Re: [dpdk-dev] [PATCH] net/mlx5: fix UAR memory mapping type

[Raslan Darawsheh <rasland@mellanox.com>]

Hi,

> -----Original Message-----
> From: Ori Kam <orika@mellanox.com>
> Sent: Thursday, July 23, 2020 2:58 PM
> To: Slava Ovsiienko <viacheslavo@mellanox.com>; dev@dpdk.org
> Cc: Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> <rasland@mellanox.com>; Thomas Monjalon <thomas@monjalon.net>;
> Dekel Peled <dekelp@mellanox.com>
> Subject: RE: [dpdk-dev] [PATCH] net/mlx5: fix UAR memory mapping type
> 
> 
> 
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Viacheslav Ovsiienko
> >
> > The User Access Region is a special mechanism to provide direct
> > access to the hardware registers, and is the part of PCI address
> > space that is mapped to CPU virtual address. The mapping can be
> > performed with the type "Write-Combining" or "Non-Cached", and
> > these ones might be supported or not on different setups.
> >
> > To prevent device probing failure the UAR allocation attempt
> > with alternative mapping type is performed. The datapath
> > takes the actual UAR mapping into account on queue creation.
> >
> > There was another issue with NULL UAR base address.
> > OFED 5.0.x and Upstream rdma_core before v29 returned the NULL as
> > UAR base address if UAR was not the first object in the UAR page.
> > It caused the PMD failure and we should try to get another UAR
> > till we get the first one with non-NULL base address returned.
> >
> > Fixes: fc4d4f732bbc ("net/mlx5: introduce shared UAR resource")
> >
> > Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> > ---
> > --
> > 1.8.3.1
> 
> Acked-by: Ori Kam <orika@mellanox.com>
> Thanks,
> Ori


Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh