linux-kernel - Re: [PATCH 7/9] firmware: arm_ffa: Add v1.1 get_partition

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Message-ID: <20220901085756.ymk3rd7zjqvjpaj6@bogus>
Date:   Thu, 1 Sep 2022 09:57:56 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Jens Wiklander <jens.wiklander@...aro.org>
Cc:     linux-kernel@...r.kernel.org, op-tee@...ts.trustedfirmware.org,
        Marc Bonnici <marc.bonnici@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Achin Gupta <achin.gupta@....com>,
        Valentin Laurent <valentin.laurent@...stonic.com>,
        Lukas Hanel <lukas.hanel@...stonic.com>,
        Coboy Chen <coboy.chen@...iatek.com>
Subject: Re: [PATCH 7/9] firmware: arm_ffa: Add v1.1 get_partition_info
 support

On Thu, Sep 01, 2022 at 10:43:58AM +0200, Jens Wiklander wrote:
> On Tue, Aug 30, 2022 at 12:07 PM Sudeep Holla <sudeep.holla@....com> wrote:
> >
> > FF-A v1.1 adds support to discovery the UUIDs of the partitions that was
> > missing in v1.0 and which the driver workarounds by using UUIDs supplied
> > by the ffa_drivers.
> >
> > Add the v1.1 get_partition_info support and disable the workaround if
> > the detected FF-A version is greater than v1.0.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> > ---
> >  drivers/firmware/arm_ffa/driver.c | 39 ++++++++++++++++++++++++-------
> >  include/linux/arm_ffa.h           |  1 +
> >  2 files changed, 32 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> > index 5c8484b05c50..6822241168d6 100644
> > --- a/drivers/firmware/arm_ffa/driver.c
> > +++ b/drivers/firmware/arm_ffa/driver.c
> > @@ -264,18 +264,24 @@ static int ffa_rxtx_unmap(u16 vm_id)
> >         return 0;
> >  }
> >
> > +#define PARTITION_INFO_GET_RETURN_COUNT_ONLY   BIT(0)
> > +
> >  /* buffer must be sizeof(struct ffa_partition_info) * num_partitions */
> >  static int
> >  __ffa_partition_info_get(u32 uuid0, u32 uuid1, u32 uuid2, u32 uuid3,
> >                          struct ffa_partition_info *buffer, int num_partitions)
> >  {
> > -       int count;
> > +       int idx, count, flags = 0, size;
> >         ffa_value_t partition_info;
> >
> > +       if (!buffer || !num_partitions) /* Just get the count for now */
> > +               flags = PARTITION_INFO_GET_RETURN_COUNT_ONLY;
> > +
> >         mutex_lock(&drv_info->rx_lock);
> >         invoke_ffa_fn((ffa_value_t){
> >                       .a0 = FFA_PARTITION_INFO_GET,
> >                       .a1 = uuid0, .a2 = uuid1, .a3 = uuid2, .a4 = uuid3,
> > +                     .a5 = flags,
> >                       }, &partition_info);
> >
> >         if (partition_info.a0 == FFA_ERROR) {
> > @@ -285,8 +291,15 @@ __ffa_partition_info_get(u32 uuid0, u32 uuid1, u32 uuid2, u32 uuid3,
> >
> >         count = partition_info.a2;
> >
> > +       if (drv_info->version > FFA_VERSION_1_0)
> > +               size = partition_info.a3;
> 
> What happens if this value is larger than sizeof(struct ffa_partition_info)?
> 

Right, I had the check for both 0 size and size > struct size. I removed
both at once instead of just dropping 0 size. I assume 0 size is non
compliant or do you prefer to keep that check as well.

Thanks a lot for the reviews.

-- 
Regards,
Sudeep