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

For MSI controllers which only support MSI_FLAG_PCI_MSI_MASK_PARENT, the
newly added callback irq_startup() and irq_shutdown() for
pci_msi[x]_template will not unmask or mask the interrupt when startup()
resp. shutdown() is invoked. This prevents the interrupt from being
enabled resp. disabled.

Invoke irq_[un]mask_parent() in cond_[startup|shutdown]_parent(), when the
interrupt has the MSI_FLAG_PCI_MSI_MASK_PARENT flag set.

Fixes: 54f45a30c0d0 ("PCI/MSI: Add startup/shutdown for per device domains")
Reported-by: Linux Kernel Functional Testing <[e-mail]>
Reported-by: Nathan Chancellor <[e-mail]>
Reported-by: Wei Fang <[e-mail]>
Signed-off-by: Inochi Amaoto <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Tested-by: Nathan Chancellor <[e-mail]>
Tested-by: Linux Kernel Functional Testing <[e-mail]>
Tested-by: Jon Hunter <[e-mail]>
Tested-by: Wei Fang <[e-mail]>
Tested-by: Chen Wang <[e-mail]> # Pioneerbox/SG2042
Acked-by: Bjorn Helgaas <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]
Closes: https://lore.kernel.org/regressions/aK4O7Hl8NCVEMznB@monster/
Closes: https://lore.kernel.org/regressions/20250826220959.GA4119563@ax162/
Closes: https://lore.kernel.org/all/[e-mail]/

drivers/pci/msi/irqdomain.c

···
 
 	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)
···
 
 	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;
 }