Re: [PATCH] device-assignment: register a reset function

[Alex Williamson <alex.williamson@redhat.com>]

On Fri, 2010-09-17 at 17:27 +0200, Bernhard Kohl wrote:
> This is necessary because during reboot of a VM the assigned devices
> continue DMA transfers which causes memory corruption.
> 
> Signed-off-by: Thomas Ostler <thomas.ostler@nsn.com>
> Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
> ---
>  hw/device-assignment.c |   14 ++++++++++++++
>  1 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/device-assignment.c b/hw/device-assignment.c
> index 87f7418..fb47813 100644
> --- a/hw/device-assignment.c
> +++ b/hw/device-assignment.c
> @@ -1450,6 +1450,17 @@ static void assigned_dev_unregister_msix_mmio(AssignedDevice *dev)
>      dev->msix_table_page = NULL;
>  }
>  
> +static void reset_assigned_device(void *opaque)
> +{
> +    PCIDevice *d = (PCIDevice *)opaque;
> +    uint32_t conf;
> +
> +    /* reset the bus master bit to avoid further DMA transfers */
> +    conf = assigned_dev_pci_read_config(d, PCI_COMMAND, 2);
> +    conf &= ~PCI_COMMAND_MASTER;
> +    assigned_dev_pci_write_config(d, PCI_COMMAND, conf, 2);
> +}
> +
>  static int assigned_initfn(struct PCIDevice *pci_dev)
>  {
>      AssignedDevice *dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
> @@ -1499,6 +1510,9 @@ static int assigned_initfn(struct PCIDevice *pci_dev)
>      if (r < 0)
>          goto assigned_out;
>  
> +    /* register reset function for the device */
> +    qemu_register_reset(reset_assigned_device, pci_dev);
> +
>      /* intercept MSI-X entry page in the MMIO */
>      if (dev->cap.available & ASSIGNED_DEVICE_CAP_MSIX)
>          if (assigned_dev_register_msix_mmio(dev))

Hmm, at a minimum, we need a qemu_unregister_reset() in the exitfn, but
upon further inspection, we should probably just do it the qdev way.
That would mean simply setting qdev.reset to reset_assigned_device() in
assign_info, then we can leave the registration/de-registration to qdev.
Does that work?  Sorry I missed that the first time.  Thanks,

Alex