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+mistranslation: 0.952
+graphic: 0.945
+peripherals: 0.926
+register: 0.888
+KVM: 0.884
+virtual: 0.871
+device: 0.846
+kernel: 0.835
+performance: 0.833
+files: 0.811
+architecture: 0.785
+semantic: 0.750
+user-level: 0.742
+hypervisor: 0.717
+debug: 0.640
+permissions: 0.635
+network: 0.570
+VMM: 0.562
+PID: 0.548
+risc-v: 0.520
+socket: 0.509
+vnc: 0.446
+x86: 0.446
+assembly: 0.397
+boot: 0.393
+ppc: 0.386
+i386: 0.340
+arm: 0.274
+TCG: 0.230
+
+min_io_size is currently limited to size uint16_t
+
+I am using LVM VGs on MD-raid1 for hosting my KVM volumes. On the host, a VG looks like this:
+
+Disk /dev/vm/vol202a: 60 GiB, 64424509440 bytes, 125829120 sectors
+Units: sectors of 1 * 512 = 512 bytes
+Sector size (logical/physical): 512 bytes / 4096 bytes
+I/O size (minimum/optimal): 131072 bytes / 131072 bytes
+
+In order to replicate the block device characteristics in the guest, I am using the following extra parameters:
+
+-set device.scsi0-0-0-0.logical_block_size=512
+-set device.scsi0-0-0-0.physical_block_size=4096
+-set device.scsi0-0-0-0.min_io_size=131072
+
+This doesn't work as qemu complains that min_io_size needs to be of type uint16_t.
+
+The value is set to uint16_t by mistake. The value is passed to Qemu in bytes, but then it is divided by the sector size and passed to the vm in sectors through a 16 bit register field. The vm kernel then multiplies it again by sector size and shows (through /sys/block/x/queue) the value in bytes. Because of this, the input value from the qemu side should be uint32_t.
+
+A simple patch is attached, correcting the problem. I think some extra logic should be added after dividing by the page size, to prevent overflowing the 16 bit register.
+
+With that patch, I can pass a 4MB min and optimal io sizes successfully, to match the stripe size used by RBD/Ceph. Sadly though, I see no improvement coming out of it, but I'll document that in a separate bug report.
+
+root@cephvm:~# lsblk -t
+NAME     ALIGNMENT  MIN-IO  OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE   RA WSAME
+sda              0 4194304 4194304     512     512    1 noop      128 4096    2G
+
+The QEMU project is currently considering to move its bug tracking to
+another system. For this we need to know which bugs are still valid
+and which could be closed already. Thus we are setting older bugs to
+"Incomplete" now.
+
+If you still think this bug report here is valid, then please switch
+the state back to "New" within the next 60 days, otherwise this report
+will be marked as "Expired". Or please mark it as "Fix Released" if
+the problem has been solved with a newer version of QEMU already.
+
+Thank you and sorry for the inconvenience.
+
+[Expired for QEMU because there has been no activity for 60 days.]
+