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

[Laszlo Ersek <lersek@redhat.com>]

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) {
         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