Re: [Xen-devel] [PATCH v4 5/5] fix: add multiboot2 protocol support for EFI platforms

[Daniel Kiper <dkiper@xxxxxxxxxxxx>]

On Wed, Jan 18, 2017 at 07:52:44AM -0700, Jan Beulich wrote:
> >>> On 18.01.17 at 15:17, <cardoe@xxxxxxxxxx> wrote:
> > This should be squashed into the 4/4 patch 'x86: add multiboot2 protocol
> > support for EFI platforms'.
> >
> > - fix incorrect assembly (identified by Andrew Cooper)
> > - fix issue where the trampoline size was left as 0 and the
> >   way the memory is allocated for the trampolines we would go to
> >   the end of an available section and then subtract off the size
> >   to decide where to place it. The end result was that we would
> >   always copy the trampolines and the 32-bit stack into some
> >   form of reserved memory after the conventional region we
> >   wanted to put things into. On some systems this did not
> >   manifest as a crash while on others it did. Reworked the
> >   changes to always reserve 64kb for both the stack and the size
> >   of the trampolines. Added a build time assert to make sure we have
> >   enough room always.
> >
> > Signed-off-by: Doug Goldstein <cardoe@xxxxxxxxxx>
>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
> with ...
>
> > --- a/xen/arch/x86/xen.lds.S
> > +++ b/xen/arch/x86/xen.lds.S
> > @@ -333,3 +333,10 @@ ASSERT(IS_ALIGNED(trampoline_start, 4),
> > "trampoline_start misaligned")
> >  ASSERT(IS_ALIGNED(trampoline_end,   4), "trampoline_end misaligned")
> >  ASSERT(IS_ALIGNED(__bss_start,      8), "__bss_start misaligned")
> >  ASSERT(IS_ALIGNED(__bss_end,        8), "__bss_end misaligned")
> > +
> > +/* The trampolines and the low memory stack must fit in 64kb. In testing
> > + * the low memory stack never exceeded 1kb so just require that the
> > + * trampolines fit in 63kb, leaving 1kb for the stack.
> > + */
> > +ASSERT((trampoline_end - trampoline_start) < KB(63),
> > +    "not enough room for trampolines and low memory stack")
>
> ... the comment style here fixed (which could be done upon commit
> or when Daniel merges this back into his series).

Hmmm... Why this patch and #0 was not CC-ed to me?

Anyway, it looks that I have cleared my backlog to some extent and now I am
able to take a stab on v12. There is a chance that I will have it with Doug's
and some additional fixes on Friday or Monday.

Daniel

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