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From: Will Deacon <will@kernel.org>
To: isaacm@codeaurora.org
Cc: kernel-team@android.com, Robin Murphy <robin.murphy@arm.com>,
	linux-kernel@vger.kernel.org, Liam Mark <lmark@codeaurora.org>,
	iommu@lists.linux-foundation.org, pratikp@codeaurora.org
Subject: Re: [RFC PATCH] iommu/dma: Allow drivers to reserve an iova range
Date: Thu, 20 Feb 2020 08:45:52 +0000	[thread overview]
Message-ID: <20200220084552.GB11827@willie-the-truck> (raw)
In-Reply-To: <d8b70a579f07c688b264e83a0ec0b6d6@codeaurora.org>

On Wed, Feb 19, 2020 at 12:06:28PM -0800, isaacm@codeaurora.org wrote:
> On 2020-02-19 03:15, Will Deacon wrote:
> > On Tue, Feb 18, 2020 at 05:57:18PM -0800, isaacm@codeaurora.org wrote:
> > > Does this mean that the driver should be managing the IOVA space and
> > > mappings for this device using the IOMMU API? If so, is the
> > > rationale for
> > > this because the device driver can have the information of what IOVA
> > > ranges
> > > can and cannot be used? Shouldn't there be a generic way of
> > > informing an
> > > IOMMU driver about these reserved ranges? Perhaps through a device
> > > tree
> > > property, instead of deferring this type of management to the driver?
> > 
> > Before we dive into designing that, can you please clarify whether the
> > reserved IOVA range applies to all DMA masters mastering through a
> > particular SMMU, or whether it's just about one specific master? I was
> > assuming the former, but wanted to be sure.
> > 
> This situation currently applies to one master.

Interesting. Is it problematic if the range is reserved for all masters
sharing that SMMU?

Will
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  reply	other threads:[~2020-02-20  8:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 22:58 [RFC PATCH] iommu/dma: Allow drivers to reserve an iova range Isaac J. Manjarres
2020-02-17  8:01 ` Christoph Hellwig
2020-02-17 15:50   ` Robin Murphy
2020-02-19  1:57     ` isaacm
2020-02-19 11:15       ` Will Deacon
2020-02-19 20:06         ` isaacm
2020-02-20  8:45           ` Will Deacon [this message]
2020-02-20 18:57             ` Pratik Patel
2020-02-19  9:46 ` Joerg Roedel

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