Re: [Qemu-devel] [PATCH 03/39] pci: split exit and finalize

[Anthony Liguori]

Paolo Bonzini <address@hidden> writes:

> To properly support devices that do DMA out of the BQL, destruction
> needs to be done in two phases.  First, the device is unrealized;
> at this point, pending memory accesses can still be completed, but
> no new accesses will be started.  The second part is freeing the
> device, which happens only after the reference count drops to zero;
> this means that all memory accesses are complete.
>
> This patch changes the PCI core to delay destruction of the
> bus-master address space and root region.
>
> Signed-off-by: Paolo Bonzini <address@hidden>

Reviewed-by: Anthony Liguori <address@hidden>

Regards,

Anthony Liguori

> ---
>  hw/pci/pci.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 776ad96..b60d9d0d 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -779,6 +779,16 @@ static void pci_config_free(PCIDevice *pci_dev)
>      g_free(pci_dev->used);
>  }
>  
> +static void pci_device_instance_finalize(Object *obj)
> +{
> +    PCIDevice *pci_dev = PCI_DEVICE(obj);
> +
> +    qemu_free_irqs(pci_dev->irq);
> +
> +    address_space_destroy(&pci_dev->bus_master_as);
> +    memory_region_destroy(&pci_dev->bus_master_enable_region);
> +}
> +
>  /* -1 for devfn means auto assign */
>  static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
>                                           const char *name, int devfn)
> @@ -866,12 +876,8 @@ static PCIDevice *do_pci_register_device(PCIDevice 
> *pci_dev, PCIBus *bus,
>  
>  static void do_pci_unregister_device(PCIDevice *pci_dev)
>  {
> -    qemu_free_irqs(pci_dev->irq);
>      pci_dev->bus->devices[pci_dev->devfn] = NULL;
>      pci_config_free(pci_dev);
> -
> -    address_space_destroy(&pci_dev->bus_master_as);
> -    memory_region_destroy(&pci_dev->bus_master_enable_region);
>  }
>  
>  static void pci_unregister_io_regions(PCIDevice *pci_dev)
> @@ -2243,6 +2249,7 @@ static const TypeInfo pci_device_type_info = {
>      .abstract = true,
>      .class_size = sizeof(PCIDeviceClass),
>      .class_init = pci_device_class_init,
> +    .instance_finalize = pci_device_instance_finalize,
>  };
>  
>  static void pci_register_types(void)
> -- 
> 1.8.1.4