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Date:   Mon, 30 Oct 2023 13:19:25 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Eric Pilmore <epilmore@gigaio.com>
Cc:     linux-pci@vger.kernel.org, dmaengine@vger.kernel.org,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: IOVA address range
Message-ID: <20231030181622.GA1878727@bhelgaas>
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On Fri, Oct 27, 2023 at 12:17:17PM -0700, Eric Pilmore wrote:
> Need a little IOVA/IOMMU help.
> 
> Is it correct that the IOVA address range for a device goes from
> address 0x0 up to the dma-mask of the respective device?
> 
> Is it correct to assume that the base of the IOVA address space for a
> device will always be zero (0x0)? Is there any reason to think that
> this has changed in some newer iteration of the kernel, perhaps 5.10,
> and that the base could be non-zero?
> 
> I realize an IOVA itself can be non-zero. I'm trying to verify what
> the base address is of the IOVA space as a whole on a per device
> basis.
> 
> Thanks,
> Eric Pilmore