From: Lu Baolu <baolu.lu@linux.intel.com>
To: Robin Murphy <robin.murphy@arm.com>, joro@8bytes.org
Cc: baolu.lu@linux.intel.com, will@kernel.org, iommu@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
suravee.suthikulpanit@amd.com, vasant.hegde@amd.com,
mjrosato@linux.ibm.com, gerald.schaefer@linux.ibm.com,
schnelle@linux.ibm.com, linux-s390@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 01/15] iommu/vt-d: Handle race between registration and device probe
Date: Tue, 19 Jul 2022 08:06:02 +0800 [thread overview]
Message-ID: <9614fd81-5feb-b9c9-8317-26ca82d30d55@linux.intel.com> (raw)
In-Reply-To: <6557623d-3e4e-9f3e-e735-fd9654305f65@arm.com>
Hi Robin,
On 2022/7/15 20:37, Robin Murphy wrote:
>> In fact the rmrr list in the Intel IOMMU driver is always static after
>> parsing the ACPI/DMAR tables. There's no need to protect it with a lock.
>> Hence we can safely remove below down/up_read().
>
> IIRC that leads to RCU warnings via for_each_dev_scope(), though. I did
> try replacing this down_read() with rcu_read_lock(), but then it doesn't
> like the GFP_KERNEL allocation in iommu_alloc_resv_region(), and that's
> where I gave up :)
>
> I'm mostly left wondering whether the dmar_drhd_units list really needs
> to be RCU protected at all, as that seems to be the root of most of the
> problems here.
I just posted a fix patch here:
https://lore.kernel.org/linux-iommu/20220718235325.3952426-1-baolu.lu@linux.intel.com/
It can remove the recursive locking and RCU warnings. Can you please
take a look at it?
Best regards,
baolu
WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com>
To: Robin Murphy <robin.murphy@arm.com>, joro@8bytes.org
Cc: baolu.lu@linux.intel.com, will@kernel.org, iommu@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
suravee.suthikulpanit@amd.com, vasant.hegde@amd.com,
mjrosato@linux.ibm.com, gerald.schaefer@linux.ibm.com,
schnelle@linux.ibm.com, linux-s390@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 01/15] iommu/vt-d: Handle race between registration and device probe
Date: Tue, 19 Jul 2022 08:06:02 +0800 [thread overview]
Message-ID: <9614fd81-5feb-b9c9-8317-26ca82d30d55@linux.intel.com> (raw)
In-Reply-To: <6557623d-3e4e-9f3e-e735-fd9654305f65@arm.com>
Hi Robin,
On 2022/7/15 20:37, Robin Murphy wrote:
>> In fact the rmrr list in the Intel IOMMU driver is always static after
>> parsing the ACPI/DMAR tables. There's no need to protect it with a lock.
>> Hence we can safely remove below down/up_read().
>
> IIRC that leads to RCU warnings via for_each_dev_scope(), though. I did
> try replacing this down_read() with rcu_read_lock(), but then it doesn't
> like the GFP_KERNEL allocation in iommu_alloc_resv_region(), and that's
> where I gave up :)
>
> I'm mostly left wondering whether the dmar_drhd_units list really needs
> to be RCU protected at all, as that seems to be the root of most of the
> problems here.
I just posted a fix patch here:
https://lore.kernel.org/linux-iommu/20220718235325.3952426-1-baolu.lu@linux.intel.com/
It can remove the recursive locking and RCU warnings. Can you please
take a look at it?
Best regards,
baolu
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-07-19 0:06 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 17:08 [PATCH v3 00/15] iommu: Retire bus_set_iommu() Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 01/15] iommu/vt-d: Handle race between registration and device probe Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-06 1:39 ` Baolu Lu
2022-07-06 1:39 ` Baolu Lu
2022-07-07 6:51 ` Tian, Kevin
2022-07-07 6:51 ` Tian, Kevin
2022-07-08 7:52 ` Baolu Lu
2022-07-08 7:52 ` Baolu Lu
2022-07-15 12:37 ` Robin Murphy
2022-07-15 12:37 ` Robin Murphy
2022-07-19 0:06 ` Lu Baolu [this message]
2022-07-19 0:06 ` Lu Baolu
2022-07-05 17:08 ` [PATCH v3 02/15] iommu/amd: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 03/15] iommu: Always register bus notifiers Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-06 1:53 ` Baolu Lu
2022-07-06 1:53 ` Baolu Lu
2022-07-06 13:43 ` Robin Murphy
2022-07-06 13:43 ` Robin Murphy
2022-07-07 0:20 ` Baolu Lu
2022-07-07 0:20 ` Baolu Lu
2022-07-07 6:34 ` Tian, Kevin
2022-07-07 6:34 ` Tian, Kevin
2022-07-07 9:38 ` Robin Murphy
2022-07-07 9:38 ` Robin Murphy
2022-07-07 6:31 ` Tian, Kevin
2022-07-07 6:31 ` Tian, Kevin
2022-07-07 9:58 ` Robin Murphy
2022-07-07 9:58 ` Robin Murphy
2022-07-08 5:50 ` Tian, Kevin
2022-07-08 5:50 ` Tian, Kevin
2022-07-05 17:08 ` [PATCH v3 04/15] iommu: Move bus setup to IOMMU device registration Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-06 2:35 ` Baolu Lu
2022-07-06 2:35 ` Baolu Lu
2022-07-06 14:37 ` Robin Murphy
2022-07-06 14:37 ` Robin Murphy
2022-07-07 1:19 ` Baolu Lu
2022-07-07 1:19 ` Baolu Lu
2022-07-07 6:51 ` Tian, Kevin
2022-07-07 6:51 ` Tian, Kevin
2022-07-07 10:58 ` Robin Murphy
2022-07-07 10:58 ` Robin Murphy
2022-07-08 5:52 ` Tian, Kevin
2022-07-08 5:52 ` Tian, Kevin
2022-07-05 17:08 ` [PATCH v3 05/15] iommu/amd: Clean up bus_set_iommu() Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 06/15] iommu/arm-smmu: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 07/15] iommu/arm-smmu-v3: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 08/15] iommu/dart: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 09/15] iommu/exynos: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 10/15] iommu/ipmmu-vmsa: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 11/15] iommu/mtk: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 12/15] iommu/omap: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 13/15] iommu/tegra-smmu: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 14/15] iommu/virtio: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-05 17:08 ` [PATCH v3 15/15] iommu: " Robin Murphy
2022-07-05 17:08 ` Robin Murphy
2022-07-07 7:45 ` Tian, Kevin
2022-07-07 7:45 ` Tian, Kevin
2022-07-07 12:49 ` Matthew Rosato
2022-07-07 12:49 ` Matthew Rosato
2022-07-07 12:54 ` Matthew Rosato
2022-07-07 12:54 ` Matthew Rosato
2022-07-07 14:58 ` Robin Murphy
2022-07-07 14:58 ` Robin Murphy
2022-07-07 16:42 ` Matthew Rosato
2022-07-07 16:42 ` Matthew Rosato
2022-07-08 8:14 ` [PATCH] iommu/s390: fail probe for non-pci device Niklas Schnelle
2022-07-08 8:14 ` Niklas Schnelle
2022-07-08 8:17 ` [PATCH v3 00/15] iommu: Retire bus_set_iommu() Niklas Schnelle
2022-07-08 8:17 ` Niklas Schnelle
2022-07-15 13:12 ` Robin Murphy
2022-07-15 13:12 ` Robin Murphy
2022-07-21 7:17 ` Tian, Kevin
2022-07-21 7:17 ` Tian, Kevin
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