Xen devel - Mar 2012 - [PATCH] xenpaging: add error code to indicate iommem passthrough

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1333120147 -7200
# Node ID 34d9828185501f6e7ea2c3c2a397176a8e54ef0a
# Parent  80653c8ea1d19dfe6130396bbc77f766eb9f9fab
xenpaging: add error code to indicate iommem passthrough

Similar to the existing ENODEV and EXDEV error codes, add EMDEV to
indicate that iommu passthrough is not compatible with paging.
All error codes are just made-up return codes to give proper error
messages in the pager.

Also update the HAP related error message now that paging is enabled
also on AMD hosts.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r 80653c8ea1d1 -r 34d982818550 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c
+++ b/tools/xenpaging/xenpaging.c
@@ -378,7 +378,10 @@ static struct xenpaging *xenpaging_init(
                 ERROR("xenpaging is (or was) active on this domain");
                 break;
             case ENODEV:
-                ERROR("EPT not supported for this guest");
+                ERROR("xenpaging requires Hardware Assisted Paging");
+                break;
+            case EMLINK:
+                ERROR("xenpaging not supported while iommu passthrough is
enabled");
                 break;
             case EXDEV:
                 ERROR("xenpaging not supported in a PoD guest");
diff -r 80653c8ea1d1 -r 34d982818550 xen/arch/x86/mm/mem_event.c
--- a/xen/arch/x86/mm/mem_event.c
+++ b/xen/arch/x86/mm/mem_event.c
@@ -564,10 +564,11 @@ int mem_event_domctl(struct domain *d, x
                 break;
 
             /* No paging if iommu is used */
-            rc = -EXDEV;
+            rc = -EMLINK;
             if ( unlikely(need_iommu(d)) )
                 break;
 
+            rc = -EXDEV;
             /* Disallow paging in a PoD guest */
             if ( p2m->pod.entry_count )
                 break;

At 17:10 +0200 on 30 Mar (1333127445), Olaf Hering
wrote:
> # HG changeset patch
> # User Olaf Hering <olaf@aepfle.de>
> # Date 1333120147 -7200
> # Node ID 34d9828185501f6e7ea2c3c2a397176a8e54ef0a
> # Parent  80653c8ea1d19dfe6130396bbc77f766eb9f9fab
> xenpaging: add error code to indicate iommem passthrough
> 
> Similar to the existing ENODEV and EXDEV error codes, add EMDEV to
> indicate that iommu passthrough is not compatible with paging.
> All error codes are just made-up return codes to give proper error
> messages in the pager.
> 
> Also update the HAP related error message now that paging is enabled
> also on AMD hosts.
I believe what I said was: 

] I''ll take a patch to change the return code if it also documents it
in
] the hypercall interface. :)

This adds another funny errno and doesn''t document anything!

Just to be clear: if you want to use these ERRNO values with something
other than their usual meaning, then please add some comments in
xen/include/public/domctl.h to describe what''s going on.

Cheers,

Tim.
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> 
> diff -r 80653c8ea1d1 -r 34d982818550 tools/xenpaging/xenpaging.c
> --- a/tools/xenpaging/xenpaging.c
> +++ b/tools/xenpaging/xenpaging.c
> @@ -378,7 +378,10 @@ static struct xenpaging *xenpaging_init(
>                  ERROR("xenpaging is (or was) active on this
domain");
>                  break;
>              case ENODEV:
> -                ERROR("EPT not supported for this guest");
> +                ERROR("xenpaging requires Hardware Assisted
Paging");
> +                break;
> +            case EMLINK:
> +                ERROR("xenpaging not supported while iommu
passthrough is enabled");
>                  break;
>              case EXDEV:
>                  ERROR("xenpaging not supported in a PoD guest");
> diff -r 80653c8ea1d1 -r 34d982818550 xen/arch/x86/mm/mem_event.c
> --- a/xen/arch/x86/mm/mem_event.c
> +++ b/xen/arch/x86/mm/mem_event.c
> @@ -564,10 +564,11 @@ int mem_event_domctl(struct domain *d, x
>                  break;
>  
>              /* No paging if iommu is used */
> -            rc = -EXDEV;
> +            rc = -EMLINK;
>              if ( unlikely(need_iommu(d)) )
>                  break;
>  
> +            rc = -EXDEV;
>              /* Disallow paging in a PoD guest */
>              if ( p2m->pod.entry_count )
>                  break;
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Olaf Hering writes ("[Xen-devel] [PATCH] xenpaging: add error code to
indicate iommem passthrough"):
> xenpaging: add error code to indicate iommem passthrough
> 
> Similar to the existing ENODEV and EXDEV error codes, add EMDEV to
> indicate that iommu passthrough is not compatible with paging.
> All error codes are just made-up return codes to give proper error
> messages in the pager.
> 
> Also update the HAP related error message now that paging is enabled
> also on AMD hosts.
The tools parts of this are fine.

Ian.

At 17:10 +0200 on 30 Mar (1333127445), Olaf Hering
wrote:
> xenpaging: add error code to indicate iommem passthrough
> 
> Similar to the existing ENODEV and EXDEV error codes, add EMDEV to
> indicate that iommu passthrough is not compatible with paging.
> All error codes are just made-up return codes to give proper error
> messages in the pager.
> 
> Also update the HAP related error message now that paging is enabled
> also on AMD hosts.
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
Applied, thanks.

Tim.