[PATCH AUTOSEL 6.16-6.6] PCI: xgene-msi: Resend an MSI racing with itself on a different CPU

[Marc Zyngier]

On Tue, 05 Aug 2025 14:59:27 +0100,
Sasha Levin <sashal at kernel.org> wrote:
> 
> On Tue, Aug 05, 2025 at 02:20:52PM +0100, Marc Zyngier wrote:
> > On Tue, 05 Aug 2025 14:09:34 +0100,
> > Sasha Levin <sashal at kernel.org> wrote:
> >> 
> >> From: Marc Zyngier <maz at kernel.org>
> >> 
> >> [ Upstream commit 3cc8f625e4c6a0e9f936da6b94166e62e387fe1d ]
> >> 
> >> Since changing the affinity of an MSI really is about changing
> >> the target address and that it isn't possible to mask an individual
> >> MSI, it is completely possible for an interrupt to race with itself,
> >> usually resulting in a lost interrupt.
> >> 
> >> Paper over the design blunder by informing the core code of this
> >> sad state of affairs.
> >> 
> >> Signed-off-by: Marc Zyngier <maz at kernel.org>
> >> Signed-off-by: Lorenzo Pieralisi <lpieralisi at kernel.org>
> >> Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
> >> Link: https://lore.kernel.org/r/20250708173404.1278635-11-maz@kernel.org
> >> Signed-off-by: Sasha Levin <sashal at kernel.org>
> >> ---
> >> 
> >> LLM Generated explanations, may be completely bogus:
> > 
> > s/may be//. It is an amusing read though, specially when quoting
> > totally unrelated patches, so thumbs up for the comical value.
> 
> Yeah, it's still very much at the "junior engineer" level

It's not, and that's the main issue. A junior engineer would get into
the rabbit hole of backporting too much, as they would be unable to
separate the essential logic from the surrounding fluff. There would
be a lot of noise, but it would be OK.

Your "thing" is very much at the "Senior Marketroid" level, in the
sense that it manages to drag some semi-relevant information from
various sources, and condenses it into an advertisement for snake oil.

I think I know who which of the two I want to work with.

	M.

-- 
Jazz isn't dead. It just smells funny.