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From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Radovanovic, Aleksandar" <aleksandar.radovanovic@amd.com>
Cc: "Gupta, Nipun" <Nipun.Gupta@amd.com>,
	Marc Zyngier <maz@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
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	"git (AMD-Xilinx)" <git@amd.com>
Subject: Re: [RFC PATCH v3 4/7] bus/cdx: add cdx-MSI domain with gic-its domain as parent
Date: Wed, 12 Oct 2022 10:02:29 -0300	[thread overview]
Message-ID: <Y0a65a9leWXpKfTo@ziepe.ca> (raw)
In-Reply-To: <MN2PR12MB43586084670E14691920952889229@MN2PR12MB4358.namprd12.prod.outlook.com>

On Wed, Oct 12, 2022 at 10:34:23AM +0000, Radovanovic, Aleksandar wrote:

> For the MSI EventID, the HW interrupt logic assumes the MSI write value is 
> equal to the MSI vector number. However, the vector number is programmable
> for most (all) of the interrupt sources, which isn't exactly the same as saying
> EventID is programmable for a vector number, but can be used to emulate the
> desired behaviour, with a translation table in firmware. 

If you do this stuff wrong you will eventually run into situations
that don't work. Like VFIO/VMs and things.

> As for GITS_TRANSLATER, we can take up to 4 different IOVAs, which limits us
> to 4 CDX devices (should be sufficient for current HW use-cases). Also, it means
> that the address part must be the same for all vectors within a single CDX 
> device. I'm assuming this is OK as it is going to be a single interrupt and IOMMU
> domain anyway.

This is not at all how MSI is supposed to work.

