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From: Jason Gunthorpe <jgg@nvidia.com>
To: Thomas Gleixner <tglx@linutronix.de>
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>,
	<ashok.raj@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>
Subject: Re: [PATCH v3 11/18] dmaengine: idxd: ims setup for the vdcm
Date: Fri, 9 Oct 2020 11:52:36 -0300	[thread overview]
Message-ID: <20201009145236.GM4734@nvidia.com> (raw)
In-Reply-To: <87v9fjtq5w.fsf@nanos.tec.linutronix.de>

On Fri, Oct 09, 2020 at 04:44:27PM +0200, Thomas Gleixner wrote:
> > This is really not that different from what I was describing for queue
> > contexts - the queue context needs to be assigned to the irq # before
> > it can be used in the irq chip other wise there is no idea where to
> > write the msg to. Just like pasid here.
> 
> Not really. In the IDXD case the storage is known when the host device
> and the irq domain is initialized which is not the case for your variant
> and it neither needs to send a magic command to the device to update the
> data.

I mean, needing the PASID vs needing the memory address before the IRQ
can be use are basically the same issue. Data needs to be attached to
the IRQ before it can be programmed.. In this case programming with
the wrong PASID could lead to a security issue.

> All the IDXD driver has to do is:
> 
>    auxval = ims_ctrl_pasid_aux(pasid, enabled);
>    irq_set_auxdata(irqnr, IMS_AUXDATA_CONTROL_WORD, auxval);
> 
> I agree that irq_set_auxdata() is not the most elegant thing, but the
> alternative solutions I looked at are just worse.

It seems reasonable, but quite an obfuscated way to tell a driver they
need to hold irq_get_desc_buslock() when touching data shared with the
irqchip ops.. Not that I have a better suggestion

Jason

  reply	other threads:[~2020-10-09 14:52 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
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 [this message]
2020-10-09 16:02                   ` Thomas Gleixner

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