[SeaBIOS] [Xen-devel] Re: [RFC] [PATCH 0/2] Basic SeaBIOS support for Xen HVM

Kevin O'Connor kevin at koconnor.net
Mon May 30 16:43:53 CEST 2011


On Fri, May 27, 2011 at 10:27:14AM +0100, Ian Campbell wrote:
> On Fri, 2011-05-27 at 02:20 +0100, Kevin O'Connor wrote:
> > Will Xen support the fw_cfg interface?
> I don't think so, at least not in general. (fw_cfg is the qemu thing on
> ports 0x510/511, right?)

Yes - 0x510/0x511.

[...]
> The existing ad-hoc structure I've defined is:
>         struct xen_seabios_info {
>             char signature[14]; /* XenHVMSeaBIOS\0 */
>             u16 length;
>             u32 acpi_rsdp;
>             u32 mptable;
>             u32 e820_nr;
>             struct e820entry e820[128];
>             u8 checksum;
>         };
> so I was mainly thinking of e.g. CB_TAG_MEMORY along with CB_MEM_TABLE.
> 
> I think I'll stick with defining a structure myself, these things are
> all discoverable via signatures so we can always transition in the
> future.

At some point, Xen will likely need "romfile" support (see
src/paravirt.h) in order to support pulling in non-device option roms
and things like "bootorder" support.  The "romfile" stuff just uses a
list of ("name", size, data) 3-tuples to pass in arbitrary data to
SeaBIOS.  You may wish to consider supporting an interface like that
from the start.

-Kevin



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