Re: [PATCH v4 04/44] x86/boot: move mmap info to boot info

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 30/08/2024 10:46 pm, Daniel P. Smith wrote:
> Transition the memory map info to be held in struct boot_info.
>
> No functional change intended.
>
> Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
> ---
>  xen/arch/x86/include/asm/bootinfo.h |  5 +++++
>  xen/arch/x86/setup.c                | 12 +++++++++---
>  2 files changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/xen/arch/x86/include/asm/bootinfo.h 
> b/xen/arch/x86/include/asm/bootinfo.h
> index d2ca077d2356..e785ed1c5982 100644
> --- a/xen/arch/x86/include/asm/bootinfo.h
> +++ b/xen/arch/x86/include/asm/bootinfo.h
> @@ -8,11 +8,16 @@
>  #ifndef __XEN_X86_BOOTINFO_H__
>  #define __XEN_X86_BOOTINFO_H__
>  
> +#include <xen/types.h>
> +
>  struct boot_info {
>      unsigned int nr_mods;
>  
>      const char *boot_loader_name;
>      const char *cmdline;
> +
> +    paddr_t mmap_addr;
> +    uint32_t mmap_length;

memmap please.

> @@ -1200,13 +1206,13 @@ void asmlinkage __init noreturn __start_xen(unsigned 
> long mbi_p)
>      {
>          memmap_type = "Xen-e820";
>      }
> -    else if ( mbi->flags & MBI_MEMMAP )
> +    else if ( boot_info->mmap_addr )
>      {
>          memmap_type = "Multiboot-e820";
> -        while ( bytes < mbi->mmap_length &&
> +        while ( bytes < boot_info->mmap_length &&
>                  e820_raw.nr_map < ARRAY_SIZE(e820_raw.map) )
>          {
> -            memory_map_t *map = __va(mbi->mmap_addr + bytes);
> +            memory_map_t *map = __va(boot_info->mmap_addr + bytes);
>  
>              /*
>               * This is a gross workaround for a BIOS bug. Some bootloaders do

This is some very gnarly logic.  pvh_init() plays with e820_raw behind
the scenes and doesn't set MBI_MEMMAP.

Perhaps for later cleanup too, this logic wants folding into the new
multiboot_fill_boot_info() and leave __start_xen().

~Andrew