Re: [Qemu-devel] [PATCH 09/11] ACPI: move PRST OperationRegion into SSDT

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 16 Dec 2013 22:44:46 +0100
Laszlo Ersek <lersek@redhat.com> wrote:

> On 12/16/13 21:38, Igor Mammedov wrote:
> > On Mon, 16 Dec 2013 21:30:14 +0200
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > 
> >> On Fri, Dec 13, 2013 at 05:22:14PM +0100, Igor Mammedov wrote:
> >>> .. and report range used by it to OSPM via _CRS.
> >>> PRST is needed in SSDT since its base will depend on
> >>> chipset and will be dynamically set by QEMU.
> >>> Also move PRSC() method along with PRST since cross
> >>> table reference to PRST doesn't work.
> >>
> >> Could you clarify this last sentence?
> >> I don't mind where it is but I'd like to know
> >> where does the limitation come from.
> > It's empiric deduction so far I haven't found such limitation in spec yet.
> > iasl builds tables just fine but neither linux nor windows were able to find
> > Operation region from SSDT when loading DSDT, failing whole table loading
> > process. Decompiling DSDT/SSDT tables in guest shows that region is in
> > expected scope but OSPM refuses to see it when referenced outside SSDT.
> > Maybe there is some AML magic to make it work, I'm not aware of.
> > The same thing I had to do for memory hotplug as well. So I've tried to play
> > nicely 2 times and I have ended up with this solution both times.
> 
> Would this work?
> 
> diff --git a/hw/i386/acpi-dsdt-cpu-hotplug.dsl b/hw/i386/acpi-dsdt-cpu-hotplug.dsl
> index 995b415..34fad66 100644
> --- a/hw/i386/acpi-dsdt-cpu-hotplug.dsl
> +++ b/hw/i386/acpi-dsdt-cpu-hotplug.dsl
> @@ -52,8 +52,8 @@ Scope(\_SB) {
>          Sleep(200)
>      }
>  
> -    OperationRegion(PRST, SystemIO, 0xaf00, 32)
> -    Field(PRST, ByteAcc, NoLock, Preserve) {
> +    External(\_SB.CPHD.PRST, OpRegionObj)
> +    Field(\_SB.CPHD.PRST, ByteAcc, NoLock, Preserve) {
that was my first patch attempt :)
You have to be careful and touch [q35-]acpi-dsdt.dsl since make doesn't
handle deps to acpi-dsdt-cpu-hotplug.dsl correctly.
After that RHEL6 guest fails to load ACPI tables.

>          PRS, 256
>      }
>      Method(PRSC, 0) {
> diff --git a/hw/i386/ssdt-misc.dsl b/hw/i386/ssdt-misc.dsl
> index a4484b8..b831fc3 100644
> --- a/hw/i386/ssdt-misc.dsl
> +++ b/hw/i386/ssdt-misc.dsl
> @@ -116,4 +116,29 @@ DefinitionBlock ("ssdt-misc.aml", "SSDT", 0x01, "BXPC", "BXSSDTSUSP", 0x1)
>              }
>          }
>      }
> +    Scope(\_SB) {
> +        Device(CPHD) {
> +            Name(_HID, EISAID("PNP0C08"))
> +            Name(CPPL, 32) // cpu-gpe length
> +            Name(CPHP, 0xaf00)
> +
> +            OperationRegion(PRST, SystemIO, CPHP, CPPL)
> +
> +            /* Leave bit 0 cleared to avoid Windows BSOD */
> +            Name(_STA, 0xA)
> +
> +            Method(_CRS, 0) {
> +                Store(ResourceTemplate() {
> +                    IO(Decode16, 0x00, 0x00, 0x01, 0x15, IO)
> +                }, Local0)
> +
> +                CreateWordField(Local0, IO._MIN, IOMN)
> +                CreateWordField(Local0, IO._MAX, IOMX)
> +
> +                Store(CPHP, IOMN)
> +                Subtract(Add(CPHP, CPPL), 1, IOMX)
> +                Return(Local0)
> +            }
> +        } // Device(CPHD)
> +    } // Scope(\_SB)
>  }
> 
> Thanks
> Laszlo
> 


-- 
Regards,
  Igor