[Xen-devel] [PATCH for 4.6] x86/mm: make {set, clear}_identity_p2m_mapping() work for HVM guests as well

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

From: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>

For Intel IGD passthrough, the guest driver programs the device to DMA
to/from its RMRR.

c/s 619ecf8 "make {set,clear}_identity_p2m_mapping() work for PV guests"
was incomplete for pre-Broadwell systems which did not support shared
EPT.

The correct check to use is iommu_use_hap_pt() not
paging_mode_translate() as IOMMU mappings also need to be created for
HVM guests with separate EPT and IOMMU tables.

Signed-off-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/arch/x86/mm/p2m.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index c4329d2..c7f437c 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -957,7 +957,7 @@ int set_identity_p2m_entry(struct domain *d, unsigned long 
gfn,
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
     int ret;
 
-    if ( !paging_mode_translate(p2m->domain) )
+    if ( !iommu_use_hap_pt(d) )
     {
         if ( !need_iommu(d) )
             return 0;
@@ -1032,7 +1032,7 @@ int clear_identity_p2m_entry(struct domain *d, unsigned 
long gfn)
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
     int ret;
 
-    if ( !paging_mode_translate(d) )
+    if ( !iommu_use_hap_pt(d) )
     {
         if ( !need_iommu(d) )
             return 0;
-- 
1.7.10.4


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