[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <86zgcgmpzl.wl-maz@kernel.org>
Date: Thu, 24 Nov 2022 13:38:54 +0000
From: Marc Zyngier <maz@...nel.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>, Will Deacon <will@...nel.org>,
linux-pci@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jason Gunthorpe <jgg@...lanox.com>,
Andrew Lunn <andrew@...n.ch>,
Gregory Clement <gregory.clement@...tlin.com>,
Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
Ammar Faizi <ammarfaizi2@...weeb.org>,
Robin Murphy <robin.murphy@....com>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>,
Santosh Shilimkar <ssantosh@...nel.org>,
linux-arm-kernel@...ts.infradead.org,
Vinod Koul <vkoul@...nel.org>, Sinan Kaya <okaya@...nel.org>,
Andy Gross <agross@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Shameerali Kolothum Thodi
<shameerali.kolothum.thodi@...wei.com>,
Zenghui Yu <yuzenghui@...wei.com>,
Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Fabio Estevam <festevam@...il.com>
Subject: Re: [patch V2 06/40] PCI/MSI: Provide static key for parent mask/unmask
On Thu, 24 Nov 2022 13:17:00 +0000,
Thomas Gleixner <tglx@...utronix.de> wrote:
>
> On Thu, Nov 24 2022 at 13:04, Marc Zyngier wrote:
> > On Mon, 21 Nov 2022 14:39:36 +0000,
> >> static void pci_mask_msi(struct irq_data *data)
> >> {
> >> struct msi_desc *desc = irq_data_get_msi_desc(data);
> >>
> >> pci_msi_mask(desc, BIT(data->irq - desc->irq));
> >> + cond_mask_parent(data);
> >
> > I find this a bit odd. If anything, I'd rather drop the masking at the
> > PCI level and keep it local to the interrupt controller, because this
> > is likely to be more universal than the equivalent PCI operation
> > (think multi-MSI, for example, which cannot masks individual MSIs).
> >
> > Another thing is that the static key is a global state. Nothing says
> > that masking one way or the other is a universal thing, specially when
> > you have multiple interrupt controllers dealing with MSIs in different
> > ways. For example, GICv3 can use both the ITS and the GICv3-MBI frame
> > at the same time for different PCI RC. OK, they happen to deal with
> > MSIs in the same way, but you hopefully get my point.
>
> I'm fine with dropping that. I did this because basically all of the
> various ARM PCI/MSI domain implementation have a copy of the same
> functions. Some of them have pointlessly the wrong order because copy &
> pasta is so wonderful....
>
> So the alternative solution is to provide _ONE_ set of correct callbacks
> and let the domain initialization code override the irq chip callbacks
> of the default PCI/MSI template.
If the various irqchips can tell the core code whether they want
things to be masked at the PCI level or at the irqchip level, this
would be a move in the right direction. For the GIC, I'd definitely
want things masked locally.
What I'd like to get rid off is the double masking, as I agree it is
on the "pretty dumb" side of things.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
Powered by blists - more mailing lists