Re: [PATCH v2 1/4] KVM: arm64: Trap FFA_VERSION host call in pKVM

Sudeep Holla
2024-06-12T13:58:57Z

On Wed, May 15, 2024 at 05:22:55PM +0000, Sebastian Ene wrote:
> The pKVM hypervisor initializes with FF-A version 1.0. The spec requires
> that no other FF-A calls to be issued before the version negotiation
> phase is complete. Split the hypervisor proxy initialization code in two
> parts so that we can move the later one after the host negotiates its
> version.

Blank line here would be nice.

> Without trapping the call, the host drivers can negotiate a higher
> version number with TEE which can result in a different memory layout
> described during the memory sharing calls.
>

LGTM(apart from minor nits),

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

> Signed-off-by: Sebastian Ene <sebastianene@google.com>
> ---
> arch/arm64/kvm/hyp/nvhe/ffa.c | 123 +++++++++++++++++++++++++---------
> 1 file changed, 92 insertions(+), 31 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
> index 320f2eaa14a9..72f1206c85fb 100644
> --- a/arch/arm64/kvm/hyp/nvhe/ffa.c
> +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
> @@ -1,4 +1,5 @@
> // SPDX-License-Identifier: GPL-2.0-only
> +//

It should be OK but still spurious for $subject 😉

[...]

> @@ -700,7 +789,6 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
> int hyp_ffa_init(void *pages)
> {
> struct arm_smccc_res res;
> - size_t min_rxtx_sz;
> void *tx, *rx;
>
> if (kvm_host_psci_config.smccc_version < ARM_SMCCC_VERSION_1_2)
> @@ -726,35 +814,7 @@ int hyp_ffa_init(void *pages)
> if (FFA_MAJOR_VERSION(res.a0) != 1)
> return -EOPNOTSUPP;
>
> - arm_smccc_1_1_smc(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0, &res);
> - if (res.a0 != FFA_SUCCESS)
> - return -EOPNOTSUPP;
> -
> - if (res.a2 != HOST_FFA_ID)
> - return -EINVAL;
> -
> - arm_smccc_1_1_smc(FFA_FEATURES, FFA_FN64_RXTX_MAP,
> - 0, 0, 0, 0, 0, 0, &res);
> - if (res.a0 != FFA_SUCCESS)
> - return -EOPNOTSUPP;
> -
> - switch (res.a2) {
> - case FFA_FEAT_RXTX_MIN_SZ_4K:
> - min_rxtx_sz = SZ_4K;
> - break;
> - case FFA_FEAT_RXTX_MIN_SZ_16K:
> - min_rxtx_sz = SZ_16K;
> - break;
> - case FFA_FEAT_RXTX_MIN_SZ_64K:
> - min_rxtx_sz = SZ_64K;
> - break;
> - default:
> - return -EINVAL;
> - }
> -
> - if (min_rxtx_sz > PAGE_SIZE)
> - return -EOPNOTSUPP;
> -
> + hyp_ffa_version = FFA_VERSION_1_0;
> tx = pages;
> pages += KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE;
> rx = pages;
> @@ -773,8 +833,9 @@ int hyp_ffa_init(void *pages)
> };
>
> host_buffers = (struct kvm_ffa_buffers) {
> - .lock = __HYP_SPIN_LOCK_UNLOCKED,
> + .lock = __HYP_SPIN_LOCK_UNLOCKED,

Spurious or intentional whitespace change ? I can't make out from the mail.

--
Regards,
Sudeep