Re: [dpdk-dev] [RFC 2/2] nfp: allow for non-root user

[Alejandro Lucero <alejandro.lucero@netronome.com>]

On Fri, Apr 13, 2018 at 2:31 PM, Aaron Conole <aconole@redhat.com> wrote:

> Alejandro Lucero <alejandro.lucero@netronome.com> writes:
>
> > Again, this patch is correct, but because NFP PMD needs to access
> > /sys/bus/pci/devices/$DEVICE_PCI_STRING/resource$RESOURCE_ID, and these
> files have just
> > read/write accesses for root, I do not know if this is really necessary.
> >
> > Being honest, I have not used a DPDK app with NFP PMD and not being
> root. Does it work
> > with non-root users and other PMDs with same requirements regarding
> sysfs resource files?
>
> We do run as non-root user definitely with Intel PMDs.
>
> I'm not very sure about other vendors, but I think mlx pmd runs as
> non-root user (and it was modified to move off of sysfs for that
> reason[1]).
>
>
It is possible to not rely on sysfs resource files if device is attached to
VFIO, but I think that is a must with UIO.



> I'll continue to push for more information from the testing side to find
> out though.
>
> [1]: http://dpdk.org/ml/archives/dev/2018-February/090586.html
>
> > On Fri, Apr 13, 2018 at 12:22 AM, Aaron Conole <aconole@redhat.com>
> wrote:
> >
> >  Currently, the nfp lock files are taken from the global lock file
> >  location, which will work when the user is running as root.  However,
> >  some distributions and applications (notably ovs 2.8+ on RHEL/Fedora)
> >  run as a non-root user.
> >
> >  Signed-off-by: Aaron Conole <aconole@redhat.com>
> >  ---
> >   drivers/net/nfp/nfp_nfpu.c | 23 ++++++++++++++++++-----
> >   1 file changed, 18 insertions(+), 5 deletions(-)
> >
> >  diff --git a/drivers/net/nfp/nfp_nfpu.c b/drivers/net/nfp/nfp_nfpu.c
> >  index 2ed985ff4..ae2e07220 100644
> >  --- a/drivers/net/nfp/nfp_nfpu.c
> >  +++ b/drivers/net/nfp/nfp_nfpu.c
> >  @@ -18,6 +18,22 @@
> >   #define NFP_CFG_EXP_BAR         7
> >
> >   #define NFP_CFG_EXP_BAR_CFG_BASE       0x30000
> >  +#define NFP_LOCKFILE_PATH_FMT "%s/nfp%d"
> >  +
> >  +/* get nfp lock file path (/var/lock if root, $HOME otherwise) */
> >  +static void
> >  +nspu_get_lockfile_path(char *buffer, int bufsz, nfpu_desc_t *desc)
> >  +{
> >  +       const char *dir = "/var/lock";
> >  +       const char *home_dir = getenv("HOME");
> >  +
> >  +       if (getuid() != 0 && home_dir != NULL)
> >  +               dir = home_dir;
> >  +
> >  +       /* use current prefix as file path */
> >  +       snprintf(buffer, bufsz, NFP_LOCKFILE_PATH_FMT, dir,
> >  +                       desc->nfp);
> >  +}
> >
> >   /* There could be other NFP userspace tools using the NSP interface.
> >    * Make sure there is no other process using it and locking the access
> for
> >  @@ -30,9 +46,7 @@ nspv_aquire_process_lock(nfpu_desc_t *desc)
> >          struct flock lock;
> >          char lockname[30];
> >
> >  -       memset(&lock, 0, sizeof(lock));
> >  -
> >  -       snprintf(lockname, sizeof(lockname), "/var/lock/nfp%d",
> desc->nfp);
> >  +       nspu_get_lockfile_path(lockname, sizeof(lockname), desc);
> >
> >          /* Using S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH |
> S_IWOTH */
> >          desc->lock = open(lockname, O_RDWR | O_CREAT, 0666);
> >  @@ -106,7 +120,6 @@ nfpu_close(nfpu_desc_t *desc)
> >          rte_free(desc->nspu);
> >          close(desc->lock);
> >
> >  -       snprintf(lockname, sizeof(lockname), "/var/lock/nfp%d",
> desc->nfp);
> >  -       unlink(lockname);
> >  +       nspu_get_lockfile_path(lockname, sizeof(lockname), desc);
> >          return 0;
> >   }
> >  --
> >  2.14.3
>