Subject: xenpaging: when populating a page, check if populating is already in progress p2m_mem_paging_populate can be called serveral times from different vcpus. If the page is already in state p2m_ram_paging_in and has a new valid mfn, invalidating this new mfn will cause trouble later if p2m_mem_paging_resume will set the new gfn/mfn pair back to state p2m_ram_rw. Detect this situation and change p2m state not if the page is in the process of being still paged-out or already paged-in. In fact, p2m state p2m_ram_paged is the only state where the mfn type can be invalidated. (xen-unstable changeset: 22443:48b10f9a436e) Signed-off-by: Olaf Hering --- xen/arch/x86/mm/p2m.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: xen-4.0.2-testing/xen/arch/x86/mm/p2m.c =================================================================== --- xen-4.0.2-testing.orig/xen/arch/x86/mm/p2m.c +++ xen-4.0.2-testing/xen/arch/x86/mm/p2m.c @@ -2588,7 +2588,7 @@ void p2m_mem_paging_populate(struct doma /* XXX: It seems inefficient to have this here, as it's only needed * in one case (ept guest accessing paging out page) */ gfn_to_mfn(d, gfn, &p2mt); - if ( p2mt != p2m_ram_paging_out ) + if ( p2mt == p2m_ram_paged ) { p2m_lock(d->arch.p2m); set_p2m_entry(d, gfn, _mfn(PAGING_MFN), 0, p2m_ram_paging_in_start);