From e201bfcc5c4fe6d58ce2b21fb4f4c2a2f0ab7ab8 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Mon, 22 Jul 2013 15:29:00 +0100 Subject: [PATCH] x86/xen: during early setup, only 1:1 map the ISA region During early setup, when the reserved regions and MMIO holes are being setup as 1:1 in the p2m, clear any mappings instead of making them 1:1 (execept for the ISA region which is expected to be mapped). This fixes a regression introduced in 3.5 by 83d51ab473dd (xen/setup: update VA mapping when releasing memory during setup) which caused hosts with tboot to fail to boot. tboot marks a region in the e820 map as unusable and the dom0 kernel would attempt to map this region and Xen does not permit unusable regions to be mapped by guests. (XEN) 0000000000000000 - 0000000000060000 (usable) (XEN) 0000000000060000 - 0000000000068000 (reserved) (XEN) 0000000000068000 - 000000000009e000 (usable) (XEN) 0000000000100000 - 0000000000800000 (usable) (XEN) 0000000000800000 - 0000000000972000 (unusable) tboot marked this region as unusable. (XEN) 0000000000972000 - 00000000cf200000 (usable) (XEN) 00000000cf200000 - 00000000cf38f000 (reserved) (XEN) 00000000cf38f000 - 00000000cf3ce000 (ACPI data) (XEN) 00000000cf3ce000 - 00000000d0000000 (reserved) (XEN) 00000000e0000000 - 00000000f0000000 (reserved) (XEN) 00000000fe000000 - 0000000100000000 (reserved) (XEN) 0000000100000000 - 0000000630000000 (usable) Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/setup.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 403f5cc5415b..6243651623d5 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -218,13 +218,19 @@ static void __init xen_set_identity_and_release_chunk( unsigned long pfn; /* - * If the PFNs are currently mapped, the VA mapping also needs - * to be updated to be 1:1. + * If the PFNs are currently mapped, clear the mappings + * (except for the ISA region which must be 1:1 mapped) to + * release the refcounts (in Xen) on the original frames. */ - for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) + for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) { + pte_t pte = __pte_ma(0); + + if (pfn < PFN_UP(ISA_END_ADDRESS)) + pte = mfn_pte(pfn, PAGE_KERNEL_IO); + (void)HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - mfn_pte(pfn, PAGE_KERNEL_IO), 0); + (unsigned long)__va(pfn << PAGE_SHIFT), pte, 0); + } if (start_pfn < nr_pages) *released += xen_release_chunk( -- 2.34.1