On Thu, Dec 05, 2024 at 02:10:55PM +0100, Thomas Gleixner wrote: > 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. Okay, at beginning I think most MSI controller is immutable. So I use MSI_FLAG_MSG_MUTABLE. It is fine change to MSI_FLAG_MSG_IMMUTABLE. Frank > > Thanks, > > tglx
