/* * Virtio MEM device * * Copyright (C) 2020 Red Hat, Inc. * * Authors: * David Hildenbrand <david@redhat.com> * * This work is licensed under the terms of the GNU GPL, version 2. * See the COPYING file in the top-level directory. */ #include "qemu/osdep.h" #include "qemu-common.h" #include "qemu/iov.h" #include "qemu/cutils.h" #include "qemu/error-report.h" #include "qemu/units.h" #include "sysemu/numa.h" #include "sysemu/sysemu.h" #include "sysemu/reset.h" #include "hw/virtio/virtio.h" #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" #include "hw/virtio/virtio-mem.h" #include "qapi/error.h" #include "qapi/visitor.h" #include "exec/ram_addr.h" #include "migration/misc.h" #include "hw/boards.h" #include "hw/qdev-properties.h" #include CONFIG_DEVICES #include "trace.h" /* * Let's not allow blocks smaller than 1 MiB, for example, to keep the tracking * bitmap small. */ #define VIRTIO_MEM_MIN_BLOCK_SIZE ((uint32_t)(1 * MiB)) #if defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) || \ defined(__powerpc64__) #define VIRTIO_MEM_DEFAULT_THP_SIZE ((uint32_t)(2 * MiB)) #else /* fallback to 1 MiB (e.g., the THP size on s390x) */ #define VIRTIO_MEM_DEFAULT_THP_SIZE VIRTIO_MEM_MIN_BLOCK_SIZE #endif /* * We want to have a reasonable default block size such that * 1. We avoid splitting THPs when unplugging memory, which degrades * performance. * 2. We avoid placing THPs for plugged blocks that also cover unplugged * blocks. * * The actual THP size might differ between Linux kernels, so we try to probe * it. In the future (if we ever run into issues regarding 2.), we might want * to disable THP in case we fail to properly probe the THP size, or if the * block size is configured smaller than the THP size. */ static uint32_t thp_size; #define HPAGE_PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" static uint32_t virtio_mem_thp_size(void) { gchar *content = NULL; const char *endptr; uint64_t tmp; if (thp_size) { return thp_size; } /* * Try to probe the actual THP size, fallback to (sane but eventually * incorrect) default sizes. */ if (g_file_get_contents(HPAGE_PMD_SIZE_PATH, &content, NULL, NULL) && !qemu_strtou64(content, &endptr, 0, &tmp) && (!endptr || *endptr == '\n')) { /* * Sanity-check the value, if it's too big (e.g., aarch64 with 64k base * pages) or weird, fallback to something smaller. */ if (!tmp || !is_power_of_2(tmp) || tmp > 16 * MiB) { warn_report("Read unsupported THP size: %" PRIx64, tmp); } else { thp_size = tmp; } } if (!thp_size) { thp_size = VIRTIO_MEM_DEFAULT_THP_SIZE; warn_report("Could not detect THP size, falling back to %" PRIx64 " MiB.", thp_size / MiB); } g_free(content); return thp_size; } static uint64_t virtio_mem_default_block_size(RAMBlock *rb) { const uint64_t page_size = qemu_ram_pagesize(rb); /* We can have hugetlbfs with a page size smaller than the THP size. */ if (page_size == qemu_real_host_page_size) { return MAX(page_size, virtio_mem_thp_size()); } return MAX(page_size, VIRTIO_MEM_MIN_BLOCK_SIZE); } /* * Size the usable region bigger than the requested size if possible. Esp. * Linux guests will only add (aligned) memory blocks in case they fully * fit into the usable region, but plug+online only a subset of the pages. * The memory block size corresponds mostly to the section size. * * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and * a section size of 1GB on arm64 (as long as the start address is properly * aligned, similar to ordinary DIMMs). * * We can change this at any time and maybe even make it configurable if * necessary (as the section size can change). But it's more likely that the * section size will rather get smaller and not bigger over time. */ #if defined(TARGET_X86_64) || defined(TARGET_I386) #define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB)) #else #error VIRTIO_MEM_USABLE_EXTENT not defined #endif static bool virtio_mem_is_busy(void) { /* * Postcopy cannot handle