Commit 71bb7304e7a7a35ea6df4b0cedebc35028e4c159 added flushing of
nested p2m tables whenever the host p2m table changed. Unfortunately
in the process, it added a filter to p2m_flush_table() function so
that the p2m would only be flushed if it was being used as a nested
p2m. This meant that the p2m was not being flushed at all for altp2m
callers.
Only check np2m_base if p2m_class is set to p2m_nested.
NB that this is not a security issue: The only time this codepath is
called is in cases where either nestedp2m or altp2m is enabled, and
neither of them are in security support.
Reported-by: Matt Leinhos <m...@starlab.io>
Signed-off-by: George Dunlap <george.dun...@citrix.com>
---
CC: Andrew Cooper <andrew.coop...@citrix.com>
CC: Jan Beulich <jbeul...@suse.com>
CC: Tim Deegan <t...@xen.org>
CC: Tamas K Lengyel <tamas.leng...@zentific.com>
---
xen/arch/x86/mm/p2m.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 6548e9f..0af2ec1 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -1627,7 +1627,9 @@ p2m_flush_table(struct p2m_domain *p2m)
ASSERT(page_list_empty(&p2m->pod.super));
ASSERT(page_list_empty(&p2m->pod.single));
- if ( p2m->np2m_base == P2M_BASE_EADDR )
+ /* No need to flush if it's already empty */
+ if ( p2m->p2m_class == p2m_nested &&
+ p2m->np2m_base == P2M_BASE_EADDR )
{
p2m_unlock(p2m);
return;
--
2.1.4
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