Re: [PATCH 02/16] hw/block/nvme: add mapping helpers

[Klaus Jensen <its@irrelevant.dk>]

On Jul 29 13:40, Andrzej Jakowski wrote:
> On 7/20/20 4:37 AM, Klaus Jensen wrote:
> > From: Klaus Jensen <k.jensen@samsung.com>
> > 
> > Add nvme_map_addr, nvme_map_addr_cmb and nvme_addr_to_cmb helpers and
> > use them in nvme_map_prp.
> > 
> > This fixes a bug where in the case of a CMB transfer, the device would
> > map to the buffer with a wrong length.
> > 
> > Fixes: b2b2b67a00574 ("nvme: Add support for Read Data and Write Data in CMBs.")
> > Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> > ---
> >  hw/block/nvme.c       | 109 +++++++++++++++++++++++++++++++++++-------
> >  hw/block/trace-events |   2 +
> >  2 files changed, 94 insertions(+), 17 deletions(-)
> > 
> > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > index 4d7b730a62b6..9b1a080cdc70 100644
> > --- a/hw/block/nvme.c
> > +++ b/hw/block/nvme.c
> > @@ -270,20 +338,27 @@ static uint16_t nvme_map_prp(QEMUSGList *qsg, QEMUIOVector *iov, uint64_t prp1,
> >          } else {
> >              if (unlikely(prp2 & (n->page_size - 1))) {
> >                  trace_pci_nvme_err_invalid_prp2_align(prp2);
> > +                status = NVME_INVALID_FIELD | NVME_DNR;
> >                  goto unmap;
> >              }
> > -            if (qsg->nsg) {
> > -                qemu_sglist_add(qsg, prp2, len);
> > -            } else {
> > -                qemu_iovec_add(iov, (void *)&n->cmbuf[prp2 - n->ctrl_mem.addr], trans_len);
> > +            status = nvme_map_addr(n, qsg, iov, prp2, len);
> > +            if (status) {
> > +                goto unmap;
> >              }
> >          }
> >      }
> >      return NVME_SUCCESS;
> >  
> > - unmap:
> > -    qemu_sglist_destroy(qsg);
> > -    return NVME_INVALID_FIELD | NVME_DNR;
> > +unmap:
> > +    if (iov && iov->iov) {
> > +        qemu_iovec_destroy(iov);
> > +    }
> > +
> > +    if (qsg && qsg->sg) {
> > +        qemu_sglist_destroy(qsg);
> > +    }
> > +
> > +    return status;
> 
> I think it would make sense to move whole unmap block to a separate function.
> That function could be called from here and after completing IO and would contain
> unified deinitialization block - so no code repetitions would be necessary.
> Other than that it looks good to me. Thx!
> 
> Reviewed-by: Andrzej Jakowski <andrzej.jakowski@linux.intel.com>
> 
 
Hi Andrzej,

Thanks for the review :)

Yes, this is done in a later patch ("hw/block/nvme: consolidate qsg/iov
clearing"), but kept here to reduce churn.