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From: Thomas Gleixner <tglx@linutronix.de>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
	iommu@lists.linux-foundation.org, linux-hyperv@vger.kernel.org,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Jon Derrick <jonathan.derrick@intel.com>,
	Lu Baolu <baolu.lu@linux.intel.com>, Wei Liu <wei.liu@kernel.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Steve Wahl <steve.wahl@hpe.com>,
	Dimitri Sivanich <sivanich@hpe.com>, Russ Anderson <rja@hpe.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	xen-devel@lists.xenproject.org, Juergen Gross <jgross@suse.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Megha Dey <megha.dey@intel.com>,
	Jason Gunthorpe <jgg@mellanox.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Jacob Pan <jacob.jun.pan@intel.com>,
	Baolu Lu <baolu.lu@intel.com>, Kevin Tian <kevin.tian@intel.com>,
	Dan Williams <dan.j.williams@intel.com>
Subject: Re: [patch RFC 30/38] PCI/MSI: Allow to disable arch fallbacks
Date: Tue, 25 Aug 2020 23:28:30 +0200	[thread overview]
Message-ID: <87a6yixvnl.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200825200742.GA1924669@bjorn-Precision-5520>

On Tue, Aug 25 2020 at 15:07, Bjorn Helgaas wrote:
>> + * The arch hooks to setup up msi irqs. Default functions are implemented
>> + * as weak symbols so that they /can/ be overriden by architecture specific
>> + * code if needed.
>> + *
>> + * They can be replaced by stubs with warnings via
>> + * CONFIG_PCI_MSI_DISABLE_ARCH_FALLBACKS when the architecture fully
>> + * utilizes direct irqdomain based setup.
>
> Do you expect *all* arches to eventually use direct irqdomain setup?

Ideally that happens some day. We have five left when x86 is converted:

IA64, MIPS, POWERPC, S390, SPARC

IA64 is unlikely to be fixed, but might be solved naturally by removal.

For the others I don't know, but it's not on the horizon anytime soon I
fear.

> And in that case, to remove the config option?

Yes, and all the code which depends on it.

> If not, it seems like it'd be nicer to have the burden on the arches
> that need/want to use arch-specific code instead of on the arches that
> do things generically.

Right, but they still share the common code there and some of them
provide only parts of the weak callbacks. I'm not sure whether it's a
good idea to copy all of this into each affected architecture.

Or did you just mean that those architectures should select
CONFIG_I_WANT_THE CRUFT instead of opting out on the fully irq domain
based ones?

Thanks,

        tglx



WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Dimitri Sivanich <sivanich@hpe.com>,
	linux-hyperv@vger.kernel.org, Steve Wahl <steve.wahl@hpe.com>,
	linux-pci@vger.kernel.org, "K. Y. Srinivasan" <kys@microsoft.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Wei Liu <wei.liu@kernel.org>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Baolu Lu <baolu.lu@intel.com>, Marc Zyngier <maz@kernel.org>,
	x86@kernel.org, Jason Gunthorpe <jgg@mellanox.com>,
	Megha Dey <megha.dey@intel.com>,
	xen-devel@lists.xenproject.org, Kevin Tian <kevin.tian@intel.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Jon Derrick <jonathan.derrick@intel.com>,
	Juergen Gross <jgross@suse.com>, Russ Anderson <rja@hpe.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	iommu@lists.linux-foundation.org,
	Jacob Pan <jacob.jun.pan@intel.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [patch RFC 30/38] PCI/MSI: Allow to disable arch fallbacks
Date: Tue, 25 Aug 2020 23:28:30 +0200	[thread overview]
Message-ID: <87a6yixvnl.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200825200742.GA1924669@bjorn-Precision-5520>

On Tue, Aug 25 2020 at 15:07, Bjorn Helgaas wrote:
>> + * The arch hooks to setup up msi irqs. Default functions are implemented
>> + * as weak symbols so that they /can/ be overriden by architecture specific
>> + * code if needed.
>> + *
>> + * They can be replaced by stubs with warnings via
>> + * CONFIG_PCI_MSI_DISABLE_ARCH_FALLBACKS when the architecture fully
>> + * utilizes direct irqdomain based setup.
>
> Do you expect *all* arches to eventually use direct irqdomain setup?

