From bd49940a35ec7d488ae63bd625639893b3385b97 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Wed, 19 Sep 2012 08:30:55 -0400 Subject: [PATCH] xen/boot: Disable BIOS SMP MP table search. 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@vger.kernel.org Fixes-Oracle-Bugzilla: https://bugzilla.oracle.com/bugzilla/show_bug.cgi?id=13665 Acked-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/enlighten.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 9642d4a38602..1fbe75a95f15 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. */