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From: Thomas Gleixner <tglx@linutronix.de>
To: "Raj\, Ashok" <ashok.raj@intel.com>, Jason Gunthorpe <jgg@nvidia.com>
Cc: Dave Jiang <dave.jiang@intel.com>,
	vkoul@kernel.org, megha.dey@intel.com, maz@kernel.org,
	bhelgaas@google.com, alex.williamson@redhat.com,
	jacob.jun.pan@intel.com, yi.l.liu@intel.com, baolu.lu@intel.com,
	kevin.tian@intel.com, sanjay.k.kumar@intel.com,
	tony.luck@intel.com, jing.lin@intel.com,
	dan.j.williams@intel.com, kwankhede@nvidia.com,
	eric.auger@redhat.com, parav@mellanox.com, rafael@kernel.org,
	netanelg@mellanox.com, shahafs@mellanox.com,
	yan.y.zhao@linux.intel.com, pbonzini@redhat.com,
	samuel.ortiz@intel.com, mona.hossain@intel.com,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
	x86@kernel.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org,
	Ashok Raj <ashok.raj@intel.com>
Subject: Re: [PATCH v3 05/18] dmaengine: idxd: add IMS support in base driver
Date: Wed, 30 Sep 2020 23:57:22 +0200	[thread overview]
Message-ID: <87d023gc71.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200930214941.GB26492@otc-nc-03>

On Wed, Sep 30 2020 at 14:49, Ashok Raj wrote:
>> It is the weirdest thing, IMHO. Intel defined a dvsec cap in their
>> SIOV cookbook, but as far as I can see it serves no purpose at
>> all.
>> 
>> Last time I asked I got some unclear mumbling about "OEMs".
>> 
> One of the parameters it has is the "supported system page-sizes" which is
> usually there in the SRIOV properties. So it needed a place holder for
> that. 
>
> IMS is a device specific capability, and I almost forgot why we needed
> until I had to checking internally. Remember when a device is given to a
> guest, MSIX routing via Interrupt Remapping is automatic via the VFIO/IRQFD
> and such.

-ENOPARSE

> When we provision an entire PCI device that is IMS capable. The guest
> driver does know it can update the IMS entries directly without going to
> the host. But in order to do remapping we need something like how we manage
> PASID allocation from guest, so an IRTE entry can be allocated and the host
> driver can write the proper values for IMS.

And how is that related to that capbility thing?

Also this stuff is host side and not guest side. I seriously doubt that
you want to hand in the whole PCI device which contains the IMS
thing. The whole point of IMS was as far as I was told that you can
create gazillions of subdevices and have seperate MSI interrupts for
each of them.

Thanks,

        tglx

  reply	other threads:[~2020-09-30 21:57 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <160021207013.67751.8220471499908137671.stgit@djiang5-desk3.ch.intel.com>
2020-09-15 23:27 ` [PATCH v3 01/18] irqchip: Add IMS (Interrupt Message Storage) driver Dave Jiang
2020-09-30 18:23   ` Thomas Gleixner
2020-10-01 22:59     ` Dey, Megha
2020-09-15 23:27 ` [PATCH v3 02/18] iommu/vt-d: Add DEV-MSI support Dave Jiang
2020-09-30 18:32   ` Thomas Gleixner
2020-10-01 23:26     ` Dey, Megha
2020-10-02 11:13       ` Thomas Gleixner
2020-10-08  7:54     ` David Woodhouse
2020-10-20 21:42       ` Dey, Megha
2020-09-15 23:28 ` [PATCH v3 05/18] dmaengine: idxd: add IMS support in base driver Dave Jiang
2020-09-30 18:47   ` Thomas Gleixner
2020-09-30 18:51     ` Jason Gunthorpe
2020-09-30 21:48       ` Thomas Gleixner
2020-09-30 21:49       ` Raj, Ashok
2020-09-30 21:57         ` Thomas Gleixner [this message]
2020-10-01  1:07           ` Raj, Ashok
2020-10-01  8:44             ` Thomas Gleixner
2020-09-30 22:38         ` Jason Gunthorpe
2020-10-01 20:48     ` Dave Jiang
2020-09-15 23:28 ` [PATCH v3 07/18] dmaengine: idxd: add basic mdev registration and helper functions Dave Jiang
2020-09-15 23:28 ` [PATCH v3 10/18] dmaengine: idxd: virtual device commands emulation Dave Jiang
2020-09-15 23:28 ` [PATCH v3 12/18] dmaengine: idxd: add mdev type as a new wq type Dave Jiang
2020-09-15 23:29 ` [PATCH v3 13/18] dmaengine: idxd: add dedicated wq mdev type Dave Jiang
2020-09-15 23:29 ` [PATCH v3 14/18] dmaengine: idxd: add new wq state for mdev Dave Jiang
2020-09-15 23:29 ` [PATCH v3 15/18] dmaengine: idxd: add error notification from host driver to mediated device Dave Jiang
2020-09-15 23:29 ` [PATCH v3 16/18] dmaengine: idxd: add ABI documentation for mediated device support Dave Jiang
2020-09-17 15:06 ` [PATCH v3 00/18] Add VFIO mediated device support and DEV-MSI support for the idxd driver Jason Gunthorpe
2020-09-17 17:15   ` Dave Jiang
2020-09-17 17:27     ` Jason Gunthorpe
2020-09-17 17:30     ` Alex Williamson
2020-09-17 17:37       ` Jason Gunthorpe
     [not found] ` <160021248280.67751.12525558281536923518.stgit@djiang5-desk3.ch.intel.com>
2020-09-30 18:36   ` [PATCH v3 04/18] dmaengine: idxd: add interrupt handle request support Thomas Gleixner
2020-10-01 20:16     ` Dave Jiang
     [not found] ` <160021253189.67751.12686144284999931703.stgit@djiang5-desk3.ch.intel.com>
2020-09-30 19:57   ` [PATCH v3 11/18] dmaengine: idxd: ims setup for the vdcm Thomas Gleixner
2020-10-07 21:54     ` Dave Jiang
2020-10-08  7:39       ` Thomas Gleixner
2020-10-08 16:51         ` Dave Jiang
2020-10-08 23:17           ` Thomas Gleixner
2020-10-08 23:32             ` Jason Gunthorpe
2020-10-09  0:27               ` Dave Jiang
2020-10-09  1:22               ` Raj, Ashok
2020-10-09 11:57                 ` Jason Gunthorpe
2020-10-09 12:43                   ` Raj, Ashok
2020-10-09 12:49                     ` Jason Gunthorpe
2020-10-09 13:02                       ` Raj, Ashok
2020-10-09 13:12                         ` Jason Gunthorpe
2020-10-09 13:40                           ` Raj, Ashok
2020-10-09 14:44               ` Thomas Gleixner
2020-10-09 14:52                 ` Jason Gunthorpe
2020-10-09 16:02                   ` Thomas Gleixner

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