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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Yang Shi <yang@os.amperecomputing.com>
Cc: nicolinc@nvidia.com, james.morse@arm.com, will@kernel.org,
	robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [v2 PATCH] iommu/arm-smmu-v3: Fix L1 stream table index calculation for 32-bit sid size
Date: Wed, 2 Oct 2024 15:14:58 -0300	[thread overview]
Message-ID: <20241002181458.GK1369530@ziepe.ca> (raw)
In-Reply-To: <20241002175514.1165299-1-yang@os.amperecomputing.com>

On Wed, Oct 02, 2024 at 10:55:14AM -0700, Yang Shi wrote:

> Using 64 bit immediate when doing shift can solve the problem.  The
> disassembly after the fix looks like:
>     ldr     w20, [x19, 828] //, smmu_7(D)->sid_bits
>     mov     x0, 1
>     lsl     x0, x0, x20
> 
> There are a couple of problematic places, extracted the shift into a helper.
> 
> [1] https://lore.kernel.org/lkml/d4b53bbb-333a-45b9-9eb0-23ddd0820a14@arm.com/
> Fixes: ce410410f1a7 ("iommu/arm-smmu-v3: Add arm_smmu_strtab_l1/2_idx()")
> Tested-by: James Morse <james.morse@arm.com>
> Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 +++++---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 5 +++++
>  2 files changed, 10 insertions(+), 3 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason


  reply	other threads:[~2024-10-02 18:16 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-02 17:55 [v2 PATCH] iommu/arm-smmu-v3: Fix L1 stream table index calculation for 32-bit sid size Yang Shi
2024-10-02 18:14 ` Jason Gunthorpe [this message]
2024-10-02 18:17 ` Nicolin Chen
2024-10-02 19:04   ` Yang Shi
2024-10-02 19:22     ` Nicolin Chen
2024-10-02 19:40       ` Jason Gunthorpe
2024-10-02 20:00         ` Yang Shi
2024-10-02 20:05         ` Yang Shi
2024-10-03 11:16           ` Jason Gunthorpe
2024-10-03 15:31             ` Yang Shi
2024-10-04 12:43               ` Jason Gunthorpe
2024-10-04 16:05                 ` Yang Shi
2024-10-04 16:14                   ` Jason Gunthorpe
2024-10-04 16:29                     ` Yang Shi
2024-10-04 16:37                       ` Yang Shi
2024-10-04 16:41                         ` Jason Gunthorpe
2024-10-04 16:46                           ` Yang Shi
2024-10-02 19:50       ` Yang Shi
2024-10-02 18:21 ` Robin Murphy
2024-10-02 18:36   ` Yang Shi

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