Re: [PATCH] PCI/MSI: Check MSI_FLAG_PCI_MSI_MASK_PARENT in cond_[startup|shutdown]_parent()

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Aug 27, 2025 at 02:29:07PM +0800, Inochi Amaoto wrote:
> For msi controller that only supports MSI_FLAG_PCI_MSI_MASK_PARENT,
> the newly added callback irq_startup() and irq_shutdown() for
> pci_msi[x]_templete will not unmask/mask the interrupt when startup/
> shutdown the interrupt. This will prevent the interrupt from being
> enabled/disabled normally.

s/templete/template/

AFAICS cond_startup_parent() is used by pci_irq_startup_msi() and
pci_irq_startup_msix() in pci_msi_template; cond_shutdown_parent() is
used by pci_irq_shutdown_msi() and pci_irq_shutdown_msix() in
pci_msix_template.

> Add the missing check for MSI_FLAG_PCI_MSI_MASK_PARENT in the
> cond_[startup|shutdown]_parent(). So the interrupt can be normally
> unmasked/masked if it does not support MSI_FLAG_PCI_MSI_MASK_PARENT.
> 
> Fixes: 54f45a30c0d0 ("PCI/MSI: Add startup/shutdown for per device domains")
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Closes: https://lore.kernel.org/regressions/aK4O7Hl8NCVEMznB@monster/

I guess there are several other reporters and reports that could be
added here.  Up to you whether to add them.

> Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
> Tested-by: Nathan Chancellor <nathan@kernel.org>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
>  drivers/pci/msi/irqdomain.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
> index e0a800f918e8..b11b7f63f0d6 100644
> --- a/drivers/pci/msi/irqdomain.c
> +++ b/drivers/pci/msi/irqdomain.c
> @@ -154,6 +154,8 @@ static void cond_shutdown_parent(struct irq_data *data)
> 
>  	if (unlikely(info->flags & MSI_FLAG_PCI_MSI_STARTUP_PARENT))
>  		irq_chip_shutdown_parent(data);
> +	else if (unlikely(info->flags & MSI_FLAG_PCI_MSI_MASK_PARENT))
> +		irq_chip_mask_parent(data);
>  }
> 
>  static unsigned int cond_startup_parent(struct irq_data *data)
> @@ -162,6 +164,9 @@ static unsigned int cond_startup_parent(struct irq_data *data)
> 
>  	if (unlikely(info->flags & MSI_FLAG_PCI_MSI_STARTUP_PARENT))
>  		return irq_chip_startup_parent(data);
> +	else if (unlikely(info->flags & MSI_FLAG_PCI_MSI_MASK_PARENT))
> +		irq_chip_unmask_parent(data);
> +
>  	return 0;
>  }
> 
> --
> 2.51.0
>