From: Alejandro Lucero <alejandro.lucero@netronome.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"jerin.jacob@caviumnetworks.com"
<jerin.jacob@caviumnetworks.com>,
"thomas@monjalon.net" <thomas@monjalon.net>
Subject: Re: [dpdk-dev] [PATCH] vfio: use right index when tracking devices in a vfio group
Date: Tue, 9 May 2017 22:16:46 +0100 [thread overview]
Message-ID: <CAD+H993Fm1O5NhJb2FGrJpN0DfFYF2Q1T1TVa9JUmLzrvOt12Q@mail.gmail.com> (raw)
In-Reply-To: <C6ECDF3AB251BE4894318F4E45123697822137FE@IRSMSX109.ger.corp.intel.com>
Hi Anatoly,
On Tue, May 9, 2017 at 4:18 PM, Burakov, Anatoly <anatoly.burakov@intel.com>
wrote:
> Hi Alejandro,
>
> > From: Alejandro Lucero [mailto:alejandro.lucero@netronome.com]
> > Sent: Monday, May 8, 2017 6:44 PM
> > To: dev@dpdk.org
> > Cc: Burakov, Anatoly <anatoly.burakov@intel.com>;
> > jerin.jacob@caviumnetworks.com; thomas@monjalon.net
> > Subject: [PATCH] vfio: use right index when tracking devices in a vfio
> group
> >
> > Previous fix for properly handling devices from the same VFIO group
> > introduced another bug where the file descriptor of a kernel vfio group
> is
> > used as the index for tracking number of devices of a vfio group struct
> > handled by dpdk vfio code. Instead of the file descriptor itself, the
> vfio group
> > object that file descriptor is registered with has to be used.
> >
> > This patch introduces specific functions for incrementing or decrementing
> > the device counter for a specific vfio group using the vfio file
> descriptor as a
> > parameter. Note the code is not optimized as the vfio group is found
> > sequentially going through the vfio group array but this should not be a
> > problem as this is not related to packet handling at all.
> >
> > Fixes: a9c349e3a100 ("vfio: fix device unplug when several devices per
> > group")
> >
> > Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
> > ---
> > lib/librte_eal/linuxapp/eal/eal_vfio.c | 60
> > +++++++++++++++++++++++++++-------
> > 1 file changed, 49 insertions(+), 11 deletions(-)
> >
> > diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c
> > b/lib/librte_eal/linuxapp/eal/eal_vfio.c
> > index d3eae20..21d126f 100644
> > --- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
> > +++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
> > @@ -172,6 +172,44 @@
> > return -1;
> > }
> >
> > +
> > +static int
> > +get_vfio_group_idx(int vfio_group_fd)
> > +{
> > + int i;
> > + for (i = 0; i < VFIO_MAX_GROUPS; i++)
> > + if (vfio_cfg.vfio_groups[i].fd == vfio_group_fd)
> > + return i;
> > + return -1;
> > +}
> > +
> > +static void
> > +vfio_group_device_get(int vfio_group_fd) {
> > + int i;
> > +
> > + i = get_vfio_group_idx(vfio_group_fd);
> > + vfio_cfg.vfio_groups[i].devices++;
>
> Maybe add a check for I < 0?
>
>
Right. I doubted about adding such a check, since being < 0 or >
VFIO_MAX_GROUPS are bad news. But better to avoid using a wrong index which
could led to a random write elsewhere. I will send another patch version
with that check and a RTE_LOG(ERR ... call.
And same for the other functions.
Thanks
> > +}
> > +
> > +static void
> > +vfio_group_device_put(int vfio_group_fd) {
> > + int i;
> > +
> > + i = get_vfio_group_idx(vfio_group_fd);
> > + vfio_cfg.vfio_groups[i].devices--;
>
> Same here.
>
> > +}
> > +
> > +static int
> > +vfio_group_device_count(int vfio_group_fd) {
> > + int i;
> > +
> > + i = get_vfio_group_idx(vfio_group_fd);
> > + return vfio_cfg.vfio_groups[i].devices; }
>
> And here.
>
> > +
> > int
> > clear_group(int vfio_group_fd)
> > {
> > @@ -180,15 +218,14 @@
> >
> > if (internal_config.process_type == RTE_PROC_PRIMARY) {
> >
> > - for (i = 0; i < VFIO_MAX_GROUPS; i++)
> > - if (vfio_cfg.vfio_groups[i].fd == vfio_group_fd) {
> > - vfio_cfg.vfio_groups[i].group_no = -1;
> > - vfio_cfg.vfio_groups[i].fd = -1;
> > - vfio_cfg.vfio_groups[i].devices = 0;
> > - vfio_cfg.vfio_active_groups--;
> > - return 0;
> > - }
> > - return -1;
> > + i = get_vfio_group_idx(vfio_group_fd);
> > + if ( i < 0)
> > + return -1;
> > + vfio_cfg.vfio_groups[i].group_no = -1;
> > + vfio_cfg.vfio_groups[i].fd = -1;
> > + vfio_cfg.vfio_groups[i].devices = 0;
> > + vfio_cfg.vfio_active_groups--;
> > + return 0;
> > }
> >
> > /* This is just for SECONDARY processes */ @@ -358,7 +395,7 @@
> > clear_group(vfio_group_fd);
> > return -1;
> > }
> > - vfio_cfg.vfio_groups[vfio_group_fd].devices++;
> > + vfio_group_device_get(vfio_group_fd);
> >
> > return 0;
> > }
> > @@ -406,7 +443,8 @@
> > /* An VFIO group can have several devices attached. Just when there
> > is
> > * no devices remaining should the group be closed.
> > */
> > - if (--vfio_cfg.vfio_groups[vfio_group_fd].devices == 0) {
> > + vfio_group_device_put(vfio_group_fd);
> > + if (!vfio_group_device_count(vfio_group_fd)) {
> >
> > if (close(vfio_group_fd) < 0) {
> > RTE_LOG(INFO, EAL, "Error when closing
> > vfio_group_fd for %s\n",
> > --
> > 1.9.1
>
>
prev parent reply other threads:[~2017-05-09 21:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-08 17:44 Alejandro Lucero
2017-05-09 4:04 ` Jerin Jacob
2017-05-09 15:18 ` Burakov, Anatoly
2017-05-09 21:16 ` Alejandro Lucero [this message]
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