/* * Virtio MEM device * * Copyright (C) 2020 Red Hat, Inc. * * Authors: * David Hildenbrand * * 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/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" /* * We only had legacy x86 guests that did not support * VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE. Other targets don't have legacy guests. */ #if defined(TARGET_X86_64) || defined(TARGET_I386) #define VIRTIO_MEM_HAS_LEGACY_GUESTS #endif /* * 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)) static uint32_t virtio_mem_default_thp_size(void) { uint32_t default_thp_size = VIRTIO_MEM_MIN_BLOCK_SIZE; #if defined(__x86_64__) || defined(__arm__) || defined(__powerpc64__) default_thp_size = 2 * MiB; #elif defined(__aarch64__) if (qemu_real_host_page_size() == 4 * KiB) { default_thp_size = 2 * MiB; } else if (qemu_real_host_page_size() == 16 * KiB) { default_thp_size = 32 * MiB; } else if (qemu_real_host_page_size() == 64 * KiB) { default_thp_size = 512 * MiB; } #endif return default_thp_size; } /* * 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 and fallback to something reasonable. */ if (!tmp || !is_power_of_2(tmp)) { 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); } #if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS) static bool virtio_mem_has_shared_zeropage(RAMBlock *rb) { /* * We only have a guaranteed shared zeropage on ordinary MAP_PRIVATE * anonymous RAM. In any other case, reading unplugged *can* populate a * fresh page, consuming actual memory. */ return !qemu_ram_is_shared(rb) && rb->fd < 0 && qemu_ram_pagesize(rb) == qemu_real_host_page_size(); } #endif /* VIRTIO_MEM_HAS_LEGACY_GUESTS */ /* * 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 512MB 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)) #elif defined(TARGET_ARM) #define VIRTIO_MEM_USABLE_EXTENT (2 * (512 * 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(); } typedef int (*virtio_mem_range_cb)(const VirtIOMEM *vmem, void *arg, uint64_t offset, uint64_t size); static int virtio_mem_for_each_unplugged_range(const VirtIOMEM *vmem, void *arg, virtio_mem_range_cb cb) { unsigned long first_zero_bit, last_zero_bit; uint64_t offset, size; int ret = 0; 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; size = (last_zero_bit - first_zero_bit + 1) * vmem->block_size; ret = cb(vmem, arg, offset, size); if (ret) { break; } first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, last_zero_bit + 2); } return ret; } /* * Adjust the memory section to cover the intersection with the given range. * * Returns false if the intersection is empty, otherwise returns true. */ static bool virito_mem_intersect_memory_section(MemoryRegionSection *s, uint64_t offset, uint64_t size) { uint64_t start = MAX(s->offset_within_region, offset); uint64_t end = MIN(s->offset_within_region + int128_get64(s->size), offset + size); if (end <= start) { return false; } s->offset_within_address_space += start - s->offset_within_region; s->offset_within_region = start; s->size = int128_make64(end - start); return true; } typedef int (*virtio_mem_section_cb)(MemoryRegionSection *s, void *arg); static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem, MemoryRegionSection *s, void *arg, virtio_mem_section_cb cb) { unsigned long first_bit, last_bit; uint64_t offset, size; int ret = 0; first_bit = s->offset_within_region / vmem->block_size; first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, first_bit); while (first_bit < vmem->bitmap_size) { MemoryRegionSection tmp = *s; offset = first_bit * vmem->block_size; last_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, first_bit + 1) - 1; size = (last_bit - first_bit + 1) * vmem->block_size; if (!virito_mem_intersect_memory_section(&tmp, offset, size)) { break; } ret = cb(&tmp, arg); if (ret) { break; } first_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, last_bit + 2); } return ret; } static int