Re: [Qemu-devel] [PATCH] hw/pci: fixed crash when using rombar=0 for hotplugged devices

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Oct 21, 2014 at 03:37:12PM +0300, Marcel Apfelbaum wrote:
> ROM images must be loaded at startup. Usage of rombar=0 after that
> is not allowed, but should not crash QEMU.
> 
> Check that the device is not hotplugged before trying to
> insert the rom file.
> 
> Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
> ---
>  hw/pci/pci.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 6ce75aa..3907c90 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1776,7 +1776,12 @@ static int pci_qdev_init(DeviceState *qdev)
>          pci_dev->romfile = g_strdup(pc->romfile);
>          is_default_rom = true;
>      }
> -    pci_add_option_rom(pci_dev, is_default_rom);
> +
> +    rc = pci_add_option_rom(pci_dev, is_default_rom);
> +    if (rc != 0) {
> +        pci_unregister_device(DEVICE(pci_dev));
> +        return rc;
> +    }
>  
>      return 0;
>  }

Fair enough for this chunk.

> @@ -1940,6 +1945,10 @@ static int pci_add_option_rom(PCIDevice *pdev, bool is_default_rom)
>          if (class == 0x0300) {
>              rom_add_vga(pdev->romfile);
>          } else {
> +            if (DEVICE(pdev)->hotplugged) {
> +                error_report("PCI: rombar can't be 0 for hotplugged devices!");
> +                return -1;
> +            }
>              rom_add_option(pdev->romfile, -1);
>          }
>          return 0;


The message is confusing. rombar=0 is ok if you
don't also try to force romfile.
Generally why are you adding this logic in pci?
And what about e.g. vga?
I think the right thing to do is to propagate return codes correctly,
and report the error where it occurs.

> -- 
> 1.8.3.1