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From: Christoph Hellwig <hch@lst.de>
To: Ben Dooks <ben.dooks@sifive.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
	Christoph Hellwig <hch@lst.de>,
	linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
	iommu@lists.linux-foundation.org,
	Sudip Mukherjee <sudip.mukherjee@sifive.com>,
	Jude Onyenegecha <jude.onyenegecha@sifive.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH] swiotlb: ensure io_tlb_default_mem spinlock always initialised
Date: Mon, 11 Jul 2022 15:40:00 +0200	[thread overview]
Message-ID: <20220711134000.GA18865@lst.de> (raw)
In-Reply-To: <265d7b6b-a0a4-ecaf-10bd-15e1ea416a06@sifive.com>

On Mon, Jul 11, 2022 at 01:54:11PM +0100, Ben Dooks wrote:
> I need to go back and check through what we did to get some that worked
> for us, and then come back and try and make some idea of how that is
> best done with upstream kernel.
>
> It might be possible for the PCIe controller to do some sort of very
> simple IOMMU for the case where we might have somehow an PCI device
> added to the system, but that is a very rare use-case I expect and
> if someone does it they can do the effort of updating the PCIe code
> and everything else that goes with it.

Unfortunately there also are plenty of PCIe devices with addressing
limitation even if the PCIe spec explicitly forbits that.  40, 44 or
48 bit limitations seems to be more common than 32-bits, though.

      reply	other threads:[~2022-07-11 13:40 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-08 17:08 [PATCH] swiotlb: ensure io_tlb_default_mem spinlock always initialised Ben Dooks
2022-07-08 20:32 ` Robin Murphy
2022-07-11  7:26   ` Ben Dooks
2022-07-11 10:07     ` Robin Murphy
2022-07-11 10:21       ` Christoph Hellwig
2022-07-11 10:24         ` Ben Dooks
2022-07-11 10:39           ` Christoph Hellwig
2022-07-11 10:42             ` Ben Dooks
2022-07-11 11:01               ` Robin Murphy
2022-07-11 11:52                 ` Conor.Dooley
2022-07-11 12:45                   ` Ben Dooks
2022-07-11 12:56                     ` Conor.Dooley
2022-07-11 12:54                 ` Ben Dooks
2022-07-11 13:40                   ` Christoph Hellwig [this message]

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