FFA_RXTX_MAP is currently limited to mapping only one 4k page for each
RX and TX buffer. If a guest tries to map more than one page, an error
is returned. Until this patch, we have been using FFA_RET_NOT_SUPPORTED.
However, that error code is reserved in the FF-A specification to report
that the function is not implemented. Of all the other defined error
codes, the least bad is FFA_RET_INVALID_PARAMETERS, so use that instead.

Fixes: 38d81e7ccb11 ("xen/arm: ffa: support mapping guest RX/TX buffers")
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
 xen/arch/arm/tee/ffa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
index 802b2dbb1d36..183528d13388 100644
--- a/xen/arch/arm/tee/ffa.c
+++ b/xen/arch/arm/tee/ffa.c
@@ -706,7 +706,7 @@ static uint32_t handle_rxtx_map(uint32_t fid, register_t tx_addr,
     {
         printk(XENLOG_ERR "ffa: RXTX_MAP: error: %u pages requested (limit %u)\n",
                page_count, FFA_MAX_RXTX_PAGE_COUNT);
-        return FFA_RET_NOT_SUPPORTED;
+        return FFA_RET_INVALID_PARAMETERS;
     }
 
     /* Already mapped */
-- 
2.34.1

Hi Jens,

> On 4 Sep 2023, at 16:58, Jens Wiklander <jens.wiklander@linaro.org> wrote:
> 
> FFA_RXTX_MAP is currently limited to mapping only one 4k page for each
> RX and TX buffer. If a guest tries to map more than one page, an error
> is returned. Until this patch, we have been using FFA_RET_NOT_SUPPORTED.
> However, that error code is reserved in the FF-A specification to report
> that the function is not implemented. Of all the other defined error
> codes, the least bad is FFA_RET_INVALID_PARAMETERS, so use that instead.

Agree and thanks for the fix.

> 
> Fixes: 38d81e7ccb11 ("xen/arm: ffa: support mapping guest RX/TX buffers")
> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

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

Cheers
Bertrand

> ---
> xen/arch/arm/tee/ffa.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> index 802b2dbb1d36..183528d13388 100644
> --- a/xen/arch/arm/tee/ffa.c
> +++ b/xen/arch/arm/tee/ffa.c
> @@ -706,7 +706,7 @@ static uint32_t handle_rxtx_map(uint32_t fid, register_t tx_addr,
>     {
>         printk(XENLOG_ERR "ffa: RXTX_MAP: error: %u pages requested (limit %u)\n",
>                page_count, FFA_MAX_RXTX_PAGE_COUNT);
> -        return FFA_RET_NOT_SUPPORTED;
> +        return FFA_RET_INVALID_PARAMETERS;
>     }
> 
>     /* Already mapped */
> -- 
> 2.34.1
>