Re: [PATCH v4 09/19] xen: add PVH boot entry code

[Daniel Kiper]

On Fri, Nov 02, 2018 at 01:37:28PM +0100, Juergen Gross wrote:
> Add the code for the Xen PVH mode boot entry.
>
> Signed-off-by: Juergen Gross <address@hidden>

One nitpick below. Otherwise
  Reviewed-by: Daniel Kiper <address@hidden>

> ---
> V3: clear %fs and %gs, too (Daniel Kiper)
>     use GRUB_MEMORY_MACHINE_PROT_STACK_SIZE for stack size (Daniel Kiper)
> ---
>  grub-core/kern/i386/xen/startup_pvh.S | 52 
> +++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
>
> diff --git a/grub-core/kern/i386/xen/startup_pvh.S 
> b/grub-core/kern/i386/xen/startup_pvh.S
> index 69b8fdcca..417655990 100644
> --- a/grub-core/kern/i386/xen/startup_pvh.S
> +++ b/grub-core/kern/i386/xen/startup_pvh.S
> @@ -19,11 +19,63 @@
>
>  #include <config.h>
>  #include <grub/symbol.h>
> +#include <grub/machine/memory.h>
>
>       .file   "startup_pvh.S"
>       .text
> +     .globl  start, _start
> +     .code32
>
> +start:
> +_start:
> +     cld
> +     lgdt    gdtdesc
> +     ljmp    $GRUB_MEMORY_MACHINE_PROT_MODE_CSEG, $1f
> +1:
> +     movl    $GRUB_MEMORY_MACHINE_PROT_MODE_DSEG, %eax
> +     mov     %eax, %ds
> +     mov     %eax, %es
> +     mov     %eax, %ss
> +     mov     %eax, %fs
> +     mov     %eax, %gs

I would do this in that order:

        mov     %eax, %ds
        mov     %eax, %es
        mov     %eax, %fs
        mov     %eax, %gs
        mov     %eax, %ss

Daniel