Re: [PATCH v15 27/37] KVM: arm64: CCA: Allow userspace to inject aborts

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 15/07/2026 15:28, Steven Price wrote:
> From: Joey Gouly <joey.gouly@arm.com>
> 
> Extend KVM_SET_VCPU_EVENTS to support realms, where KVM cannot set the
> system registers, and the RMM must perform it on next REC entry.
> 
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Signed-off-by: Steven Price <steven.price@arm.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> ---

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>


>   Documentation/virt/kvm/api.rst |  2 ++
>   arch/arm64/kvm/guest.c         | 24 ++++++++++++++++++++++++
>   2 files changed, 26 insertions(+)
> 
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index e39d146b34a3..85bec9b4f021 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -1314,6 +1314,8 @@ User space may need to inject several types of events to the guest.
>   Set the pending SError exception state for this VCPU. It is not possible to
>   'cancel' an Serror that has been made pending.
>   
> +User space cannot inject SErrors into Realms.
> +
>   If the guest performed an access to I/O memory which could not be handled by
>   userspace, for example because of missing instruction syndrome decode
>   information or because there is no device mapped at the accessed IPA, then
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 3e970c4f6214..5469c9a97fad 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -827,6 +827,30 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
>   	u64 esr = events->exception.serror_esr;
>   	int ret = 0;
>   
> +	if (vcpu_is_rec(vcpu)) {
> +		/* Cannot inject SError into a Realm. */
> +		if (serror_pending)
> +			return -EINVAL;
> +
> +		/*
> +		 * If a data abort is pending, set the flag and let the RMM
> +		 * inject an SEA when the REC is scheduled to be run.
> +		 */
> +		if (ext_dabt_pending) {
> +			/*
> +			 * Can only inject SEA into a Realm if the previous exit
> +			 * was due to a data abort of an Unprotected IPA.
> +			 */
> +			if (!(vcpu->arch.rec.run->enter.flags & REC_ENTER_FLAG_EMULATED_MMIO))
> +				return -EINVAL;
> +
> +			vcpu->arch.rec.run->enter.flags &= ~REC_ENTER_FLAG_EMULATED_MMIO;
> +			vcpu->arch.rec.run->enter.flags |= REC_ENTER_FLAG_INJECT_SEA;
> +		}
> +
> +		return 0;
> +	}
> +
>   	/*
>   	 * Immediately commit the pending SEA to the vCPU's architectural
>   	 * state which is necessary since we do not return a pending SEA