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

[Klaus Jensen]

On May  1 12:27, Berg, John wrote:
> On Thu, 2024-04-04 at 15:01 +0200, Klaus Jensen wrote:
> > 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!
> 
> 
> Hello
> 
> Sorry for chasing. I was just wondering when this patch will be
> applied. I can send a second revision if that helps.
> 

No need for the sorry. My apologies. It feel off my radar, so thanks for
the bump.

I've queued this on nvme-next, will send a pull for master ASAP.

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