On Mon Aug 7, 2023 at 11:45 AM AEST, Jordan Niethe wrote:
> The LPID register is 32 bits long. The host keeps the lpids for each
> guest in an unsigned word struct kvm_arch. Currently, LPIDs are already
> limited by mmu_lpid_bits and KVM_MAX_NESTED_GUESTS_SHIFT.
>
> The nestedv2 API returns a 64 bit "Guest ID" to be used be the L1 host
> for each L2 guest. This value is used as an lpid, e.g. it is the
> parameter used by H_RPT_INVALIDATE. To minimize needless special casing
> it makes sense to keep this "Guest ID" in struct kvm_arch::lpid.
>
> This means that struct kvm_arch::lpid is too small so prepare for this
> and make it an unsigned long. This is not a problem for the KVM-HV and
> nestedv1 cases as their lpid values are already limited to valid ranges
> so in those contexts the lpid can be used as an unsigned word safely as
> needed.
>
> In the PAPR, the H_RPT_INVALIDATE pid/lpid parameter is already
> specified as an unsigned long so change pseries_rpt_invalidate() to
> match that. Update the callers of pseries_rpt_invalidate() to also take
> an unsigned long if they take an lpid value.
I don't suppose it would be worth having an lpid_t.
> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
> index 4adff4f1896d..229f0a1ffdd4 100644
> --- a/arch/powerpc/kvm/book3s_xive.c
> +++ b/arch/powerpc/kvm/book3s_xive.c
> @@ -886,10 +886,10 @@ int kvmppc_xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio,
>
> if (single_escalation)
> name = kasprintf(GFP_KERNEL, "kvm-%d-%d",
> - vcpu->kvm->arch.lpid, xc->server_num);
> + (unsigned int)vcpu->kvm->arch.lpid, xc->server_num);
> else
> name = kasprintf(GFP_KERNEL, "kvm-%d-%d-%d",
> - vcpu->kvm->arch.lpid, xc->server_num, prio);
> + (unsigned int)vcpu->kvm->arch.lpid, xc->server_num, prio);
> if (!name) {
> pr_err("Failed to allocate escalation irq name for queue %d of VCPU %d\n",
> prio, xc->server_num);
I would have thought you'd keep the type and change the format.
Otherwise seems okay too.
Thanks,
Nick
