From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Sun, 24 Aug 2025 07:18:33 +0000 (+0200)
Subject: hw/sd/sdcard: Fix size check for backing block image
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a362b19a39e458256cc7e3acd0dc7825b0389b48;p=thirdparty%2Fqemu.git

hw/sd/sdcard: Fix size check for backing block image

Alignment rules apply the the individual partitions (user, boot, later
on also RPMB) and depend both on the size of the image and the type of
the device. Up to and including 2GB, the power-of-2 rule applies to the
user data area. For larger images, multiples of 512 sectors must be used
for eMMC and multiples of 512K for SD-cards. Fix the check accordingly
and also detect if the image is too small to even hold the boot
partitions.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-ID: <591f6d8a9dc86428723cb6876df6e717cc41a70e.1762261430.git.jan.kiszka@siemens.com>
Tested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index d7a496d77c9..76e915e1900 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -2759,9 +2759,32 @@ static void sd_instance_finalize(Object *obj)
     timer_free(sd->ocr_power_timer);
 }
 
+static void sd_blk_size_error(SDState *sd, int64_t blk_size,
+                              int64_t blk_size_aligned, const char *rule,
+                              Error **errp)
+{
+    const char *dev_type = sd_is_emmc(sd) ? "eMMC" : "SD card";
+    char *blk_size_str;
+
+    blk_size_str = size_to_str(blk_size);
+    error_setg(errp, "Invalid %s size: %s", dev_type, blk_size_str);
+    g_free(blk_size_str);
+
+    blk_size_str = size_to_str(blk_size_aligned);
+    error_append_hint(errp,
+                      "%s size has to be %s, e.g. %s.\n"
+                      "You can resize disk images with"
+                      " 'qemu-img resize <imagefile> <new-size>'\n"
+                      "(note that this will lose data if you make the"
+                      " image smaller than it currently is).\n",
+                      dev_type, rule, blk_size_str);
+    g_free(blk_size_str);
+}
+
 static void sd_realize(DeviceState *dev, Error **errp)
 {
     SDState *sd = SDMMC_COMMON(dev);
+    int64_t blk_size = -ENOMEDIUM;
     int ret;
 
     switch (sd->spec_version) {
@@ -2774,32 +2797,36 @@ static void sd_realize(DeviceState *dev, Error **errp)
     }
 
     if (sd->blk) {
-        int64_t blk_size;
-
         if (!blk_supports_write_perm(sd->blk)) {
             error_setg(errp, "Cannot use read-only drive as SD card");
             return;
         }
 
         blk_size = blk_getlength(sd->blk);
-        if (blk_size > 0 && !is_power_of_2(blk_size)) {
-            int64_t blk_size_aligned = pow2ceil(blk_size);
-            char *blk_size_str;
-
-            blk_size_str = size_to_str(blk_size);
-            error_setg(errp, "Invalid SD card size: %s", blk_size_str);
-            g_free(blk_size_str);
-
-            blk_size_str = size_to_str(blk_size_aligned);
-            error_append_hint(errp,
-                              "SD card size has to be a power of 2, e.g. %s.\n"
-                              "You can resize disk images with"
-                              " 'qemu-img resize <imagefile> <new-size>'\n"
-                              "(note that this will lose data if you make the"
-                              " image smaller than it currently is).\n",
-                              blk_size_str);
-            g_free(blk_size_str);
-
+    }
+    if (blk_size >= 0) {
+        blk_size -= sd->boot_part_size * 2;
+        if (blk_size > SDSC_MAX_CAPACITY) {
+            if (sd_is_emmc(sd) &&
+                !QEMU_IS_ALIGNED(blk_size, 1 << HWBLOCK_SHIFT)) {
+                int64_t blk_size_aligned =
+                    ((blk_size >> HWBLOCK_SHIFT) + 1) << HWBLOCK_SHIFT;
+                sd_blk_size_error(sd, blk_size, blk_size_aligned,
+                                  "multiples of 512", errp);
+                return;
+            } else if (!sd_is_emmc(sd) &&
+                !QEMU_IS_ALIGNED(blk_size, 512 * KiB)) {
+                int64_t blk_size_aligned = ((blk_size >> 19) + 1) << 19;
+                sd_blk_size_error(sd, blk_size, blk_size_aligned,
+                                  "multiples of 512K", errp);
+                return;
+            }
+        } else if (blk_size > 0 && !is_power_of_2(blk_size)) {
+            sd_blk_size_error(sd, blk_size, pow2ceil(blk_size), "a power of 2",
+                              errp);
+            return;
+        } else if (blk_size < 0) {
+            error_setg(errp, "eMMC image smaller than boot partitions");
             return;
         }
 
@@ -2810,7 +2837,7 @@ static void sd_realize(DeviceState *dev, Error **errp)
         }
         blk_set_dev_ops(sd->blk, &sd_block_ops, sd);
     }
-    if (sd->boot_part_size % (128 * KiB) ||
+    if (!QEMU_IS_ALIGNED(sd->boot_part_size, 128 * KiB) ||
         sd->boot_part_size > 255 * 128 * KiB) {
         g_autofree char *size_str = size_to_str(sd->boot_part_size);