[Xen-devel] [PATCH v6 5/9] x86/mem_sharing: use default_access in add_to_physmap

[Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>]

When plugging a hole in the target physmap don't use the access permission
returned by __get_gfn_type_access as it can be non-sensical, leading to
spurious vm_events being sent out for access violations at unexpected
locations. Make use of p2m->default_access instead.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>
---
 xen/arch/x86/mm/mem_sharing.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index 2b3be5b125..52b139c1bb 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -1071,11 +1071,10 @@ int add_to_physmap(struct domain *sd, unsigned long 
sgfn, shr_handle_t sh,
     p2m_type_t smfn_type, cmfn_type;
     struct gfn_info *gfn_info;
     struct p2m_domain *p2m = p2m_get_hostp2m(cd);
-    p2m_access_t a;
     struct two_gfns tg;
 
     get_two_gfns(sd, _gfn(sgfn), &smfn_type, NULL, &smfn,
-                 cd, _gfn(cgfn), &cmfn_type, &a, &cmfn, 0, &tg, lock);
+                 cd, _gfn(cgfn), &cmfn_type, NULL, &cmfn, 0, &tg, lock);
 
     /* Get the source shared page, check and lock */
     ret = XENMEM_SHARING_OP_S_HANDLE_INVALID;
@@ -1110,7 +1109,7 @@ int add_to_physmap(struct domain *sd, unsigned long sgfn, 
shr_handle_t sh,
     }
 
     ret = p2m_set_entry(p2m, _gfn(cgfn), smfn, PAGE_ORDER_4K,
-                        p2m_ram_shared, a);
+                        p2m_ram_shared, p2m->default_access);
 
     /* Tempted to turn this into an assert */
     if ( ret )
-- 
2.20.1


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