virtio_mem_for_each_unplugged_section(const VirtIOMEM *vmem, MemoryRegionSection *s, void *arg, virtio_mem_section_cb cb) { unsigned long first_bit, last_bit; uint64_t offset, size; int ret = 0; first_bit = s->offset_within_region / vmem->block_size; first_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, first_bit); while (first_bit < vmem->bitmap_size) { MemoryRegionSection tmp = *s; offset = first_bit * vmem->block_size; last_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, first_bit + 1) - 1; size = (last_bit - first_bit + 1) * vmem->block_size; if (!virito_mem_intersect_memory_section(&tmp, offset, size)) { break; } ret = cb(&tmp, arg); if (ret) { break; } first_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, last_bit + 2); } return ret; } static int virtio_mem_notify_populate_cb(MemoryRegionSection *s, void *arg) { RamDiscardListener *rdl = arg; return rdl->notify_populate(rdl, s); } static int virtio_mem_notify_discard_cb(MemoryRegionSection *s, void *arg) { RamDiscardListener *rdl = arg; rdl->notify_discard(rdl, s); return 0; } static void virtio_mem_notify_unplug(VirtIOMEM *vmem, uint64_t offset, uint64_t size) { RamDiscardListener *rdl; QLIST_FOREACH(rdl, &vmem->rdl_list, next) { MemoryRegionSection tmp = *rdl->section; if (!virito_mem_intersect_memory_section(&tmp, offset, size)) { continue; } rdl->notify_discard(rdl, &tmp); } } static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset, uint64_t size) { RamDiscardListener *rdl, *rdl2; int ret = 0; QLIST_FOREACH(rdl, &vmem->rdl_list, next) { MemoryRegionSection tmp = *rdl->section; if (!virito_mem_intersect_memory_section(&tmp, offset, size)) { continue; } ret = rdl->notify_populate(rdl, &tmp); if (ret) { break; } } if (ret) { /* Notify all already-notified listeners. */ QLIST_FOREACH(rdl2, &vmem->rdl_list, next) { MemoryRegionSection tmp = *rdl2->section; if (rdl2 == rdl) { break; } if (!virito_mem_intersect_memory_section(&tmp, offset, size)) { continue; } rdl2->notify_discard(rdl2, &tmp); } } return ret; } static void virtio_mem_notify_unplug_all(VirtIOMEM *vmem) { RamDiscardListener *rdl; if (!vmem->size) { return; } QLIST_FOREACH(rdl, &vmem->rdl_list, next) { if (rdl->double_discard_supported) { rdl->notify_discard(rdl, rdl->section); } else { virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl, virtio_mem_notify_discard_cb); } } } static bool virtio_mem_test_bitmap(const 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(const 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; RAMBlock *rb = vmem->memdev->mr.ram_block; if (virtio_mem_is_busy()) { return -EBUSY; } if (!plug) { if (ram_block_discard_range(rb, offset, size)) { return -EBUSY; } virtio_mem_notify_unplug(vmem, offset, size); } else { int ret = 0; if (vmem->prealloc) { void *area = memory_region_get_ram_ptr(&vmem->memdev->mr) + offset; int fd = memory_region_get_fd(&vmem->memdev->mr); Error *local_err = NULL; qemu_prealloc_mem(fd, area, size, 1, NULL, &local_err); if (local_err) { static bool warned; /* * Warn only once, we don't want to fill the log with these * warnings. */ if (!warned) { warn_report_err(local_err); warned = true; } else { error_free(local_err); } ret = -EBUSY; } } if (!ret) { ret = virtio_mem_notify_plug(vmem, offset, size); } if (ret) { /* Could be preallocation or a notifier populated memory. */ ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); 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; if (virtio_mem_is_busy()) { return -EBUSY; } if (ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb))) { return -EBUSY; } virtio_mem_notify_unplug_all(vmem); 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()); VirtIOMEM *vmem = VIRTIO_MEM(vdev); if (ms->numa_state) { #if defined(CONFIG_ACPI) virtio_add_feature(&features, VIRTIO_MEM_F_ACPI_PXM); #endif } assert(vmem->unplugged_inaccessible != ON_OFF_AUTO_AUTO); if (vmem->unplugged_inaccessible == ON_OFF_AUTO_ON) { virtio_add_feature(&features, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE); } return features; } static int virtio_mem_validate_features(VirtIODevice *vdev) { if (virtio_host_has_feature(vdev, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE) && !virtio_vdev_has_feature(vdev, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE)) { return -EFAULT; } return 0; } 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 defined(VIRTIO_MEM_HAS_LEGACY_GUESTS) switch (vmem->unplugged_inaccessible) { case ON_OFF_AUTO_AUTO: if (virtio_mem_has_shared_zeropage(rb)) { vmem->unplugged_inaccessible = ON_OFF_AUTO_OFF; } else { vmem->unplugged_inaccessible = ON_OFF_AUTO_ON; } break; case ON_OFF_AUTO_OFF: if (!virtio_mem_has_shared_zeropage(rb)) { warn_report("'%s' property set to 'off' with a memdev that does" " not support the shared zeropage.", VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP); } break; default: break; } #else /* VIRTIO_MEM_HAS_LEGACY_GUESTS */ vmem->unplugged_inaccessible = ON_OFF_AUTO_ON; #endif /* VIRTIO_MEM_HAS_LEGACY_GUESTS */ /* * 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); } 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_coordinated_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_coordinated_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, 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); /* * Set ourselves as RamDiscardManager before the plug handler maps the * memory region and exposes it via an address space. */ memory_region_set_ram_discard_manager(&vmem->memdev->mr, RAM_DISCARD_MANAGER(vmem)); } static void virtio_mem_device_unrealize(DeviceState *dev) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtIOMEM *vmem = VIRTIO_MEM(dev); /* * The unplug handler unmapped the memory region, it cannot be * found via an address space anymore. Unset ourselves. */ memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL); 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_coordinated_discard_require(false); } static int virtio_mem_discard_range_cb(const VirtIOMEM *vmem, void *arg, uint64_t offset, uint64_t size) { RAMBlock *rb = vmem->memdev->mr.ram_block; return ram_block_discard_range(rb, offset, size) ? -EINVAL : 0; } static int virtio_mem_restore_unplugged(VirtIOMEM *vmem) { /* Make sure all memory is really discarded after migration. */ return virtio_mem_for_each_unplugged_range(vmem, NULL, virtio_mem_discard_range_cb); } static int virtio_mem_post_load(void *opaque, int version_id) { VirtIOMEM *vmem = VIRTIO_MEM(opaque); RamDiscardListener *rdl; int ret; /* * We started out with all memory discarded and our memory region is mapped * into an address space. Replay, now that we updated the bitmap. */ QLIST_FOREACH(rdl, &vmem->rdl_list, next) { ret = virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl, virtio_mem_notify_populate_cb); if (ret) { return ret; } } if (migration_in_incoming_postcopy()) { return 0; } return virtio_mem_restore_unplugged(vmem); } 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, .priority = MIG_PRI_VIRTIO_MEM, .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); uint64_t value; if (!visit_type_size(v, name, &value, errp)) { 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); uint64_t value; if (DEVICE(obj)->realized) { error_setg(errp, "'%s' cannot be changed", name); return; } if (!visit_type_size(v, name, &value, errp)) { 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_instance_init(Object *obj) { VirtIOMEM *vmem = VIRTIO_MEM(obj); notifier_list_init(&vmem->size_change_notifiers); QLIST_INIT(&vmem->rdl_list); 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_BOOL(VIRTIO_MEM_PREALLOC_PROP, VirtIOMEM, prealloc, false), DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev, TYPE_MEMORY_BACKEND, HostMemoryBackend *), #if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS) DEFINE_PROP_ON_OFF_AUTO(VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP, VirtIOMEM, unplugged_inaccessible, ON_OFF_AUTO_AUTO), #endif