Re: [XEN PATCH] xen/arm: ffa: return fpi size from FFA_PARTITION_INFO_GET

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Jens,

> On 13 Dec 2023, at 11:31, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> 
> Until now has FFA_PARTITION_INFO_GET always returned zero in w3, but
> FF-A v1.1 requires FFA_PARTITION_INFO_GET to return the size of each
> partition information descriptor returned if
> FFA_PARTITION_INFO_GET_COUNT_FLAG isn't set.
> 

Good finding.

> The SPMC queried with FFA_PARTITION_INFO_GET must also return the each
> partition information descriptor returned so fix this by passing along
> the same value.
> 
> Fixes: caf6491e95a9 ("xen/arm: ffa: support guest FFA_PARTITION_INFO_GET")
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>

Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

Cheers
Bertrand

> ---
> xen/arch/arm/tee/ffa.c | 21 +++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> index 183528d13388..1d4e0a083006 100644
> --- a/xen/arch/arm/tee/ffa.c
> +++ b/xen/arch/arm/tee/ffa.c
> @@ -514,7 +514,7 @@ static int32_t ffa_rxtx_map(paddr_t tx_addr, paddr_t 
> rx_addr,
> 
> static int32_t ffa_partition_info_get(uint32_t w1, uint32_t w2, uint32_t w3,
>                                       uint32_t w4, uint32_t w5,
> -                                      uint32_t *count)
> +                                      uint32_t *count, uint32_t *fpi_size)
> {
>     const struct arm_smccc_1_2_regs arg = {
>         .a0 = FFA_PARTITION_INFO_GET,
> @@ -531,7 +531,10 @@ static int32_t ffa_partition_info_get(uint32_t w1, 
> uint32_t w2, uint32_t w3,
> 
>     ret = get_ffa_ret_code(&resp);
>     if ( !ret )
> +    {
>         *count = resp.a2;
> +        *fpi_size = resp.a3;
> +    }
> 
>     return ret;
> }
> @@ -784,7 +787,7 @@ static uint32_t handle_rxtx_unmap(void)
> 
> static int32_t handle_partition_info_get(uint32_t w1, uint32_t w2, uint32_t 
> w3,
>                                          uint32_t w4, uint32_t w5,
> -                                         uint32_t *count)
> +                                         uint32_t *count, uint32_t *fpi_size)
> {
>     int32_t ret = FFA_RET_DENIED;
>     struct domain *d = current->domain;
> @@ -799,7 +802,7 @@ static int32_t handle_partition_info_get(uint32_t w1, 
> uint32_t w2, uint32_t w3,
>      */
>     if ( w5 == FFA_PARTITION_INFO_GET_COUNT_FLAG &&
>          ctx->guest_vers == FFA_VERSION_1_1 )
> -        return ffa_partition_info_get(w1, w2, w3, w4, w5, count);
> +        return ffa_partition_info_get(w1, w2, w3, w4, w5, count, fpi_size);
>     if ( w5 )
>         return FFA_RET_INVALID_PARAMETERS;
> 
> @@ -812,7 +815,7 @@ static int32_t handle_partition_info_get(uint32_t w1, 
> uint32_t w2, uint32_t w3,
>     if ( !ctx->page_count || !ctx->rx_is_free )
>         goto out;
>     spin_lock(&ffa_rx_buffer_lock);
> -    ret = ffa_partition_info_get(w1, w2, w3, w4, w5, count);
> +    ret = ffa_partition_info_get(w1, w2, w3, w4, w5, count, fpi_size);
>     if ( ret )
>         goto out_rx_buf_unlock;
>     /*
> @@ -842,7 +845,7 @@ static int32_t handle_partition_info_get(uint32_t w1, 
> uint32_t w2, uint32_t w3,
>     }
>     else
>     {
> -        size_t sz = *count * sizeof(struct ffa_partition_info_1_1);
> +        size_t sz = *count * *fpi_size;
> 
>         if ( ctx->page_count * FFA_PAGE_SIZE < sz )
>         {
> @@ -1409,6 +1412,7 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
>     uint32_t fid = get_user_reg(regs, 0);
>     struct domain *d = current->domain;
>     struct ffa_ctx *ctx = d->arch.tee;
> +    uint32_t fpi_size;
>     uint32_t count;
>     int e;
> 
> @@ -1444,11 +1448,11 @@ static bool ffa_handle_call(struct cpu_user_regs 
> *regs)
>                                       get_user_reg(regs, 2),
>                                       get_user_reg(regs, 3),
>                                       get_user_reg(regs, 4),
> -                                      get_user_reg(regs, 5), &count);
> +                                      get_user_reg(regs, 5), &count, 
> &fpi_size);
>         if ( e )
>             set_regs_error(regs, e);
>         else
> -            set_regs_success(regs, count, 0);
> +            set_regs_success(regs, count, fpi_size);
>         return true;
>     case FFA_RX_RELEASE:
>         e = handle_rx_release();
> @@ -1629,10 +1633,11 @@ static bool init_subscribers(struct 
> ffa_partition_info_1_1 *fpi, uint16_t count)
> static bool init_sps(void)
> {
>     bool ret = false;
> +    uint32_t fpi_size;
>     uint32_t count;
>     int e;
> 
> -    e = ffa_partition_info_get(0, 0, 0, 0, 0, &count);
> +    e = ffa_partition_info_get(0, 0, 0, 0, 0, &count, &fpi_size);
>     if ( e )
>     {
>         printk(XENLOG_ERR "ffa: Failed to get list of SPs: %d\n", e);
> -- 
> 2.34.1
>