Ideally that happens some day. We have five left when x86 is converted:

IA64, MIPS, POWERPC, S390, SPARC

IA64 is unlikely to be fixed, but might be solved naturally by removal.

For the others I don't know, but it's not on the horizon anytime soon I
fear.

> And in that case, to remove the config option?

Yes, and all the code which depends on it.

> If not, it seems like it'd be nicer to have the burden on the arches
> that need/want to use arch-specific code instead of on the arches that
> do things generically.

Right, but they still share the common code there and some of them
provide only parts of the weak callbacks. I'm not sure whether it's a
good idea to copy all of this into each affected architecture.

Or did you just mean that those architectures should select
CONFIG_I_WANT_THE CRUFT instead of opting out on the fully irq domain
based ones?

Thanks,

        tglx


_______________________________________________
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iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2020-08-25 21:28 UTC|newest]

Thread overview: 146+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21  0:24 [patch RFC 00/38] x86, PCI, XEN, genirq ...: Prepare for device MSI Thomas Gleixner
2020-08-21  0:24 ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 01/38] iommu/amd: Prevent NULL pointer dereference Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 02/38] x86/init: Remove unused init ops Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 03/38] x86/irq: Rename X86_IRQ_ALLOC_TYPE_MSI* to reflect PCI dependency Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 04/38] x86/irq: Add allocation type for parent domain retrieval Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 05/38] iommu/vt-d: Consolidate irq domain getter Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 06/38] iommu/amd: " Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 07/38] iommu/irq_remapping: Consolidate irq domain lookup Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 08/38] x86/irq: Prepare consolidation of irq_alloc_info Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 09/38] x86/msi: Consolidate HPET allocation Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 10/38] x86/ioapic: Consolidate IOAPIC allocation Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-26  8:40   ` Boqun Feng
2020-08-26  8:40     ` Boqun Feng
2020-08-26  8:40     ` Boqun Feng
2020-08-26  9:53     ` Thomas Gleixner
2020-08-26  9:53       ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 11/38] x86/irq: Consolidate DMAR irq allocation Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 12/38] x86/irq: Consolidate UV domain allocation Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 13/38] PCI: MSI: Rework pci_msi_domain_calc_hwirq() Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-25 20:03   ` Bjorn Helgaas
2020-08-25 20:03     ` Bjorn Helgaas
2020-08-25 21:11     ` Thomas Gleixner
2020-08-25 21:11       ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 14/38] x86/msi: Consolidate MSI allocation Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 15/38] x86/msi: Use generic MSI domain ops Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 16/38] x86/irq: Move apic_post_init() invocation to one place Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 17/38] x86/pci: Reducde #ifdeffery in PCI init code Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-25 20:20   ` Bjorn Helgaas
2020-08-25 20:20     ` Bjorn Helgaas
2020-08-21  0:24 ` [patch RFC 18/38] x86/irq: Initialize PCI/MSI domain at PCI init time Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  6:31   ` kernel test robot
2020-08-21  0:24 ` [patch RFC 19/38] irqdomain/msi: Provide DOMAIN_BUS_VMD_MSI Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 20/38] PCI: vmd: Mark VMD irqdomain with DOMAIN_BUS_VMD_MSI Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-25 20:04   ` Bjorn Helgaas
2020-08-25 20:04     ` Bjorn Helgaas
2020-08-21  0:24 ` [patch RFC 21/38] PCI: MSI: Provide pci_dev_has_special_msi_domain() helper Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-25 20:16   ` Bjorn Helgaas
2020-08-25 20:16     ` Bjorn Helgaas
