[Xen-devel] [PATCH v3 06/17] x86: allow per-domain mappings without NX bit or with specific mfn

[Juergen Gross <jgross@xxxxxxxx>]

For support of per-vcpu stacks we need per-vcpu trampolines. To be
able to put those into the per-domain mappings the upper levels
page tables must not have NX set for per-domain mappings.

As create_perdomain_mapping() creates L1 mappings with flags being
__PAGE_HYPERVISOR_RW this won't change any of the current per domain
mappings to become executable.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3:
- remove functions for modifying per-domain mappings (Jan Beulich)
---
 xen/arch/x86/mm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e795239829..d86e07e9f8 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1568,7 +1568,7 @@ void init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
 
     /* Slot 260: Per-domain mappings (if applicable). */
     l4t[l4_table_offset(PERDOMAIN_VIRT_START)] =
-        d ? l4e_from_page(d->arch.perdomain_l3_pg, __PAGE_HYPERVISOR_RW)
+        d ? l4e_from_page(d->arch.perdomain_l3_pg, __PAGE_HYPERVISOR)
           : l4e_empty();
 
     /* Slot 261-: text/data/bss, RW M2P, vmap, frametable, directmap. */
@@ -5319,7 +5319,7 @@ int create_perdomain_mapping(struct domain *d, unsigned 
long va,
         }
         l2tab = __map_domain_page(pg);
         clear_page(l2tab);
-        l3tab[l3_table_offset(va)] = l3e_from_page(pg, __PAGE_HYPERVISOR_RW);
+        l3tab[l3_table_offset(va)] = l3e_from_page(pg, __PAGE_HYPERVISOR);
     }
     else
         l2tab = map_l2t_from_l3e(l3tab[l3_table_offset(va)]);
@@ -5361,7 +5361,7 @@ int create_perdomain_mapping(struct domain *d, unsigned 
long va,
                 l1tab = __map_domain_page(pg);
             }
             clear_page(l1tab);
-            *pl2e = l2e_from_page(pg, __PAGE_HYPERVISOR_RW);
+            *pl2e = l2e_from_page(pg, __PAGE_HYPERVISOR);
         }
         else if ( !l1tab )
             l1tab = map_l1t_from_l2e(*pl2e);
-- 
2.13.6


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