[PATCH v6 4/5] KVM: arm64: Bump the supported version of FF-A to 1.2
Marc Zyngier
maz at kernel.org
Mon Jun 30 01:41:09 PDT 2025
On Fri, 27 Jun 2025 08:12:28 +0100,
Per Larsen via B4 Relay <devnull+perlarsen.google.com at kernel.org> wrote:
>
> From: Per Larsen <perlarsen at google.com>
>
> FF-A version 1.2 introduces the DIRECT_REQ2 ABI. Bump the FF-A version
> preferred by the hypervisor as a precursor to implementing the 1.2-only
> FFA_MSG_SEND_DIRECT_REQ2 and FFA_MSG_SEND_RESP2 messaging interfaces.
>
> We must also use SMCCC 1.2 for 64-bit SMCs if hypervisor negotiated FF-A
> 1.2, so ffa_set_retval is updated and a new function to call 64-bit smcs
> using SMCCC 1.2 with fallback to SMCCC 1.1 is introduced.
>
> Update ffa_call_supported to mark FF-A 1.2 interfaces as unsupported
> lest they get forwarded.
>
> Co-developed-by: Ayrton Munoz <ayrton at google.com>
> Signed-off-by: Ayrton Munoz <ayrton at google.com>
> Signed-off-by: Per Larsen <perlarsen at google.com>
> ---
> arch/arm64/kvm/hyp/nvhe/ffa.c | 14 ++++++++++----
> include/linux/arm_ffa.h | 1 +
> 2 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
> index 5fd6474d96ae4b90d99796ee81bb36373219afc4..d543d1f5ddd62fb15f8d39f4ff7d5bb0006da4a1 100644
> --- a/arch/arm64/kvm/hyp/nvhe/ffa.c
> +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
> @@ -678,6 +678,12 @@ static bool ffa_call_supported(u64 func_id)
> case FFA_NOTIFICATION_SET:
> case FFA_NOTIFICATION_GET:
> case FFA_NOTIFICATION_INFO_GET:
> + /* Unimplemented interfaces added in FF-A 1.2 */
> + case FFA_MSG_SEND_DIRECT_REQ2:
> + case FFA_MSG_SEND_DIRECT_RESP2:
Are those actually optional?
> + case FFA_CONSOLE_LOG:
> + case FFA_PARTITION_INFO_GET_REGS:
> + case FFA_EL3_INTR_HANDLE:
> return false;
> }
>
> @@ -734,7 +740,7 @@ 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) {
You should also check that the MBZ fields are still 0. Ideally, you'd
also do that with x3.
> case FFA_FEAT_RXTX_MIN_SZ_4K:
> min_rxtx_sz = SZ_4K;
> break;
> @@ -931,7 +937,7 @@ int hyp_ffa_init(void *pages)
>
> arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {
> .a0 = FFA_VERSION,
> - .a1 = FFA_VERSION_1_1,
> + .a1 = FFA_VERSION_1_2,
> }, &res);
> if (res.a0 == FFA_RET_NOT_SUPPORTED)
> return 0;
> @@ -952,10 +958,10 @@ int hyp_ffa_init(void *pages)
> if (FFA_MAJOR_VERSION(res.a0) != 1)
> return -EOPNOTSUPP;
>
> - if (FFA_MINOR_VERSION(res.a0) < FFA_MINOR_VERSION(FFA_VERSION_1_1))
> + if (FFA_MINOR_VERSION(res.a0) < FFA_MINOR_VERSION(FFA_VERSION_1_2))
> hyp_ffa_version = res.a0;
> else
> - hyp_ffa_version = FFA_VERSION_1_1;
> + hyp_ffa_version = FFA_VERSION_1_2;
>
> tx = pages;
> pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE;
> diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
> index 5bded24dc24fea8cdcbe42bf79c7c025c3fa5f4b..c0dd6183d956043192114a522b7eef465e7078ac 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 3
nit: a mask is better expressed with GENMASK, making it obvious that
this is not just another value.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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