[Xen-devel] [PATCH V2 24/40] arm: fix locking in create_p2m_entries

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

For some reason we were holding the lock over only the unmaps at the end of
the function, rather than for the whole walk.

We might want to be more clever in the future, but for now lets just lock for
the whole walk+create process.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
 xen/arch/arm/p2m.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 35bfa2f..5f20246 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -132,6 +132,8 @@ static int create_p2m_entries(struct domain *d,
     paddr_t addr;
     unsigned long cur_first_offset = ~0, cur_second_offset = ~0;
 
+    spin_lock(&p2m->lock);
+
     /* XXX Don't actually handle 40 bit guest physical addresses */
     BUG_ON(start_gpaddr & 0x8000000000ULL);
     BUG_ON(end_gpaddr   & 0x8000000000ULL);
@@ -213,8 +215,6 @@ static int create_p2m_entries(struct domain *d,
     rc = 0;
 
 out:
-    spin_lock(&p2m->lock);
-
     if (third) unmap_domain_page(third);
     if (second) unmap_domain_page(second);
     if (first) unmap_domain_page(first);
-- 
1.7.9.1


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