diff options
Diffstat (limited to 'arch/x86/kvm/mmu/page_track.c')
| -rw-r--r-- | arch/x86/kvm/mmu/page_track.c | 72 |
1 files changed, 69 insertions, 3 deletions
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index 16e7176c97a5..bb5d60bd4dbf 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -19,6 +19,16 @@ #include "mmu.h" #include "mmu_internal.h" +static bool write_tracking_enabled(struct kvm *kvm) +{ + /* + * Read memslots_mmu_write_tracking before gfn_track pointers. Pairs + * with smp_store_release in kvm_page_track_enable_mmu_write_tracking. + */ + return IS_ENABLED(CONFIG_KVM_EXTERNAL_WRITE_TRACKING) || + smp_load_acquire(&kvm->arch.memslots_mmu_write_tracking); +} + void kvm_page_track_free_memslot(struct kvm_memory_slot *slot) { int i; @@ -29,12 +39,16 @@ void kvm_page_track_free_memslot(struct kvm_memory_slot *slot) } } -int kvm_page_track_create_memslot(struct kvm_memory_slot *slot, +int kvm_page_track_create_memslot(struct kvm *kvm, + struct kvm_memory_slot *slot, unsigned long npages) { - int i; + int i; for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) { + if (i == KVM_PAGE_TRACK_WRITE && !write_tracking_enabled(kvm)) + continue; + slot->arch.gfn_track[i] = kvcalloc(npages, sizeof(*slot->arch.gfn_track[i]), GFP_KERNEL_ACCOUNT); @@ -57,6 +71,46 @@ static inline bool page_track_mode_is_valid(enum kvm_page_track_mode mode) return true; } +int kvm_page_track_enable_mmu_write_tracking(struct kvm *kvm) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *slot; + unsigned short **gfn_track; + int i; + + if (write_tracking_enabled(kvm)) + return 0; + + mutex_lock(&kvm->slots_arch_lock); + + if (write_tracking_enabled(kvm)) { + mutex_unlock(&kvm->slots_arch_lock); + return 0; + } + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + slots = __kvm_memslots(kvm, i); + kvm_for_each_memslot(slot, slots) { + gfn_track = slot->arch.gfn_track + KVM_PAGE_TRACK_WRITE; + *gfn_track = kvcalloc(slot->npages, sizeof(*gfn_track), + GFP_KERNEL_ACCOUNT); + if (*gfn_track == NULL) { + mutex_unlock(&kvm->slots_arch_lock); + return -ENOMEM; + } + } + } + + /* + * Ensure that memslots_mmu_write_tracking becomes true strictly + * after all the pointers are set. + */ + smp_store_release(&kvm->arch.memslots_mmu_write_tracking, true); + mutex_unlock(&kvm->slots_arch_lock); + + return 0; +} + static void update_gfn_track(struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode, short count) { @@ -92,6 +146,10 @@ void kvm_slot_page_track_add_page(struct kvm *kvm, if (WARN_ON(!page_track_mode_is_valid(mode))) return; + if (WARN_ON(mode == KVM_PAGE_TRACK_WRITE && + !write_tracking_enabled(kvm))) + return; + update_gfn_track(slot, gfn, mode, 1); /* @@ -126,6 +184,10 @@ void kvm_slot_page_track_remove_page(struct kvm *kvm, if (WARN_ON(!page_track_mode_is_valid(mode))) return; + if (WARN_ON(mode == KVM_PAGE_TRACK_WRITE && + !write_tracking_enabled(kvm))) + return; + update_gfn_track(slot, gfn, mode, -1); /* @@ -139,7 +201,8 @@ EXPORT_SYMBOL_GPL(kvm_slot_page_track_remove_page); /* * check if the corresponding access on the specified guest page is tracked. */ -bool kvm_slot_page_track_is_active(struct kvm_memory_slot *slot, gfn_t gfn, +bool kvm_slot_page_track_is_active(struct kvm_vcpu *vcpu, + struct kvm_memory_slot *slot, gfn_t gfn, enum kvm_page_track_mode mode) { int index; @@ -150,6 +213,9 @@ bool kvm_slot_page_track_is_active(struct kvm_memory_slot *slot, gfn_t gfn, if (!slot) return false; + if (mode == KVM_PAGE_TRACK_WRITE && !write_tracking_enabled(vcpu->kvm)) + return false; + index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K); return !!READ_ONCE(slot->arch.gfn_track[mode][index]); } |