From: Will Deacon <will@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: robdclark@gmail.com, joro@8bytes.org, jcrouse@codeaurora.org,
iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/4] iommu/io-pgtable-arm: Rationalise TCR handling
Date: Tue, 20 Aug 2019 11:31:16 +0100 [thread overview]
Message-ID: <20190820103115.o7neehdethf7sbqi@willie-the-truck> (raw)
In-Reply-To: <78df4f8e2510e88f3ded59eb385f79b4442ed4f2.1566238530.git.robin.murphy@arm.com>
On Mon, Aug 19, 2019 at 07:19:30PM +0100, Robin Murphy wrote:
> Although it's conceptually nice for the io_pgtable_cfg to provide a
> standard VMSA TCR value, the reality is that no VMSA-compliant IOMMU
> looks exactly like an Arm CPU, and they all have various other TCR
> controls which io-pgtable can't be expected to understand. Thus since
> there is an expectation that drivers will have to add to the given TCR
> value anyway, let's strip it down to just the essentials that are
> directly relevant to io-pgatble's inner workings - namely the address
> sizes, walk attributes, and where appropriate, format selection.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> drivers/iommu/arm-smmu-v3.c | 7 +------
> drivers/iommu/arm-smmu.c | 1 +
> drivers/iommu/arm-smmu.h | 2 ++
> drivers/iommu/io-pgtable-arm-v7s.c | 6 ++----
> drivers/iommu/io-pgtable-arm.c | 4 ----
> drivers/iommu/qcom_iommu.c | 2 +-
> 6 files changed, 7 insertions(+), 15 deletions(-)
Hmm, so I'm a bit nervous about this one since I think we really should
be providing a TCR with EPD1 set if we're only giving you TTBR0. Relying
on the driver to do this worries me. See my comments on the next patch.
Will
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next prev parent reply other threads:[~2019-08-20 10:31 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 18:19 [PATCH 0/4] iommu/io-pgtable: Cleanup and prep for split tables Robin Murphy
2019-08-19 18:19 ` [PATCH 1/4] iommu/io-pgtable-arm: Rationalise MAIR handling Robin Murphy
2019-08-19 18:19 ` [PATCH 2/4] iommu/io-pgtable-arm: Rationalise TTBRn handling Robin Murphy
2019-08-20 10:19 ` Will Deacon
2019-08-20 14:17 ` Robin Murphy
2019-08-20 15:50 ` Will Deacon
2019-08-19 18:19 ` [PATCH 3/4] iommu/io-pgtable-arm: Rationalise TCR handling Robin Murphy
2019-08-20 10:31 ` Will Deacon [this message]
2019-08-20 15:25 ` Robin Murphy
2019-08-20 16:07 ` Will Deacon
2019-08-20 18:41 ` Robin Murphy
2019-08-21 12:11 ` Will Deacon
2019-08-21 12:56 ` Robin Murphy
2019-10-03 17:33 ` Jordan Crouse
2019-10-24 10:51 ` Will Deacon
2019-10-24 11:23 ` Robin Murphy
2019-10-24 11:40 ` Will Deacon
2019-08-20 16:23 ` Jordan Crouse
2019-08-19 18:19 ` [PATCH 4/4] iommu/io-pgtable-arm: Prepare for TTBR1 usage Robin Murphy
2019-08-19 22:34 ` Jordan Crouse
2019-08-20 13:51 ` Robin Murphy
2019-08-20 10:30 ` Will Deacon
2019-08-20 14:51 ` Robin Murphy
2019-08-20 15:58 ` Will Deacon
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