[PATCH-for-7.2] Revert "hw/block/pflash_cfi: Error out if dev length isn't power of 2"

[Philippe Mathieu-Daudé]

Commit 334c388f25 ("pflash_cfi: Error out if device length
isn't a power of two") aimed to finish the effort started by
commit 06f1521795 ("pflash: Require backend size to match device,
improve errors"), but unfortunately we are not quite there since
various machines are still ready to accept incomplete / oversized
pflash backend images, and now fail, i.e. on Debian bullseye:

 $ qemu-system-x86_64 \
   -drive \
   if=pflash,format=raw,unit=0,readonly=on,file=/usr/share/OVMF/OVMF_CODE.fd
 qemu-system-x86_64: Device size must be a power of two.

where OVMF_CODE.fd comes from the ovmf package, which doesn't
pad the firmware images to the flash size:

 $ ls -lh /usr/share/OVMF/
 -rw-r--r-- 1 root root 3.5M Aug 19  2021 OVMF_CODE_4M.fd
 -rw-r--r-- 1 root root 1.9M Aug 19  2021 OVMF_CODE.fd
 -rw-r--r-- 1 root root 128K Aug 19  2021 OVMF_VARS.fd

Since we entered the freeze period to prepare the v7.2.0 release,
the safest is to revert commit 334c388f25707a234c4a0dea05b9df08d.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1294
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
Cc: Sunil V L <sunilvl@ventanamicro.com>
Cc: Daniel Henrique Barboza <danielhb413@gmail.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Bernhard Beschow <shentey@gmail.com>
---
 hw/block/pflash_cfi01.c | 8 ++------
 hw/block/pflash_cfi02.c | 5 -----
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 9c235bf66e..0cbc2fb4cb 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -690,7 +690,7 @@ static const MemoryRegionOps pflash_cfi01_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static void pflash_cfi01_fill_cfi_table(PFlashCFI01 *pfl, Error **errp)
+static void pflash_cfi01_fill_cfi_table(PFlashCFI01 *pfl)
 {
     uint64_t blocks_per_device, sector_len_per_device, device_len;
     int num_devices;
@@ -708,10 +708,6 @@ static void pflash_cfi01_fill_cfi_table(PFlashCFI01 *pfl, 
Error **errp)
         sector_len_per_device = pfl->sector_len / num_devices;
     }
     device_len = sector_len_per_device * blocks_per_device;
-    if (!is_power_of_2(device_len)) {
-        error_setg(errp, "Device size must be a power of two.");
-        return;
-    }
 
     /* Hardcoded CFI table */
     /* Standard "QRY" string */
@@ -869,7 +865,7 @@ static void pflash_cfi01_realize(DeviceState *dev, Error 
**errp)
      */
     pfl->cmd = 0x00;
     pfl->status = 0x80; /* WSM ready */
-    pflash_cfi01_fill_cfi_table(pfl, errp);
+    pflash_cfi01_fill_cfi_table(pfl);
 }
 
 static void pflash_cfi01_system_reset(DeviceState *dev)
diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
index ff2fe154c1..2a99b286b0 100644
--- a/hw/block/pflash_cfi02.c
+++ b/hw/block/pflash_cfi02.c
@@ -880,11 +880,6 @@ static void pflash_cfi02_realize(DeviceState *dev, Error 
**errp)
         return;
     }
 
-    if (!is_power_of_2(pfl->chip_len)) {
-        error_setg(errp, "Device size must be a power of two.");
-        return;
-    }
-
     memory_region_init_rom_device(&pfl->orig_mem, OBJECT(pfl),
                                   &pflash_cfi02_ops, pfl, pfl->name,
                                   pfl->chip_len, errp);
-- 
2.38.1