On Fri, Oct 11, 2024 at 1:56 PM Alejandro Vallejo <[email protected]> wrote: > > On Fri, Oct 11, 2024 at 09:52:44AM +0100, Frediano Ziglio wrote: > > Signed-off-by: Frediano Ziglio <[email protected]> > > --- > > xen/arch/x86/boot/reloc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/xen/arch/x86/boot/reloc.c b/xen/arch/x86/boot/reloc.c > > index e50e161b27..e725cfb6eb 100644 > > --- a/xen/arch/x86/boot/reloc.c > > +++ b/xen/arch/x86/boot/reloc.c > > @@ -65,7 +65,7 @@ typedef struct memctx { > > /* > > * Simple bump allocator. > > * > > - * It starts from the base of the trampoline and allocates downwards. > > + * It starts on top of space reserved for the trampoline and allocates > > downwards. > > nit: Not sure this is much clearer. The trampoline is not a stack (and even if > it was, I personally find "top" and "bottom" quite ambiguous when it grows > backwards), so calling top to its lowest address seems more confusing than > not. > > If anything clarification ought to go in the which direction it takes. Leaving > "base" instead of "top" and replacing "downwards" by "backwards" to make it > crystal clear that it's a pointer that starts where the trampoline starts, but > moves in the opposite direction. >
Base looks confusing to me, but surely that comment could be confusing. For the trampoline 64 KB are reserved. Last 4 KB are used as a normal stack (push/pop/call/whatever), first part gets a copy of the trampoline code/data (about 6 Kb) the rest (so 64 - 4 - ~6 = ~54 kb) is used for the copy of MBI information. That "rest" is what we are talking about here. > My .02 anyway. > > > */ > > uint32_t ptr; > > } memctx; > > -- > > 2.34.1 > > > > > > Cheers, > Alejandro Frediano
