Re: PVH boot with qemu

On Mon, Dec 11, 2023 at 10:22:18AM +0100, Emile `iMil' Heitor wrote:
> 
> Hi Manuel,
> 
> On Mon, 11 Dec 2023, Manuel Bouyer wrote:
> 
> > #ifndef GENPVH
> > 	/* get a page for HYPERVISOR_shared_info */
> > 	addl	$PAGE_SIZE, %ebx
> > 	addl	$PGOFSET,%ebx
> > 	andl	$~PGOFSET,%ebx
> > 	movl	$RELOC(HYPERVISOR_shared_info_pa),%ebp
> > 	movl	%ebx,(%ebp)
> > 	movl	$0,4(%ebp)
> > #endif
> > 
> > How can this work on Xen when GENPVH is defined ?
> > Shouldn't this be made conditional on vm_guest == VM_GUEST_XENPVH ?
> 
> Well the point is that you don't define GENPVH when using Xen, PVH using
> qemu and friends don't need HYPERVISOR_shared_info neither any of the
> hypercall portion of the code. A big chunk of Xen related code is
> ifndef'ed to GENPVH in hypervisor.c; And I was planning on isolating GENPVH
> so there's as little ifdef's as possible.
> 
> Or would you prefer the same kernel to be able to boot in both XENPVH and
> GENPVH modes? I am focusing on making the resulting kernel smaller but this
> could be done also.

Yes, right now GENERIC can be used on bare-metal, PVHVM and XENPVH.
It would be good to have GENERIC working on GENPVH too.

-- 
Manuel Bouyer <[email protected]>
     NetBSD: 26 ans d'experience feront toujours la difference
--