Re: [RFC PATCH v7 03/14] x86/domain: Defer domain iommu initialization.

[Jan Beulich <jbeulich@suse.com>]

On 20.11.2025 12:09, Teddy Astie wrote:
> For the IOMMU redesign, the iommu context pagetable is defined once during
> initialization. When reusing P2M pagetable, we want to ensure that this
> pagetable is properly initialized.
> 
> Signed-off-by Teddy Astie <teddy.astie@vates.tech>

From what is said, I for one cannot deduce why the move is (a) necessary and
(b) correct / safe to do.

Jan

> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -927,9 +927,6 @@ int arch_domain_create(struct domain *d,
>      if ( (rc = init_domain_irq_mapping(d)) != 0 )
>          goto fail;
>  
> -    if ( (rc = iommu_domain_init(d, config->iommu_opts)) != 0 )
> -        goto fail;
> -
>      psr_domain_init(d);
>  
>      if ( is_hvm_domain(d) )
> @@ -948,6 +945,9 @@ int arch_domain_create(struct domain *d,
>      else
>          ASSERT_UNREACHABLE(); /* Not HVM and not PV? */
>  
> +    if ( (rc = iommu_domain_init(d, config->iommu_opts)) != 0 )
> +        goto fail;
> +
>      if ( (rc = tsc_set_info(d, XEN_CPUID_TSC_MODE_DEFAULT, 0, 0, 0)) != 0 )
>      {
>          ASSERT_UNREACHABLE();