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[PATCH v6 5/5] block: lift blocksize property limit to 2 MiB

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

This appears unnecessary 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@xxxxxxxxxxxxxx>
v4 -> v5:
- split out into separate patch [Philippe]
- as this patch has changed significantly lose Eric's r-b

 hw/core/qdev-properties.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index e7ccd4d276..ecd84262a9 100644
--- 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      stringify(MIN_BLOCK_SIZE)
-/* upper limit is the max power of 2 that fits in uint16_t */
-#define MAX_BLOCK_SIZE          32768
-#define MAX_BLOCK_SIZE_STR      stringify(MAX_BLOCK_SIZE)
+ * 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)



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