2020-08-21  0:24 ` [patch RFC 22/38] x86/xen: Make xen_msi_init() static and rename it to xen_hvm_msi_init() Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-24  4:48   ` Jürgen Groß
2020-08-24  4:48     ` Jürgen Groß
2020-08-21  0:24 ` [patch RFC 23/38] x86/xen: Rework MSI teardown Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-24  5:09   ` Jürgen Groß
2020-08-24  5:09     ` Jürgen Groß
2020-08-21  0:24 ` [patch RFC 24/38] x86/xen: Consolidate XEN-MSI init Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-24  4:59   ` Jürgen Groß
2020-08-24  4:59     ` Jürgen Groß
2020-08-24 21:21     ` Thomas Gleixner
2020-08-24 21:21       ` Thomas Gleixner
2020-08-25  4:21       ` Jürgen Groß
2020-08-25  4:21         ` Jürgen Groß
2020-08-25  9:51         ` Thomas Gleixner
2020-08-25  9:51           ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 25/38] irqdomain/msi: Allow to override msi_domain_alloc/free_irqs() Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 26/38] x86/xen: Wrap XEN MSI management into irqdomain Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-24  6:21   ` Jürgen Groß
2020-08-24  6:21     ` Jürgen Groß
2020-08-25  7:57     ` Thomas Gleixner
2020-08-25  7:57       ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 27/38] iommm/vt-d: Store irq domain in struct device Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  7:03   ` kernel test robot
2020-08-21  0:24 ` [patch RFC 28/38] iommm/amd: " Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 29/38] x86/pci: Set default irq domain in pcibios_add_device() Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 30/38] PCI/MSI: Allow to disable arch fallbacks Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-25 20:07   ` Bjorn Helgaas
2020-08-25 20:07     ` Bjorn Helgaas
2020-08-25 21:28     ` Thomas Gleixner [this message]
2020-08-25 21:28       ` Thomas Gleixner
2020-08-25 21:35       ` Bjorn Helgaas
2020-08-25 21:35         ` Bjorn Helgaas
2020-08-25 21:40         ` Thomas Gleixner
2020-08-25 21:40           ` Thomas Gleixner
2020-08-25 22:03           ` Thomas Gleixner
2020-08-25 22:03             ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 31/38] x86/irq: Cleanup the arch_*_msi_irqs() leftovers Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 32/38] x86/irq: Make most MSI ops XEN private Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 33/38] x86/irq: Add DEV_MSI allocation type Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:24 ` [patch RFC 34/38] x86/msi: Let pci_msi_prepare() handle non-PCI MSI Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-25 20:24   ` Bjorn Helgaas
2020-08-25 20:24     ` Bjorn Helgaas
2020-08-25 21:30     ` Thomas Gleixner
2020-08-25 21:30       ` Thomas Gleixner
2020-08-25 21:50       ` Bjorn Helgaas
2020-08-25 21:50         ` Bjorn Helgaas
2020-08-21  0:24 ` [patch RFC 35/38] platform-msi: Provide default irq_chip::ack Thomas Gleixner
2020-08-21  0:24   ` Thomas Gleixner
2020-08-21  0:25 ` [patch RFC 36/38] platform-msi: Add device MSI infrastructure Thomas Gleixner
2020-08-21  0:25   ` Thomas Gleixner
2020-08-21  0:25 ` [patch RFC 37/38] irqdomain/msi: Provide msi_alloc/free_store() callbacks Thomas Gleixner
2020-08-21  0:25   ` Thomas Gleixner
2020-08-21  0:25 ` [patch RFC 38/38] irqchip: Add IMS array driver - NOT FOR MERGING Thomas Gleixner
2020-08-21  0:25   ` Thomas Gleixner
2020-08-21  8:48   ` kernel test robot
2020-08-21 12:45   ` Jason Gunthorpe
2020-08-21 12:45     ` Jason Gunthorpe
2020-08-21 19:47     ` Thomas Gleixner
2020-08-21 19:47       ` Thomas Gleixner
2020-08-21 20:17       ` Jason Gunthorpe
2020-08-21 20:17         ` Jason Gunthorpe
2020-08-21 23:47         ` Thomas Gleixner
2020-08-21 23:47           ` Thomas Gleixner
2020-08-22  0:51           ` Jason Gunthorpe
2020-08-22  0:51             ` Jason Gunthorpe
2020-08-22  1:34             ` Thomas Gleixner
2020-08-22  1:34               ` Thomas Gleixner
2020-08-22 23:05               ` Jason Gunthorpe
2020-08-22 23:05                 ` Jason Gunthorpe
2020-08-23  8:03                 ` Thomas Gleixner
2020-08-23  8:03                   ` Thomas Gleixner
2020-08-22 14:19 ` [patch RFC 00/38] x86, PCI, XEN, genirq ...: Prepare for device MSI Jürgen Groß
2020-08-22 14:19   ` Jürgen Groß

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