Re: [PATCH hyperv-next] x86/hyperv: Fix APIC ID and VP ID confusion in hv_snp_boot_ap()

[Wei Liu]

On Thu, Apr 24, 2025 at 02:57:46PM -0700, Roman Kisel wrote:
> To start an application processor in SNP-isolated guest, a hypercall
> is used that takes a virtual processor index. The hv_snp_boot_ap()
> function uses that START_VP hypercall but passes as VP ID to it what
> it receives as a wakeup_secondary_cpu_64 callback: the APIC ID.
> 
> As those two aren't generally interchangeable, that may lead to hung
> APs if VP IDs and APIC IDs don't match, e.g. APIC IDs might be sparse
> whereas VP IDs never are.
> 
> Update the parameter names to avoid confusion as to what the parameter
> is. Use the APIC ID to VP ID conversion to provide correct input to the
> hypercall.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 44676bb9d566 ("x86/hyperv: Add smp support for SEV-SNP guest")
> Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>

Applied to hyperv-fixes.