On Thu, Apr 04, 2024 at 01:04:18PM +0100, John Berg wrote: > The MQES field in the CAP register describes the Maximum Queue Entries > Supported for the IO queues of an NVMe controller. Adding a +1 to the > value in this field results in the total queue size. A full queue is > when a queue of size N contains N - 1 entries, and the minimum queue > size is 2. Thus the lowest MQES value is 1. > > This patch adds the new mqes property to the NVMe emulation which allows > a user to specify the maximum queue size by setting this property. This > is useful as it enables testing of NVMe controller where the MQES is > relatively small. The smallest NVMe queue size supported in NVMe is 2 > submission and completion entries, which means that the smallest legal > mqes value is 1. > > The following example shows how the mqes can be set for a the NVMe > emulation: > > -drive id=nvme0,if=none,file=nvme.img,format=raw > -device nvme,drive=nvme0,serial=foo,mqes=1 > > If the mqes property is not provided then the default mqes will still be > 0x7ff (the queue size is 2048 entries).
Looks good. I had to double check where nvme_create_sq() was getting its limit from when processing the host command, and sure enough it's directly from the register field. Reviewed-by: Keith Busch <kbu...@kernel.org>
