SDState *sd, uint8_t value)
         break;
 
     case 56:  /* CMD56:  GEN_CMD */
-        sd->data[sd->data_offset ++] = value;
-        if (sd->data_offset >= sd->blk_len) {
-            APP_WRITE_BLOCK(sd->data_start, sd->data_offset);
+        sd->vendor_data[sd->data_offset ++] = value;
+        if (sd->data_offset >= sizeof(sd->vendor_data)) {
             sd->state = sd_transfer_state;
         }
         break;
@@ -2156,12 +2158,11 @@  uint8_t sd_read_byte(SDState *sd)
         break;
 
     case 56:  /* CMD56:  GEN_CMD */
-        if (sd->data_offset == 0)
-            APP_READ_BLOCK(sd->data_start, sd->blk_len);
-        ret = sd->data[sd->data_offset ++];
+        ret = sd->vendor_data[sd->data_offset ++];
 
-        if (sd->data_offset >= sd->blk_len)
+        if (sd->data_offset >= sizeof(sd->vendor_data)) {
             sd->state = sd_transfer_state;
+        }
         break;
 
     default: