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[PATCH] x86/EPT: squash meaningless TLB flush
- To: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Tue, 30 Nov 2021 17:10:53 +0100
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- Cc: Jun Nakajima <jun.nakajima@xxxxxxxxx>, Kevin Tian <kevin.tian@xxxxxxxxx>
- Delivery-date: Tue, 30 Nov 2021 16:11:15 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
ept_free_entry() gets called after a flush - if one is necessary in the
first place - was already issued. That behavior is similar to NPT, which
also doesn't have any further flush in p2m_free_entry(). (Furthermore,
the function being recursive, in case of recursiveness way too many
flushes would have been issued.)
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -246,8 +246,7 @@ static void ept_free_entry(struct p2m_do
ept_free_entry(p2m, epte + i, level - 1);
unmap_domain_page(epte);
}
-
- p2m_tlb_flush_sync(p2m);
+
p2m_free_ptp(p2m, mfn_to_page(_mfn(ept_entry->mfn)));
}
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