From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> The check for sp->unsync_children in link_shadow_page() can be removed since FNAME(fetch) ensures it is zero. (@sp is direct when link_shadow_page() is called from other places, which also means sp->unsync_children is zero.) link_shadow_page() is not a fast path, check it and warn instead. Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> --- arch/x86/kvm/mmu/mmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 086f32dffdbe..f61416818116 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2197,7 +2197,13 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, mmu_page_add_parent_pte(vcpu, sp, sptep); - if (sp->unsync_children || sp->unsync) + /* + * Propagate the unsync bit when sp->unsync. + * + * The caller ensures the sp is synced when it has unsync children, + * so sp->unsync_children must be zero. See FNAME(fetch). + */ + if (sp->unsync || WARN_ON_ONCE(sp->unsync_children)) mark_unsync(sptep); } -- 2.19.1.6.gb485710b
