virtio-vga: add '-vga virtio' support

Some convinience fluff:  Add support for '-vga virtio', also add
virtio-vga to the list of vga cards so '-device virtio-vga' will
turn off the default vga.

Written by Dave Airlie and Gerd Hoffmann.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/isa/isa-bus.c

@@ -179,6 +179,9 @@ ISADevice *isa_vga_init(ISABus *bus)
     case VGA_VMWARE:
         fprintf(stderr, "%s: vmware_vga: no PCI bus\n", __func__);
         return NULL;
+    case VGA_VIRTIO:
+        fprintf(stderr, "%s: virtio-vga: no PCI bus\n", __func__);
+        return NULL;
     case VGA_NONE:
     default:
         return NULL;

hw/pci/pci.c

@@ -1698,6 +1698,8 @@ PCIDevice *pci_vga_init(PCIBus *bus)
         return pci_create_simple(bus, -1, "VGA");
     case VGA_VMWARE:
         return pci_create_simple(bus, -1, "vmware-svga");
+    case VGA_VIRTIO:
+        return pci_create_simple(bus, -1, "virtio-vga");
     case VGA_NONE:
     default: /* Other non-PCI types. Checking for unsupported types is already
                 done in vl.c. */

include/sysemu/sysemu.h

@@ -104,7 +104,7 @@ extern int autostart;
 
 typedef enum {
     VGA_NONE, VGA_STD, VGA_CIRRUS, VGA_VMWARE, VGA_XENFB, VGA_QXL,
-    VGA_TCX, VGA_CG3, VGA_DEVICE
+    VGA_TCX, VGA_CG3, VGA_DEVICE, VGA_VIRTIO,
 } VGAInterfaceType;
 
 extern int vga_interface_type;

qemu-options.hx

@@ -1103,7 +1103,7 @@ Rotate graphical output some deg left (only PXA LCD).
 ETEXI
 
 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
-    "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|none]\n"
+    "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n"
     "                select video card type\n", QEMU_ARCH_ALL)
 STEXI
 @item -vga @var{type}
@@ -1136,6 +1136,8 @@ fixed resolution of 1024x768.
 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
 for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
 resolutions aimed at people wishing to run older Solaris versions.
+@item virtio
+Virtio VGA card.
 @item none
 Disable VGA card.
 @end table

vl.c

@@ -231,6 +231,7 @@ static struct {
     { .driver = "isa-cirrus-vga",       .flag = &default_vga       },
     { .driver = "vmware-svga",          .flag = &default_vga       },
     { .driver = "qxl-vga",              .flag = &default_vga       },
+    { .driver = "virtio-vga",           .flag = &default_vga       },
 };
 
 static QemuOptsList qemu_rtc_opts = {
@@ -1884,6 +1885,11 @@ static bool cg3_vga_available(void)
     return object_class_by_name("cgthree");
 }
 
+static bool virtio_vga_available(void)
+{
+    return object_class_by_name("virtio-vga");
+}
+
 static void select_vgahw (const char *p)
 {
     const char *opts;
@@ -1910,6 +1916,13 @@ static void select_vgahw (const char *p)
             fprintf(stderr, "Error: VMWare SVGA not available\n");
             exit(0);
         }
+    } else if (strstart(p, "virtio", &opts)) {
+        if (virtio_vga_available()) {
+            vga_interface_type = VGA_VIRTIO;
+        } else {
+            fprintf(stderr, "Error: Virtio VGA not available\n");
+            exit(0);
+        }
     } else if (strstart(p, "xenfb", &opts)) {
         vga_interface_type = VGA_XENFB;
     } else if (strstart(p, "qxl", &opts)) {