[yydawx]

Motivation

ECAM base can differ across x86_64 devices. hvisor already parses ACPI MCFG, but hvisor-tool needs a way to obtain the correct base before constructing the zone configuration.

Changes

• src/hypercall/mod.rs: add HvGetEcamBase = 9 hypercall and dispatch it.
• src/arch/x86_64/hypercall.rs: implement hv_get_ecam_base() to write the ACPI MCFG ECAM base into the caller-provided address.
• aarch64/riscv64/loongarch64 hypercall files: add a no-op handler returning 0 so the shared hypercall dispatch compiles.

hvisor-tool

hvisor-tool queries this hypercall before starting a zone and overrides pci_config[0].ecam_base. See syswonder/hvisor-tool#115.

Verification

• hvisor x86_64 build passes.
• Tested with zone JSON ecam_base=0x12345000; hvisor receives 0xe0000000 after hvisor-tool correction, Asterinas starts and the shell responds to echo ci-ok.

[Solicey]

We'd better not called apply_dynamic_ecam inside hv_zone_start, because it is a x86-specific function. (We are avoiding things like #[cfg(target_arch = "x86_64")] in shared functions). It might be a good idea to call this function in hvisor-tool. You can add a new hyper-code such as HvGetEcamBase, and a hypercall function which gives hvisor-tool the correct ecam base. Then, hvisor-tool can correct this address and pass it to hvisor.

[yydawx]

Thanks for the review. I updated the implementation to follow your suggestion:

• Removed apply_dynamic_ecam from the shared hv_zone_start path.
• Added an HvGetEcamBase hypercall that lets hvisor-tool query the ACPI MCFG ECAM base.
• hvisor-tool now queries this hypercall before starting a zone and overrides pci_config[0].ecam_base.

Related hvisor-tool PR: syswonder/hvisor-tool#115.

Verification: with zone JSON ecam_base=0x12345000, hvisor receives 0xe0000000 after the hvisor-tool correction, and Asterinas boots to the shell.