Re: [PATCH v3 16/17] x86/ioapic: export a few functions and data structures via io_apic.h

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Wei Liu <wei.liu@kernel.org>
Cc: Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
	virtualization@lists.linux-foundation.org,
	Linux Kernel List <linux-kernel@vger.kernel.org>,
	Michael Kelley <mikelley@microsoft.com>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	Sunil Muthuswamy <sunilmut@microsoft.com>,
	Nuno Das Neves <nunodasneves@linux.microsoft.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Joerg Roedel <jroedel@suse.de>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Jon Derrick <jonathan.derrick@intel.com>,
	YueHaibing <yuehaibing@huawei.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>
Subject: Re: [PATCH v3 16/17] x86/ioapic: export a few functions and data structures via io_apic.h
Date: Wed, 2 Dec 2020 17:18:02 +0200	[thread overview]
Message-ID: <20201202151802.GI4077@smile.fi.intel.com> (raw)
In-Reply-To: <20201202141107.covsx4ugipuyl6he@liuwe-devbox-debian-v2>

On Wed, Dec 02, 2020 at 02:11:07PM +0000, Wei Liu wrote:
> On Wed, Nov 25, 2020 at 12:26:12PM +0200, Andy Shevchenko wrote:
> > On Wed, Nov 25, 2020 at 1:46 AM Wei Liu <wei.liu@kernel.org> wrote:
> > >
> > > We are about to implement an irqchip for IO-APIC when Linux runs as root
> > > on Microsoft Hypervisor. At the same time we would like to reuse
> > > existing code as much as possible.
> > >
> > > Move mp_chip_data to io_apic.h and make a few helper functions
> > > non-static.
> > 
> > > +struct mp_chip_data {
> > > +       struct list_head irq_2_pin;
> > > +       struct IO_APIC_route_entry entry;
> > > +       int trigger;
> > > +       int polarity;
> > > +       u32 count;
> > > +       bool isa_irq;
> > > +};
> > 
> > Since I see only this patch I am puzzled why you need to have this in
> > the header?
> > Maybe a couple of words in the commit message to elaborate?
> 
> Andy, does the following answer your question?
> 
> "The chip_data stashed in IO-APIC's irq chip is mp_chip_data.  The
> implementation of Microsoft Hypevisor's IO-APIC irqdomain would like to
> manipulate that data structure, so move it to io_apic.h as well."

At least it sheds some light, thanks.

> If that's good enough, I can add it to the commit message.

It's good for a starter, but I think you have to wait for what Thomas and other
related people can say.

-- 
With Best Regards,
Andy Shevchenko