From 7775834a233478ec855b97e30727248f12eafe76 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Fri, 4 Jun 2010 21:53:54 +0800 Subject: [PATCH] KVM: MMU: split the operations of kvm_mmu_zap_page() Using kvm_mmu_prepare_zap_page() and kvm_mmu_commit_zap_page() to split kvm_mmu_zap_page() function, then we can: - traverse hlist safely - easily to gather remote tlb flush which occurs during page zapped Those feature can be used in the later patches Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/kvm/mmu.c | 52 ++++++++++++++++++++++++++++++++++------- arch/x86/kvm/mmutrace.h | 2 +- 2 files changed, 44 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 881ad918455c..9b849a70742d 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -916,6 +916,7 @@ static int is_empty_shadow_page(u64 *spt) static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp) { ASSERT(is_empty_shadow_page(sp->spt)); + hlist_del(&sp->hash_link); list_del(&sp->link); __free_page(virt_to_page(sp->spt)); if (!sp->role.direct) @@ -1200,6 +1201,10 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp) } static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp); +static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp, + struct list_head *invalid_list); +static void kvm_mmu_commit_zap_page(struct kvm *kvm, + struct list_head *invalid_list); #define for_each_gfn_sp(kvm, sp, gfn, pos, n) \ hlist_for_each_entry_safe(sp, pos, n, \ @@ -1530,7 +1535,8 @@ static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp) } static int mmu_zap_unsync_children(struct kvm *kvm, - struct kvm_mmu_page *parent) + struct kvm_mmu_page *parent, + struct list_head *invalid_list) { int i, zapped = 0; struct mmu_page_path parents; @@ -1544,7 +1550,7 @@ static int mmu_zap_unsync_children(struct kvm *kvm, struct kvm_mmu_page *sp; for_each_sp(pages, sp, parents, i) { - kvm_mmu_zap_page(kvm, sp); + kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); mmu_pages_clear_parents(&parents); zapped++; } @@ -1554,16 +1560,16 @@ static int mmu_zap_unsync_children(struct kvm *kvm, return zapped; } -static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) +static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp, + struct list_head *invalid_list) { int ret; - trace_kvm_mmu_zap_page(sp); + trace_kvm_mmu_prepare_zap_page(sp); ++kvm->stat.mmu_shadow_zapped; - ret = mmu_zap_unsync_children(kvm, sp); + ret = mmu_zap_unsync_children(kvm, sp, invalid_list); kvm_mmu_page_unlink_children(kvm, sp); kvm_mmu_unlink_parents(kvm, sp); - kvm_flush_remote_tlbs(kvm); if (!sp->role.invalid && !sp->role.direct) unaccount_shadowed(kvm, sp->gfn); if (sp->unsync) @@ -1571,17 +1577,45 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) if (!sp->root_count) { /* Count self */ ret++; - hlist_del(&sp->hash_link); - kvm_mmu_free_page(kvm, sp); + list_move(&sp->link, invalid_list); } else { - sp->role.invalid = 1; list_move(&sp->link, &kvm->arch.active_mmu_pages); kvm_reload_remote_mmus(kvm); } + + sp->role.invalid = 1; kvm_mmu_reset_last_pte_updated(kvm); return ret; } +static void kvm_mmu_commit_zap_page(struct kvm *kvm, + struct list_head *invalid_list) +{ + struct kvm_mmu_page *sp; + + if (list_empty(invalid_list)) + return; + + kvm_flush_remote_tlbs(kvm); + + do { + sp = list_first_entry(invalid_list, struct kvm_mmu_page, link); + WARN_ON(!sp->role.invalid || sp->root_count); + kvm_mmu_free_page(kvm, sp); + } while (!list_empty(invalid_list)); + +} + +static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) +{ + LIST_HEAD(invalid_list); + int ret; + + ret = kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); + kvm_mmu_commit_zap_page(kvm, &invalid_list); + return ret; +} + /* * Changing the number of mmu pages allocated to the vm * Note: if kvm_nr_mmu_pages is too small, you will get dead lock diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h index 42f07b1bfbc9..3aab0f0930ef 100644 --- a/arch/x86/kvm/mmutrace.h +++ b/arch/x86/kvm/mmutrace.h @@ -190,7 +190,7 @@ DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_unsync_page, TP_ARGS(sp) ); -DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_zap_page, +DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_prepare_zap_page, TP_PROTO(struct kvm_mmu_page *sp), TP_ARGS(sp) -- 2.39.5