Re: [patch 4/8] PCI/MSI: Enforce MSI[X] entry updates to be visible

Bjorn Helgaas
2021-07-22T21:48:47Z

On Wed, Jul 21, 2021 at 09:11:30PM +0200, Thomas Gleixner wrote:
> Nothing enforces the posted writes to be visible when the function
> returns. Flush them even if the flush might be redundant when the entry is
> masked already as the unmask will flush as well. This is either setup or a
> rare affinity change event so the extra flush is not the end of the world.
>
> While this is more a theoretical issue especially the X86 MSI affinity
> stter mechanism relies on the assumption that the update has reached the

stter?

> hardware when the function returns.
>
> Again, as this never has been enfocred the Fixes tag refers to a commit in:

s/enfocred/enforced/

> git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git