Re: [PATCH 3/3] s390x/pci: drive ISM reset from subsystem reset

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 1/16/24 10:01 PM, Eric Farman wrote:
> On Tue, 2024-01-16 at 17:31 -0500, Matthew Rosato wrote:

>>  
>> +void s390_pci_ism_reset(void)
>> +{
>> +    S390pciState *s = s390_get_phb();
>> +
>> +    S390PCIBusDevice *pbdev, *next;
>> +
>> +    /* Trigger reset event for each passthrough ISM device currently
>> in-use */
>> +    QTAILQ_FOREACH_SAFE(pbdev, &s->zpci_devs, link, next) {
>> +        if (pbdev->interp && pbdev->pft == ZPCI_PFT_ISM &&
>> +            pbdev->fh & FH_MASK_ENABLE) {
>> +            s390_pci_kvm_aif_disable(pbdev);
>> +
>> +            pci_device_reset(pbdev->pdev);
> 
> Do we care about the loss of a reset for ISM devices in a
> !interpretation case? (I seem to think such a configuration is not
> possible today, and so we don't care, but could use a reminder.)
> 

ISM passthrough is currently only allowed when interpretation is enabled.  So the check is redundant today but allows us to re-evaluate the need if we ever add support for ISM without interpretation.