On Mar 25 12:39, Maxim Levitsky wrote: > On Mon, 2020-03-16 at 07:28 -0700, Klaus Jensen wrote: > > From: Klaus Jensen <k.jen...@samsung.com> > > > > The num_queues device paramater has a slightly confusing meaning because > > it accounts for the admin queue pair which is not really optional. > > Secondly, it is really a maximum value of queues allowed. > > > > Add a new max_ioqpairs parameter that only accounts for I/O queue pairs, > > but keep num_queues for compatibility. > > > > Signed-off-by: Klaus Jensen <k.jen...@samsung.com> > > --- > > hw/block/nvme.c | 45 ++++++++++++++++++++++++++------------------- > > hw/block/nvme.h | 4 +++- > > 2 files changed, 29 insertions(+), 20 deletions(-) > > > > diff --git a/hw/block/nvme.c b/hw/block/nvme.c > > index 7cf7cf55143e..7dfd8a1a392d 100644 > > --- a/hw/block/nvme.c > > +++ b/hw/block/nvme.c > > @@ -1332,9 +1333,15 @@ static void nvme_realize(PCIDevice *pci_dev, Error > > **errp) > > int64_t bs_size; > > uint8_t *pci_conf; > > > > - if (!n->params.num_queues) { > > - error_setg(errp, "num_queues can't be zero"); > > - return; > > + if (n->params.num_queues) { > > + warn_report("nvme: num_queues is deprecated; please use > > max_ioqpairs " > > + "instead"); > > + > > + n->params.max_ioqpairs = n->params.num_queues - 1; > > + } > > + > > + if (!n->params.max_ioqpairs) { > > + error_setg(errp, "max_ioqpairs can't be less than 1"); > > } > This is not even a nitpick, but just and idea. > > It might be worth it to allow max_ioqpairs=0 to simulate a 'broken' > nvme controller. I know that kernel has special handling for such controllers, > which include only creation of the control character device (/dev/nvme*) > through > which the user can submit commands to try and 'fix' the controller (by > re-uploading firmware > maybe or something like that). > >
Not sure about the implications of this, so I'll leave that on the TODO :) But a controller with no I/O queues is an "Administrative Controller" and perfectly legal in NVMe v1.4 AFAIK. > > > > if (!n->conf.blk) { > > @@ -1365,19 +1372,19 @@ static void nvme_realize(PCIDevice *pci_dev, Error > > **errp) > > pcie_endpoint_cap_init(pci_dev, 0x80); > > > > n->num_namespaces = 1; > > - n->reg_size = pow2ceil(0x1004 + 2 * (n->params.num_queues + 1) * 4); > > + n->reg_size = pow2ceil(0x1008 + 2 * (n->params.max_ioqpairs) * 4); > > I hate to say it, but it looks like this thing (which I mentioned to you in > V5) > was pre-existing bug, which is indeed fixed now. > In theory such fixes should go to separate patches, but in this case, I guess > it would > be too much to ask for it. > Maybe mention this in the commit message instead, so that this fix doesn't > stay hidden like that? > > I'm convinced now. I have added a preparatory bugfix patch before this patch. > > Reviewed-by: Maxim Levitsky <mlevi...@redhat.com> > > Best regards, > Maxim Levitsky >