concurrent discards and we don't want to migrate * pages on-demand with stale content when plugging new blocks. * * For precopy, we don't want unplugged blocks in our migration stream, and * when plugging new blocks, the page content might differ between source * and destination (observable by the guest when not initializing pages * after plugging them) until we're running on the destination (as we didn't * migrate these blocks when they were unplugged). */ return migration_in_incoming_postcopy() || !migration_is_idle(); } static bool virtio_mem_test_bitmap(VirtIOMEM *vmem, uint64_t start_gpa, uint64_t size, bool plugged) { const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size; const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1; unsigned long found_bit; /* We fake a shorter bitmap to avoid searching too far. */ if (plugged) { found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit); } else { found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit); } return found_bit > last_bit; } static void virtio_mem_set_bitmap(VirtIOMEM *vmem, uint64_t start_gpa, uint64_t size, bool plugged) { const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size; const unsigned long nbits = size / vmem->block_size; if (plugged) { bitmap_set(vmem->bitmap, bit, nbits); } else { bitmap_clear(vmem->bitmap, bit, nbits); } } static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem, struct virtio_mem_resp *resp) { VirtIODevice *vdev = VIRTIO_DEVICE(vmem); VirtQueue *vq = vmem->vq; trace_virtio_mem_send_response(le16_to_cpu(resp->type)); iov_from_buf(elem->in_sg, elem->in_num, 0, resp, sizeof(*resp)); virtqueue_push(vq, elem, sizeof(*resp)); virtio_notify(vdev, vq); } static void virtio_mem_send_response_simple(VirtIOMEM *vmem, VirtQueueElement *elem, uint16_t type) { struct virtio_mem_resp resp = { .type = cpu_to_le16(type), }; virtio_mem_send_response(vmem, elem, &resp); } static bool virtio_mem_valid_range(VirtIOMEM *vmem, uint64_t gpa, uint64_t size) { if (!QEMU_IS_ALIGNED(gpa, vmem->block_size)) { return false; } if (gpa + size < gpa || !size) { return false; } if (gpa < vmem->addr || gpa >= vmem->addr + vmem->usable_region_size) { return false; } if (gpa + size > vmem->addr + vmem->usable_region_size) { return false; } return true; } static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, uint64_t size, bool plug) { const uint64_t offset = start_gpa - vmem->addr; int ret; if (virtio_mem_is_busy()) { return -EBUSY; } if (!plug) { ret = ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); if (ret) { error_report("Unexpected error discarding RAM: %s", strerror(-ret)); return -EBUSY; } } virtio_mem_set_bitmap(vmem, start_gpa, size, plug); return 0; } static int virtio_mem_state_change_request(VirtIOMEM *vmem, uint64_t gpa, uint16_t nb_blocks, bool plug) { const uint64_t size = nb_blocks * vmem->block_size; int ret; if (!virtio_mem_valid_range(vmem, gpa, size)) { return VIRTIO_MEM_RESP_ERROR; } if (plug && (vmem->size + size > vmem->requested_size)) { return VIRTIO_MEM_RESP_NACK; } /* test if really all blocks are in the opposite state */ if (!virtio_mem_test_bitmap(vmem, gpa, size, !plug)) { return VIRTIO_MEM_RESP_ERROR; } ret = virtio_mem_set_block_state(vmem, gpa, size, plug); if (ret) { return VIRTIO_MEM_RESP_BUSY; } if (plug) { vmem->size += size; } else { vmem->size -= size; } notifier_list_notify(&vmem->size_change_notifiers, &vmem->size); return VIRTIO_MEM_RESP_ACK; } static void virtio_mem_plug_request(VirtIOMEM *vmem, VirtQueueElement *elem, struct virtio_mem_req *req) { const uint64_t gpa = le64_to_cpu(req->u.plug.addr); const uint16_t nb_blocks = le16_to_cpu(req->u.plug.nb_blocks); uint16_t type; trace_virtio_mem_plug_request(gpa, nb_blocks); type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, true); virtio_mem_send_response_simple(vmem, elem, type); } static void virtio_mem_unplug_request(VirtIOMEM *vmem, VirtQueueElement *elem, struct virtio_mem_req *req) { const uint64_t gpa = le64_to_cpu(req->u.unplug.addr); const uint16_t nb_blocks = le16_to_cpu(req->u.unplug.nb_blocks); uint16_t type; trace_virtio_mem_unplug_request(gpa, nb_blocks); type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, false); virtio_mem_send_response_simple(vmem, elem, type); } static void virtio_mem_resize_usable_region(VirtIOMEM *vmem, uint64_t requested_size, bool can_shrink) { uint64_t newsize = MIN(memory_region_size(&vmem->memdev->mr), requested_size + VIRTIO_MEM_USABLE_EXTENT); /* The usable region size always has to be multiples of the block size. */ newsize = QEMU_ALIGN_UP(newsize, vmem->block_size); if (!requested_size) { newsize = 0; } if (newsize < vmem->usable_region_size && !can_shrink) { return; } trace_virtio_mem_resized_usable_region(vmem->usable_region_size, newsize); vmem->usable_region_size = newsize; } static int virtio_mem_unplug_all(VirtIOMEM *vmem) { RAMBlock *rb = vmem->memdev->mr.ram_block; int ret; if (virtio_mem_is_busy()) { return -EBUSY; } ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb)); if (ret) { error_report("Unexpected error discarding RAM: %s", strerror(-ret)); return -EBUSY; } bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size); if (vmem->size) { vmem->size = 0; notifier_list_notify(&vmem->size_change_notifiers, &vmem->size); } trace_virtio_mem_unplugged_all(); virtio_mem_resize_usable_region(vmem, vmem->requested_size, true); return 0; } static void virtio_mem_unplug_all_request(VirtIOMEM *vmem, VirtQueueElement *elem) { trace_virtio_mem_unplug_all_request(); if (virtio_mem_unplug_all(vmem)) { virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_BUSY); } else { virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ACK); } } static void virtio_mem_state_request(VirtIOMEM *vmem, VirtQueueElement *elem, struct virtio_mem_req *req) { const uint16_t nb_blocks = le16_to_cpu(req->u.state.nb_blocks); const uint64_t gpa = le64_to_cpu(req->u.state.addr); const uint64_t size = nb_blocks * vmem->block_size; struct virtio_mem_resp resp = { .type = cpu_to_le16(VIRTIO_MEM_RESP_ACK), }; trace_virtio_mem_state_request(gpa, nb_blocks); if (!virtio_mem_valid_range(vmem, gpa, size)) { virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ERROR); return; } if (virtio_mem_test_bitmap(vmem, gpa, size, true)) { resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED); } else if (virtio_mem_test_bitmap(vmem, gpa, size, false)) { resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED); } else { resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED); } trace_virtio_mem_state_response(le16_to_cpu(resp.u.state.state)); virtio_mem_send_response(vmem, elem, &resp); } static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq) { const int len = sizeof(struct virtio_mem_req); VirtIOMEM *vmem = VIRTIO_MEM(vdev); VirtQueueElement *elem; struct virtio_mem_req req; uint16_t type; while (true) { elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); if (!elem) { return; } if (iov_to_buf(elem->out_sg, elem->out_num, 0, &req, len) < len) { virtio_error(vdev, "virtio-mem protocol violation: invalid request" " size: %d", len); virtqueue_detach_element(vq, elem, 0); g_free(elem); return; } if (iov_size(elem->in_sg, elem->in_num) < sizeof(struct virtio_mem_resp)) { virtio_error(vdev, "virtio-mem protocol violation: not enough space" " for response: %zu", iov_size(elem->in_sg, elem->in_num)); virtqueue_detach_element(vq, elem, 0); g_free(elem); return; } type = le16_to_cpu(req.type); switch (type) { case VIRTIO_MEM_REQ_PLUG: virtio_mem_plug_request(vmem, elem, &req); break; case VIRTIO_MEM_REQ_UNPLUG: virtio_mem_unplug_request(vmem, elem, &req); break; case VIRTIO_MEM_REQ_UNPLUG_ALL: virtio_mem_unplug_all_request(vmem, elem); break; case VIRTIO_MEM_REQ_STATE: virtio_mem_state_request(vmem, elem, &req); break; default: virtio_error(vdev, "virtio-mem