On 06/13/19 10:40, David Woodhouse wrote:
> The DX register is supposed to contain the required alignment for the
> allocation. It was zero, and SeaBIOS doesn't (well, didn't) cope well
> with that. Set it appropriately.
>
> Also set BX to indicate the regions it's OK to allocate in too. That
> wasn't being initialised and was just using whatever the previous user
> of the structure had left there.
>
> Finally, actually return an error if the allocation fails. Instead of
> going all the way through into the CSM and just letting it have a bogus
> pointer to the E820 data.
>
> Signed-off-by: David Woodhouse <dw...@infradead.org>
> Reviewed-by: Hao A Wu <hao.a...@intel.com>
> ---
> OvmfPkg/Csm/LegacyBiosDxe/LegacyBootSupport.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/OvmfPkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
> b/OvmfPkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
> index 211750c012..cd4cd24f42 100644
> --- a/OvmfPkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
> +++ b/OvmfPkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
> @@ -928,7 +928,9 @@ GenericLegacyBoot (
> if (CopySize > Private->Legacy16Table->E820Length) {
> ZeroMem (&Regs, sizeof (EFI_IA32_REGISTER_SET));
> Regs.X.AX = Legacy16GetTableAddress;
> + Regs.X.BX = (UINT16) 0x0; // Any region
> Regs.X.CX = (UINT16) CopySize;
> + Regs.X.DX = (UINT16) 0x4; // Alignment
> Private->LegacyBios.FarCall86 (
> &Private->LegacyBios,
> Private->Legacy16Table->Compatibility16CallSegment,
> @@ -942,6 +944,7 @@ GenericLegacyBoot (
> Private->Legacy16Table->E820Length = (UINT32) CopySize;
> if (Regs.X.AX != 0) {
> DEBUG ((EFI_D_ERROR, "Legacy16 E820 length insufficient\n"));
> + return EFI_OUT_OF_RESOURCES;
> } else {
> CopyMem (
> (VOID *)(UINTN) Private->Legacy16Table->E820Pointer,
>
Acked-by: Laszlo Ersek <ler...@redhat.com>
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