block: lift blocksize property limit to 2 MiB

Logical and physical block sizes in QEMU are limited to 32 KiB.

This appears unnecessarily tight, and we've seen bigger block sizes
handy at times.

Lift the limitation up to 2 MiB which appears to be good enough for
everybody, and matches the qcow2 cluster size limit.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200528225516.1676602-9-rvkagan@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 63d48db70cafd9c49b91458b1d4097354ef8f559..ead35d7ffd191039596c9c7a132f3d030c1f754a 100644 (file)
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -784,9 +784,12 @@ const PropertyInfo qdev_prop_size32 = {
 /* lower limit is sector size */
 #define MIN_BLOCK_SIZE          512
 #define MIN_BLOCK_SIZE_STR      "512 B"
-/* upper limit is the max power of 2 that fits in uint16_t */
-#define MAX_BLOCK_SIZE          (32 * KiB)
-#define MAX_BLOCK_SIZE_STR      "32 KiB"
+/*
+ * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and
+ * matches qcow2 cluster size limit
+ */
+#define MAX_BLOCK_SIZE          (2 * MiB)
+#define MAX_BLOCK_SIZE_STR      "2 MiB"
 
 static void set_blocksize(Object *obj, Visitor *v, const char *name,
                           void *opaque, Error **errp)