On 21.11.2022 11:21, Roger Pau Monne wrote: > --- a/drivers/acpi/processor_pdc.c > +++ b/drivers/acpi/processor_pdc.c > @@ -137,6 +137,14 @@ acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in) > buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH); > > } > + if (xen_initial_domain()) > + /* > + * When Linux is running as Xen dom0 it's the hypervisor the > + * entity in charge of the processor power management, and so > + * Xen needs to check the OS capabilities reported in the _PDC > + * buffer matches what the hypervisor driver supports. > + */ > + xen_sanitize_pdc((uint32_t *)pdc_in->pointer->buffer.pointer); > status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL); Again looking at our old XenoLinux forward port we had this inside the earlier if(), as an _alternative_ to the &= (I don't think it's valid to apply both the kernel's and Xen's adjustments). That would also let you use "buffer" rather than re-calculating it via yet another (risky from an abstract pov) cast. It was the very nature of requiring Xen-specific conditionals which I understand was the reason why so far no attempt was made to get this (incl the corresponding logic for patch 1) into any upstream kernel. Jan
