Re: [PATCH v3 1/3] iommu/amd: Drop unused global exclusion range fields and init

[Jindal, Akshay]

On 06-11-2026 09:46, Sairaj Kodilkar wrote:
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> 
> 
> From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> 
> Remove unused struct amd_iommu.exclusion_start/exclusion_length, the
> MMIO_EXCL_* flag masks, and iommu_set_exclusion_range(). These struct
> amd_iommu fields were never assigned, so early_enable_iommu() never
> programmed the hardware exclusion registers through this path.
> 
> Please note that the exclusion range registers have been repurposed
> to SNP completion-wait store base / limit registers. So, rename
> MMIO_EXCL_BASE/LIMIT via to MMIO_COMPL_STORE_BASE/LIMIT instead.
Reviewed-by: Akshay Jindal <Akshay.Jindal@xxxxxxx>
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> Signed-off-by: Sairaj Kodilkar <sarunkod@xxxxxxx>
> Tested-by: Adam Pelka <adampelka26@xxxxxxxxx>
> ---
>  drivers/iommu/amd/amd_iommu_types.h | 4 ++--
>  drivers/iommu/amd/init.c            | 6 +++---
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
> index 8241ef922519..678ceddd711c 100644
> --- a/drivers/iommu/amd/amd_iommu_types.h
> +++ b/drivers/iommu/amd/amd_iommu_types.h
> @@ -44,8 +44,8 @@
>  #define MMIO_CMD_BUF_OFFSET     0x0008
>  #define MMIO_EVT_BUF_OFFSET     0x0010
>  #define MMIO_CONTROL_OFFSET     0x0018
> -#define MMIO_EXCL_BASE_OFFSET   0x0020
> -#define MMIO_EXCL_LIMIT_OFFSET  0x0028
> +#define MMIO_COMPL_STORE_BASE_OFFSET   0x0020
> +#define MMIO_COMPL_STORE_LIMIT_OFFSET  0x0028
nit:
1. since it is SW based re-purpose and used in function iommu_set_cwwb_range()
suggesting renaming to MMIO_CWWB_BASE_OFFSET & MMIO_CWWB_LIMIT_OFFSET
>  #define MMIO_EXT_FEATURES      0x0030
>  #define MMIO_PPR_LOG_OFFSET    0x0038
>  #define MMIO_GA_LOG_BASE_OFFSET        0x00e0
> diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> index 8a410d4aa370..13c96feed64f 100644
> --- a/drivers/iommu/amd/init.c
> +++ b/drivers/iommu/amd/init.c
> @@ -370,14 +370,14 @@ static void iommu_set_cwwb_range(struct amd_iommu *iommu)
>          * Re-purpose Exclusion base/limit registers for Completion wait
>          * write-back base/limit.
>          */
> -       memcpy_toio(iommu->mmio_base + MMIO_EXCL_BASE_OFFSET,
> +       memcpy_toio(iommu->mmio_base + MMIO_COMPL_STORE_BASE_OFFSET,
>                     &entry, sizeof(entry));
> 
>         /* Note:
>          * Default to 4 Kbytes, which can be specified by setting base
>          * address equal to the limit address.
>          */
> -       memcpy_toio(iommu->mmio_base + MMIO_EXCL_LIMIT_OFFSET,
> +       memcpy_toio(iommu->mmio_base + MMIO_COMPL_STORE_LIMIT_OFFSET,
>                     &entry, sizeof(entry));
>  }
> 
> @@ -1022,7 +1022,7 @@ static int __init remap_or_alloc_cwwb_sem(struct amd_iommu *iommu)
>                  * completion wait buffer (CWB) address. Read and re-use it.
>                  */
>                 pr_info_once("Re-using CWB buffers from the previous kernel\n");
> -               paddr = readq(iommu->mmio_base + MMIO_EXCL_BASE_OFFSET) & PM_ADDR_MASK;
> +               paddr = readq(iommu->mmio_base + MMIO_COMPL_STORE_BASE_OFFSET) & PM_ADDR_MASK;
>                 iommu->cmd_sem = iommu_memremap(paddr, PAGE_SIZE);
>                 if (!iommu->cmd_sem)
>                         return -ENOMEM;
> --
> 2.34.1
> 
>