Make possible point to system seabios instead include it in hvmloader

Make possible point to system seabios instead include it in hvmloader

[Fabio Fantoni]

Actually is possible specify upstream qemu and seabios from distro's 
packages or custom builds with xen configure.
If these are used and qemu package will be updated, xen will use updated 
qemu but if seabios package will be updated, xen will use the new one 
only with xen rebuild.
If for example seabios will be updated with fixes and/or new version (in 
some case required by newer qemu) xen will still have the bug fixed and 
will have new bugs until will be rebuilded.

Is possible make hvmloader point to seabios specified in configure 
instead include it in hvmloader?

Thanks for any reply and sorry for my bad english.

Re: Make possible point to system seabios instead include it in hvmloader

[Ian Campbell]

On Sat, 2014-05-10 at 14:08 +0200, Fabio Fantoni wrote:
> Actually is possible specify upstream qemu and seabios from distro's 
> packages or custom builds with xen configure.
> If these are used and qemu package will be updated, xen will use updated 
> qemu but if seabios package will be updated, xen will use the new one 
> only with xen rebuild.

Correct.

> If for example seabios will be updated with fixes and/or new version (in 
> some case required by newer qemu) xen will still have the bug fixed and 
> will have new bugs until will be rebuilded.

Correct.

> Is possible make hvmloader point to seabios specified in configure 
> instead include it in hvmloader?

You would have to arrange for something (probably the toolstack) to load
the seabios file off disk and place it into guest memory as part of
building the domain and then you would need to invent some protocol
(perhaps xenstore based) so that the toolstack could signal to hvmloader
where to go an look for the seabios binary in guest RAM.

Ian.

Re: Make possible point to system seabios instead include it in hvmloader

[Andrew Cooper]

On 12/05/2014 09:43, Ian Campbell wrote:
> On Sat, 2014-05-10 at 14:08 +0200, Fabio Fantoni wrote:
>> Actually is possible specify upstream qemu and seabios from distro's 
>> packages or custom builds with xen configure.
>> If these are used and qemu package will be updated, xen will use updated 
>> qemu but if seabios package will be updated, xen will use the new one 
>> only with xen rebuild.
> Correct.
>
>> If for example seabios will be updated with fixes and/or new version (in 
>> some case required by newer qemu) xen will still have the bug fixed and 
>> will have new bugs until will be rebuilded.
> Correct.
>
>> Is possible make hvmloader point to seabios specified in configure 
>> instead include it in hvmloader?
> You would have to arrange for something (probably the toolstack) to load
> the seabios file off disk and place it into guest memory as part of
> building the domain and then you would need to invent some protocol
> (perhaps xenstore based) so that the toolstack could signal to hvmloader
> where to go an look for the seabios binary in guest RAM.

Making the BIOS a multiboot module and teaching hvmloader about
multiboot seems much simpler.

The toolstack already has code for doing this in the PV case.

~Andrew

Re: Make possible point to system seabios instead include it in hvmloader

[Ian Campbell]

On Mon, 2014-05-12 at 09:49 +0100, Andrew Cooper wrote:
> On 12/05/2014 09:43, Ian Campbell wrote:
> > On Sat, 2014-05-10 at 14:08 +0200, Fabio Fantoni wrote:
> >> Actually is possible specify upstream qemu and seabios from distro's 
> >> packages or custom builds with xen configure.
> >> If these are used and qemu package will be updated, xen will use updated 
> >> qemu but if seabios package will be updated, xen will use the new one 
> >> only with xen rebuild.
> > Correct.
> >
> >> If for example seabios will be updated with fixes and/or new version (in 
> >> some case required by newer qemu) xen will still have the bug fixed and 
> >> will have new bugs until will be rebuilded.
> > Correct.
> >
> >> Is possible make hvmloader point to seabios specified in configure 
> >> instead include it in hvmloader?
> > You would have to arrange for something (probably the toolstack) to load
> > the seabios file off disk and place it into guest memory as part of
> > building the domain and then you would need to invent some protocol
> > (perhaps xenstore based) so that the toolstack could signal to hvmloader
> > where to go an look for the seabios binary in guest RAM.
> 
> Making the BIOS a multiboot module and teaching hvmloader about
> multiboot seems much simpler.

"much simpler" seems unlikely. At best I'd expect it to be about the
same.

Ian.

> The toolstack already has code for doing this in the PV case.
> 
> ~Andrew