From 615897bc6c01c862a4136816f1354acbab2d40c2 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Fri, 21 Dec 2018 16:26:47 +0000 Subject: [PATCH] xen/arm: Allow a privileged domain to map foreign page from DOMID_XEN For auto-translated domain, the only way to map a page to itself is the using the foreign map API. The current code does not allow mapping page from special page (such as DOMID_XEN). As xentrace buffers 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 Reviewed-by: Andrii Anisov Reviewed-by: Stefano Stabellini --- 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 3bf11eec4f..01ae2cccc0 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -1233,20 +1233,20 @@ 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; } @@ -1255,7 +1255,7 @@ int xenmem_add_to_physmap_one( page = get_page_from_gfn(od, idx, &p2mt, P2M_ALLOC); if ( !page ) { - rcu_unlock_domain(od); + put_pg_owner(od); return -EINVAL; } @@ -1264,13 +1264,13 @@ int xenmem_add_to_physmap_one( else { put_page(page); - rcu_unlock_domain(od); + put_pg_owner(od); return -EINVAL; } mfn = page_to_mfn(page); - rcu_unlock_domain(od); + put_pg_owner(od); break; } case XENMAPSPACE_dev_mmio: -- 2.30.2