Re: [PATCH] hw/block/nvme: slba equal to nsze is out of bounds if nlb is 1-based

[Klaus Jensen]

On Apr  9 20:05, Minwoo Im wrote:
> On 21-04-09 13:14:02, Gollu Appalanaidu wrote:
> > NSZE is the total size of the namespace in logical blocks. So the max
> > addressable logical block is NLB minus 1. So your starting logical
> > block is equal to NSZE it is a out of range.
> >
> > Signed-off-by: Gollu Appalanaidu <anaidu.gollu@samsung.com>
> > ---
> >  hw/block/nvme.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > index 953ec64729..be9edb1158 100644
> > --- a/hw/block/nvme.c
> > +++ b/hw/block/nvme.c
> > @@ -2527,7 +2527,7 @@ static uint16_t nvme_dsm(NvmeCtrl *n, NvmeRequest *req)
> >              uint64_t slba = le64_to_cpu(range[i].slba);
> >              uint32_t nlb = le32_to_cpu(range[i].nlb);
> >
> > -            if (nvme_check_bounds(ns, slba, nlb)) {
> > +            if (nvme_check_bounds(ns, slba, nlb) || slba == ns->id_ns.nsze) {
>
> This patch also looks like check the boundary about slba.  Should it be
> also checked inside of nvme_check_bounds() ?

The catch here is that DSM is like the only command where the number of 
logical blocks is a 1s-based value. Otherwise we always have nlb > 0, 
which means that nvme_check_bounds() will always "do the right thing".

My main gripe here is that (in my mind), by definition, a "zero length 
range" does not reference any LBAs at all. So how can it result in LBA 
Out of Range?

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