protocol violation: unknown request" " type: %d", type); virtqueue_detach_element(vq, elem, 0); g_free(elem); return; } g_free(elem); } } static void virtio_mem_get_config(VirtIODevice *vdev, uint8_t *config_data) { VirtIOMEM *vmem = VIRTIO_MEM(vdev); struct virtio_mem_config *config = (void *) config_data; config->block_size = cpu_to_le64(vmem->block_size); config->node_id = cpu_to_le16(vmem->node); config->requested_size = cpu_to_le64(vmem->requested_size); config->plugged_size = cpu_to_le64(vmem->size); config->addr = cpu_to_le64(vmem->addr); config->region_size = cpu_to_le64(memory_region_size(&vmem->memdev->mr)); config->usable_region_size = cpu_to_le64(vmem->usable_region_size); } static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features, Error **errp) { MachineState *ms = MACHINE(qdev_get_machine()); if (ms->numa_state) { #if defined(CONFIG_ACPI) virtio_add_feature(&features, VIRTIO_MEM_F_ACPI_PXM); #endif } return features; } static void virtio_mem_system_reset(void *opaque) { VirtIOMEM *vmem = VIRTIO_MEM(opaque); /* * During usual resets, we will unplug all memory and shrink the usable * region size. This is, however, not possible in all scenarios. Then, * the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL). */ virtio_mem_unplug_all(vmem); } static void virtio_mem_device_realize(DeviceState *dev, Error **errp) { MachineState *ms = MACHINE(qdev_get_machine()); int nb_numa_nodes = ms->numa_state ? ms->numa_state->num_nodes : 0; VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtIOMEM *vmem = VIRTIO_MEM(dev); uint64_t page_size; RAMBlock *rb; int ret; if (!vmem->memdev) { error_setg(errp, "'%s' property is not set", VIRTIO_MEM_MEMDEV_PROP); return; } else if (host_memory_backend_is_mapped(vmem->memdev)) { error_setg(errp, "'%s' property specifies a busy memdev: %s", VIRTIO_MEM_MEMDEV_PROP, object_get_canonical_path_component(OBJECT(vmem->memdev))); return; } else if (!memory_region_is_ram(&vmem->memdev->mr) || memory_region_is_rom(&vmem->memdev->mr) || !vmem->memdev->mr.ram_block) { error_setg(errp, "'%s' property specifies an unsupported memdev", VIRTIO_MEM_MEMDEV_PROP); return; } if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) || (!nb_numa_nodes && vmem->node)) { error_setg(errp, "'%s' property has value '%" PRIu32 "', which exceeds" "the number of numa nodes: %d", VIRTIO_MEM_NODE_PROP, vmem->node, nb_numa_nodes ? nb_numa_nodes : 1); return; } if (enable_mlock) { error_setg(errp, "Incompatible with mlock"); return; } rb = vmem->memdev->mr.ram_block; page_size = qemu_ram_pagesize(rb); /* * If the block size wasn't configured by the user, use a sane default. This * allows using hugetlbfs backends of any page size without manual * intervention. */ if (!vmem->block_size) { vmem->block_size = virtio_mem_default_block_size(rb); } if (vmem->block_size < page_size) { error_setg(errp, "'%s' property has to be at least the page size (0x%" PRIx64 ")", VIRTIO_MEM_BLOCK_SIZE_PROP, page_size); return; } else if (vmem->block_size < virtio_mem_default_block_size(rb)) { warn_report("'%s' property is smaller than the default block size (%" PRIx64 " MiB)", VIRTIO_MEM_BLOCK_SIZE_PROP, virtio_mem_default_block_size(rb) / MiB); } else if (!QEMU_IS_ALIGNED(vmem->requested_size, vmem->block_size)) { error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64 ")", VIRTIO_MEM_REQUESTED_SIZE_PROP, VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size); return; } else if (!QEMU_IS_ALIGNED(vmem->addr, vmem->block_size)) { error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64 ")", VIRTIO_MEM_ADDR_PROP, VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size); return; } else if (!QEMU_IS_ALIGNED(memory_region_size(&vmem->memdev->mr), vmem->block_size)) { error_setg(errp, "'%s' property memdev size has to be multiples of" "'%s' (0x%" PRIx64 ")", VIRTIO_MEM_MEMDEV_PROP, VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size); return; } if (ram_block_discard_require(true)) { error_setg(errp, "Discarding RAM is disabled"); return; } ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb)); if (ret) { error_setg_errno(errp, -ret, "Unexpected error discarding RAM"); ram_block_discard_require(false); return; } virtio_mem_resize_usable_region(vmem, vmem->requested_size, true); vmem->bitmap_size = memory_region_size(&vmem->memdev->mr) / vmem->block_size; vmem->bitmap = bitmap_new(vmem->bitmap_size); virtio_init(vdev, TYPE_VIRTIO_MEM, VIRTIO_ID_MEM, sizeof(struct virtio_mem_config)); vmem->vq = virtio_add_queue(vdev, 128, virtio_mem_handle_request); host_memory_backend_set_mapped(vmem->memdev, true); vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem)); qemu_register_reset(virtio_mem_system_reset, vmem); precopy_add_notifier(&vmem->precopy_notifier); } static void virtio_mem_device_unrealize(DeviceState *dev) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtIOMEM *vmem = VIRTIO_MEM(dev); precopy_remove_notifier(&vmem->precopy_notifier); qemu_unregister_reset(virtio_mem_system_reset, vmem); vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem)); host_memory_backend_set_mapped(vmem->memdev, false); virtio_del_queue(vdev, 0); virtio_cleanup(vdev); g_free(vmem->bitmap); ram_block_discard_require(false); } static int virtio_mem_restore_unplugged(VirtIOMEM *vmem) { RAMBlock *rb = vmem->memdev->mr.ram_block; unsigned long first_zero_bit, last_zero_bit; uint64_t offset, length; int ret; /* Find consecutive unplugged blocks and discard the consecutive range. */ first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size); while (first_zero_bit < vmem->bitmap_size) { offset = first_zero_bit * vmem->block_size; last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, first_zero_bit + 1) - 1; length = (last_zero_bit - first_zero_bit + 1) * vmem->block_size; ret = ram_block_discard_range(rb, offset, length); if (ret) { error_report("Unexpected error discarding RAM: %s", strerror(-ret)); return -EINVAL; } first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, last_zero_bit + 2); } return 0; } static int virtio_mem_post_load(void *opaque, int version_id) { if (migration_in_incoming_postcopy()) { return 0; } return virtio_mem_restore_unplugged(VIRTIO_MEM(opaque)); } typedef struct VirtIOMEMMigSanityChecks { VirtIOMEM *parent; uint64_t addr; uint64_t region_size; uint64_t block_size; uint32_t node; } VirtIOMEMMigSanityChecks; static int virtio_mem_mig_sanity_checks_pre_save(void *opaque) { VirtIOMEMMigSanityChecks *tmp = opaque; VirtIOMEM *vmem = tmp->parent; tmp->addr = vmem->addr; tmp->region_size = memory_region_size(&vmem->memdev->mr); tmp->block_size = vmem->block_size; tmp->node = vmem->node; return 0; } static int virtio_mem_mig_sanity_checks_post_load(void *opaque, int version_id) { VirtIOMEMMigSanityChecks *tmp = opaque; VirtIOMEM *vmem = tmp->parent; const uint64_t new_region_size = memory_region_size(&vmem->memdev->mr); if (tmp->addr != vmem->addr) { error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64, VIRTIO_MEM_ADDR_PROP, tmp->addr, vmem->addr); return -EINVAL; } /* * Note: Preparation for resizeable memory regions. The maximum size * of the memory region must not change during migration. */ if (tmp->region_size != new_region_size) { error_report("Property '%s' size changed from 0x%" PRIx64 " to 0x%" PRIx64, VIRTIO_MEM_MEMDEV_PROP, tmp->region_size, new_region_size); return -EINVAL; } if (tmp->block_size != vmem->block_size) { error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64, VIRTIO_MEM_BLOCK_SIZE_PROP, tmp->block_size, vmem->block_size); return -EINVAL; } if (tmp->node != vmem->node) { error_report("Property '%s' changed from %" PRIu32 " to %" PRIu32, VIRTIO_MEM_NODE_PROP, tmp->node, vmem->node); return -EINVAL; } return 0; } static const VMStateDescription vmstate_virtio_mem_sanity_checks = { .name = "virtio-mem-device/sanity-checks", .pre_save = virtio_mem_mig_sanity_checks_pre_save, .post_load = virtio_mem_mig_sanity_checks_post_load, .fields = (VMStateField[]) { VMSTATE_UINT64(addr, VirtIOMEMMigSanityChecks), VMSTATE_UINT64(region_size, VirtIOMEMMigSanityChecks), VMSTATE_UINT64(block_size, VirtIOMEMMigSanityChecks), VMSTATE_UINT32(node, VirtIOMEMMigSanityChecks), VMSTATE_END_OF_LIST(), }, }; static const VMStateDescription vmstate_virtio_mem_device = { .name = "virtio-mem-device", .minimum_version_id = 1, .version_id = 1, .post_load = virtio_mem_post_load, .fields = (VMStateField[]) { VMSTATE_WITH_TMP(VirtIOMEM, VirtIOMEMMigSanityChecks, vmstate_virtio_mem_sanity_checks), VMSTATE_UINT64(usable_region_size, VirtIOMEM), VMSTATE_UINT64(size, VirtIOMEM), VMSTATE_UINT64(requested_size, VirtIOMEM), VMSTATE_BITMAP(bitmap, VirtIOMEM, 0, bitmap_size), VMSTATE_END_OF_LIST() }, }; static const VMStateDescription vmstate_virtio_mem = { .name = "virtio-mem", .minimum_version_id = 1, .version_id = 1, .fields = (VMStateField[]) { VMSTATE_VIRTIO_DEVICE, VMSTATE_END_OF_LIST() }, }; static void virtio_mem_fill_device_info(const VirtIOMEM *vmem, VirtioMEMDeviceInfo *vi) { vi->memaddr = vmem->addr; vi->node = vmem->node; vi->requested_size = vmem->requested_size; vi->size = vmem->size; vi->max_size = memory_region_size(&vmem->memdev->mr); vi->block_size = vmem->block_size; vi->memdev = object_get_canonical_path(OBJECT(vmem->memdev)); } static MemoryRegion *virtio_mem_get_memory_region(VirtIOMEM *vmem, Error **errp) { if (!vmem->memdev) { error_setg(errp, "'%s' property must be set", VIRTIO_MEM_MEMDEV_PROP); return NULL; } return &vmem->memdev->mr; } static void virtio_mem_add_size_change_notifier(VirtIOMEM *vmem, Notifier *notifier) { notifier_list_add(&vmem->size_change_notifiers, notifier); } static void virtio_mem_remove_size_change_notifier(VirtIOMEM *vmem, Notifier *notifier) { notifier_remove(notifier); } static void virtio_mem_get_size(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { const VirtIOMEM *vmem = VIRTIO_MEM(obj); uint64_t value = vmem->size; visit_type_size(v, name, &value, errp); } static void virtio_mem_get_requested_size(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { const VirtIOMEM *vmem = VIRTIO_MEM(obj); uint64_t value = vmem->requested_size; visit_type_size(v, name, &value, errp); } static void virtio_mem_set_requested_size(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { VirtIOMEM *vmem = VIRTIO_MEM(obj); Error *err = NULL; uint64_t value; visit_type_size(v, name, &value, &err); if (err) { error_propagate(errp, err); return; } /* * The block size and memory backend are not fixed until the device was * realized. realize() will verify these properties then. */ if (DEVICE(obj)->realized) { if (!QEMU_IS_ALIGNED(value, vmem->block_size)) { error_setg(errp, "'%s' has to be multiples of '%s' (0x%" PRIx64 ")", name, VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size); return; } else if (value > memory_region_size(&vmem->memdev->mr)) { error_setg(errp, "'%s' cannot exceed the memory backend size" "(0x%" PRIx64 ")", name, memory_region_size(&vmem->memdev->mr)); return; } if (value != vmem->requested_size) { virtio_mem_resize_usable_region(vmem, value, false); vmem->requested_size = value; } /* * Trigger a config update so the guest gets notified. We trigger * even if the size didn't change (especially helpful for debugging). */ virtio_notify_config(VIRTIO_DEVICE(vmem)); } else { vmem->requested_size = value; } } static void virtio_mem_get_block_size(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { const VirtIOMEM *vmem = VIRTIO_MEM(obj); uint64_t value = vmem->block_size; /* * If not configured by the user (and we're not realized yet), use the * default block size we would use with the current memory backend. */ if (!value) { if (vmem->memdev && memory_region_is_ram(&vmem->memdev->mr)) { value = virtio_mem_default_block_size(vmem->memdev->mr.ram_block); } else { value = virtio_mem_thp_size(); } } visit_type_size(v, name, &value, errp); } static void virtio_mem_set_block_size(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) { VirtIOMEM *vmem = VIRTIO_MEM(obj); Error *err = NULL; uint64_t value; if (DEVICE(obj)->realized) { error_setg(errp, "'%s' cannot be changed", name); return; } visit_type_size(v, name, &value, &err); if (err) { error_propagate(errp, err); return; } if (value < VIRTIO_MEM_MIN_BLOCK_SIZE) { error_setg(errp, "'%s' property has to be at least 0x%" PRIx32, name, VIRTIO_MEM_MIN_BLOCK_SIZE); return; } else if (!is_power_of_2(value)) { error_setg(errp, "'%s' property has to be a power of two", name); return; } vmem->block_size = value; } static void virtio_mem_precopy_exclude_unplugged(VirtIOMEM *vmem) { void * const host = qemu_ram_get_host_addr(vmem->memdev->mr.ram_block); unsigned long first_zero_bit, last_zero_bit; uint64_t offset, length; /* * Find consecutive unplugged blocks and exclude them from migration. * * Note: Blocks cannot get (un)plugged during precopy, no locking needed. */ first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size); while (first_zero_bit < vmem->bitmap_size) { offset = first_zero_bit * vmem->block_size; last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, first_zero_bit + 1) - 1; length = (last_zero_bit - first_zero_bit + 1) * vmem->block_size; qemu_guest_free_page_hint(host + offset, length); first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, last_zero_bit + 2); } } static int virtio_mem_precopy_notify(NotifierWithReturn *n, void *data) { VirtIOMEM *vmem = container_of(n, VirtIOMEM, precopy_notifier); PrecopyNotifyData *pnd = data; switch (pnd->reason) { case PRECOPY_NOTIFY_SETUP: precopy_enable_free_page_optimization(); break; case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC: virtio_mem_precopy_exclude_unplugged(vmem); break; default: break; } return 0; } static void virtio_mem_instance_init(Object *obj) { VirtIOMEM *vmem = VIRTIO_MEM(obj); notifier_list_init(&vmem->size_change_notifiers); vmem->precopy_notifier.notify = virtio_mem_precopy_notify; object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", virtio_mem_get_size, NULL, NULL, NULL); object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size", virtio_mem_get_requested_size, virtio_mem_set_requested_size, NULL, NULL); object_property_add(obj, VIRTIO_MEM_BLOCK_SIZE_PROP, "size", virtio_mem_get_block_size, virtio_mem_set_block_size, NULL, NULL); } static Property virtio_mem_properties[] = { DEFINE_PROP_UINT64(VIRTIO_MEM_ADDR_PROP, VirtIOMEM, addr, 0), DEFINE_PROP_UINT32(VIRTIO_MEM_NODE_PROP, VirtIOMEM, node, 0), DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev, TYPE_MEMORY_BACKEND, HostMemoryBackend *), DEFINE_PROP_END_OF_LIST(), }; static void virtio_mem_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); VirtIOMEMClass *vmc = VIRTIO_MEM_CLASS(klass); device_class_set_props(dc, virtio_mem_properties); dc->vmsd = &vmstate_virtio_mem; set_bit(DEVICE_CATEGORY_MISC, dc->categories); vdc->realize = virtio_mem_device_realize; vdc->unrealize = virtio_mem_device_unrealize; vdc->get_config = virtio_mem_get_config; vdc->get_features = virtio_mem_get_features; vdc->vmsd = &vmstate_virtio_mem_device; vmc->fill_device_info = virtio_mem_fill_device_info; vmc->get_memory_region = virtio_mem_get_memory_region; vmc->add_size_change_notifier = virtio_mem_add_size_change_notifier; vmc->remove_size_change_notifier = virtio_mem_remove_size_change_notifier; } static const TypeInfo virtio_mem_info = { .name = TYPE_VIRTIO_MEM, .parent = TYPE_VIRTIO_DEVICE, .instance_size = sizeof(VirtIOMEM), .instance_init = virtio_mem_instance_init, .class_init = virtio_mem_class_init, .class_size = sizeof(VirtIOMEMClass), }; static void virtio_register_types(void) { type_register_static(&virtio_mem_info); } type_init(virtio_register_types)