diff options
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 25 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu.c | 6 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 71 |
3 files changed, 93 insertions, 9 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 67a98d7..57916ec 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -802,6 +802,31 @@ struct kvm_x86_ops { int (*check_nested_events)(struct kvm_vcpu *vcpu, bool external_intr); void (*sched_in)(struct kvm_vcpu *kvm, int cpu); + + /* + * Arch-specific dirty logging hooks. These hooks are only supposed to + * be valid if the specific arch has hardware-accelerated dirty logging + * mechanism. Currently only for PML on VMX. + * + * - slot_enable_log_dirty: + * called when enabling log dirty mode for the slot. + * - slot_disable_log_dirty: + * called when disabling log dirty mode for the slot. + * also called when slot is created with log dirty disabled. + * - flush_log_dirty: + * called before reporting dirty_bitmap to userspace. + * - enable_log_dirty_pt_masked: + * called when reenabling log dirty for the GFNs in the mask after + * corresponding bits are cleared in slot->dirty_bitmap. + */ + void (*slot_enable_log_dirty)(struct kvm *kvm, + struct kvm_memory_slot *slot); + void (*slot_disable_log_dirty)(struct kvm *kvm, + struct kvm_memory_slot *slot); + void (*flush_log_dirty)(struct kvm *kvm); + void (*enable_log_dirty_pt_masked)(struct kvm *kvm, + struct kvm_memory_slot *slot, + gfn_t offset, unsigned long mask); }; struct kvm_arch_async_pf { diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index ec62ecd..cee7592 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1335,7 +1335,11 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn_offset, unsigned long mask) { - kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask); + if (kvm_x86_ops->enable_log_dirty_pt_masked) + kvm_x86_ops->enable_log_dirty_pt_masked(kvm, slot, gfn_offset, + mask); + else + kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask); } static bool rmap_write_protect(struct kvm *kvm, u64 gfn) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3a7fcff..442ee7d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3780,6 +3780,12 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log) mutex_lock(&kvm->slots_lock); + /* + * Flush potentially hardware-cached dirty pages to dirty_bitmap. + */ + if (kvm_x86_ops->flush_log_dirty) + kvm_x86_ops->flush_log_dirty(kvm); + r = kvm_get_dirty_log_protect(kvm, log, &is_dirty); /* @@ -7533,6 +7539,56 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return 0; } +static void kvm_mmu_slot_apply_flags(struct kvm *kvm, + struct kvm_memory_slot *new) +{ + /* Still write protect RO slot */ + if (new->flags & KVM_MEM_READONLY) { + kvm_mmu_slot_remove_write_access(kvm, new); + return; + } + + /* + * Call kvm_x86_ops dirty logging hooks when they are valid. + * + * kvm_x86_ops->slot_disable_log_dirty is called when: + * + * - KVM_MR_CREATE with dirty logging is disabled + * - KVM_MR_FLAGS_ONLY with dirty logging is disabled in new flag + * + * The reason is, in case of PML, we need to set D-bit for any slots + * with dirty logging disabled in order to eliminate unnecessary GPA + * logging in PML buffer (and potential PML buffer full VMEXT). This + * guarantees leaving PML enabled during guest's lifetime won't have + * any additonal overhead from PML when guest is running with dirty + * logging disabled for memory slots. + * + * kvm_x86_ops->slot_enable_log_dirty is called when switching new slot + * to dirty logging mode. + * + * If kvm_x86_ops dirty logging hooks are invalid, use write protect. + * + * In case of write protect: + * + * Write protect all pages for dirty logging. + * + * All the sptes including the large sptes which point to this + * slot are set to readonly. We can not create any new large + * spte on this slot until the end of the logging. + * + * See the comments in fast_page_fault(). + */ + if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) { + if (kvm_x86_ops->slot_enable_log_dirty) + kvm_x86_ops->slot_enable_log_dirty(kvm, new); + else + kvm_mmu_slot_remove_write_access(kvm, new); + } else { + if (kvm_x86_ops->slot_disable_log_dirty) + kvm_x86_ops->slot_disable_log_dirty(kvm, new); + } +} + void kvm_arch_commit_memory_region(struct kvm *kvm, struct kvm_userspace_memory_region *mem, const struct kvm_memory_slot *old, @@ -7562,16 +7618,15 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, new = id_to_memslot(kvm->memslots, mem->slot); /* - * Write protect all pages for dirty logging. + * Set up write protection and/or dirty logging for the new slot. * - * All the sptes including the large sptes which point to this - * slot are set to readonly. We can not create any new large - * spte on this slot until the end of the logging. - * - * See the comments in fast_page_fault(). + * For KVM_MR_DELETE and KVM_MR_MOVE, the shadow pages of old slot have + * been zapped so no dirty logging staff is needed for old slot. For + * KVM_MR_FLAGS_ONLY, the old slot is essentially the same one as the + * new and it's also covered when dealing with the new slot. */ - if ((change != KVM_MR_DELETE) && (new->flags & KVM_MEM_LOG_DIRTY_PAGES)) - kvm_mmu_slot_remove_write_access(kvm, new); + if (change != KVM_MR_DELETE) + kvm_mmu_slot_apply_flags(kvm, new); } void kvm_arch_flush_shadow_all(struct kvm *kvm) |
