On 29.10.25 11:08, Kevin Brodsky wrote:
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.
Signed-off-by: Kevin Brodsky <[email protected]>
---
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();
}
Looks like that was moved to XEN code in
commit a4a7644c15096f57f92252dd6e1046bf269c87d8
Author: Juergen Gross <[email protected]>
Date: Wed Sep 13 13:38:27 2023 +0200
x86/xen: move paravirt lazy code
And essentially the previous implementation lived in
arch/x86/kernel/paravirt.c:paravirt_flush_lazy_mmu(void) in an
implementation-agnostic way:
void paravirt_flush_lazy_mmu(void)
{
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
arch_leave_lazy_mmu_mode();
arch_enter_lazy_mmu_mode();
}
preempt_enable();
}
So indeed, I assume just doing the flush here is sufficient.
Reviewed-by: David Hildenbrand <[email protected]>
--
Cheers
David / dhildenb
