* Peter Xu ([email protected]) wrote: > Introduce KVMMemoryListener.slots_lock to protect the slots inside the > kvm memory listener. Currently it is close to useless because all the > KVM code path now is always protected by the BQL. But it'll start to > make sense in follow up patches where we might do remote dirty bitmap > clear and also we'll update the per-slot cached dirty bitmap even > without the BQL. So let's prepare for it. > > We can also use per-slot lock for above reason but it seems to be an > overkill. Let's just use this bigger one (which covers all the slots > of a single address space) but anyway this lock is still much smaller > than the BQL. > > Signed-off-by: Peter Xu <[email protected]>
No one ever frees it? Huh OK, in that case if no one ever frees the listener then I guess you don't need to cleanup the lock. Reviewed-by: Dr. David Alan Gilbert <[email protected]> > --- > accel/kvm/kvm-all.c | 58 +++++++++++++++++++++++++++++++--------- > include/sysemu/kvm_int.h | 2 ++ > 2 files changed, 48 insertions(+), 12 deletions(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index 334c610918..e687060296 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -138,6 +138,9 @@ static const KVMCapabilityInfo kvm_required_capabilites[] > = { > KVM_CAP_LAST_INFO > }; > > +#define kvm_slots_lock(kml) qemu_mutex_lock(&(kml)->slots_lock) > +#define kvm_slots_unlock(kml) qemu_mutex_unlock(&(kml)->slots_lock) > + > int kvm_get_max_memslots(void) > { > KVMState *s = KVM_STATE(current_machine->accelerator); > @@ -165,6 +168,7 @@ int kvm_memcrypt_encrypt_data(uint8_t *ptr, uint64_t len) > return 1; > } > > +/* Called with KVMMemoryListener.slots_lock held */ > static KVMSlot *kvm_get_free_slot(KVMMemoryListener *kml) > { > KVMState *s = kvm_state; > @@ -182,10 +186,17 @@ static KVMSlot *kvm_get_free_slot(KVMMemoryListener > *kml) > bool kvm_has_free_slot(MachineState *ms) > { > KVMState *s = KVM_STATE(ms->accelerator); > + bool result; > + KVMMemoryListener *kml = &s->memory_listener; > + > + kvm_slots_lock(kml); > + result = !!kvm_get_free_slot(kml); > + kvm_slots_unlock(kml); > > - return kvm_get_free_slot(&s->memory_listener); > + return result; > } > > +/* Called with KVMMemoryListener.slots_lock held */ > static KVMSlot *kvm_alloc_slot(KVMMemoryListener *kml) > { > KVMSlot *slot = kvm_get_free_slot(kml); > @@ -244,18 +255,21 @@ int kvm_physical_memory_addr_from_host(KVMState *s, > void *ram, > hwaddr *phys_addr) > { > KVMMemoryListener *kml = &s->memory_listener; > - int i; > + int i, ret = 0; > > + kvm_slots_lock(kml); > for (i = 0; i < s->nr_slots; i++) { > KVMSlot *mem = &kml->slots[i]; > > if (ram >= mem->ram && ram < mem->ram + mem->memory_size) { > *phys_addr = mem->start_addr + (ram - mem->ram); > - return 1; > + ret = 1; > + break; > } > } > + kvm_slots_unlock(kml); > > - return 0; > + return ret; > } > > static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot, > bool new) > @@ -391,6 +405,7 @@ static int kvm_mem_flags(MemoryRegion *mr) > return flags; > } > > +/* Called with KVMMemoryListener.slots_lock held */ > static int kvm_slot_update_flags(KVMMemoryListener *kml, KVMSlot *mem, > MemoryRegion *mr) > { > @@ -409,19 +424,26 @@ static int kvm_section_update_flags(KVMMemoryListener > *kml, > { > hwaddr start_addr, size; > KVMSlot *mem; > + int ret = 0; > > size = kvm_align_section(section, &start_addr); > if (!size) { > return 0; > } > > + kvm_slots_lock(kml); > + > mem = kvm_lookup_matching_slot(kml, start_addr, size); > if (!mem) { > /* We don't have a slot if we want to trap every access. */ > - return 0; > + goto out; > } > > - return kvm_slot_update_flags(kml, mem, section->mr); > + ret = kvm_slot_update_flags(kml, mem, section->mr); > + > +out: > + kvm_slots_unlock(kml); > + return ret; > } > > static void kvm_log_start(MemoryListener *listener, > @@ -478,6 +500,8 @@ static int > kvm_get_dirty_pages_log_range(MemoryRegionSection *section, > * This function will first try to fetch dirty bitmap from the kernel, > * and then updates qemu's dirty bitmap. > * > + * NOTE: caller must be with kml->slots_lock held. > + * > * @kml: the KVM memory listener object > * @section: the memory section to sync the dirty bitmap with > */ > @@ -488,26 +512,28 @@ static int > kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml, > struct kvm_dirty_log d = {}; > KVMSlot *mem; > hwaddr start_addr, size; > + int ret = 0; > > size = kvm_align_section(section, &start_addr); > if (size) { > mem = kvm_lookup_matching_slot(kml, start_addr, size); > if (!mem) { > /* We don't have a slot if we want to trap every access. */ > - return 0; > + goto out; > } > > d.dirty_bitmap = mem->dirty_bmap; > d.slot = mem->slot | (kml->as_id << 16); > if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) { > DPRINTF("ioctl failed %d\n", errno); > - return -1; > + ret = -1; > + goto out; > } > > kvm_get_dirty_pages_log_range(section, d.dirty_bitmap); > } > - > - return 0; > +out: > + return ret; > } > > static void kvm_coalesce_mmio_region(MemoryListener *listener, > @@ -770,10 +796,12 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, > ram = memory_region_get_ram_ptr(mr) + section->offset_within_region + > (start_addr - section->offset_within_address_space); > > + kvm_slots_lock(kml); > + > if (!add) { > mem = kvm_lookup_matching_slot(kml, start_addr, size); > if (!mem) { > - return; > + goto out; > } > if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) { > kvm_physical_sync_dirty_bitmap(kml, section); > @@ -790,7 +818,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, > __func__, strerror(-err)); > abort(); > } > - return; > + goto out; > } > > /* > @@ -823,6 +851,9 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, > strerror(-err)); > abort(); > } > + > +out: > + kvm_slots_unlock(kml); > } > > static void kvm_region_add(MemoryListener *listener, > @@ -849,7 +880,9 @@ static void kvm_log_sync(MemoryListener *listener, > KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, > listener); > int r; > > + kvm_slots_lock(kml); > r = kvm_physical_sync_dirty_bitmap(kml, section); > + kvm_slots_unlock(kml); > if (r < 0) { > abort(); > } > @@ -929,6 +962,7 @@ void kvm_memory_listener_register(KVMState *s, > KVMMemoryListener *kml, > { > int i; > > + qemu_mutex_init(&kml->slots_lock); > kml->slots = g_malloc0(s->nr_slots * sizeof(KVMSlot)); > kml->as_id = as_id; > > diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h > index 687a2ee423..31df465fdc 100644 > --- a/include/sysemu/kvm_int.h > +++ b/include/sysemu/kvm_int.h > @@ -27,6 +27,8 @@ typedef struct KVMSlot > > typedef struct KVMMemoryListener { > MemoryListener listener; > + /* Protects the slots and all inside them */ > + QemuMutex slots_lock; > KVMSlot *slots; > int as_id; > } KVMMemoryListener; > -- > 2.17.1 > -- Dr. David Alan Gilbert / [email protected] / Manchester, UK
