From 19d4e55a01cdeafb6b14262806892fcd34bd205d Mon Sep 17 00:00:00 2001 From: George Dunlap Date: Mon, 20 Feb 2017 16:02:12 +0100 Subject: [PATCH] xen/p2m: Fix p2m_flush_table for non-nested cases 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 for nested p2m's. 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 Signed-off-by: George Dunlap Reviewed-by: Tim Deegan Tested-by: Tamas K Lengyel master commit: 6192e6378e094094906950120470a621d5b2977c master date: 2017-02-15 17:15:56 +0000 --- xen/arch/x86/mm/p2m.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index 9b19769abe..d289c1cf3c 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -1965,7 +1965,8 @@ 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_is_nestedp2m(p2m) && p2m->np2m_base == P2M_BASE_EADDR ) { p2m_unlock(p2m); return; -- 2.39.5