[Qemu-devel] [PATCH RFC] PCMachineState: introduce acpi_build_enabled field

[Wei Liu <wei.liu2@citrix.com>]

Introduce this field to control whether ACPI build is enabled by a
particular machine or accelerator.

It defaults to true so that PC machine has ACPI build by default. Xen
accelerator will disable it because Xen is in charge of building ACPI
tables for the guest.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Anthony PERARD <anthony.perard@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Sander Eikelenboom <linux@eikelenboom.it>

Tested a backport version which only involves trivial code movement. It
worked with both -m xenfv and -m pc,accel=xen.

Sander, if you want the backported patch please let me know.
---
 hw/i386/acpi-build.c |  2 +-
 hw/i386/pc.c         | 19 +++++++++++++++++++
 include/hw/i386/pc.h |  3 +++
 xen-common.c         |  6 ++++++
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 93be96f..a5cd2fd 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2954,7 +2954,7 @@ void acpi_setup(void)
         return;
     }
 
-    if (!pcmc->has_acpi_build) {
+    if (!pcmc->has_acpi_build || !pcms->acpi_build_enabled) {
         ACPI_BUILD_DPRINTF("ACPI build disabled. Bailing out.\n");
         return;
     }
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index f56ea0f..3e7982f 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2143,6 +2143,20 @@ static bool pc_machine_get_nvdimm(Object *obj, Error **errp)
     return pcms->acpi_nvdimm_state.is_enabled;
 }
 
+static bool pc_machine_get_acpi_build(Object *obj, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+
+    return pcms->acpi_build_enabled;
+}
+
+static void pc_machine_set_acpi_build(Object *obj, bool value, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+
+    pcms->acpi_build_enabled = value;
+}
+
 static void pc_machine_set_nvdimm(Object *obj, bool value, Error **errp)
 {
     PCMachineState *pcms = PC_MACHINE(obj);
@@ -2159,6 +2173,8 @@ static void pc_machine_initfn(Object *obj)
     pcms->vmport = ON_OFF_AUTO_AUTO;
     /* nvdimm is disabled on default. */
     pcms->acpi_nvdimm_state.is_enabled = false;
+    /* acpi build is enabled by default. */
+    pcms->acpi_build_enabled = true;
 }
 
 static void pc_machine_reset(void)
@@ -2319,6 +2335,9 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
 
     object_class_property_add_bool(oc, PC_MACHINE_NVDIMM,
         pc_machine_get_nvdimm, pc_machine_set_nvdimm, &error_abort);
+
+    object_class_property_add_bool(oc, PC_MACHINE_ACPI_BUILD,
+        pc_machine_get_acpi_build, pc_machine_set_acpi_build, &error_abort);
 }
 
 static const TypeInfo pc_machine_info = {
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 17fff80..ec8cd0c 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -63,6 +63,8 @@ struct PCMachineState {
 
     AcpiNVDIMMState acpi_nvdimm_state;
 
+    bool acpi_build_enabled;
+
     /* RAM information (sizes, addresses, configuration): */
     ram_addr_t below_4g_mem_size, above_4g_mem_size;
 
@@ -87,6 +89,7 @@ struct PCMachineState {
 #define PC_MACHINE_VMPORT           "vmport"
 #define PC_MACHINE_SMM              "smm"
 #define PC_MACHINE_NVDIMM           "nvdimm"
+#define PC_MACHINE_ACPI_BUILD       "acpi-build"
 
 /**
  * PCMachineClass:
diff --git a/xen-common.c b/xen-common.c
index e641ad1..b1858d7 100644
--- a/xen-common.c
+++ b/xen-common.c
@@ -9,6 +9,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "hw/i386/pc.h"
 #include "hw/xen/xen_backend.h"
 #include "qmp-commands.h"
 #include "sysemu/char.h"
@@ -114,6 +115,11 @@ static void xen_change_state_handler(void *opaque, int running,
 
 static int xen_init(MachineState *ms)
 {
+    PCMachineState *pcms = PC_MACHINE(ms);
+
+    /* Disable ACPI build because Xen handles it */
+    pcms->acpi_build_enabled = false;
+
     xen_xc = xc_interface_open(0, 0, 0);
     if (xen_xc == NULL) {
         xen_be_printf(NULL, 0, "can't open xen interface\n");
-- 
2.1.4