From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754932Ab2ISOyy (ORCPT ); Wed, 19 Sep 2012 10:54:54 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:36858 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751790Ab2ISOyv convert rfc822-to-8bit (ORCPT ); Wed, 19 Sep 2012 10:54:51 -0400 Message-Id: <5059F8D8020000780009C5CD@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Wed, 19 Sep 2012 15:54:48 +0100 From: "Jan Beulich" To: "Konrad Rzeszutek Wilk" Cc: , "xen-devel" , Subject: Re: [Xen-devel] [PATCH] xen/boot: Disable BIOS SMP MP table search. References: <1348061269-19133-1-git-send-email-konrad.wilk@oracle.com> In-Reply-To: <1348061269-19133-1-git-send-email-konrad.wilk@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 19.09.12 at 15:27, Konrad Rzeszutek Wilk wrote: > As the initial domain we are able to search/map certain regions > of memory to harvest configuration data. For all low-level we > use ACPI tables - for interrupts we use exclusively ACPI _PRT > (so DSDT) and MADT for INT_SRC_OVR. > > The SMP MP table is not used at all. As a matter of fact we do > not even support machines that only have SMP MP but no ACPI tables. > > Lets follow how Moorestown does it and just disable searching > for BIOS SMP tables. > > This also fixes an issue on HP Proliant BL680c G5 and DL380 G6: > > 9f->100 for 1:1 PTE > Freeing 9f-100 pfn range: 97 pages freed > 1-1 mapping on 9f->100 > .. snip.. > e820: BIOS-provided physical RAM map: > Xen: [mem 0x0000000000000000-0x000000000009efff] usable > Xen: [mem 0x000000000009f400-0x00000000000fffff] reserved > Xen: [mem 0x0000000000100000-0x00000000cfd1dfff] usable > .. snip.. > Scan for SMP in [mem 0x00000000-0x000003ff] > Scan for SMP in [mem 0x0009fc00-0x0009ffff] > Scan for SMP in [mem 0x000f0000-0x000fffff] > found SMP MP-table at [mem 0x000f4fa0-0x000f4faf] mapped at [ffff8800000f4fa0] > (XEN) mm.c:908:d0 Error getting mfn 100 (pfn 5555555555555555) from L1 entry > 0000000000100461 for l1e_owner=0, pg_owner=0 > (XEN) mm.c:4995:d0 ptwr_emulate: could not get_page_from_l1e() > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [] xen_set_pte_init+0x66/0x71 > . snip.. > Pid: 0, comm: swapper Not tainted 3.6.0-rc6upstream-00188-gb6fb969-dirty #2 HP > ProLiant BL680c G5 > .. snip.. > Call Trace: > [] __early_ioremap+0x18a/0x248 > [] ? printk+0x48/0x4a > [] early_ioremap+0x13/0x15 > [] get_mpc_size+0x2f/0x67 > [] smp_scan_config+0x10c/0x136 > [] default_find_smp_config+0x36/0x5a > [] setup_arch+0x5b3/0xb5b > [] ? printk+0x48/0x4a > [] start_kernel+0x90/0x390 > [] x86_64_start_reservations+0x131/0x136 > [] xen_start_kernel+0x65f/0x661 > (XEN) Domain 0 crashed: 'noreboot' set - not rebooting. > > which is that ioremap would end up mapping 0xff using _PAGE_IOMAP > (which is what early_ioremap sticks as a flag) - which meant > we would get MFN 0xFF (pte ff461, which is OK), and then it would > also map 0x100 (b/c ioremap tries to get page aligned request, and > it was trying to map 0xf4fa0 + PAGE_SIZE - so it mapped the next page) > as _PAGE_IOMAP. Since 0x100 is actually a RAM page, and the _PAGE_IOMAP > bypasses the P2M lookup we would happily set the PTE to 1000461. > Xen would deny the request since we do not have access to the > Machine Frame Number (MFN) of 0x100. The P2M[0x100] is for example > 0x80140. > > CC: stable@kernel.org > Fixes-Oracle-Bugzilla: > https://bugzilla.oracle.com/bugzilla/show_bug.cgi?id=13665 > Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Jan Beulich > --- > arch/x86/xen/enlighten.c | 4 ++++ > 1 files changed, 4 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > index 9642d4a..1fbe75a 100644 > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -1452,6 +1452,10 @@ asmlinkage void __init xen_start_kernel(void) > pci_request_acs(); > > xen_acpi_sleep_register(); > + > + /* Avoid searching for BIOS MP tables */ > + x86_init.mpparse.find_smp_config = x86_init_noop; > + x86_init.mpparse.get_smp_config = x86_init_uint_noop; > } > #ifdef CONFIG_PCI > /* PCI BIOS service won't work from a PV guest. */ > -- > 1.7.7.6 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel