Re: [Xen-devel] [PATCH 10 of 16] amd iommu: Enable FC bit in iommu host level PTE

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 23.12.11 at 12:29, Wei Wang <wei.wang2@xxxxxxx> wrote:
> # HG changeset patch
> # User Wei Wang <wei.wang2@xxxxxxx>
> # Date 1324569401 -3600
> # Node ID 30b1f434160d989be5e0bb6c6956bb7e3985db59
> # Parent  dd808bdd61c581b041d5b7e816b18674de51da6f
> amd iommu: Enable FC bit in iommu host level PTE
> 
> Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>
> 
> diff -r dd808bdd61c5 -r 30b1f434160d xen/drivers/passthrough/amd/iommu_map.c
> --- a/xen/drivers/passthrough/amd/iommu_map.c Thu Dec 22 16:56:38 2011 +0100
> +++ b/xen/drivers/passthrough/amd/iommu_map.c Thu Dec 22 16:56:41 2011 +0100
> @@ -83,6 +83,11 @@ static bool_t set_iommu_pde_present(u32 
>      set_field_in_reg_u32(ir, entry,
>                           IOMMU_PDE_IO_READ_PERMISSION_MASK,
>                           IOMMU_PDE_IO_READ_PERMISSION_SHIFT, &entry);
> +
> +    /* IOMMUv2 needs FC bit enabled  */

This comment suggests that the patches prior to that aren't consistent.
Is this really a proper standalone patch, or is the word "needs" too
strict, or should it really be moved ahead in the series?

> +    if ( next_level == IOMMU_PAGING_MODE_LEVEL_0 )
> +        set_field_in_reg_u32(IOMMU_CONTROL_ENABLED, entry,
> +                             IOMMU_PTE_FC_MASK, IOMMU_PTE_FC_SHIFT, &entry);

This is being done no matter whether it actually is a v2 IOMMU that
you deal with here - if that's correct, the comment above should be
adjusted accordingly.

Jan

>      pde[1] = entry;
>  
>      /* mark next level as 'present' */




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