From: Baolu Lu <baolu.lu@linux.intel.com>
To: Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>, Jason Gunthorpe <jgg@nvidia.com>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
Jean-Philippe Brucker <jean-philippe@linaro.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Jacob jun Pan <jacob.jun.pan@intel.com>
Subject: Re: [PATCH 2/5] iommu: Add blocking_domain_ops field in iommu_ops
Date: Mon, 16 May 2022 21:43:43 +0800 [thread overview]
Message-ID: <64f49746-1ae7-7516-8e92-06ffb4d5f8e5@linux.intel.com> (raw)
In-Reply-To: <8a0fc6cf-f46e-f17e-2b76-099ada1683c3@arm.com>
Hi Robin,
On 2022/5/16 19:22, Robin Murphy wrote:
> On 2022-05-16 02:57, Lu Baolu wrote:
>> Each IOMMU driver must provide a blocking domain ops. If the hardware
>> supports detaching domain from device, setting blocking domain equals
>> detaching the existing domain from the deivce. Otherwise, an UNMANAGED
>> domain without any mapping will be used instead.
>
> Unfortunately that's backwards - most of the implementations of
> .detach_dev are disabling translation entirely, meaning the device ends
> up effectively in passthrough rather than blocked. Conversely, at least
> arm-smmu and arm-smmu-v3 could implement IOMMU_DOMAIN_BLOCKED properly
> with fault-type S2CRs and STEs respectively, it just needs a bit of
> wiring up.
Thank you for letting me know this.
This means that we need to add an additional UNMANAGED domain for each
iommu group, although it is not used most of the time. If most IOMMU
drivers could implement real dumb blocking domains, this burden may be
reduced.
Best regards,
baolu
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next prev parent reply other threads:[~2022-05-16 13:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-16 1:57 [PATCH 0/5] iommu: Make blocking domain static for group Lu Baolu
2022-05-16 1:57 ` [PATCH 1/5] iommu: Rename attach_dev to set_dev in domain ops Lu Baolu
2022-05-16 1:57 ` [PATCH 2/5] iommu: Add blocking_domain_ops field in iommu_ops Lu Baolu
2022-05-16 7:27 ` Christoph Hellwig
2022-05-16 13:05 ` Jason Gunthorpe via iommu
2022-05-16 11:22 ` Robin Murphy
2022-05-16 13:43 ` Baolu Lu [this message]
2022-05-16 13:57 ` Jason Gunthorpe via iommu
2022-05-17 2:37 ` Baolu Lu
2022-05-17 12:43 ` Robin Murphy
2022-05-17 13:13 ` Jason Gunthorpe via iommu
2022-05-18 6:43 ` Baolu Lu
2022-05-17 13:08 ` Jason Gunthorpe via iommu
2022-05-20 8:45 ` Joerg Roedel
2022-05-20 11:03 ` Baolu Lu
2022-05-16 1:57 ` [PATCH 3/5] iommu: Make blocking domain static for iommu group Lu Baolu
2022-05-16 1:57 ` [PATCH 4/5] iommu: Use blocking domain for empty domain attaching Lu Baolu
2022-05-16 1:57 ` [PATCH 5/5] iommu: Remove .detach_dev from iommu domain ops Lu Baolu
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