From: Jason Gunthorpe <jgg@nvidia.com>
To: Mostafa Saleh <smostafa@google.com>
Cc: will@kernel.org, robin.murphy@arm.com,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, joro@8bytes.org,
nicolinc@nvidia.com, mshavit@google.com
Subject: Re: [PATCH] iommu/arm-smmu-v3: Fix access for STE.SHCFG
Date: Mon, 25 Mar 2024 10:18:05 -0300 [thread overview]
Message-ID: <20240325131805.GB6245@nvidia.com> (raw)
In-Reply-To: <20240323134658.464743-1-smostafa@google.com>
On Sat, Mar 23, 2024 at 01:46:58PM +0000, Mostafa Saleh wrote:
> STE attributes(NSCFG, PRIVCFG, INSTCFG) use value 0 for "Use Icomming",
> for some reason SHCFG doesn't follow that, and it is defined as "0b01".
>
> Currently the driver sets SHCFG to Use Incoming for stage-2 and bypass
> domains.
>
> However according to the User Manual (ARM IHI 0070 F.b):
> When SMMU_IDR1.ATTR_TYPES_OVR == 0, this field is RES0 and the
> incoming Shareability attribute is used.
>
> This patch adds a condition for writing SHCFG to Use incoming to be
> compliant with the architecture, and defines ATTR_TYPE_OVR as a new
> feature discovered from IDR1.
> This also required to propagate the SMMU through some functions args.
>
> There is no need to add similar condition for the newly introduced function
> arm_smmu_get_ste_used() as the values of the STE are the same before and
> after any transition, so this will not trigger any change. (we already
> do the same for the VMID).
>
> Although this is a misconfiguration from the driver, this has been there
> for a long time, so probably no HW running Linux is affected by it.
>
> Reported-by: Will Deacon <will@kernel.org>
> Closes: https://lore.kernel.org/all/20240215134952.GA690@willie-the-truck/
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 35 ++++++++++++++-------
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 ++
> 2 files changed, 25 insertions(+), 12 deletions(-)
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Thanks,
Jason
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next prev parent reply other threads:[~2024-03-25 13:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-23 13:46 [PATCH] iommu/arm-smmu-v3: Fix access for STE.SHCFG Mostafa Saleh
2024-03-25 13:18 ` Jason Gunthorpe [this message]
2024-03-26 17:23 ` Will Deacon
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