[Xen-devel] [PATCH] x86/p2m: fix non-translated handling of iommu mappings

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

The current usage of need_iommu_pt_sync in p2m for non-translated
guests is wrong because it doesn't correctly handle a relaxed PV
hardware domain, that has need_sync set to false, but still need
entries to be added from calls to {set/clear}_identity_p2m_entry.

Adjust the code in guest_physmap_add_page to also check whether the
domain has an iommu instead of whether it needs syncing or not in
order to take a reference to a page to be mapped.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
---
 xen/arch/x86/mm/p2m.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index fef97c82f6..88a2430c8c 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -836,7 +836,7 @@ guest_physmap_add_page(struct domain *d, gfn_t gfn, mfn_t 
mfn,
          */
         for ( i = 0; i < (1UL << page_order); ++i, ++page )
         {
-            if ( !need_iommu_pt_sync(d) )
+            if ( !has_iommu_pt(d) )
                 /* nothing */;
             else if ( get_page_and_type(page, d, PGT_writable_page) )
                 put_page_and_type(page);
@@ -1341,7 +1341,7 @@ int set_identity_p2m_entry(struct domain *d, unsigned 
long gfn_l,
 
     if ( !paging_mode_translate(p2m->domain) )
     {
-        if ( !need_iommu_pt_sync(d) )
+        if ( !has_iommu_pt(d) )
             return 0;
         return iommu_legacy_map(d, _dfn(gfn_l), _mfn(gfn_l), PAGE_ORDER_4K,
                                 IOMMUF_readable | IOMMUF_writable);
@@ -1432,7 +1432,7 @@ int clear_identity_p2m_entry(struct domain *d, unsigned 
long gfn_l)
 
     if ( !paging_mode_translate(d) )
     {
-        if ( !need_iommu_pt_sync(d) )
+        if ( !has_iommu_pt(d) )
             return 0;
         return iommu_legacy_unmap(d, _dfn(gfn_l), PAGE_ORDER_4K);
     }
-- 
2.20.1 (Apple Git-117)


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