From 60c8aec6e2c9923492dabbd6b67e34692bd26c20 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Mon, 1 Dec 2008 22:32:02 -0200 Subject: [PATCH] KVM: MMU: use page array in unsync walk Instead of invoking the handler directly collect pages into an array so the caller can work with it. Simplifies TLB flush collapsing. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/mmu.c | 195 +++++++++++++++++++++++--------- 2 files changed, 141 insertions(+), 56 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f58f7ebdea81..93d0aed35880 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -200,7 +200,7 @@ struct kvm_mmu_page { int multimapped; /* More than one parent_pte? */ int root_count; /* Currently serving as active root */ bool unsync; - bool unsync_children; + unsigned int unsync_children; union { u64 *parent_pte; /* !multimapped */ struct hlist_head parent_ptes; /* multimapped, kvm_pte_chain */ diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index dd20b199a7c0..7ce92f78f337 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -908,8 +908,9 @@ static void kvm_mmu_update_unsync_bitmap(u64 *spte) struct kvm_mmu_page *sp = page_header(__pa(spte)); index = spte - sp->spt; - __set_bit(index, sp->unsync_child_bitmap); - sp->unsync_children = 1; + if (!__test_and_set_bit(index, sp->unsync_child_bitmap)) + sp->unsync_children++; + WARN_ON(!sp->unsync_children); } static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp) @@ -936,7 +937,6 @@ static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp) static int unsync_walk_fn(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { - sp->unsync_children = 1; kvm_mmu_update_parents_unsync(sp); return 1; } @@ -967,18 +967,41 @@ static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva) { } +#define KVM_PAGE_ARRAY_NR 16 + +struct kvm_mmu_pages { + struct mmu_page_and_offset { + struct kvm_mmu_page *sp; + unsigned int idx; + } page[KVM_PAGE_ARRAY_NR]; + unsigned int nr; +}; + #define for_each_unsync_children(bitmap, idx) \ for (idx = find_first_bit(bitmap, 512); \ idx < 512; \ idx = find_next_bit(bitmap, 512, idx+1)) -static int mmu_unsync_walk(struct kvm_mmu_page *sp, - struct kvm_unsync_walk *walker) +int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp, + int idx) { - int i, ret; + int i; - if (!sp->unsync_children) - return 0; + if (sp->unsync) + for (i=0; i < pvec->nr; i++) + if (pvec->page[i].sp == sp) + return 0; + + pvec->page[pvec->nr].sp = sp; + pvec->page[pvec->nr].idx = idx; + pvec->nr++; + return (pvec->nr == KVM_PAGE_ARRAY_NR); +} + +static int __mmu_unsync_walk(struct kvm_mmu_page *sp, + struct kvm_mmu_pages *pvec) +{ + int i, ret, nr_unsync_leaf = 0; for_each_unsync_children(sp->unsync_child_bitmap, i) { u64 ent = sp->spt[i]; @@ -988,17 +1011,22 @@ static int mmu_unsync_walk(struct kvm_mmu_page *sp, child = page_header(ent & PT64_BASE_ADDR_MASK); if (child->unsync_children) { - ret = mmu_unsync_walk(child, walker); - if (ret) + if (mmu_pages_add(pvec, child, i)) + return -ENOSPC; + + ret = __mmu_unsync_walk(child, pvec); + if (!ret) + __clear_bit(i, sp->unsync_child_bitmap); + else if (ret > 0) + nr_unsync_leaf += ret; + else return ret; - __clear_bit(i, sp->unsync_child_bitmap); } if (child->unsync) { - ret = walker->entry(child, walker); - __clear_bit(i, sp->unsync_child_bitmap); - if (ret) - return ret; + nr_unsync_leaf++; + if (mmu_pages_add(pvec, child, i)) + return -ENOSPC; } } } @@ -1006,7 +1034,17 @@ static int mmu_unsync_walk(struct kvm_mmu_page *sp, if (find_first_bit(sp->unsync_child_bitmap, 512) == 512) sp->unsync_children = 0; - return 0; + return nr_unsync_leaf; +} + +static int mmu_unsync_walk(struct kvm_mmu_page *sp, + struct kvm_mmu_pages *pvec) +{ + if (!sp->unsync_children) + return 0; + + mmu_pages_add(pvec, sp, 0); + return __mmu_unsync_walk(sp, pvec); } static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn) @@ -1056,30 +1094,81 @@ static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) return 0; } -struct sync_walker { - struct kvm_vcpu *vcpu; - struct kvm_unsync_walk walker; +struct mmu_page_path { + struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1]; + unsigned int idx[PT64_ROOT_LEVEL-1]; }; -static int mmu_sync_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk) +#define for_each_sp(pvec, sp, parents, i) \ + for (i = mmu_pages_next(&pvec, &parents, -1), \ + sp = pvec.page[i].sp; \ + i < pvec.nr && ({ sp = pvec.page[i].sp; 1;}); \ + i = mmu_pages_next(&pvec, &parents, i)) + +int mmu_pages_next(struct kvm_mmu_pages *pvec, struct mmu_page_path *parents, + int i) { - struct sync_walker *sync_walk = container_of(walk, struct sync_walker, - walker); - struct kvm_vcpu *vcpu = sync_walk->vcpu; + int n; + + for (n = i+1; n < pvec->nr; n++) { + struct kvm_mmu_page *sp = pvec->page[n].sp; + + if (sp->role.level == PT_PAGE_TABLE_LEVEL) { + parents->idx[0] = pvec->page[n].idx; + return n; + } - kvm_sync_page(vcpu, sp); - return (need_resched() || spin_needbreak(&vcpu->kvm->mmu_lock)); + parents->parent[sp->role.level-2] = sp; + parents->idx[sp->role.level-1] = pvec->page[n].idx; + } + + return n; } -static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) +void mmu_pages_clear_parents(struct mmu_page_path *parents) { - struct sync_walker walker = { - .walker = { .entry = mmu_sync_fn, }, - .vcpu = vcpu, - }; + struct kvm_mmu_page *sp; + unsigned int level = 0; + + do { + unsigned int idx = parents->idx[level]; + + sp = parents->parent[level]; + if (!sp) + return; + + --sp->unsync_children; + WARN_ON((int)sp->unsync_children < 0); + __clear_bit(idx, sp->unsync_child_bitmap); + level++; + } while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children); +} + +static void kvm_mmu_pages_init(struct kvm_mmu_page *parent, + struct mmu_page_path *parents, + struct kvm_mmu_pages *pvec) +{ + parents->parent[parent->role.level-1] = NULL; + pvec->nr = 0; +} - while (mmu_unsync_walk(sp, &walker.walker)) +static void mmu_sync_children(struct kvm_vcpu *vcpu, + struct kvm_mmu_page *parent) +{ + int i; + struct kvm_mmu_page *sp; + struct mmu_page_path parents; + struct kvm_mmu_pages pages; + + kvm_mmu_pages_init(parent, &parents, &pages); + while (mmu_unsync_walk(parent, &pages)) { + for_each_sp(pages, sp, parents, i) { + kvm_sync_page(vcpu, sp); + mmu_pages_clear_parents(&parents); + } cond_resched_lock(&vcpu->kvm->mmu_lock); + kvm_mmu_pages_init(parent, &parents, &pages); + } } static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, @@ -1245,33 +1334,29 @@ static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp) } } -struct zap_walker { - struct kvm_unsync_walk walker; - struct kvm *kvm; - int zapped; -}; - -static int mmu_zap_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk) -{ - struct zap_walker *zap_walk = container_of(walk, struct zap_walker, - walker); - kvm_mmu_zap_page(zap_walk->kvm, sp); - zap_walk->zapped = 1; - return 0; -} - -static int mmu_zap_unsync_children(struct kvm *kvm, struct kvm_mmu_page *sp) +static int mmu_zap_unsync_children(struct kvm *kvm, + struct kvm_mmu_page *parent) { - struct zap_walker walker = { - .walker = { .entry = mmu_zap_fn, }, - .kvm = kvm, - .zapped = 0, - }; + int i, zapped = 0; + struct mmu_page_path parents; + struct kvm_mmu_pages pages; - if (sp->role.level == PT_PAGE_TABLE_LEVEL) + if (parent->role.level == PT_PAGE_TABLE_LEVEL) return 0; - mmu_unsync_walk(sp, &walker.walker); - return walker.zapped; + + kvm_mmu_pages_init(parent, &parents, &pages); + while (mmu_unsync_walk(parent, &pages)) { + struct kvm_mmu_page *sp; + + for_each_sp(pages, sp, parents, i) { + kvm_mmu_zap_page(kvm, sp); + mmu_pages_clear_parents(&parents); + } + zapped += pages.nr; + kvm_mmu_pages_init(parent, &parents, &pages); + } + + return zapped; } static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) -- 2.39.5