[PATCH] x86/mm: make {set, clear}_identity_p2m_mapping() work for PV guests

[PATCH] x86/mm: make {set, clear}_identity_p2m_mapping() work for PV guests

[Jan Beulich]

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Namely Dom0 suffers from commit 5ae03990c1 ("xen/vtd: create RMRR
mapping") having removed the creation of such mappings for non-
translated guests.

Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -957,7 +957,11 @@ int set_identity_p2m_entry(struct domain
     int ret;
 
     if ( !paging_mode_translate(p2m->domain) )
-        return 0;
+    {
+        if ( !need_iommu(d) )
+            return 0;
+        return iommu_map_page(d, gfn, gfn, IOMMUF_readable|IOMMUF_writable);
+    }
 
     gfn_lock(p2m, gfn, 0);
 
@@ -1028,7 +1032,11 @@ int clear_identity_p2m_entry(struct doma
     int ret;
 
     if ( !paging_mode_translate(d) )
-        return 0;
+    {
+        if ( !need_iommu(d) )
+            return 0;
+        return iommu_unmap_page(d, gfn);
+    }
 
     gfn_lock(p2m, gfn, 0);
 




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x86/mm: make {set,clear}_identity_p2m_mapping() work for PV guests

Namely Dom0 suffers from commit 5ae03990c1 ("xen/vtd: create RMRR
mapping") having removed the creation of such mappings for non-
translated guests.

Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -957,7 +957,11 @@ int set_identity_p2m_entry(struct domain
     int ret;
 
     if ( !paging_mode_translate(p2m->domain) )
-        return 0;
+    {
+        if ( !need_iommu(d) )
+            return 0;
+        return iommu_map_page(d, gfn, gfn, IOMMUF_readable|IOMMUF_writable);
+    }
 
     gfn_lock(p2m, gfn, 0);
 
@@ -1028,7 +1032,11 @@ int clear_identity_p2m_entry(struct doma
     int ret;
 
     if ( !paging_mode_translate(d) )
-        return 0;
+    {
+        if ( !need_iommu(d) )
+            return 0;
+        return iommu_unmap_page(d, gfn);
+    }
 
     gfn_lock(p2m, gfn, 0);
 

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Re: [PATCH] x86/mm: make {set, clear}_identity_p2m_mapping() work for PV guests

[Andrew Cooper]

On 28/08/15 17:10, Jan Beulich wrote:
> Namely Dom0 suffers from commit 5ae03990c1 ("xen/vtd: create RMRR
> mapping") having removed the creation of such mappings for non-
> translated guests.
>
> Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

I will get this into testing ASAP to confirm that it fixes the original
issue.

~Andrew

Re: [PATCH] x86/mm: make {set, clear}_identity_p2m_mapping() work for PV guests

[George Dunlap]

On Fri, Aug 28, 2015 at 5:10 PM, Jan Beulich <JBeulich@suse.com> wrote:
> Namely Dom0 suffers from commit 5ae03990c1 ("xen/vtd: create RMRR
> mapping") having removed the creation of such mappings for non-
> translated guests.
>
> Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

This is logically an IOMMU thing; so on the basis that it was
submitted by the vendor-independent IOMMU maintainer, after having
taken a look and verified the claims in the changelog:

Acked-by: George Dunlap <george.dunlap@citrix.com>

Re: [PATCH] x86/mm: make {set, clear}_identity_p2m_mapping() work for PV guests

[Jan Beulich]

>>> On 28.08.15 at 18:10, <JBeulich@suse.com> wrote:
> Namely Dom0 suffers from commit 5ae03990c1 ("xen/vtd: create RMRR
> mapping") having removed the creation of such mappings for non-
> translated guests.
> 
> Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Wei,

looks like I forgot to Cc you on the original submission.

Jan

> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -957,7 +957,11 @@ int set_identity_p2m_entry(struct domain
>      int ret;
>  
>      if ( !paging_mode_translate(p2m->domain) )
> -        return 0;
> +    {
> +        if ( !need_iommu(d) )
> +            return 0;
> +        return iommu_map_page(d, gfn, gfn, IOMMUF_readable|IOMMUF_writable);
> +    }
>  
>      gfn_lock(p2m, gfn, 0);
>  
> @@ -1028,7 +1032,11 @@ int clear_identity_p2m_entry(struct doma
>      int ret;
>  
>      if ( !paging_mode_translate(d) )
> -        return 0;
> +    {
> +        if ( !need_iommu(d) )
> +            return 0;
> +        return iommu_unmap_page(d, gfn);
> +    }
>  
>      gfn_lock(p2m, gfn, 0);
>  

Re: [PATCH] x86/mm: make {set, clear}_identity_p2m_mapping() work for PV guests

[Wei Liu]

On Tue, Sep 01, 2015 at 07:53:40AM -0600, Jan Beulich wrote:
> >>> On 28.08.15 at 18:10, <JBeulich@suse.com> wrote:
> > Namely Dom0 suffers from commit 5ae03990c1 ("xen/vtd: create RMRR
> > mapping") having removed the creation of such mappings for non-
> > translated guests.
> > 
> > Reported-by: Malcolm Crossley <malcolm.crossley@citrix.com>
> > Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 

Release-acked-by: Wei Liu <wei.liu2@citrix.com>