[PATCH v10 3/7] PCI: endpoint: pci-ep-msi: Add MSI address/data pair mutable check

[Thomas Gleixner]

On Wed, Dec 04 2024 at 18:25, Frank Li wrote:
> Some MSI controller change address/data pair when irq_set_affinity().
> Current PCI endpoint can't support this type MSI controller. So add flag
> MSI_FLAG_MUTABLE in include/linux/msi.h and check it when allocate
> doorbell.

Q: Who is going to annotate the affected domains with that flag?

A: Nobody.

Q: What's the value of the flag?

A: Zero, as as it prevents exactly nothing.

You want a MSI_FLAG_MSG_IMMUTABLE and set that on the domains which
provide it. That way you ensure that someone looked at the domain to
validate it.

Thanks,

        tglx