From: John Garry <john.garry@huawei.com>
To: Lu Baolu <baolu.lu@linux.intel.com>, <joro@8bytes.org>,
<will@kernel.org>, <dwmw2@infradead.org>, <robin.murphy@arm.com>
Cc: <linux-kernel@vger.kernel.org>,
<iommu@lists.linux-foundation.org>, <linuxarm@huawei.com>,
<thunder.leizhen@huawei.com>, <chenxiang66@hisilicon.com>
Subject: Re: [PATCH v12 2/5] iommu: Enhance IOMMU default DMA mode build options
Date: Mon, 14 Jun 2021 09:11:14 +0100 [thread overview]
Message-ID: <953e1210-c88f-3e50-fbb9-cc559923829e@huawei.com> (raw)
In-Reply-To: <a4c85f00-918b-5952-7585-8e1110ac5195@linux.intel.com>
On 12/06/2021 02:21, Lu Baolu wrote:
> On 2021/6/11 20:20, John Garry wrote:
>> +config IOMMU_DEFAULT_LAZY
>> + bool "lazy"
>> + help
>> + Support lazy mode, where for every IOMMU DMA unmap operation, the
>> + flush operation of IOTLB and the free operation of IOVA are
>> deferred.
>> + They are only guaranteed to be done before the related IOVA
>> will be
>> + reused.
>> +
>> + The isolation provided in this mode is not as secure as STRICT
>> mode,
>> + such that a vulnerable time window may be created between the DMA
>> + unmap and the mapping finally being torn down in the IOMMU,
>> where the
>> + device can still access the system memory. However this mode may
>
> " ... and the mappings cached in the IOMMU IOTLB or device TLB finally
> being invalidated, where the device probably can still access the memory
> which has already been unmapped by the device driver."
ok, I can try to incorporate some of this wording.
As for this:
On 12/06/2021 03:12, Lu Baolu wrote:
> On 2021/6/11 20:20, John Garry wrote:
>> +choice
>> + prompt "IOMMU default DMA mode"
>
> This is not explicit.
>
> How about
>
> "IOMMU DMA default cache invalidation policy"
>
> ?
>
OK, but I'd rather use IOTLB, as that better matches the relevant
iommu.c API name (iommu_ops.flush_iotlb_all).
Thanks,
john
next prev parent reply other threads:[~2021-06-14 8:17 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-11 12:20 [PATCH v12 0/5] Enhance IOMMU default DMA mode build options John Garry
2021-06-11 12:20 ` [PATCH v12 1/5] iommu: Print strict or lazy mode at init time John Garry
2021-06-14 15:54 ` Robin Murphy
2021-06-11 12:20 ` [PATCH v12 2/5] iommu: Enhance IOMMU default DMA mode build options John Garry
2021-06-12 1:21 ` Lu Baolu
2021-06-14 8:11 ` John Garry [this message]
2021-06-12 2:12 ` Lu Baolu
2021-06-14 16:03 ` Robin Murphy
2021-06-11 12:20 ` [PATCH v12 3/5] iommu/vt-d: Add support for " John Garry
2021-06-12 2:14 ` Lu Baolu
2021-06-14 8:03 ` John Garry
2021-06-15 7:26 ` Lu Baolu
2021-06-15 8:25 ` Robin Murphy
2021-06-16 8:42 ` Lu Baolu
2021-06-12 2:22 ` Lu Baolu
2021-06-14 7:53 ` John Garry
2021-06-14 14:11 ` Robin Murphy
2021-06-14 14:19 ` John Garry
2021-06-14 15:05 ` Robin Murphy
2021-06-11 12:20 ` [PATCH v12 4/5] iommu/amd: " John Garry
2021-06-11 12:20 ` [PATCH v12 5/5] iommu: Remove mode argument from iommu_set_dma_strict() John Garry
2021-06-12 2:23 ` Lu Baolu
2021-06-14 7:46 ` John Garry
2021-06-14 16:25 ` Robin Murphy
2021-06-14 17:03 ` John Garry
2021-06-14 17:19 ` Robin Murphy
2021-06-14 17:24 ` John Garry
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