if multiple regions in vfio are mmaped, their corresponding ramblocks are like below, i.e. their idstrs are "".
(qemu) info ramblock Block Name PSize Offset Used Total pc.ram 4 KiB 0x0000000000000000 0x0000000020000000 0x0000000020000000 4 KiB 0x0000000021100000 0x0000000020000000 0x0000000020000000 4 KiB 0x0000000020900000 0x0000000000800000 0x0000000000800000 4 KiB 0x0000000020240000 0x0000000000687000 0x0000000000687000 4 KiB 0x00000000200c0000 0x0000000000178000 0x0000000000178000 pc.bios 4 KiB 0x0000000020000000 0x0000000000040000 0x0000000000040000 pc.rom 4 KiB 0x0000000020040000 0x0000000000020000 0x0000000000020000 This is because ramblocks' idstr are assigned by calling vmstate_register_ram(), but memory region of type ram device ptr does not call vmstate_register_ram(). vfio_region_mmap |->memory_region_init_ram_device_ptr |-> memory_region_init_ram_ptr Without empty idstrs will cause problem to snapshot copying during migration, because it uses ramblocks' idstr to identify ramblocks. ram_save_setup { … RAMBLOCK_FOREACH(block) { qemu_put_byte(f, strlen(block->idstr)); qemu_put_buffer(f, (uint8_t *)block->idstr,strlen(block->idstr)); qemu_put_be64(f, block->used_length); } … } ram_load() { block = qemu_ram_block_by_name(id); if (block) { if (length != block->used_length) { qemu_ram_resize(block, length, &local_err); } …. } } Therefore, in this patch, vmstate_register_ram() is called for memory region of type ram ptr, also a unique vfioid is assigned to vfio devices across source and target vms. e.g. in source vm, use qemu parameter -device vfio-pci,sysfsdev=/sys/bus/pci/devices/0000:00:02.0/ 882cc4da-dede-11e7-9180-078a62063ab1,vfioid=igd and in target vm, use qemu paramter -device vfio-pci,sysfsdev=/sys/bus/pci/devices/0000:00:02.0/ 5ac1fb20-2bbf-4842-bb7e-36c58c3be9cd,vfioid=igd Signed-off-by: Zhao Yan <yan.y.z...@intel.com> --- hw/vfio/pci.c | 8 +++++++- include/hw/vfio/vfio-common.h | 1 + memory.c | 4 ++++ 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index c0cb1ec289..7bc2ed0752 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -2533,7 +2533,12 @@ static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp) } for (i = VFIO_PCI_BAR0_REGION_INDEX; i < VFIO_PCI_ROM_REGION_INDEX; i++) { - char *name = g_strdup_printf("%s BAR %d", vbasedev->name, i); + char *name; + if (vbasedev->vfioid) { + name = g_strdup_printf("%s BAR %d", vbasedev->vfioid, i); + } else { + name = g_strdup_printf("%s BAR %d", vbasedev->name, i); + } ret = vfio_region_setup(OBJECT(vdev), vbasedev, &vdev->bars[i].region, i, name); @@ -3180,6 +3185,7 @@ static void vfio_instance_init(Object *obj) static Property vfio_pci_dev_properties[] = { DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIOPCIDevice, host), DEFINE_PROP_STRING("sysfsdev", VFIOPCIDevice, vbasedev.sysfsdev), + DEFINE_PROP_STRING("vfioid", VFIOPCIDevice, vbasedev.vfioid), DEFINE_PROP_ON_OFF_AUTO("display", VFIOPCIDevice, display, ON_OFF_AUTO_OFF), DEFINE_PROP_UINT32("x-intx-mmap-timeout-ms", VFIOPCIDevice, diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index 1b434d02f6..84bab94f52 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -108,6 +108,7 @@ typedef struct VFIODevice { struct VFIOGroup *group; char *sysfsdev; char *name; + char *vfioid; DeviceState *dev; int fd; int type; diff --git a/memory.c b/memory.c index d14c6dec1d..dbb29fa989 100644 --- a/memory.c +++ b/memory.c @@ -1588,6 +1588,7 @@ void memory_region_init_ram_ptr(MemoryRegion *mr, uint64_t size, void *ptr) { + DeviceState *owner_dev; memory_region_init(mr, owner, name, size); mr->ram = true; mr->terminates = true; @@ -1597,6 +1598,9 @@ void memory_region_init_ram_ptr(MemoryRegion *mr, /* qemu_ram_alloc_from_ptr cannot fail with ptr != NULL. */ assert(ptr != NULL); mr->ram_block = qemu_ram_alloc_from_ptr(size, ptr, mr, &error_fatal); + + owner_dev = DEVICE(owner); + vmstate_register_ram(mr, owner_dev); } void memory_region_init_ram_device_ptr(MemoryRegion *mr, -- 2.17.1