Re: [Qemu-devel] [PATCH v4 23/47] ivshmem: migrate with VMStateDescription

[Claudio Fontana]

On 24.09.2015 13:37, address@hidden wrote:
> From: Marc-André Lureau <address@hidden>
> 
> load_state_old() is used to keep compatibility with version 0.
> 
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  hw/misc/ivshmem.c | 141 
> ++++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 88 insertions(+), 53 deletions(-)
> 
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index 8207a98..54f7093 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -651,56 +651,6 @@ static int ivshmem_setup_msi(IVShmemState * s)
>      return 0;
>  }
>  
> -static void ivshmem_save(QEMUFile* f, void *opaque)
> -{
> -    IVShmemState *proxy = opaque;
> -    PCIDevice *pci_dev = PCI_DEVICE(proxy);
> -
> -    IVSHMEM_DPRINTF("ivshmem_save\n");
> -    pci_device_save(pci_dev, f);
> -
> -    if (ivshmem_has_feature(proxy, IVSHMEM_MSI)) {
> -        msix_save(pci_dev, f);
> -    } else {
> -        qemu_put_be32(f, proxy->intrstatus);
> -        qemu_put_be32(f, proxy->intrmask);
> -    }
> -
> -}
> -
> -static int ivshmem_load(QEMUFile* f, void *opaque, int version_id)
> -{
> -    IVSHMEM_DPRINTF("ivshmem_load\n");
> -
> -    IVShmemState *proxy = opaque;
> -    PCIDevice *pci_dev = PCI_DEVICE(proxy);
> -    int ret;
> -
> -    if (version_id > 0) {
> -        return -EINVAL;
> -    }
> -
> -    if (proxy->role_val == IVSHMEM_PEER) {
> -        error_report("'peer' devices are not migratable");
> -        return -EINVAL;
> -    }
> -
> -    ret = pci_device_load(pci_dev, f);
> -    if (ret) {
> -        return ret;
> -    }
> -
> -    if (ivshmem_has_feature(proxy, IVSHMEM_MSI)) {
> -        msix_load(pci_dev, f);
> -     ivshmem_use_msix(proxy);
> -    } else {
> -        proxy->intrstatus = qemu_get_be32(f);
> -        proxy->intrmask = qemu_get_be32(f);
> -    }
> -
> -    return 0;
> -}
> -
>  static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address,
>                                   uint32_t val, int len)
>  {
> @@ -726,8 +676,7 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error 
> **errp)
>      }
>  
>      fifo8_create(&s->incoming_fifo, sizeof(long));
> -    register_savevm(DEVICE(dev), "ivshmem", 0, 0, ivshmem_save, ivshmem_load,
> -                                                                        dev);
> +
>      /* IRQFD requires MSI */
>      if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD) &&
>          !ivshmem_has_feature(s, IVSHMEM_MSI)) {
> @@ -853,10 +802,95 @@ static void pci_ivshmem_exit(PCIDevice *dev)
>  
>      memory_region_del_subregion(&s->bar, &s->ivshmem);
>      vmstate_unregister_ram(&s->ivshmem, DEVICE(dev));
> -    unregister_savevm(DEVICE(dev), "ivshmem", s);
>      fifo8_destroy(&s->incoming_fifo);
>  }
>  
> +static bool test_msix(void *opaque, int version_id)
> +{
> +    IVShmemState *s = opaque;
> +
> +    return ivshmem_has_feature(s, IVSHMEM_MSI);
> +}
> +
> +static bool test_no_msix(void *opaque, int version_id)
> +{
> +    return !test_msix(opaque, version_id);
> +}
> +
> +static int ivshmem_pre_load(void *opaque)
> +{
> +    IVShmemState *s = opaque;
> +
> +    if (s->role_val == IVSHMEM_PEER) {
> +        error_report("'peer' devices are not migratable");
> +        return -EINVAL;
> +    }
> +
> +    return 0;
> +}
> +
> +static int ivshmem_post_load(void *opaque, int version_id)
> +{
> +    IVShmemState *s = opaque;
> +
> +    if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
> +        ivshmem_use_msix(s);
> +    }
> +
> +    return 0;
> +}
> +
> +static int ivshmem_load_old(QEMUFile *f, void *opaque, int version_id)
> +{
> +    IVShmemState *s = opaque;
> +    PCIDevice *pdev = PCI_DEVICE(s);
> +    int ret;
> +
> +    IVSHMEM_DPRINTF("ivshmem_load_old\n");
> +
> +    if (version_id != 0) {
> +        return -EINVAL;
> +    }
> +
> +    if (s->role_val == IVSHMEM_PEER) {
> +        error_report("'peer' devices are not migratable");
> +        return -EINVAL;
> +    }
> +
> +    ret = pci_device_load(pdev, f);
> +    if (ret) {
> +        return ret;
> +    }
> +
> +    if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
> +        msix_load(pdev, f);
> +        ivshmem_use_msix(s);
> +    } else {
> +        s->intrstatus = qemu_get_be32(f);
> +        s->intrmask = qemu_get_be32(f);
> +    }
> +
> +    return 0;
> +}
> +
> +static const VMStateDescription ivshmem_vmsd = {
> +    .name = "ivshmem",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .pre_load = ivshmem_pre_load,
> +    .post_load = ivshmem_post_load,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_PCI_DEVICE(parent_obj, IVShmemState),
> +
> +        VMSTATE_MSIX_TEST(parent_obj, IVShmemState, test_msix),
> +        VMSTATE_UINT32_TEST(intrstatus, IVShmemState, test_no_msix),
> +        VMSTATE_UINT32_TEST(intrmask, IVShmemState, test_no_msix),
> +
> +        VMSTATE_END_OF_LIST()
> +    },
> +    .load_state_old = ivshmem_load_old

Should you not have a minimum_version_id_old if you want to support 
load_state_old?
Granted, it should be =0, so it probably works anyway..

> +};
> +
>  static Property ivshmem_properties[] = {
>      DEFINE_PROP_CHR("chardev", IVShmemState, server_chr),
>      DEFINE_PROP_STRING("size", IVShmemState, sizearg),
> @@ -882,6 +916,7 @@ static void ivshmem_class_init(ObjectClass *klass, void 
> *data)
>      k->class_id = PCI_CLASS_MEMORY_RAM;
>      dc->reset = ivshmem_reset;
>      dc->props = ivshmem_properties;
> +    dc->vmsd = &ivshmem_vmsd;
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>  }
>  
> 


-- 
Claudio Fontana
Server Virtualization Architect
Huawei Technologies Duesseldorf GmbH
Riesstraße 25 - 80992 München