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Use the new acpi_build_madt_standalone() function to fill the MADT parameter field. The IGVM parameter can be consumed by Coconut SVSM [1], instead of relying on the fw_cfg interface, which has caused problems before due to unexpected access [2,3]. Using IGVM parameters is the default way for Coconut SVSM across hypervisors; switching over would allow removing specialized code paths for QEMU in Coconut. Coconut SVSM needs to know the SMP configuration, but does not look at any other ACPI data, nor does it interact with the PCI bus settings. Since the MADT is static and not linked with other ACPI tables, it can be supplied stand-alone like this. Generating the MADT twice (during ACPI table building and IGVM processing) seems acceptable, since there is no infrastructure to obtain the MADT out of the ACPI table memory area. In any case OVMF, which runs after SVSM has already been initialized, will continue reading all ACPI tables via fw_cfg and provide fixed up ACPI data to the OS as before without any changes. The IGVM parameter handler is implemented for the i386 machine target and stubbed for all others. [1] https://github.com/coconut-svsm/svsm/pull/858 [2] https://gitlab.com/qemu-project/qemu/-/issues/2882 [3] https://github.com/coconut-svsm/svsm/issues/646 Signed-off-by: Oliver Steffen <osteffen@redhat.com> Message-ID: <20260130054714.715928-10-osteffen@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>