pc: acpi-build: generate pvpanic device description dynamically

Drops AML template patching and allows to
save some space in SSDT if pvpanic device doesn't
exist by not including disabled device description
into SSDT. It also makes device description
smaller by replacing _STA method with named value
and dropping _INI method.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/acpi-build.c

@@ -924,7 +924,7 @@ build_ssdt(GArray *table_data, GArray *linker,
     uint32_t nr_mem = machine->ram_slots;
     unsigned acpi_cpus = guest_info->apic_id_limit;
     uint8_t *ssdt_ptr;
-    Aml *ssdt, *sb_scope, *scope, *pkg;
+    Aml *ssdt, *sb_scope, *scope, *pkg, *dev, *method, *crs, *field;
     int i;
 
     ssdt = init_aml_allocator();
@@ -939,9 +939,6 @@ build_ssdt(GArray *table_data, GArray *linker,
 
     patch_pci_windows(pci, ssdt_ptr, sizeof(ssdp_misc_aml));
 
-    ACPI_BUILD_SET_LE(ssdt_ptr, sizeof(ssdp_misc_aml),
-                      ssdt_isa_pest[0], 16, misc->pvpanic_port);
-
     ACPI_BUILD_SET_LE(ssdt_ptr, sizeof(ssdp_misc_aml),
                       ssdt_mctrl_nr_slots[0], 32, nr_mem);
 
@@ -974,6 +971,37 @@ build_ssdt(GArray *table_data, GArray *linker,
     aml_append(scope, aml_name_decl("_S5", pkg));
     aml_append(ssdt, scope);
 
+    if (misc->pvpanic_port) {
+        scope = aml_scope("\\_SB.PCI0.ISA");
+
+        dev = aml_device("PEVR");
+        aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0002")));
+
+        crs = aml_resource_template();
+        aml_append(crs,
+            aml_io(aml_decode16, misc->pvpanic_port, misc->pvpanic_port, 1, 1)
+        );
+        aml_append(dev, aml_name_decl("_CRS", crs));
+
+        aml_append(dev, aml_operation_region("PEOR", aml_system_io,
+                                              misc->pvpanic_port, 1));
+        field = aml_field("PEOR", aml_byte_acc);
+        aml_append(field, aml_named_field("PEPT", 8));
+        aml_append(dev, field);
+
+        method = aml_method("RDPT", 0);
+        aml_append(method, aml_store(aml_name("PEPT"), aml_local(0)));
+        aml_append(method, aml_return(aml_local(0)));
+        aml_append(dev, method);
+
+        method = aml_method("WRPT", 1);
+        aml_append(method, aml_store(aml_arg(0), aml_name("PEPT")));
+        aml_append(dev, method);
+
+        aml_append(scope, dev);
+        aml_append(ssdt, scope);
+    }
+
     sb_scope = aml_scope("_SB");
     {
         /* build Processor object for each processor */

hw/i386/ssdt-misc.dsl

@@ -39,51 +39,4 @@ DefinitionBlock ("ssdt-misc.aml", "SSDT", 0x01, "BXPC", "BXSSDTSUSP", 0x1)
        ACPI_EXTRACT_NAME_DWORD_CONST ssdt_mctrl_nr_slots
        Name(MEMORY_SLOTS_NUMBER, 0x12345678)
     }
-
-
-    External(\_SB.PCI0, DeviceObj)
-    External(\_SB.PCI0.ISA, DeviceObj)
-
-    Scope(\_SB.PCI0.ISA) {
-        Device(PEVT) {
-            Name(_HID, "QEMU0001")
-            /* PEST will be patched to be Zero if no such device */
-            ACPI_EXTRACT_NAME_WORD_CONST ssdt_isa_pest
-            Name(PEST, 0xFFFF)
-            OperationRegion(PEOR, SystemIO, PEST, 0x01)
-            Field(PEOR, ByteAcc, NoLock, Preserve) {
-                PEPT,   8,
-            }
-
-            Method(_STA, 0, NotSerialized) {
-                Store(PEST, Local0)
-                If (LEqual(Local0, Zero)) {
-                    Return (0x00)
-                } Else {
-                    Return (0x0F)
-                }
-            }
-
-            Method(RDPT, 0, NotSerialized) {
-                Store(PEPT, Local0)
-                Return (Local0)
-            }
-
-            Method(WRPT, 1, NotSerialized) {
-                Store(Arg0, PEPT)
-            }
-
-            Name(_CRS, ResourceTemplate() {
-                IO(Decode16, 0x00, 0x00, 0x01, 0x01, IO)
-            })
-
-            CreateWordField(_CRS, IO._MIN, IOMN)
-            CreateWordField(_CRS, IO._MAX, IOMX)
-
-            Method(_INI, 0, NotSerialized) {
-                Store(PEST, IOMN)
-                Store(PEST, IOMX)
-            }
-        }
-    }
 }