x86: don't allow page table updates on non-PV page tables in do_mmu_update()
paging_write_guest_entry() and paging_cmpxchg_guest_entry() aren't
consistently supported for non-PV guests (they'd deref NULL for PVH or
non-HAP HVM ones). Don't allow respective MMU_* operations on the
page tables of such domains.
This is XSA-109.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tim Deegan <tim@xen.org>
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -3493,6 +3493,10 @@ long do_mmu_update(
{
p2m_type_t p2mt;
+ rc = -EOPNOTSUPP;
+ if ( unlikely(paging_mode_refcounts(pt_owner)) )
+ break;
+
xsm_needed |= XSM_MMU_NORMAL_UPDATE;
if ( get_pte_flags(req.val) & _PAGE_PRESENT )
{