x86/iommu: Conditionally compile platform-specific union entries

[XEN PATCH] x86/iommu: Conditionally compile platform-specific union entries

Posted by Teddy Astie 6 months ago

If some platform driver isn't compiled in, remove its related union
entries as they are not used.

Signed-off-by Teddy Astie <teddy.astie@vates.tech>
---
 xen/arch/x86/include/asm/iommu.h | 4 ++++
 xen/arch/x86/include/asm/pci.h   | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/xen/arch/x86/include/asm/iommu.h b/xen/arch/x86/include/asm/iommu.h
index 8dc464fbd3..99180940c4 100644
--- a/xen/arch/x86/include/asm/iommu.h
+++ b/xen/arch/x86/include/asm/iommu.h
@@ -42,17 +42,21 @@ struct arch_iommu
     struct list_head identity_maps;
 
     union {
+        #ifdef CONFIG_INTEL_IOMMU
         /* Intel VT-d */
         struct {
             uint64_t pgd_maddr; /* io page directory machine address */
             unsigned int agaw; /* adjusted guest address width, 0 is level 2 30-bit */
             unsigned long *iommu_bitmap; /* bitmap of iommu(s) that the domain uses */
         } vtd;
+        #endif
+        #ifdef CONFIG_AMD_IOMMU
         /* AMD IOMMU */
         struct {
             unsigned int paging_mode;
             struct page_info *root_table;
         } amd;
+        #endif
     };
 };
 
diff --git a/xen/arch/x86/include/asm/pci.h b/xen/arch/x86/include/asm/pci.h
index fd5480d67d..842710f0dc 100644
--- a/xen/arch/x86/include/asm/pci.h
+++ b/xen/arch/x86/include/asm/pci.h
@@ -22,12 +22,16 @@ struct arch_pci_dev {
      */
     union {
         /* Subset of struct arch_iommu's fields, to be used in dom_io. */
+        #ifdef CONFIG_INTEL_IOMMU
         struct {
             uint64_t pgd_maddr;
         } vtd;
+        #endif
+        #ifdef CONFIG_AMD_IOMMU
         struct {
             struct page_info *root_table;
         } amd;
+        #endif
     };
     domid_t pseudo_domid;
     mfn_t leaf_mfn;
-- 
2.45.1



Teddy Astie | Vates XCP-ng Intern

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech

Re: [XEN PATCH] x86/iommu: Conditionally compile platform-specific union entries

Posted by Roger Pau Monné 6 months ago

On Thu, May 23, 2024 at 09:19:53AM +0000, Teddy Astie wrote:
> If some platform driver isn't compiled in, remove its related union
> entries as they are not used.
> 
> Signed-off-by Teddy Astie <teddy.astie@vates.tech>
> ---
>  xen/arch/x86/include/asm/iommu.h | 4 ++++
>  xen/arch/x86/include/asm/pci.h   | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/xen/arch/x86/include/asm/iommu.h b/xen/arch/x86/include/asm/iommu.h
> index 8dc464fbd3..99180940c4 100644
> --- a/xen/arch/x86/include/asm/iommu.h
> +++ b/xen/arch/x86/include/asm/iommu.h
> @@ -42,17 +42,21 @@ struct arch_iommu
>      struct list_head identity_maps;
>  
>      union {
> +        #ifdef CONFIG_INTEL_IOMMU
>          /* Intel VT-d */
>          struct {
>              uint64_t pgd_maddr; /* io page directory machine address */
>              unsigned int agaw; /* adjusted guest address width, 0 is level 2 30-bit */
>              unsigned long *iommu_bitmap; /* bitmap of iommu(s) that the domain uses */
>          } vtd;
> +        #endif
> +        #ifdef CONFIG_AMD_IOMMU
>          /* AMD IOMMU */
>          struct {
>              unsigned int paging_mode;
>              struct page_info *root_table;
>          } amd;
> +        #endif
>      };
>  };
>  
> diff --git a/xen/arch/x86/include/asm/pci.h b/xen/arch/x86/include/asm/pci.h
> index fd5480d67d..842710f0dc 100644
> --- a/xen/arch/x86/include/asm/pci.h
> +++ b/xen/arch/x86/include/asm/pci.h
> @@ -22,12 +22,16 @@ struct arch_pci_dev {
>       */
>      union {
>          /* Subset of struct arch_iommu's fields, to be used in dom_io. */
> +        #ifdef CONFIG_INTEL_IOMMU
>          struct {
>              uint64_t pgd_maddr;
>          } vtd;
> +        #endif
> +        #ifdef CONFIG_AMD_IOMMU
>          struct {
>              struct page_info *root_table;
>          } amd;
> +        #endif
>      };

The #ifdef and #endif processor directives shouldn't be indented.

Would you mind adding /* CONFIG_{AMD,INTEL}_IOMMU */ comments in the
#endif directives?

I wonder if we could move the definitions of those structures to the
vendor specific headers, but that's more convoluted, and would require
including the iommu headers in pci.h

Thanks, Roger.

Re: [XEN PATCH] x86/iommu: Conditionally compile platform-specific union entries

Posted by Teddy Astie 6 months ago

Le 23/05/2024 à 11:52, Roger Pau Monné a écrit :
> The #ifdef and #endif processor directives shouldn't be indented.
> 
> Would you mind adding /* CONFIG_{AMD,INTEL}_IOMMU */ comments in the
> #endif directives?
>

Sure, will change it for v2.

> I wonder if we could move the definitions of those structures to the
> vendor specific headers, but that's more convoluted, and would require
> including the iommu headers in pci.h

Do you mean moving the vtd/amd union entries to separate structures (e.g 
vtd_arch_iommu) and put them into another file (I don't see any 
vendor-specific headers for this, perhaps create ones ?).

> 
> Thanks, Roger.

Teddy


Teddy Astie | Vates XCP-ng Intern

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech