On 7/9/2025 4:40 PM, Wei Liu wrote:
> CC Nuno who is also touching on this file.
> 
> Nam, thanks for this patch. 
> 
> Nuno's patches fix a few bugs with the current implementation. I expect
> those patches to have contextual conflicts with this patch. I would like
> to commit Nuno's patches first since those are bug fixes, and then
> circle back to this one.
> 
> Nuno, can you please review this patch?
> 

I don't think I can give a Reviewed-by since I don't have the context
for these changes.

It doesn't look like this conflicts with the changes in my patches.

The TODO looks fine to me, it can be addressed in a followup.

Nuno

> On Mon, Jun 30, 2025 at 12:26:15PM +0200, Nam Cao wrote:
>> Move away from the legacy MSI domain setup, switch to use
>> msi_create_parent_irq_domain().
>>
>> While doing the conversion, I noticed that hv_irq_compose_msi_msg() is
>> doing more than it is supposed to (composing message content). The
>> interrupt allocation bits should be moved into hv_msi_domain_alloc().
>> However, I have no hardware to test this change, therefore I leave a TODO
>> note.
>>
>> Signed-off-by: Nam Cao <[email protected]>
>> ---
>>  arch/x86/hyperv/irqdomain.c | 111 ++++++++++++++++++++++++------------
>>  drivers/hv/Kconfig          |   1 +
>>  2 files changed, 77 insertions(+), 35 deletions(-)
>>
>> diff --git a/arch/x86/hyperv/irqdomain.c b/arch/x86/hyperv/irqdomain.c
>> index 31f0d29cbc5e3..9b3b65ffbd2e2 100644
>> --- a/arch/x86/hyperv/irqdomain.c
>> +++ b/arch/x86/hyperv/irqdomain.c
>> @@ -10,6 +10,7 @@
>>  
>>  #include <linux/pci.h>
>>  #include <linux/irq.h>
>> +#include <linux/irqchip/irq-msi-lib.h>
>>  #include <asm/mshyperv.h>
>>  
>>  static int hv_map_interrupt(union hv_device_id device_id, bool level,
>> @@ -276,59 +277,99 @@ static void hv_teardown_msi_irq(struct pci_dev *dev, 
>> struct irq_data *irqd)
>>              hv_status_err(status, "\n");
>>  }
>>  
>> -static void hv_msi_free_irq(struct irq_domain *domain,
>> -                        struct msi_domain_info *info, unsigned int virq)
>> -{
>> -    struct irq_data *irqd = irq_get_irq_data(virq);
>> -    struct msi_desc *desc;
>> -
>> -    if (!irqd)
>> -            return;
>> -
>> -    desc = irq_data_get_msi_desc(irqd);
>> -    if (!desc || !desc->irq || WARN_ON_ONCE(!dev_is_pci(desc->dev)))
>> -            return;
>> -
>> -    hv_teardown_msi_irq(to_pci_dev(desc->dev), irqd);
>> -}
>> -
>>  /*
>>   * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
>>   * which implement the MSI or MSI-X Capability Structure.
>>   */
>>  static struct irq_chip hv_pci_msi_controller = {
>>      .name                   = "HV-PCI-MSI",
>> -    .irq_unmask             = pci_msi_unmask_irq,
>> -    .irq_mask               = pci_msi_mask_irq,
>>      .irq_ack                = irq_chip_ack_parent,
>> -    .irq_retrigger          = irq_chip_retrigger_hierarchy,
>>      .irq_compose_msi_msg    = hv_irq_compose_msi_msg,
>> -    .irq_set_affinity       = msi_domain_set_affinity,
>> -    .flags                  = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED,
>> +    .irq_set_affinity       = irq_chip_set_affinity_parent,
>>  };
>>  
>> -static struct msi_domain_ops pci_msi_domain_ops = {
>> -    .msi_free               = hv_msi_free_irq,
>> -    .msi_prepare            = pci_msi_prepare,
>> +static bool hv_init_dev_msi_info(struct device *dev, struct irq_domain 
>> *domain,
>> +                             struct irq_domain *real_parent, struct 
>> msi_domain_info *info)
>> +{
>> +    struct irq_chip *chip = info->chip;
>> +
>> +    if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info))
>> +            return false;
>> +
>> +    chip->flags |= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED;
>> +
>> +    info->ops->msi_prepare = pci_msi_prepare;
