Re: [PATCH v2 17/27] KVM: arm64: Route SEAs to the SError vector when EASE is set

[Marc Zyngier <maz@kernel.org>]

On Tue, 17 Jun 2025 00:02:58 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> One of the finest additions of FEAT_DoubleFault2 is the ability for
> software to request *synchronous* external aborts be taken to the
> SError vector, which of coure are *asynchronous* in nature.
> 
> Opinions be damned, implement the architecture and send SEAs to the
> SError vector if EASE is set for the target context.

As they say, there is no accounting for taste! :)

> 
> Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
> ---
>  arch/arm64/kvm/emulate-nested.c |  3 +++
>  arch/arm64/kvm/hyp/exception.c  |  6 +++++-
>  arch/arm64/kvm/inject_fault.c   | 38 ++++++++++++++++++++++++++++++++-
>  3 files changed, 45 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
> index 86c9a48fc8b6..7f9081c6ab11 100644
> --- a/arch/arm64/kvm/emulate-nested.c
> +++ b/arch/arm64/kvm/emulate-nested.c
> @@ -2833,6 +2833,9 @@ int kvm_inject_nested_sea(struct kvm_vcpu *vcpu, bool iabt, u64 addr)
>  			     iabt ? ESR_ELx_EC_IABT_LOW : ESR_ELx_EC_DABT_LOW);
>  	esr |= ESR_ELx_FSC_EXTABT | ESR_ELx_IL;
>  
> +	if (__vcpu_sys_reg(vcpu, SCTLR2_EL2) & SCTLR2_EL1_EASE)
> +		return kvm_inject_nested(vcpu, esr, except_type_serror);

Are we allowed to not set FAR_EL2 here? My reading of R_RYXCL is that
only the exception vector changes, not what is reported.

But the spec is clear as mud, and I wonder if I'm reading too much
into it.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.