Re: [PATCH] hw/nvme: Add support for setting the MQES for the NVMe emulation

[Klaus Jensen]

On Apr  4 13:04, John Berg wrote:
> From: John Berg <jhnberg@amazon.com>
> 
> 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).
> 
> Signed-off-by: John Berg <jhnberg@amazon.co.uk>
> ---
>  hw/nvme/ctrl.c | 9 ++++++++-
>  hw/nvme/nvme.h | 1 +
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
> index 127c3d2383..86cda9bc73 100644
> --- a/hw/nvme/ctrl.c
> +++ b/hw/nvme/ctrl.c
> @@ -7805,6 +7805,12 @@ static bool nvme_check_params(NvmeCtrl *n, Error 
> **errp)
>          return false;
>      }
>  
> +    if (params->mqes < 1)
> +    {

Please keep the `{` on the same line as the `if`. I think checkpatch.pl
should catch this.

No need to send a v2, I'll fix it up when I apply it to nvme-next :)

Thanks!

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