From: Ian Campbell Date: Fri, 18 Jul 2014 13:33:59 +0000 (+0100) Subject: xen: arm: avoid reusing incorrect mappings when walking the p2m. X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~4636 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=964fd5a99c13c707c0c3355743ed1fadf88fc9d9;p=xen.git xen: arm: avoid reusing incorrect mappings when walking the p2m. When we change which PT page we are mapping at a given level then we need to invalidate any cached mappings further down the tree, otherwise we risk using them because their offset might match but be based on a different offset further up the table. e.g. when remapping first then cur_first_offset and cur_second_offset (which indicate the currently mapped second and third tables respectively) both become invalid Signed-off-by: Ian Campbell Acked-by: Julien Grall --- diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index 2f855b5d5c..8ffddacb06 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -743,6 +743,8 @@ static int apply_p2m_changes(struct domain *d, goto out; } cur_first_page = p2m_first_level_index(addr); + /* Any mapping further down is now invalid */ + cur_first_offset = cur_second_offset = ~0; } /* We only use a 3 level p2m at the moment, so no level 0, @@ -765,6 +767,8 @@ static int apply_p2m_changes(struct domain *d, if (second) unmap_domain_page(second); second = map_domain_page(first[first_table_offset(addr)].p2m.base); cur_first_offset = first_table_offset(addr); + /* Any mapping further down is now invalid */ + cur_second_offset = ~0; } /* else: second already valid */