diff options
| -rw-r--r-- | accel/kvm/kvm-all.c | 182 | ||||
| -rw-r--r-- | accel/kvm/trace-events | 1 |
2 files changed, 183 insertions, 0 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 621c9a43ab..35ea3cb624 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -91,6 +91,7 @@ struct KVMState int many_ioeventfds; int intx_set_mask; bool sync_mmu; + bool manual_dirty_log_protect; /* The man page (and posix) say ioctl numbers are signed int, but * they're not. Linux, glibc and *BSD all treat ioctl numbers as * unsigned, and treating them as signed here can break things */ @@ -560,6 +561,159 @@ out: return ret; } +/* Alignment requirement for KVM_CLEAR_DIRTY_LOG - 64 pages */ +#define KVM_CLEAR_LOG_SHIFT 6 +#define KVM_CLEAR_LOG_ALIGN (qemu_real_host_page_size << KVM_CLEAR_LOG_SHIFT) +#define KVM_CLEAR_LOG_MASK (-KVM_CLEAR_LOG_ALIGN) + +/** + * kvm_physical_log_clear - Clear the kernel's dirty bitmap for range + * + * NOTE: this will be a no-op if we haven't enabled manual dirty log + * protection in the host kernel because in that case this operation + * will be done within log_sync(). + * + * @kml: the kvm memory listener + * @section: the memory range to clear dirty bitmap + */ +static int kvm_physical_log_clear(KVMMemoryListener *kml, + MemoryRegionSection *section) +{ + KVMState *s = kvm_state; + struct kvm_clear_dirty_log d; + uint64_t start, end, bmap_start, start_delta, bmap_npages, size; + unsigned long *bmap_clear = NULL, psize = qemu_real_host_page_size; + KVMSlot *mem = NULL; + int ret, i; + + if (!s->manual_dirty_log_protect) { + /* No need to do explicit clear */ + return 0; + } + + start = section->offset_within_address_space; + size = int128_get64(section->size); + + if (!size) { + /* Nothing more we can do... */ + return 0; + } + + kvm_slots_lock(kml); + + /* Find any possible slot that covers the section */ + for (i = 0; i < s->nr_slots; i++) { + mem = &kml->slots[i]; + if (mem->start_addr <= start && + start + size <= mem->start_addr + mem->memory_size) { + break; + } + } + + /* + * We should always find one memslot until this point, otherwise + * there could be something wrong from the upper layer + */ + assert(mem && i != s->nr_slots); + + /* + * We need to extend either the start or the size or both to + * satisfy the KVM interface requirement. Firstly, do the start + * page alignment on 64 host pages + */ + bmap_start = (start - mem->start_addr) & KVM_CLEAR_LOG_MASK; + start_delta = start - mem->start_addr - bmap_start; + bmap_start /= psize; + + /* + * The kernel interface has restriction on the size too, that either: + * + * (1) the size is 64 host pages aligned (just like the start), or + * (2) the size fills up until the end of the KVM memslot. + */ + bmap_npages = DIV_ROUND_UP(size + start_delta, KVM_CLEAR_LOG_ALIGN) + << KVM_CLEAR_LOG_SHIFT; + end = mem->memory_size / psize; + if (bmap_npages > end - bmap_start) { + bmap_npages = end - bmap_start; + } + start_delta /= psize; + + /* + * Prepare the bitmap to clear dirty bits. Here we must guarantee + * that we won't clear any unknown dirty bits otherwise we might + * accidentally clear some set bits which are not yet synced from + * the kernel into QEMU's bitmap, then we'll lose track of the + * guest modifications upon those pages (which can directly lead + * to guest data loss or panic after migration). + * + * Layout of the KVMSlot.dirty_bmap: + * + * |<-------- bmap_npages -----------..