On Sat, Jul 19, 2025 at 02:11:27AM +0000, Per Larsen via B4 Relay wrote:
> From: Per Larsen <perlarsen@google.com>
>
> The minimum size and alignment boundary for FFA_RXTX_MAP is returned in
> bit[1:0]. Mask off any other bits in w2 when reading the minimum buffer
> size in hyp_ffa_post_init.
>
> Signed-off-by: Per Larsen <perlarsen@google.com>
> ---
> arch/arm64/kvm/hyp/nvhe/ffa.c | 2 +-
> include/linux/arm_ffa.h | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
> index 5a173ea481940236356e2bc4248d094a858a0923..2cbecc9af5d27a9e7c8497001cf9b0987c72bdb4 100644
> --- a/arch/arm64/kvm/hyp/nvhe/ffa.c
> +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
> @@ -733,7 +733,7 @@ static int hyp_ffa_post_init(void)
> if (res.a0 != FFA_SUCCESS)
> return -EOPNOTSUPP;
>
> - switch (res.a2) {
> + switch (res.a2 & FFA_FEAT_RXTX_MIN_SZ_MASK) {
> case FFA_FEAT_RXTX_MIN_SZ_4K:
> min_rxtx_sz = SZ_4K;
> break;
> diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
> index e1634897e159cdc208931938649eb0fb04d5a070..cd7ee4df9045dceca1c4e0dca2d533b770b1b056 100644
> --- a/include/linux/arm_ffa.h
> +++ b/include/linux/arm_ffa.h
> @@ -128,6 +128,7 @@
> #define FFA_FEAT_RXTX_MIN_SZ_4K 0
> #define FFA_FEAT_RXTX_MIN_SZ_64K 1
> #define FFA_FEAT_RXTX_MIN_SZ_16K 2
> +#define FFA_FEAT_RXTX_MIN_SZ_MASK GENMASK(1, 0)
Acked-by: Will Deacon <will@kernel.org>
Will