Re: [XEN PATCH 6/6] xen/arm: ffa: support FFA_FEATURES

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Jens,

> On 25 Mar 2024, at 10:39, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> 
> Add support for the mandatory FF-A ABI function FFA_FEATURES.
> 
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>

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

Cheers
Bertrand

> ---
> xen/arch/arm/tee/ffa.c | 57 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 57 insertions(+)
> 
> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> index 4f7775b8c890..8665201e34a9 100644
> --- a/xen/arch/arm/tee/ffa.c
> +++ b/xen/arch/arm/tee/ffa.c
> @@ -192,6 +192,60 @@ out:
>                  resp.a7 & mask);
> }
> 
> +static void handle_features(struct cpu_user_regs *regs)
> +{
> +    uint32_t a1 = get_user_reg(regs, 1);
> +    unsigned int n;
> +
> +    for ( n = 2; n <= 7; n++ )
> +    {
> +        if ( get_user_reg(regs, n) )
> +        {
> +            ffa_set_regs_error(regs, FFA_RET_NOT_SUPPORTED);
> +            return;
> +        }
> +    }
> +
> +    switch ( a1 )
> +    {
> +    case FFA_ERROR:
> +    case FFA_VERSION:
> +    case FFA_SUCCESS_32:
> +    case FFA_SUCCESS_64:
> +    case FFA_FEATURES:
> +    case FFA_ID_GET:
> +    case FFA_RX_RELEASE:
> +    case FFA_RXTX_UNMAP:
> +    case FFA_MEM_RECLAIM:
> +    case FFA_PARTITION_INFO_GET:
> +    case FFA_MSG_SEND_DIRECT_REQ_32:
> +    case FFA_MSG_SEND_DIRECT_REQ_64:
> +        ffa_set_regs_success(regs, 0, 0);
> +        break;
> +    case FFA_MEM_SHARE_64:
> +    case FFA_MEM_SHARE_32:
> +        /*
> +         * We currently don't support dynamically allocated buffers. Report
> +         * that with 0 in bit[0] of w2.
> +         */
> +        ffa_set_regs_success(regs, 0, 0);
> +        break;
> +    case FFA_RXTX_MAP_64:
> +    case FFA_RXTX_MAP_32:
> +        /*
> +         * We currently support 4k pages only, report that as 00 in
> +         * bit[0:1] in w0. This needs to be revised if Xen page size
> +         * differs from FFA_PAGE_SIZE (SZ_4K).
> +         */
> +        BUILD_BUG_ON(PAGE_SIZE != FFA_PAGE_SIZE);
> +        ffa_set_regs_success(regs, 0, 0);
> +        break;
> +    default:
> +        ffa_set_regs_error(regs, FFA_RET_NOT_SUPPORTED);
> +        break;
> +    }
> +}
> +
> static bool ffa_handle_call(struct cpu_user_regs *regs)
> {
>     uint32_t fid = get_user_reg(regs, 0);
> @@ -212,6 +266,9 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
>     case FFA_ID_GET:
>         ffa_set_regs_success(regs, ffa_get_vm_id(d), 0);
>         return true;
> +    case FFA_FEATURES:
> +        handle_features(regs);
> +        return true;
>     case FFA_RXTX_MAP_32:
>     case FFA_RXTX_MAP_64:
>         e = ffa_handle_rxtx_map(fid, get_user_reg(regs, 1),
> -- 
> 2.34.1
>