>> +
>> +    return true;
>> +}
>> +
>> +#define HV_MSI_FLAGS_SUPPORTED      (MSI_GENERIC_FLAGS_MASK | 
>> MSI_FLAG_PCI_MSIX)
>> +#define HV_MSI_FLAGS_REQUIRED       (MSI_FLAG_USE_DEF_DOM_OPS | 
>> MSI_FLAG_USE_DEF_CHIP_OPS)
>> +
>> +static struct msi_parent_ops hv_msi_parent_ops = {
>> +    .supported_flags        = HV_MSI_FLAGS_SUPPORTED,
>> +    .required_flags         = HV_MSI_FLAGS_REQUIRED,
>> +    .bus_select_token       = DOMAIN_BUS_NEXUS,
>> +    .bus_select_mask        = MATCH_PCI_MSI,
>> +    .chip_flags             = MSI_CHIP_FLAG_SET_ACK,
>> +    .prefix                 = "HV-",
>> +    .init_dev_msi_info      = hv_init_dev_msi_info,
>>  };
>>  
>> -static struct msi_domain_info hv_pci_msi_domain_info = {
>> -    .flags          = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
>> -                      MSI_FLAG_PCI_MSIX,
>> -    .ops            = &pci_msi_domain_ops,
>> -    .chip           = &hv_pci_msi_controller,
>> -    .handler        = handle_edge_irq,
>> -    .handler_name   = "edge",
>> +static int hv_msi_domain_alloc(struct irq_domain *d, unsigned int virq, 
>> unsigned int nr_irqs,
>> +                           void *arg)
>> +{
>> +    /*
>> +     * TODO: The allocation bits of hv_irq_compose_msi_msg(), i.e. 
>> everything except
>> +     * entry_to_msi_msg() should be in here.
>> +     */
>> +
>> +    int ret;
>> +
>> +    ret = irq_domain_alloc_irqs_parent(d, virq, nr_irqs, arg);
>> +    if (ret)
>> +            return ret;
>> +
>> +    for (int i = 0; i < nr_irqs; ++i) {
>> +            irq_domain_set_info(d, virq + i, 0, &hv_pci_msi_controller, 
>> NULL,
>> +                                handle_edge_irq, NULL, "edge");
>> +    }
>> +    return 0;
>> +}
>> +
>> +static void hv_msi_domain_free(struct irq_domain *d, unsigned int virq, 
>> unsigned int nr_irqs)
>> +{
>> +    for (int i = 0; i < nr_irqs; ++i) {
>> +            struct irq_data *irqd = irq_domain_get_irq_data(d, virq);
>> +            struct msi_desc *desc;
>> +
>> +            desc = irq_data_get_msi_desc(irqd);
>> +            if (!desc || !desc->irq || WARN_ON_ONCE(!dev_is_pci(desc->dev)))
>> +                    continue;
>> +
>> +            hv_teardown_msi_irq(to_pci_dev(desc->dev), irqd);
>> +    }
>> +    irq_domain_free_irqs_top(d, virq, nr_irqs);
>> +}
>> +
>> +static const struct irq_domain_ops hv_msi_domain_ops = {
>> +    .select = msi_lib_irq_domain_select,
>> +    .alloc  = hv_msi_domain_alloc,
>> +    .free   = hv_msi_domain_free,
>>  };
>>  
>>  struct irq_domain * __init hv_create_pci_msi_domain(void)
>>  {
>>      struct irq_domain *d = NULL;
>> -    struct fwnode_handle *fn;
>>  
>> -    fn = irq_domain_alloc_named_fwnode("HV-PCI-MSI");
>> -    if (fn)
>> -            d = pci_msi_create_irq_domain(fn, &hv_pci_msi_domain_info, 
>> x86_vector_domain);
>> +    struct irq_domain_info info = {
>> +            .fwnode         = irq_domain_alloc_named_fwnode("HV-PCI-MSI"),
>> +            .ops            = &hv_msi_domain_ops,
>> +            .parent         = x86_vector_domain,
>> +    };
>> +
>> +    if (info.fwnode)
>> +            d = msi_create_parent_irq_domain(&info, &hv_msi_parent_ops);
>>  
>>      /* No point in going further if we can't get an irq domain */
>>      BUG_ON(!d);
>> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
>> index 1cd188b73b743..e62a0f8b34198 100644
>> --- a/drivers/hv/Kconfig
>> +++ b/drivers/hv/Kconfig
>> @@ -10,6 +10,7 @@ config HYPERV
>>      select X86_HV_CALLBACK_VECTOR if X86
>>      select OF_EARLY_FLATTREE if OF
>>      select SYSFB if !HYPERV_VTL_MODE
>> +    select IRQ_MSI_LIB if X86
>>      help
>>        Select this option to run Linux as a Hyper-V client operating
>>        system.
>> -- 
>> 2.39.5
>>


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