Re: [Qemu-devel] [PATCH] virtio-vga: only enable for specific boards

[Laszlo Ersek]

On 03/21/19 15:29, Paolo Bonzini wrote:
> When virtio-vga was added, the intention was to only support it for
> those machines where the firmware does not know about virtio-gpu,
> and supported VGA legacy hardware before virtio-{gpu,vga} were
> introduced.
> 
> The Kconfig switch however enabled virtio-vga for all machines with
> a PCI bus, and libvirt then prefers it even on hardware where
> virtio-gpu would be preferrable.  At least for now, only enable
> virtio-vga for PC, hppa and pSeries machines, as was the case
> before Kconfig dependencies were introduced.
> 
> Reported-by: Laszlo Ersek <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  hw/display/Kconfig | 2 +-
>  hw/hppa/Kconfig    | 1 +
>  hw/i386/Kconfig    | 1 +
>  hw/ppc/Kconfig     | 1 +
>  4 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/display/Kconfig b/hw/display/Kconfig
> index 86c1d544c5..72be57a403 100644
> --- a/hw/display/Kconfig
> +++ b/hw/display/Kconfig
> @@ -100,7 +100,7 @@ config VIRTIO_GPU
>  
>  config VIRTIO_VGA
>      bool
> -    default y if PCI_DEVICES
> +    # defaults to "N", enabled by specific boards
>      depends on VIRTIO_PCI
>      select VGA
>  
> diff --git a/hw/hppa/Kconfig b/hw/hppa/Kconfig
> index 7334f57081..6e5d74a825 100644
> --- a/hw/hppa/Kconfig
> +++ b/hw/hppa/Kconfig
> @@ -2,6 +2,7 @@ config DINO
>      bool
>      imply PCI_DEVICES
>      imply E1000_PCI
> +    imply VIRTIO_VGA
>      select PCI
>      select SERIAL
>      select ISA_BUS
> diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
> index 8e8444dbf9..a6aed7c131 100644
> --- a/hw/i386/Kconfig
> +++ b/hw/i386/Kconfig
> @@ -19,6 +19,7 @@ config PC
>      imply TPM_CRB
>      imply TPM_TIS
>      imply VGA_PCI
> +    imply VIRTIO_VGA
>      select FDC
>      select I8259
>      select I8254
> diff --git a/hw/ppc/Kconfig b/hw/ppc/Kconfig
> index ae07b4da63..a3465155f0 100644
> --- a/hw/ppc/Kconfig
> +++ b/hw/ppc/Kconfig
> @@ -2,6 +2,7 @@ config PSERIES
>      bool
>      imply PCI_DEVICES
>      imply TEST_DEVICES
> +    imply VIRTIO_VGA
>      select DIMM
>      select PCI
>      select SPAPR_VSCSI
> 

I tried to apply this for testing, on top of
c692931cda9dc6cbc16b89d5094a725a10dbb641, but git-am failed. The
conflicts are in "hw/hppa/Kconfig" and "hw/i386/Kconfig". In the former,
the conflict is due to E1000_PCI, in the latter, the conflict occurs due
to VGA_PCI -- upstream doesn't seem to have either of those.

Thanks
Laszlo