For auto-translated domain, the only way to map page to itself is the
using foreign map API. The current code does not allow mapping page from
special page (such as DOMID_XEN).
As xentrace buffer are shared using DOMID_XEN, it is not possible to use
tracing for Arm.
This could be solved by using the helper get_pg_owner(). This helper will
be able to get a reference on DOMID_XEN and therefore allow mapping for
privileged domain.
This patch replace the call to rcu_lock_domain_by_any_id() with
get_pg_owner(). For consistency, all the call to rcu_unlock_domain are
replaced by put_pg_owner().
Signed-off-by: Julien grall
---
xen/arch/arm/mm.c | 12 ++--
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index e31b47a394..72d0285768 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1249,20 +1249,20 @@ int xenmem_add_to_physmap_one(
struct domain *od;
p2m_type_t p2mt;
-od = rcu_lock_domain_by_any_id(extra.foreign_domid);
+od = get_pg_owner(extra.foreign_domid);
if ( od == NULL )
return -ESRCH;
if ( od == d )
{
-rcu_unlock_domain(od);
+put_pg_owner(od);
return -EINVAL;
}
rc = xsm_map_gmfn_foreign(XSM_TARGET, d, od);
if ( rc )
{
-rcu_unlock_domain(od);
+put_pg_owner(od);
return rc;
}
@@ -1271,21 +1271,21 @@ int xenmem_add_to_physmap_one(
page = get_page_from_gfn(od, idx, , P2M_ALLOC);
if ( !page )
{
-rcu_unlock_domain(od);
+put_pg_owner(od);
return -EINVAL;
}
if ( !p2m_is_ram(p2mt) )
{
put_page(page);
-rcu_unlock_domain(od);
+put_pg_owner(od);
return -EINVAL;
}
mfn = page_to_mfn(page);
t = (p2mt == p2m_ram_rw) ? p2m_map_foreign_rw : p2m_map_foreign_ro;
-rcu_unlock_domain(od);
+put_pg_owner(od);
break;
}
case XENMAPSPACE_dev_mmio:
--
2.11.0
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