i386: acpi: Don't build HPET ACPI entry if HPET is disabled

Omit HPET AML if the HPET is disabled, QEMU is not emulating it and the
guest may get confused by seeing HPET in the ACPI tables without a
"physical" device present.

The change of DSDT when -no-hpet is as follows.

@@ -141,47 +141,6 @@ DefinitionBlock ("", "DSDT", 1, "BOCHS "
         }
     }

-    Scope (_SB)
-    {
-        Device (HPET)
-        {
-            Name (_HID, EisaId ("PNP0103") /* HPET System Timer */)  // _HID: Hardware ID
-            Name (_UID, Zero)  // _UID: Unique ID
-            OperationRegion (HPTM, SystemMemory, 0xFED00000, 0x0400)
-            Field (HPTM, DWordAcc, Lock, Preserve)
-            {
-                VEND,   32,
-                PRD,    32
-            }
-
-            Method (_STA, 0, NotSerialized)  // _STA: Status
-            {
-                Local0 = VEND /* \_SB_.HPET.VEND */
-                Local1 = PRD /* \_SB_.HPET.PRD_ */
-                Local0 >>= 0x10
-                If (((Local0 == Zero) || (Local0 == 0xFFFF)))
-                {
-                    Return (Zero)
-                }
-
-                If (((Local1 == Zero) || (Local1 > 0x05F5E100)))
-                {
-                    Return (Zero)
-                }
-
-                Return (0x0F)
-            }
-
-            Name (_CRS, ResourceTemplate ()  // _CRS: Current Resource Settings
-            {
-                Memory32Fixed (ReadOnly,
-                    0xFED00000,         // Address Base
-                    0x00000400,         // Address Length
-                    )
-            })
-        }
-    }
-
     Scope (_SB.PCI0)
     {
         Device (ISA)

Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Igor Mammedov <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <66114dead09232d04891b9e5f5a4081e85cc2c4d.1613615732[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 96497475d171026ca169a805664bc38ec3633e8a..31a5f6f4a54d7f9146679e4b7db58a8f56325872 100644 (file)
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1281,7 +1281,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         aml_append(sb_scope, dev);
         aml_append(dsdt, sb_scope);
 
-        build_hpet_aml(dsdt);
+        if (misc->has_hpet) {
+            build_hpet_aml(dsdt);
+        }
         build_piix4_isa_bridge(dsdt);
         build_isa_devices_aml(dsdt);
         if (pm->pcihp_bridge_en || pm->pcihp_root_en) {
@@ -1328,7 +1330,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
 
         aml_append(dsdt, sb_scope);
 
-        build_hpet_aml(dsdt);
+        if (misc->has_hpet) {
+            build_hpet_aml(dsdt);
+        }
         build_q35_isa_bridge(dsdt);
         build_isa_devices_aml(dsdt);
         build_q35_pci0_int(dsdt);