Re: [Xen-devel] [v3][PATCH 1/1] xen:vtd: missing RMRR mapping while share EPT

[Tim Deegan <tim@xxxxxxx>]

At 19:00 +0800 on 24 Jul (1406224818), Tiejun Chen wrote:
> intel_iommu_map_page() does nothing if VT-d shares EPT page table.
> So rmrr_identity_mapping() never create RMRR mapping but in some
> cases like some GFX drivers it still need to access RMRR.
> 
> Here we will create those RMRR mappings even in shared EPT case.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>

For the interaction with p2m code:

Acked-by: Tim Deegn <tim@xxxxxxx>

though I am still worried about what happens if this overwrites an
existing mapping. 

Tim.

> ---
>  xen/drivers/passthrough/vtd/iommu.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> v3:
> 
> * Use set_mmio_p2m_entry() to replace p2m_set_entry()
> * Use ASSERT to check
> 
> v2:
> 
> * Fix coding style.
> * Still need to abide intel_iommu_map_page(), so we should do nothing
>   if dom0 and iommu supports pass thru.
> 
> diff --git a/xen/drivers/passthrough/vtd/iommu.c 
> b/xen/drivers/passthrough/vtd/iommu.c
> index 042b882..f08a1fc 100644
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -1867,8 +1867,14 @@ static int rmrr_identity_mapping(struct domain *d,
>  
>      while ( base_pfn < end_pfn )
>      {
> -        if ( intel_iommu_map_page(d, base_pfn, base_pfn,
> -                                  IOMMUF_readable|IOMMUF_writable) )
> +        if ( iommu_use_hap_pt(d) )
> +        {
> +            ASSERT(!iommu_passthrough || !is_hardware_domain(d));
> +            if ( set_mmio_p2m_entry(d, base_pfn, _mfn(base_pfn)) )
> +                return -1;
> +        }
> +        else if ( intel_iommu_map_page(d, base_pfn, base_pfn,
> +                                       IOMMUF_readable|IOMMUF_writable) )
>              return -1;
>          base_pfn++;
>      }
> -- 
> 1.9.1
> 
> 
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