DEFINE_PROP_END_OF_LIST(), }; static uint64_t virtio_mem_rdm_get_min_granularity(const RamDiscardManager *rdm, const MemoryRegion *mr) { const VirtIOMEM *vmem = VIRTIO_MEM(rdm); g_assert(mr == &vmem->memdev->mr); return vmem->block_size; } static bool virtio_mem_rdm_is_populated(const RamDiscardManager *rdm, const MemoryRegionSection *s) { const VirtIOMEM *vmem = VIRTIO_MEM(rdm); uint64_t start_gpa = vmem->addr + s->offset_within_region; uint64_t end_gpa = start_gpa + int128_get64(s->size); g_assert(s->mr == &vmem->memdev->mr); start_gpa = QEMU_ALIGN_DOWN(start_gpa, vmem->block_size); end_gpa = QEMU_ALIGN_UP(end_gpa, vmem->block_size); if (!virtio_mem_valid_range(vmem, start_gpa, end_gpa - start_gpa)) { return false; } return virtio_mem_test_bitmap(vmem, start_gpa, end_gpa - start_gpa, true); } struct VirtIOMEMReplayData { void *fn; void *opaque; }; static int virtio_mem_rdm_replay_populated_cb(MemoryRegionSection *s, void *arg) { struct VirtIOMEMReplayData *data = arg; return ((ReplayRamPopulate)data->fn)(s, data->opaque); } static int virtio_mem_rdm_replay_populated(const RamDiscardManager *rdm, MemoryRegionSection *s, ReplayRamPopulate replay_fn, void *opaque) { const VirtIOMEM *vmem = VIRTIO_MEM(rdm); struct VirtIOMEMReplayData data = { .fn = replay_fn, .opaque = opaque, }; g_assert(s->mr == &vmem->memdev->mr); return virtio_mem_for_each_plugged_section(vmem, s, &data, virtio_mem_rdm_replay_populated_cb); } static int virtio_mem_rdm_replay_discarded_cb(MemoryRegionSection *s, void *arg) { struct VirtIOMEMReplayData *data = arg; ((ReplayRamDiscard)data->fn)(s, data->opaque); return 0; } static void virtio_mem_rdm_replay_discarded(const RamDiscardManager *rdm, MemoryRegionSection *s, ReplayRamDiscard replay_fn, void *opaque) { const VirtIOMEM *vmem = VIRTIO_MEM(rdm); struct VirtIOMEMReplayData data = { .fn = replay_fn, .opaque = opaque, }; g_assert(s->mr == &vmem->memdev->mr); virtio_mem_for_each_unplugged_section(vmem, s, &data, virtio_mem_rdm_replay_discarded_cb); } static void virtio_mem_rdm_register_listener(RamDiscardManager *rdm, RamDiscardListener *rdl, MemoryRegionSection *s) { VirtIOMEM *vmem = VIRTIO_MEM(rdm); int ret; g_assert(s->mr == &vmem->memdev->mr); rdl->section = memory_region_section_new_copy(s); QLIST_INSERT_HEAD(&vmem->rdl_list, rdl, next); ret = virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl, virtio_mem_notify_populate_cb); if (ret) { error_report("%s: Replaying plugged ranges failed: %s", __func__, strerror(-ret)); } } static void virtio_mem_rdm_unregister_listener(RamDiscardManager *rdm, RamDiscardListener *rdl) { VirtIOMEM *vmem = VIRTIO_MEM(rdm); g_assert(rdl->section->mr == &vmem->memdev->mr); if (vmem->size) { if (rdl->double_discard_supported) { rdl->notify_discard(rdl, rdl->section); } else { virtio_mem_for_each_plugged_section(vmem, rdl->section, rdl, virtio_mem_notify_discard_cb); } } memory_region_section_free_copy(rdl->section); rdl->section = NULL; QLIST_REMOVE(rdl, next); } 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); RamDiscardManagerClass *rdmc = RAM_DISCARD_MANAGER_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->validate_features = virtio_mem_validate_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; rdmc->get_min_granularity = virtio_mem_rdm_get_min_granularity; rdmc->is_populated = virtio_mem_rdm_is_populated; rdmc->replay_populated = virtio_mem_rdm_replay_populated; rdmc->replay_discarded = virtio_mem_rdm_replay_discarded; rdmc->register_listener = virtio_mem_rdm_register_listener; rdmc->unregister_listener = virtio_mem_rdm_unregister_listener; } 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), .interfaces = (InterfaceInfo[]) { { TYPE_RAM_DISCARD_MANAGER }, { } }, }; static void virtio_register_types(void) { type_register_static(&virtio_mem_info); } type_init(virtio_register_types)