Re: [PATCH v16 21/45] KVM: arm64: CCA: Handle realm enter/exit

[Steven Price]

On 04/08/2026 14:36, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@xxxxxxx> writes:
>> +
>> +	switch (rec->run->exit.exit_reason) {
>> +	case RMI_EXIT_SYNC:
>> +		/*
>> +		 * HPFAR_EL2_NS is hijacked to indicate a valid HPFAR value,
>> +		 * see __get_fault_info()
>> +		 */
>> +		vcpu->arch.fault.hpfar_el2 = rec->run->exit.hpfar | HPFAR_EL2_NS;
>> +		rec_exit_sync(vcpu);
>> +		return ARM_EXCEPTION_TRAP;
>> +	case RMI_EXIT_IRQ:
>> +	case RMI_EXIT_FIQ:
>> +		return ARM_EXCEPTION_IRQ;
>> +	case RMI_EXIT_SERROR:
>> +		return ARM_EXCEPTION_EL1_SERROR;
>> +	case RMI_EXIT_PSCI:
>> +		rec_exit_hvc(vcpu);
>> +		kvm_make_request(KVM_REQ_RMI, vcpu);
>>
> 
> I'm also wondering whether we can move the kvm_make_request() call until
> after the PSCI/HOST_CALL handling is complete. I tried a quick hack, but
> it did not look particularly clean, since we would end up adding
> RMM-specific checks in handle_hvc():
> 
> ret = kvm_smccc_call_handler(vcpu);
> 
> if (vcpu_is_rec(vcpu) &&
>     (vcpu->arch.rec.run->exit.exit_reason == RMI_EXIT_PSCI ||
>      vcpu->arch.rec.run->exit.exit_reason == RMI_EXIT_HOST_CALL))
> 	kvm_make_request(KVM_REQ_RMI, vcpu);
> 
> That said, having rec_exit_hvc(vcpu) and kvm_make_request() back-to-back
> is also somewhat confusing. Perhaps we could at least add a comment
> explaining why the request must always be made here.

Agreed, a comment would make it clearer what's going on. I'll add that.
As you say I'm not convinced trying to delay the kvm_make_request() call
is the answer because it ends up with an ugly RMM-specific check.

Thanks,
Steve

> 
>> +		return ARM_EXCEPTION_TRAP;
>> +	case RMI_EXIT_RIPAS_CHANGE:
>> +		rec_exit_hvc(vcpu);
>> +		return ARM_EXCEPTION_TRAP;
>> +	}
>> +
>> +	return rec_exit_fatal(vcpu, "Unsupported Realm exit reason",
>> +			      rec->run->exit.exit_reason);
>> +}
> 
> -aneesh