From 2c2ae1976da06283e923d97720c0bdcbebf04515 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Thu, 14 Sep 2017 16:39:01 +0100 Subject: [PATCH] xen/arm: p2m: Read *_mapped_gfn with the p2m lock taken *_mapped_gfn are currently read before acquiring the lock. However, they may be modified by the p2m code before the lock was acquired. This means we will use the wrong values. Fix it by moving the read inside the section protected by the p2m lock. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini Signed-off-by: Stefano Stabellini --- xen/arch/arm/p2m.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index 0410b1e86b..68b488997d 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -1303,13 +1303,13 @@ int relinquish_p2m_mapping(struct domain *d) p2m_type_t t; int rc = 0; unsigned int order; - - /* Convenience alias */ - gfn_t start = p2m->lowest_mapped_gfn; - gfn_t end = p2m->max_mapped_gfn; + gfn_t start, end; p2m_write_lock(p2m); + start = p2m->lowest_mapped_gfn; + end = p2m->max_mapped_gfn; + for ( ; gfn_x(start) < gfn_x(end); start = gfn_next_boundary(start, order) ) { @@ -1364,9 +1364,6 @@ int p2m_cache_flush(struct domain *d, gfn_t start, unsigned long nr) p2m_type_t t; unsigned int order; - start = gfn_max(start, p2m->lowest_mapped_gfn); - end = gfn_min(end, p2m->max_mapped_gfn); - /* * The operation cache flush will invalidate the RAM assigned to the * guest in a given range. It will not modify the page table and @@ -1375,6 +1372,9 @@ int p2m_cache_flush(struct domain *d, gfn_t start, unsigned long nr) */ p2m_read_lock(p2m); + start = gfn_max(start, p2m->lowest_mapped_gfn); + end = gfn_min(end, p2m->max_mapped_gfn); + for ( ; gfn_x(start) < gfn_x(end); start = next_gfn ) { mfn_t mfn = p2m_get_entry(p2m, start, &t, NULL, &order); -- 2.30.2