[PATCH v2 2/2] powerpc/pci: unmap all interrupts when a PHB is removed

[Cédric Le Goater]

On 8/7/20 8:01 AM, Alexey Kardashevskiy wrote:
> 
> 
> On 18/06/2020 02:29, Cédric Le Goater wrote:
>> Some PCI adapters, like GPUs, use the "interrupt-map" property to
>> describe interrupt mappings other than the legacy INTx interrupts.
>> There can be more than 4 mappings.
>>
>> To clear all interrupts when a PHB is removed, we need to increase the
>> 'irq_map' array in which mappings are recorded. Compute the number of
>> interrupt mappings from the "interrupt-map" property and allocate a
>> bigger 'irq_map' array.
>>
>> Signed-off-by: Cédric Le Goater <clg at kaod.org>
>> ---
>>  arch/powerpc/kernel/pci-common.c | 49 +++++++++++++++++++++++++++++++-
>>  1 file changed, 48 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
>> index 515480a4bac6..deb831f0ae13 100644
>> --- a/arch/powerpc/kernel/pci-common.c
>> +++ b/arch/powerpc/kernel/pci-common.c
>> @@ -353,9 +353,56 @@ struct pci_controller *pci_find_controller_for_domain(int domain_nr)
>>  	return NULL;
>>  }
>>  
>> +/*
>> + * Assumption is made on the interrupt parent. All interrupt-map
>> + * entries are considered to have the same parent.
>> + */
>> +static int pcibios_irq_map_count(struct pci_controller *phb)
> 
> I wonder if
> int of_irq_count(struct device_node *dev)
> could work here too. If it does not, then never mind.

I wished it would, but no.

> Other than that, the only other comment is - merge this one into 1/2 as
> 1/2 alone won't properly fix the problem but it may look like that it does:
> 
> for phyp, the test machine just happens to have 4 entries in the map but
> this is the phyp implementation detail;

yes
 
> for qemu, there are more but we only unregister 4 but kvm does not care
> in general so it is ok which is also implementation detail;
>
> and 2/2 just makes these details not matter. Thanks,

OK. It will ease backport. Sending a v2.

Thanks for the review Alexey !

C.
 
> 
> 
>> +{
>> +	const __be32 *imap;
>> +	int imaplen;
>> +	struct device_node *parent;
>> +	u32 intsize, addrsize, parintsize, paraddrsize;
>> +
>> +	if (of_property_read_u32(phb->dn, "#interrupt-cells", &intsize))
>> +		return 0;
>> +	if (of_property_read_u32(phb->dn, "#address-cells", &addrsize))
>> +		return 0;
>> +
>> +	imap = of_get_property(phb->dn, "interrupt-map", &imaplen);
>> +	if (!imap) {
>> +		pr_debug("%pOF : no interrupt-map\n", phb->dn);
>> +		return 0;
>> +	}
>> +	imaplen /= sizeof(u32);
>> +	pr_debug("%pOF : imaplen=%d\n", phb->dn, imaplen);
>> +
>> +	if (imaplen < (addrsize + intsize + 1))
>> +		return 0;
>> +
>> +	imap += intsize + addrsize;
>> +	parent = of_find_node_by_phandle(be32_to_cpup(imap));
>> +	if (!parent) {
>> +		pr_debug("%pOF : no imap parent found !\n", phb->dn);
>> +		return 0;
>> +	}
>> +
>> +	if (of_property_read_u32(parent, "#interrupt-cells", &parintsize)) {
>> +		pr_debug("%pOF : parent lacks #interrupt-cells!\n", phb->dn);
>> +		return 0;
>> +	}
>> +
>> +	if (of_property_read_u32(parent, "#address-cells", &paraddrsize))
>> +		paraddrsize = 0;
>> +
>> +	return imaplen / (addrsize + intsize + 1 + paraddrsize + parintsize);
>> +}
>> +
>>  static void pcibios_irq_map_init(struct pci_controller *phb)
>>  {
>> -	phb->irq_count = PCI_NUM_INTX;
>> +	phb->irq_count = pcibios_irq_map_count(phb);
>> +	if (phb->irq_count < PCI_NUM_INTX)
>> +		phb->irq_count = PCI_NUM_INTX;
>>  
>>  	pr_debug("%pOF : interrupt map #%d\n", phb->dn, phb->irq_count);
>>  
>>
>