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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	David Woodhouse <dwmw2@infradead.org>,
	intel-gfx@lists.freedesktop.org, baolu.lu@linux.intel.com
Subject: Re: [RFC PATCH] iommu/vt-d: Fix IOMMU field not populated on device hot re-plug
Date: Thu, 29 Aug 2019 09:43:31 +0800	[thread overview]
Message-ID: <0cf4e930-1132-1e7f-815b-57a08a1fe5de@linux.intel.com> (raw)
In-Reply-To: <3275480.HMaYE7B3nd@jkrzyszt-desk.ger.corp.intel.com>

Hi Janusz,

On 8/28/19 10:17 PM, Janusz Krzysztofik wrote:
>> We should avoid kernel panic when a intel_unmap() is called against
>> a non-existent domain.
> Does that mean you suggest to replace
> 	BUG_ON(!domain);
> with something like
> 	if (WARN_ON(!domain))
> 		return;
> and to not care of orphaned mappings left allocated?  Is there a way to inform
> users that their active DMA mappings are no longer valid and they shouldn't
> call dma_unmap_*()?
> 
>> But we shouldn't expect the IOMMU driver not
>> cleaning up the domain info when a device remove notification comes and
>> wait until all file descriptors being closed, right?
> Shouldn't then the IOMMU driver take care of cleaning up resources still
> allocated on device remove before it invalidates and forgets their pointers?
> 

You are right. We need to wait until all allocated resources (iova and
mappings) to be released.

How about registering a callback for BUS_NOTIFY_UNBOUND_DRIVER, and
removing the domain info when the driver detachment completes?

> Thanks,
> Janusz

Best regards,
Baolu
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  reply	other threads:[~2019-08-29  1:44 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-22 14:29 [RFC PATCH] iommu/vt-d: Fix IOMMU field not populated on device hot re-plug Janusz Krzysztofik
2019-08-22 15:34 ` ✓ Fi.CI.BAT: success for " Patchwork
2019-08-23  1:51 ` [RFC PATCH] " Lu Baolu
2019-08-26  8:15   ` Janusz Krzysztofik
2019-08-26  8:29     ` Lu Baolu
     [not found]       ` <790a4a20-7517-fe54-177d-850b9beeb88e-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2019-08-27  9:35         ` Janusz Krzysztofik
2019-08-28  0:56           ` Lu Baolu
2019-08-28 14:17             ` Janusz Krzysztofik
2019-08-29  1:43               ` Lu Baolu [this message]
2019-08-29  7:58                 ` Janusz Krzysztofik
2019-08-29  9:08                   ` Lu Baolu
2019-09-02  8:37                     ` Janusz Krzysztofik
2019-09-03  1:29                       ` Lu Baolu
2019-09-03  7:41                         ` Janusz Krzysztofik
2019-10-01 15:01                           ` Janusz Krzysztofik
     [not found]                             ` <7739498.9tyZrNxj5X-RCb3PieevP79BXuAQUXR0fooFf0ArEBIu+b9c/7xato@public.gmane.org>
2019-10-08  2:27                               ` Lu Baolu
2019-10-11  6:54                           ` Lu Baolu
2019-10-11 10:27                             ` Janusz Krzysztofik
2019-08-23  8:47 ` ✓ Fi.CI.IGT: success for " Patchwork

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