[PATCH v6 02/14] x86/xen: simplify flush_lazy_mmu()

Kevin Brodsky
2025-12-15T15:03:49Z

arch_flush_lazy_mmu_mode() is called when outstanding batched
pgtable operations must be completed immediately. There should
however be no need to leave and re-enter lazy MMU completely. The
only part of that sequence that we really need is xen_mc_flush();
call it directly.

Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
arch/x86/xen/mmu_pv.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 2a4a8deaf612..7a35c3393df4 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2139,10 +2139,8 @@ static void xen_flush_lazy_mmu(void)
{
preempt_disable();

- if (xen_get_lazy_mode() == XEN_LAZY_MMU) {
- arch_leave_lazy_mmu_mode();
- arch_enter_lazy_mmu_mode();
- }
+ if (xen_get_lazy_mode() == XEN_LAZY_MMU)
+ xen_mc_flush();

preempt_enable();
}
--
2.51.2