Re: [Qemu-devel] [PATCH v2 3/3] virtio: Make disable-legacy/disable-modern compat properties optional

[Marc-André Lureau]

Hi

On Thu, Jan 10, 2019 at 6:05 AM Eduardo Habkost <address@hidden> wrote:
>
> The disable-legacy and disable-modern properties apply only to
> some virtio-pci devices.  Make those properties optional.
>
> This fixes the crash introduced by commit f6e501a28ef9 ("virtio: Provide
> version-specific variants of virtio PCI devices"):
>
>   $ qemu-system-x86_64 -machine pc-i440fx-2.6 \
>     -device virtio-net-pci-non-transitional
>   Unexpected error in object_property_find() at qom/object.c:1092:
>   qemu-system-x86_64: -device virtio-net-pci-non-transitional: can't apply \
>   global virtio-pci.disable-modern=on: Property '.disable-modern' not found
>   Aborted (core dumped)
>
> Reported-by: Thomas Huth <address@hidden>
> Fixes: f6e501a28ef9 ("virtio: Provide version-specific variants of virtio PCI 
> devices")
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
>  hw/core/machine.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 5530b71981..a19143aa44 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -91,8 +91,9 @@ const size_t hw_compat_2_7_len = 
> G_N_ELEMENTS(hw_compat_2_7);
>
>  GlobalProperty hw_compat_2_6[] = {
>      { "virtio-mmio", "format_transport_address", "off" },
> -    { "virtio-pci", "disable-modern", "on" },
> -    { "virtio-pci", "disable-legacy", "off" },
> +    /* Optional because not all virtio-pci devices support legacy mode */
> +    { "virtio-pci", "disable-modern", "on",  .optional = true },
> +    { "virtio-pci", "disable-legacy", "off", .optional = true },

Could the generic devices implement a specific interface instead?
virtio-pci-generic?

Adding "optional" handling looks like it may hide some other errors.

>  };
>  const size_t hw_compat_2_6_len = G_N_ELEMENTS(hw_compat_2_6);
>
> --
> 2.18.0.rc1.1.g3f1ff2140
>
>


-- 
Marc-André Lureau