Subject: Re: [PATCH 07/11] x86: remove the IOMMU table infrastructure

From: Anshuman Khandual <[email-masked]>
Date: Thu, 24 Feb 2022 15:48:59 +0530

On 2/22/22 9:05 PM, Christoph Hellwig wrote:
> The IOMMU table tries to separate the different IOMMUs into different
> backends, but actually requires various cross calls.
> 
> Rewrite the code to do the generic swiotlb/swiotlb-xen setup directly
> in pci-dma.c and then just call into the IOMMU drivers.
> 
> Signed-off-by: Christoph Hellwig <[email-masked]>
> ---
>  arch/ia64/include/asm/iommu_table.h    |   7 --
>  arch/x86/include/asm/dma-mapping.h     |   1 -
>  arch/x86/include/asm/gart.h            |   5 +-
>  arch/x86/include/asm/iommu.h           |   6 ++
>  arch/x86/include/asm/iommu_table.h     | 102 ----------------------
>  arch/x86/include/asm/swiotlb.h         |  30 -------
>  arch/x86/include/asm/xen/swiotlb-xen.h |   2 -
>  arch/x86/kernel/Makefile               |   2 -
>  arch/x86/kernel/amd_gart_64.c          |   5 +-
>  arch/x86/kernel/aperture_64.c          |  14 ++--
>  arch/x86/kernel/pci-dma.c              | 112 ++++++++++++++++++++-----
>  arch/x86/kernel/pci-iommu_table.c      |  77 -----------------
>  arch/x86/kernel/pci-swiotlb.c          |  77 -----------------
>  arch/x86/kernel/tboot.c                |   1 -
>  arch/x86/kernel/vmlinux.lds.S          |  12 ---
>  arch/x86/xen/Makefile                  |   2 -
>  arch/x86/xen/pci-swiotlb-xen.c         |  96 ---------------------
>  drivers/iommu/amd/init.c               |   6 --
>  drivers/iommu/amd/iommu.c              |   5 +-
>  drivers/iommu/intel/dmar.c             |   6 +-
>  include/linux/dmar.h                   |   6 +-
>  21 files changed, 115 insertions(+), 459 deletions(-)
>  delete mode 100644 arch/ia64/include/asm/iommu_table.h
>  delete mode 100644 arch/x86/include/asm/iommu_table.h
>  delete mode 100644 arch/x86/include/asm/swiotlb.h
>  delete mode 100644 arch/x86/kernel/pci-iommu_table.c
>  delete mode 100644 arch/x86/kernel/pci-swiotlb.c
>  delete mode 100644 arch/x86/xen/pci-swiotlb-xen.c

checkpatch.pl has some warnings here.

WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#44: 
deleted file mode 100644

WARNING: Prefer [subsystem eg: netdev]_info([subsystem]dev, ... then dev_info(dev, ... then pr_info(...  to printk(KERN_INFO ...
#496: FILE: arch/x86/kernel/pci-dma.c:171:
+               printk(KERN_INFO "PCI-DMA: "

WARNING: quoted string split across lines
#497: FILE: arch/x86/kernel/pci-dma.c:172:
+               printk(KERN_INFO "PCI-DMA: "
+                      "Using software bounce buffering for IO (SWIOTLB)\n");

ERROR: trailing whitespace
#881: FILE: drivers/iommu/amd/iommu.c:1837:
+^Iif (iommu_default_passthrough() || sme_me_mask) $

total: 1 errors, 3 warnings, 389 lines checked