diff options
| -rw-r--r-- | Documentation/kvm/mmu.txt | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu.c | 38 | ||||
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 3 |
3 files changed, 35 insertions, 10 deletions
diff --git a/Documentation/kvm/mmu.txt b/Documentation/kvm/mmu.txt index 0e872ae..2201dcb 100644 --- a/Documentation/kvm/mmu.txt +++ b/Documentation/kvm/mmu.txt @@ -180,7 +180,9 @@ Shadow pages contain the following information: guest pages as leaves. gfns: An array of 512 guest frame numbers, one for each present pte. Used to - perform a reverse map from a pte to a gfn. + perform a reverse map from a pte to a gfn. When role.direct is set, any + element of this array can be calculated from the gfn field when used, in + this case, the array of gfns is not allocated. See role.direct and gfn. slot_bitmap: A bitmap containing one bit per memory slot. If the page contains a pte mapping a page from memory slot n, then bit n of slot_bitmap will be set diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 0767348..f46b6c9 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -397,6 +397,22 @@ static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd) kmem_cache_free(rmap_desc_cache, rd); } +static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index) +{ + if (!sp->role.direct) + return sp->gfns[index]; + + return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS)); +} + +static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn) +{ + if (sp->role.direct) + BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index)); + else + sp->gfns[index] = gfn; +} + /* * Return the pointer to the largepage write count for a given * gfn, handling slots that are not large page aligned. @@ -547,7 +563,7 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) return count; gfn = unalias_gfn(vcpu->kvm, gfn); sp = page_header(__pa(spte)); - sp->gfns[spte - sp->spt] = gfn; + kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn); rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level); if (!*rmapp) { rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte); @@ -605,6 +621,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) struct kvm_rmap_desc *prev_desc; struct kvm_mmu_page *sp; pfn_t pfn; + gfn_t gfn; unsigned long *rmapp; int i; @@ -616,7 +633,8 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) kvm_set_pfn_accessed(pfn); if (is_writable_pte(*spte)) kvm_set_pfn_dirty(pfn); - rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], sp->role.level); + gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt); + rmapp = gfn_to_rmap(kvm, gfn, sp->role.level); if (!*rmapp) { printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte); BUG(); @@ -900,7 +918,8 @@ static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp) ASSERT(is_empty_shadow_page(sp->spt)); list_del(&sp->link); __free_page(virt_to_page(sp->spt)); - __free_page(virt_to_page(sp->gfns)); + if (!sp->role.direct) + __free_page(virt_to_page(sp->gfns)); kmem_cache_free(mmu_page_header_cache, sp); ++kvm->arch.n_free_mmu_pages; } @@ -911,13 +930,15 @@ static unsigned kvm_page_table_hashfn(gfn_t gfn) } static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, - u64 *parent_pte) + u64 *parent_pte, int direct) { struct kvm_mmu_page *sp; sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp); sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE); - sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE); + if (!direct) + sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, + PAGE_SIZE); set_page_private(virt_to_page(sp->spt), (unsigned long)sp); list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS); @@ -1386,7 +1407,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, return sp; } ++vcpu->kvm->stat.mmu_cache_miss; - sp = kvm_mmu_alloc_page(vcpu, parent_pte); + sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct); if (!sp) return sp; sp->gfn = gfn; @@ -3403,7 +3424,7 @@ void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep) if (*sptep & PT_WRITABLE_MASK) { rev_sp = page_header(__pa(sptep)); - gfn = rev_sp->gfns[sptep - rev_sp->spt]; + gfn = kvm_mmu_page_get_gfn(rev_sp, sptep - rev_sp->spt); if (!gfn_to_memslot(kvm, gfn)) { if (!printk_ratelimit()) @@ -3417,8 +3438,7 @@ void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep) return; } - rmapp = gfn_to_rmap(kvm, rev_sp->gfns[sptep - rev_sp->spt], - rev_sp->role.level); + rmapp = gfn_to_rmap(kvm, gfn, rev_sp->role.level); if (!*rmapp) { if (!printk_ratelimit()) return; diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 167f533..2ee7060 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -582,6 +582,9 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) offset = nr_present = 0; + /* direct kvm_mmu_page can not be unsync. */ + BUG_ON(sp->role.direct); + if (PTTYPE == 32) offset = sp->role.quadrant << PT64_LEVEL_BITS; |