xen: convert "-machine igd-passthru" to an accelerator property

The first machine property to fall is Xen's Intel integrated graphics
passthrough.  The "-machine igd-passthru" option does not set anymore
a property on the machine object, but desugars to a GlobalProperty on
accelerator objects.

The setter is very simple, since the value ends up in a
global variable, so this patch also provides an example before the more
complicated cases that follow it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/core/machine.c

@@ -417,20 +417,6 @@ static void machine_set_graphics(Object *obj, bool value, Error **errp)
     ms->enable_graphics = value;
 }
 
-static bool machine_get_igd_gfx_passthru(Object *obj, Error **errp)
-{
-    MachineState *ms = MACHINE(obj);
-
-    return ms->igd_gfx_passthru;
-}
-
-static void machine_set_igd_gfx_passthru(Object *obj, bool value, Error **errp)
-{
-    MachineState *ms = MACHINE(obj);
-
-    ms->igd_gfx_passthru = value;
-}
-
 static char *machine_get_firmware(Object *obj, Error **errp)
 {
     MachineState *ms = MACHINE(obj);
@@ -867,12 +853,6 @@ static void machine_class_init(ObjectClass *oc, void *data)
     object_class_property_set_description(oc, "graphics",
         "Set on/off to enable/disable graphics emulation", &error_abort);
 
-    object_class_property_add_bool(oc, "igd-passthru",
-        machine_get_igd_gfx_passthru, machine_set_igd_gfx_passthru,
-        &error_abort);
-    object_class_property_set_description(oc, "igd-passthru",
-        "Set on/off to enable/disable igd passthrou", &error_abort);
-
     object_class_property_add_str(oc, "firmware",
         machine_get_firmware, machine_set_firmware,
         &error_abort);

hw/xen/xen-common.c

@@ -11,7 +11,9 @@
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
+#include "qapi/error.h"
 #include "hw/xen/xen-legacy-backend.h"
+#include "hw/xen/xen_pt.h"
 #include "chardev/char.h"
 #include "sysemu/accel.h"
 #include "sysemu/runstate.h"
@@ -124,6 +126,16 @@ static void xen_change_state_handler(void *opaque, int running,
     }
 }
 
+static bool xen_get_igd_gfx_passthru(Object *obj, Error **errp)
+{
+    return has_igd_gfx_passthru;
+}
+
+static void xen_set_igd_gfx_passthru(Object *obj, bool value, Error **errp)
+{
+    has_igd_gfx_passthru = value;
+}
+
 static void xen_setup_post(MachineState *ms, AccelState *accel)
 {
     int rc;
@@ -177,6 +189,12 @@ static void xen_accel_class_init(ObjectClass *oc, void *data)
     ac->compat_props = g_ptr_array_new();
 
     compat_props_add(ac->compat_props, compat, G_N_ELEMENTS(compat));
+
+    object_class_property_add_bool(oc, "igd-passthru",
+        xen_get_igd_gfx_passthru, xen_set_igd_gfx_passthru,
+        &error_abort);
+    object_class_property_set_description(oc, "igd-passthru",
+        "Set on/off to enable/disable igd passthrou", &error_abort);
 }
 
 #define TYPE_XEN_ACCEL ACCEL_CLASS_NAME("xen")

hw/xen/xen_pt.c

@@ -65,6 +65,8 @@
 #include "qemu/range.h"
 #include "exec/address-spaces.h"
 
+bool has_igd_gfx_passthru;
+
 #define XEN_PT_NR_IRQS (256)
 static uint8_t xen_pt_mapped_machine_irq[XEN_PT_NR_IRQS] = {0};
 

include/hw/boards.h

@@ -287,7 +287,6 @@ struct MachineState {
     bool mem_merge;
     bool usb;
     bool usb_disabled;
-    bool igd_gfx_passthru;
     char *firmware;
     bool iommu;
     bool suppress_vmdesc;

qemu-options.hx

@@ -37,7 +37,6 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
     "                kvm_shadow_mem=size of KVM shadow MMU in bytes\n"
     "                dump-guest-core=on|off include guest memory in a core dump (default=on)\n"
     "                mem-merge=on|off controls memory merge support (default: on)\n"
-    "                igd-passthru=on|off controls IGD GFX passthrough support (default=off)\n"
     "                aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n"
     "                dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n"
     "                suppress-vmdesc=on|off disables self-describing migration (default=off)\n"
@@ -71,8 +70,6 @@ more than one accelerator specified, the next one is used if the previous one
 fails to initialize.
 @item kernel_irqchip=on|off
 Controls in-kernel irqchip support for the chosen accelerator when available.
-@item gfx_passthru=on|off
-Enables IGD GFX passthrough support for the chosen machine when available.
 @item vmport=on|off|auto
 Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the
 value based on accel. For accel=xen the default is off otherwise the default
@@ -120,6 +117,7 @@ ETEXI
 DEF("accel", HAS_ARG, QEMU_OPTION_accel,
     "-accel [accel=]accelerator[,prop[=value][,...]]\n"
     "                select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n"
+    "                igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n"
     "                tb-size=n (TCG translation block cache size)\n"
     "                thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
 STEXI
@@ -130,6 +128,9 @@ kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If th
 more than one accelerator specified, the next one is used if the previous one
 fails to initialize.
 @table @option
+@item igd-passthru=on|off
+When Xen is in use, this option controls whether Intel integrated graphics
+devices can be passed through to the guest (default=off)
 @item tb-size=@var{n}
 Controls the size (in MiB) of the TCG translation block cache.
 @item thread=single|multi

vl.c

@@ -1133,13 +1133,6 @@ static void configure_msg(QemuOpts *opts)
 }
 
 
-/* Now we still need this for compatibility with XEN. */
-bool has_igd_gfx_passthru;
-static void igd_gfx_passthru(void)
-{
-    has_igd_gfx_passthru = current_machine->igd_gfx_passthru;
-}
-
 /***********************************************************/
 /* USB devices */
 
@@ -2517,6 +2510,10 @@ static int machine_set_property(void *opaque,
     if (g_str_equal(qom_name, "accel")) {
         return 0;
     }
+    if (g_str_equal(qom_name, "igd-passthru")) {
+        object_register_sugar_prop(ACCEL_CLASS_NAME("xen"), qom_name, value);
+        return 0;
+    }
 
     return object_parse_property_opt(opaque, name, value, "type", errp);
 }
@@ -4297,9 +4294,6 @@ int main(int argc, char **argv, char **envp)
             exit(1);
     }
 
-    /* Check if IGD GFX passthrough. */
-    igd_gfx_passthru();
-
     /* init generic devices */
     rom_set_order_override(FW_CFG_ORDER_OVERRIDE_DEVICE);
     qemu_opts_foreach(qemu_find_opts("device"),