On Tue, 8 Jan 2019 01:03:48 -0500 Zhao Yan <yan.y.z...@intel.com> wrote:
> 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 Why wouldn't we just use the id= (DeviceState.id) value instead of adding yet another one? I can't imagine anyone, especially libvirt, wants to deal with a vfio specific id for a device. > 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); Where does the corresponding vmstate_unregister_ram() call occur when unplugged? Thanks, Alex > } > > void memory_region_init_ram_device_ptr(MemoryRegion *mr,