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From: Thomas Gleixner <tglx@linutronix.de>
To: 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, 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, 09 Oct 2020 18:02:51 +0200	[thread overview]
Message-ID: <87d01rtmj8.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20201009145236.GM4734@nvidia.com>

On Fri, Oct 09 2020 at 11:52, Jason Gunthorpe wrote:
> 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.

Yeah. I looked at doing it similar to the callback I added for
retrieving the shadow storage pointer, but the PASID is not necessarily
established at that point.

>> 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

It's an obfuscated way to make obfuscated hardware supported :)

Thanks,

        tglx

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

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