Re: [PATCH 2/2] arm/acpi: fix an out of spec _UID for PCI root

[Peter Maydell]

On Thu, 30 Jul 2020 at 16:58, Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On ARM/virt machine type QEMU currently reports an incorrect _UID in
> ACPI.
>
> The particular node in question is the primary PciRoot (PCI0 in ACPI),
> which gets assigned PCI0 in ACPI UID and 0 in the
> DevicePath. This is due to the _UID assigned to it by build_dsdt in
> hw/arm/virt-acpi-build.c Which does not correspond to the primary PCI
> identifier given by pcibus_num in hw/pci/pci.c
>
> In UEFI v2.8, section "10.4.2 Rules with ACPI _HID and _UID" ends with
> the paragraph,
>
>     Root PCI bridges will use the plug and play ID of PNP0A03, This will
>     be stored in the ACPI Device Path _HID field, or in the Expanded
>     ACPI Device Path _CID field to match the ACPI name space. The _UID
>     in the ACPI Device Path structure must match the _UID in the ACPI
>     name space.
>
> (See especially the last sentence.)
>
> A similar bug has been reported on i386, on that architecture it has
> been reported to confuse at least macOS which uses ACPI UIDs to build
> the DevicePath for NVRAM boot options, while OVMF firmware gets them via
> an internal channel through QEMU.  When UEFI firmware and ACPI have
> different values, this makes the underlying operating system unable to
> report its boot option.
>
> Reported-by: vit9696 <vit9696@protonmail.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
> Peter can you either ack or merge this one pls?

Since you have the x86 one to do anyway, I'll let you take
this one.
Acked-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM