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From: Thomas Gleixner <tglx@linutronix.de>
To: 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, jgg@mellanox.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
Cc: 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: Thu, 08 Oct 2020 09:39:26 +0200	[thread overview]
Message-ID: <87r1q92mkx.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <0f9bdae0-73d7-1b4e-b478-3cbd05c095f4@intel.com>

On Wed, Oct 07 2020 at 14:54, Dave Jiang wrote:
> On 9/30/2020 12:57 PM, Thomas Gleixner wrote:
>> Aside of that this is fiddling in the IMS storage array behind the irq
>> chips back without any comment here and a big fat comment about the
>> shared usage of ims_slot::ctrl in the irq chip driver.
>> 
> This is to program the pasid fields in the IMS table entry. Was
> thinking the pasid fields may be considered device specific so didn't
> attempt to add the support to the core code.

Well, the problem is that this is not really irq chip functionality.

But the PASID programming needs to touch the IMS storage which is also
touched by the irq chip.

This might be correct as is, but without a big fat comment explaining
WHY it is safe to do so without any form of serialization this is just
voodoo and unreviewable.

Can you please explain when the PASID is programmed and what the state
of the interrupt is at that point? Is this a one off setup operation or
does this happen dynamically at random points during runtime?

This needs to be clarified first.

Thanks,

        tglx



  reply	other threads:[~2020-10-08  7:39 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 [this message]
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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