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, and set BX to indicate the regions it's OK to allocate in too. That was already OK but let's make sure it's initialised properly and not just working by chance.
Also 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 E82o data. Signed-off-by: David Woodhouse <dw...@infradead.org> --- I made SeaBIOS cope with the zero too: https://mail.coreboot.org/hyperkitty/list/seab...@seabios.org/thread/4PHW3O3Y3HJFENODFV5INBGDLZMXA5KE/ 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..e7766eb2b1 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) 0x3; // 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, -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#42317): https://edk2.groups.io/g/devel/message/42317 Mute This Topic: https://groups.io/mt/32045939/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
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