From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: [PATCH 10/21] xenpaging: when populating a page, check if populating is already in progress Date: Fri, 26 Nov 2010 14:49:11 +0100 Message-ID: <20101126134904.868035612@aepfle.de> References: <20101126134901.384130351@aepfle.de> Return-path: Content-Disposition: inline; filename=xen-unstable.xenpaging.p2m_mem_paging_populate_if_p2m_ram_paged.patch List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org 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 keep p2m state 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. Signed-off-by: Olaf Hering --- xen/arch/x86/mm/p2m.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- xen-unstable.hg-4.1.22433.orig/xen/arch/x86/mm/p2m.c +++ xen-unstable.hg-4.1.22433/xen/arch/x86/mm/p2m.c @@ -2767,7 +2767,7 @@ void p2m_mem_paging_populate(struct p2m_ /* 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(p2m, gfn, &p2mt); - if ( p2mt != p2m_ram_paging_out ) + if ( p2mt == p2m_ram_paged ) { p2m_lock(p2m); set_p2m_entry(p2m, gfn, _mfn(PAGING_MFN), 0, p2m_ram_paging_in_start);