[SeaBIOS] Re: [PATCH] Fix high memory zone initialization in CSM mode

[Kevin O'Connor]

On Fri, May 12, 2023 at 02:14:47PM +0100, José Martínez via SeaBIOS wrote:
> malloc_high() cannot allocate any memory in CSM mode due to an empty
> ZoneHigh. SeaBIOS cannot find any disk to boot from because device
> initialization fails.
>
> The bug was introduced in 1.16.1 (commit dc88f9b) when the meaning of
> BUILD_MAX_HIGHTABLE changed but CSM code was not updated. This patch
> reverts to the previous behavior by using BUILD_MIN_HIGHTABLE in CSM
> methods.

Thanks.  The change makes sense to me.  Gerd, do you have any comments
on this change?

-Kevin
> Signed-off-by: José Martínez
>
> src/fw/csm.c | 4 ++--
>  src/malloc.c | 6 +++---
>  2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/src/fw/csm.c b/src/fw/csm.c
> index bc14a92..579debd 100644
> --- a/src/fw/csm.c
> +++ b/src/fw/csm.c
> @@ -150,9 +150,9 @@ handle_csm_0002(struct bregs *regs)
>      for (i=0; i < csm_compat_table.E820Length / sizeof(struct e820entry); i++)
>          e820_add(p[i].start, p[i].size, p[i].type);
> if (csm_init_table->HiPmmMemorySizeInBytes > BUILD_MAX_HIGHTABLE) {
> if (csm_init_table->HiPmmMemorySizeInBytes > BUILD_MIN_HIGHTABLE) {
>     u32 hi_pmm_end = csm_init_table->HiPmmMemory +
>
> csm_init_table->HiPmmMemorySizeInBytes;
>    e820_add(hi_pmm_end - BUILD_MAX_HIGHTABLE,
>
> BUILD_MAX_HIGHTABLE, E820_RESERVED);
>    e820_add(hi_pmm_end - BUILD_MIN_HIGHTABLE,
>
> BUILD_MIN_HIGHTABLE, E820_RESERVED);
>      }
>  // For PCIBIOS 1ab10e
>
> diff --git a/src/malloc.c b/src/malloc.c
> index da84098..30b2c92 100644
> --- a/src/malloc.c
> +++ b/src/malloc.c
> @@ -460,10 +460,10 @@ malloc_csm_preinit(u32 low_pmm, u32
> low_pmm_size, u32 hi_pmm, u32 hi_pmm_size)
>  {
>      ASSERT32FLAT();
> if (hi_pmm_size > BUILD_MAX_HIGHTABLE) {
> if (hi_pmm_size > BUILD_MIN_HIGHTABLE) {
>     u32 hi_pmm_end = hi_pmm + hi_pmm_size;
>    alloc_add(&ZoneTmpHigh, hi_pmm, hi_pmm_end - BUILD_MAX_HIGHTABLE);
>    alloc_add(&ZoneHigh, hi_pmm_end - BUILD_MAX_HIGHTABLE, hi_pmm_end);
>    alloc_add(&ZoneTmpHigh, hi_pmm, hi_pmm_end - BUILD_MIN_HIGHTABLE);
>    alloc_add(&ZoneHigh, hi_pmm_end - BUILD_MIN_HIGHTABLE, hi_pmm_end);
> } else {
>        alloc_add(&ZoneTmpHigh, hi_pmm, hi_pmm + hi_pmm_size);
>    }