Jason

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  reply	other threads:[~2022-10-12 13:04 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-03 12:26 [RFC PATCH 0/2] add support for CDX bus MSI domain Nipun Gupta
2022-08-03 12:26 ` [RFC PATCH 1/2] irqchip: cdx-bus: add cdx-MSI domain with gic-its domain as parent Nipun Gupta
2022-08-03 12:33   ` Greg KH
2022-08-03 12:37     ` Gupta, Nipun
2022-08-04  8:49   ` Marc Zyngier
2022-08-04  9:18     ` Gupta, Nipun
2022-08-04 10:38       ` Marc Zyngier
2022-08-04 12:11         ` Gupta, Nipun
2022-08-03 12:26 ` [RFC PATCH 2/2] driver core: add compatible string in sysfs for platform devices Nipun Gupta
2022-08-03 12:31   ` Greg KH
2022-08-03 12:46     ` Gupta, Nipun
2022-08-03 14:16 ` [RFC PATCH 0/2] add support for CDX bus MSI domain Robin Murphy
2022-08-04  4:23   ` Gupta, Nipun
2022-08-17 16:00   ` Jason Gunthorpe
2022-09-06 13:47 ` [RFC PATCH v3 0/7] add support for CDX bus Nipun Gupta
2022-09-06 13:47   ` [RFC PATCH v3 1/7] dt-bindings: bus: add CDX bus device tree bindings Nipun Gupta
2022-09-06 17:46     ` Rob Herring
2022-09-07  3:13       ` Gupta, Nipun
2022-09-08 10:51         ` Krzysztof Kozlowski
2022-09-06 13:47   ` [RFC PATCH v3 2/7] bus/cdx: add the cdx bus driver Nipun Gupta
2022-09-07  0:32     ` Saravana Kannan
2022-09-07  3:21       ` Gupta, Nipun
2022-09-07 18:06         ` Saravana Kannan
2022-09-07 12:32     ` Greg KH
2022-09-08 13:29       ` Gupta, Nipun
2022-09-06 13:47   ` [RFC PATCH v3 3/7] iommu/arm-smmu-v3: support ops registration for CDX bus Nipun Gupta
2022-09-07  0:10     ` Saravana Kannan
2022-09-07  3:17       ` Gupta, Nipun
2022-09-07  8:27         ` Robin Murphy
2022-09-07 18:24           ` Saravana Kannan
2022-09-07 20:40             ` Robin Murphy
2022-09-08  0:14               ` Saravana Kannan
2022-09-06 13:47   ` [RFC PATCH v3 4/7] bus/cdx: add cdx-MSI domain with gic-its domain as parent Nipun Gupta
2022-09-06 17:19     ` Jason Gunthorpe
2022-09-07 11:17       ` Marc Zyngier
2022-09-07 11:33         ` Robin Murphy
2022-09-07 12:14           ` Marc Zyngier
2022-09-07 11:35         ` Radovanovic, Aleksandar
2022-09-07 12:32           ` Marc Zyngier
2022-09-07 13:18             ` Radovanovic, Aleksandar
2022-09-08  8:08               ` Marc Zyngier
2022-09-08  9:51                 ` Radovanovic, Aleksandar
2022-09-08 11:49                   ` Robin Murphy
2022-09-08 14:18                   ` Marc Zyngier
2022-09-07 13:18     ` Marc Zyngier
2022-09-08 14:13       ` Gupta, Nipun
2022-09-08 14:29         ` Marc Zyngier
2022-09-09  6:32           ` Gupta, Nipun
2022-10-12 10:04       ` Gupta, Nipun
2022-10-12 10:34         ` Radovanovic, Aleksandar
2022-10-12 13:02           ` Jason Gunthorpe [this message]
2022-10-12 13:37             ` Radovanovic, Aleksandar
2022-10-12 14:38               ` Jason Gunthorpe
2022-10-12 15:09                 ` Radovanovic, Aleksandar
2022-10-13 12:43                   ` Jason Gunthorpe
2022-10-14 11:18                     ` Radovanovic, Aleksandar
2022-10-14 11:54                       ` gregkh
2022-10-14 12:13                         ` Radovanovic, Aleksandar
2022-10-14 13:46                           ` gregkh
2022-10-14 13:58                       ` Jason Gunthorpe
2022-09-06 13:47   ` [RFC PATCH v3 5/7] bus/cdx: add bus and device attributes Nipun Gupta
2022-09-06 13:48   ` [RFC PATCH v3 6/7] vfio/cdx: add support for CDX bus Nipun Gupta
2022-09-06 17:20     ` Jason Gunthorpe
2022-09-06 17:23       ` Gupta, Nipun
2022-09-06 13:48   ` [RFC PATCH v3 7/7] vfio/cdx: add interrupt support Nipun Gupta
2022-10-14  4:40 ` [RFC PATCH v4 0/8] add support for CDX bus Nipun Gupta
2022-10-14  4:40   ` [RFC PATCH v4 1/8] dt-bindings: bus: add CDX bus device tree bindings Nipun Gupta
2022-10-14 14:17     ` Rob Herring
2022-10-17 10:18       ` Gupta, Nipun
2022-10-14  4:40   ` [RFC PATCH v4 2/8] bus/cdx: add the cdx bus driver Nipun Gupta
2022-10-14  7:15     ` Greg KH
2022-10-14  8:12       ` Gupta, Nipun
2022-10-14  7:18     ` Greg KH
2022-10-14  8:20       ` Gupta, Nipun
2022-10-14  4:40   ` [RFC PATCH v4 3/8] iommu/arm-smmu-v3: support ops registration for CDX bus Nipun Gupta
2022-10-14  4:51     ` Gupta, Nipun
2022-10-14  4:40   ` [RFC PATCH v4 4/8] bux/cdx: support dma configuration for CDX devices Nipun Gupta
2022-10-14  4:40   ` [RFC PATCH v4 5/8] bus/cdx: add bus and device attributes Nipun Gupta
2022-10-14  4:40   ` [RFC PATCH v4 6/8] irq/msi: use implicit msi domain for alloc and free Nipun Gupta
2022-10-14  4:40   ` [RFC PATCH v4 7/8] bus/cdx: add cdx-MSI domain with gic-its domain as parent Nipun Gupta
2022-11-17 19:10     ` Thomas Gleixner
2022-10-14  4:40   ` [RFC PATCH v4 8/8] bus/cdx: add cdx controller Nipun Gupta
2022-10-14 14:10   ` [RFC PATCH v4 0/8] add support for CDX bus Rob Herring
2022-10-17 10:08     ` Gupta, Nipun

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