[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [RFC v1 4/8] x86/init: add linker table support
On 01/21/16 11:46, Luis R. Rodriguez wrote: > On Thu, Jan 21, 2016 at 11:25 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: >>> And that's exactly what HVMlite does. Most of this shim layer is setting >>> up boot_params, after which we jump to standard x86 boot path (i.e. >>> startup_{32|64}). With hardware_subarch set to zero. >> >> Which is the way to do it as long as the early code can be the same. > > To be clear, with the subarchand linker table suggested in my patch > series, it should be possible to have the same exact entry point, the > Xen PV setup code could run early in the order. For instance in the > linker table we could use the reserved order levels 01-09 for PV > hypervisor code: > > +/* Init order levels, we can start at 01 but reserve 01-09 for now */ > +#define X86_INIT_ORDER_EARLY 10 > +#define X86_INIT_ORDER_NORMAL 30 > +#define X86_INIT_ORDER_LATE 50 > > So perhaps X86_INIT_ORDER_PV as 05 later. > > The standard x86 init would just then be: > > asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) > { > x86_init_fn_init_tables(); > x86_init_fn_early_init(); > } > > The PV init code would kick in early and could parse the > boot_params.hdr.hardware_subarch_data pointer as it sees fit. > Right... we already do that. I don't even think you need to initialize any tables. At least on i386, we have to do this in assembly code. However, it is just a simple table walk. :) -hpa _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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