[TODO TDX] Convert apicid and vpid from the TDX module

[ramesh-thomas]

In arch/x86/hyperv/hv_vtl.c: hv_vtl_wakeup_secondary_cpu(),

/* TODO TDX: we cannot trust the hypervisor to perform this mapping...
Instead, we need hypervisor support for TDX 1.5 ENUM_TOPOLOGY to query
this directly from the tdx module. */

(Migrated internal issue #1261)

[ramesh-thomas]

yjiang5 on Oct 30:

This will not be needed once we have the ACPI mailbox code merged.

[ramesh-thomas]

Depends on #581

[ramesh-thomas]

@chris-oo once #581 is merged, what should we do about the below code?

    /*
     * TODO TDX: we cannot trust the hypervisor to perform this mapping...
     * Instead, we need hypervisor support for TDX 1.5 ENUM_TOPOLOGY to
     * query this directly from the TDX module.
     */
    vp_id = hv_vtl_apicid_to_vp_id(apicid);

    if (vp_id < 0) {
            pr_err("Couldn't find CPU with APIC ID %d\n", apicid);
            return -EINVAL;
    }
    if (vp_id > ms_hyperv.max_vp_index) {
            pr_err("Invalid CPU id %d for APIC ID %d\n", vp_id, apicid);
            return -EINVAL;
    }

    if (hv_isolation_type_tdx())
            return hv_vtl_bringup_tdx_vcpu(vp_id, start_eip);
    else
            return hv_vtl_bringup_vcpu(vp_id, cpu, start_eip);

[chris-oo]

We should leave that TODO in there until we have the right hypervisor support. I can start a conversation internally about this.

[ricardon]

@chris-oo @ramesh-thomas I fail to see why yjiang5 stated that "This will not be needed once we have the ACPI mailbox code merged". When using the ACPI mailbox to boot secondary CPUs, the OS needs the ID of the CPU it wants to boot.

Is it the case that we will not need to do the HVCALL_GET_VP_ID_FROM_APIC_ID hypercall (from hv_vtl_apicid_to_vp_id()) because with TDX 1.5 ENUM_TOPOLOGY in Hyper-V we will read the APICID from CPUID(1).EBX[31:24]?

[ramesh-thomas]

@chris-oo also please let us know if anything needs to be done by me for the M3 milestone and if yes, what needs to be done. Thanks.