Re: [Qemu-devel] [PATCH] vgabios update: handle compatibility with older qemu versions

[Anthony Liguori]

On 11/17/2010 05:06 AM, Gerd Hoffmann wrote:
> As pointed out by avi the vgabios update is guest-visible and thus has
> migration implications.
>
> One change is that the vga has a valid pci rom bar now.  We already have
> a pci bus property to enable/disable the rom bar and we'll load the bios
> via fw_cfg as fallback for the no-rom-bar case.  So we just have to add
> compat properties to handle this case.
>
> A second change is that the magic bochs lfb @ 0xe0000000 is gone.  When
> live-migrating a guest from a older qemu version it might be using the
> lfb though, so we have to keep it for the old machine types.  The patch
> enables the bochs lfb in case we don't have the pci rom bar enabled
> (i.e. we are in 0.13+older compat mode).
>
> This patch depends on these patches which add (and use) the pc-0.13
> machine type:
>    http://patchwork.ozlabs.org/patch/70797/
>    http://patchwork.ozlabs.org/patch/70798/
>
> Signed-off-by: Gerd Hoffmann<address@hidden>
>    

Applied.  Thanks.

Regards,

Anthony Liguori

> Cc: address@hidden
> ---
>   hw/pc_piix.c    |   16 ++++++++++++++++
>   hw/vga-pci.c    |    5 +++++
>   hw/vmware_vga.c |    5 +++++
>   3 files changed, 26 insertions(+), 0 deletions(-)
>
> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> index e9752db..a85d58e 100644
> --- a/hw/pc_piix.c
> +++ b/hw/pc_piix.c
> @@ -231,6 +231,14 @@ static QEMUMachine pc_machine_v0_13 = {
>               .driver   = "virtio-9p-pci",
>               .property = "vectors",
>               .value    = stringify(0),
> +        },{
> +            .driver   = "VGA",
> +            .property = "rombar",
> +            .value    = stringify(0),
> +        },{
> +            .driver   = "vmware-svga",
> +            .property = "rombar",
> +            .value    = stringify(0),
>           },
>           { /* end of list */ }
>       },
> @@ -250,6 +258,14 @@ static QEMUMachine pc_machine_v0_12 = {
>               .driver   = "virtio-serial-pci",
>               .property = "vectors",
>               .value    = stringify(0),
> +        },{
> +            .driver   = "VGA",
> +            .property = "rombar",
> +            .value    = stringify(0),
> +        },{
> +            .driver   = "vmware-svga",
> +            .property = "rombar",
> +            .value    = stringify(0),
>           },
>           { /* end of list */ }
>       }
> diff --git a/hw/vga-pci.c b/hw/vga-pci.c
> index 28b174b..4931eee 100644
> --- a/hw/vga-pci.c
> +++ b/hw/vga-pci.c
> @@ -96,6 +96,11 @@ static int pci_vga_initfn(PCIDevice *dev)
>        pci_register_bar(&d->dev, 0, VGA_RAM_SIZE,
>                         PCI_BASE_ADDRESS_MEM_PREFETCH, vga_map);
>
> +     if (!dev->rom_bar) {
> +         /* compatibility with pc-0.13 and older */
> +         vga_init_vbe(s);
> +     }
> +
>        return 0;
>   }
>
> diff --git a/hw/vmware_vga.c b/hw/vmware_vga.c
> index e96b7db..e852620 100644
> --- a/hw/vmware_vga.c
> +++ b/hw/vmware_vga.c
> @@ -1305,6 +1305,11 @@ static int pci_vmsvga_initfn(PCIDevice *dev)
>
>       vmsvga_init(&s->chip, VGA_RAM_SIZE);
>
> +    if (!dev->rom_bar) {
> +        /* compatibility with pc-0.13 and older */
> +        vga_init_vbe(&s->chip.vga);
> +    }
> +
>       return 0;
>   }
>
>