>| + * [1] + * start_delta size + * |----------------|-------------|------------------|------------| + * ^ ^ ^ ^ + * | | | | + * start bmap_start (start) end + * of memslot of memslot + * + * [1] bmap_npages can be aligned to either 64 pages or the end of slot + */ + + assert(bmap_start % BITS_PER_LONG == 0); + /* We should never do log_clear before log_sync */ + assert(mem->dirty_bmap); + if (start_delta) { + /* Slow path - we need to manipulate a temp bitmap */ + bmap_clear = bitmap_new(bmap_npages); + bitmap_copy_with_src_offset(bmap_clear, mem->dirty_bmap, + bmap_start, start_delta + size / psize); + /* + * We need to fill the holes at start because that was not + * specified by the caller and we extended the bitmap only for + * 64 pages alignment + */ + bitmap_clear(bmap_clear, 0, start_delta); + d.dirty_bitmap = bmap_clear; + } else { + /* Fast path - start address aligns well with BITS_PER_LONG */ + d.dirty_bitmap = mem->dirty_bmap + BIT_WORD(bmap_start); + } + + d.first_page = bmap_start; + /* It should never overflow. If it happens, say something */ + assert(bmap_npages <= UINT32_MAX); + d.num_pages = bmap_npages; + d.slot = mem->slot | (kml->as_id << 16); + + if (kvm_vm_ioctl(s, KVM_CLEAR_DIRTY_LOG, &d) == -1) { + ret = -errno; + error_report("%s: KVM_CLEAR_DIRTY_LOG failed, slot=%d, " + "start=0x%"PRIx64", size=0x%"PRIx32", errno=%d", + __func__, d.slot, (uint64_t)d.first_page, + (uint32_t)d.num_pages, ret); + } else { + ret = 0; + trace_kvm_clear_dirty_log(d.slot, d.first_page, d.num_pages); + } + + /* + * After we have updated the remote dirty bitmap, we update the + * cached bitmap as well for the memslot, then if another user + * clears the same region we know we shouldn't clear it again on + * the remote otherwise it's data loss as well. + */ + bitmap_clear(mem->dirty_bmap, bmap_start + start_delta, + size / psize); + /* This handles the NULL case well */ + g_free(bmap_clear); + + kvm_slots_unlock(kml); + + return ret; +} + static void kvm_coalesce_mmio_region(MemoryListener *listener, MemoryRegionSection *secion, hwaddr start, hwaddr size) @@ -894,6 +1048,22 @@ static void kvm_log_sync(MemoryListener *listener, } } +static void kvm_log_clear(MemoryListener *listener, + MemoryRegionSection *section) +{ + KVMMemoryListener *kml = container_of(listener, KVMMemoryListener, listener); + int r; + + r = kvm_physical_log_clear(kml, section); + if (r < 0) { + error_report_once("%s: kvm log clear failed: mr=%s " + "offset=%"HWADDR_PRIx" size=%"PRIx64, __func__, + section->mr->name, section->offset_within_region, + int128_get64(section->size)); + abort(); + } +} + static void kvm_mem_ioeventfd_add(MemoryListener *listener, MemoryRegionSection *section, bool match_data, uint64_t data, @@ -985,6 +1155,7 @@ void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml, kml->listener.log_start = kvm_log_start; kml->listener.log_stop = kvm_log_stop; kml->listener.log_sync = kvm_log_sync; + kml->listener.log_clear = kvm_log_clear; kml->listener.priority = 10; memory_listener_register(&kml->listener, as); @@ -1709,6 +1880,17 @@ static int kvm_init(MachineState *ms) s->coalesced_pio = s->coalesced_mmio && kvm_check_extension(s, KVM_CAP_COALESCED_PIO); + s->manual_dirty_log_protect = + kvm_check_extension(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2); + if (s->manual_dirty_log_protect) { + ret = kvm_vm_enable_cap(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, 0, 1); + if (ret) { + warn_report("Trying to enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 " + "but failed. Falling back to the legacy mode. "); + s->manual_dirty_log_protect = false; + } + } + #ifdef KVM_CAP_VCPU_EVENTS s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS); #endif diff --git a/accel/kvm/trace-events b/accel/kvm/trace-events index 33c5b1b3af..4fb6e59d19 100644 --- a/accel/kvm/trace-events +++ b/accel/kvm/trace-events @@ -15,4 +15,5 @@ kvm_irqchip_release_virq(int virq) "virq %d" kvm_set_ioeventfd_mmio(int fd, uint64_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%" PRIx64 " val=0x%x assign: %d size: %d match: %d" kvm_set_ioeventfd_pio(int fd, uint16_t addr, uint32_t val, bool assign, uint32_t size, bool datamatch) "fd: %d @0x%x val=0x%x assign: %d size: %d match: %d" kvm_set_user_memory(uint32_t slot, uint32_t flags, uint64_t guest_phys_addr, uint64_t memory_size, uint64_t userspace_addr, int ret) "Slot#%d flags=0x%x gpa=0x%"PRIx64 " size=0x%"PRIx64 " ua=0x%"PRIx64 " ret=%d" +kvm_clear_dirty_log(uint32_t slot, uint64_t start, uint32_t size) "slot#%"PRId32" start 0x%"PRIx64" size 0x%"PRIx32 |