[Qemu-devel] [PATCH 9/9] [RfC] stdvga: use graphic_* variables.

[Gerd Hoffmann <kraxel@redhat.com>]

Add two new registers to the qemu extended register range, carrying the
suggested width and height of the display device.  In case the graphic_*
variables are set (via -g switch), fill these new registers accordingly.

Additionally guest driver updates are needed to support the new
registers.  These changes will probably land in linux kernel 4.12.

TODO: add compat properties to turn off qemu-display-size for machine
      types older than 2.9-or-10

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/vga-pci.c    | 52 ++++++++++++++++++++++++++++++++++---------------
 hw/display/vga_int.h    |  4 ++--
 hw/display/virtio-vga.c |  3 ++-
 3 files changed, 40 insertions(+), 19 deletions(-)

diff --git a/hw/display/vga-pci.c b/hw/display/vga-pci.c
index ac9a764..78e00df 100644
--- a/hw/display/vga-pci.c
+++ b/hw/display/vga-pci.c
@@ -31,23 +31,28 @@
 #include "ui/pixel_ops.h"
 #include "qemu/timer.h"
 #include "hw/loader.h"
+#include "sysemu/sysemu.h"
 
 #define PCI_VGA_IOPORT_OFFSET 0x400
 #define PCI_VGA_IOPORT_SIZE   (0x3e0 - 0x3c0)
 #define PCI_VGA_BOCHS_OFFSET  0x500
 #define PCI_VGA_BOCHS_SIZE    (0x0b * 2)
 #define PCI_VGA_QEXT_OFFSET   0x600
-#define PCI_VGA_QEXT_SIZE     (2 * 4)
+#define PCI_VGA_QEXT_SIZE_V1  (2 * 4)
+#define PCI_VGA_QEXT_SIZE_V2  (4 * 4)
 #define PCI_VGA_MMIO_SIZE     0x1000
 
 #define PCI_VGA_QEXT_REG_SIZE         (0 * 4)
 #define PCI_VGA_QEXT_REG_BYTEORDER    (1 * 4)
 #define  PCI_VGA_QEXT_LITTLE_ENDIAN   0x1e1e1e1e
 #define  PCI_VGA_QEXT_BIG_ENDIAN      0xbebebebe
+#define PCI_VGA_QEXT_REG_WIDTH        (2 * 4)
+#define PCI_VGA_QEXT_REG_HEIGHT       (3 * 4)
 
 enum vga_pci_flags {
-    PCI_VGA_FLAG_ENABLE_MMIO = 1,
-    PCI_VGA_FLAG_ENABLE_QEXT = 2,
+    PCI_VGA_FLAG_ENABLE_MMIO    = 1,
+    PCI_VGA_FLAG_ENABLE_QEXT    = 2,
+    PCI_VGA_FLAG_ENABLE_QEXT_V2 = 3,
 };
 
 typedef struct PCIVGAState {
@@ -157,10 +162,14 @@ static uint64_t pci_vga_qext_read(void *ptr, hwaddr addr, unsigned size)
 
     switch (addr) {
     case PCI_VGA_QEXT_REG_SIZE:
-        return PCI_VGA_QEXT_SIZE;
+        return s->qext_size;
     case PCI_VGA_QEXT_REG_BYTEORDER:
         return s->big_endian_fb ?
             PCI_VGA_QEXT_BIG_ENDIAN : PCI_VGA_QEXT_LITTLE_ENDIAN;
+    case PCI_VGA_QEXT_REG_WIDTH:
+        return graphic_width;
+    case PCI_VGA_QEXT_REG_HEIGHT:
+        return graphic_height;
     default:
         return 0;
     }
@@ -207,8 +216,7 @@ static const MemoryRegionOps pci_vga_qext_ops = {
 
 void pci_std_vga_mmio_region_init(VGACommonState *s,
                                   MemoryRegion *parent,
-                                  MemoryRegion *subs,
-                                  bool qext)
+                                  MemoryRegion *subs)
 {
     memory_region_init_io(&subs[0], NULL, &pci_vga_ioport_ops, s,
                           "vga ioports remapped", PCI_VGA_IOPORT_SIZE);
@@ -220,9 +228,9 @@ void pci_std_vga_mmio_region_init(VGACommonState *s,
     memory_region_add_subregion(parent, PCI_VGA_BOCHS_OFFSET,
                                 &subs[1]);
 
-    if (qext) {
+    if (s->qext_size) {
         memory_region_init_io(&subs[2], NULL, &pci_vga_qext_ops, s,
-                              "qemu extended regs", PCI_VGA_QEXT_SIZE);
+                              "qemu extended regs", s->qext_size);
         memory_region_add_subregion(parent, PCI_VGA_QEXT_OFFSET,
                                     &subs[2]);
     }
@@ -232,7 +240,6 @@ static void pci_std_vga_realize(PCIDevice *dev, Error **errp)
 {
     PCIVGAState *d = PCI_VGA(dev);
     VGACommonState *s = &d->vga;
-    bool qext = false;
 
     /* vga + console init */
     vga_common_init(s, OBJECT(dev), true);
@@ -249,10 +256,15 @@ static void pci_std_vga_realize(PCIDevice *dev, Error **errp)
         memory_region_init(&d->mmio, NULL, "vga.mmio", 4096);
 
         if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT)) {
-            qext = true;
-            pci_set_byte(&d->dev.config[PCI_REVISION_ID], 2);
+            if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT_V2)) {
+                s->qext_size = PCI_VGA_QEXT_SIZE_V2;
+                pci_set_byte(&d->dev.config[PCI_REVISION_ID], 3);
+            } else {
+                s->qext_size = PCI_VGA_QEXT_SIZE_V1;
+                pci_set_byte(&d->dev.config[PCI_REVISION_ID], 2);
+            }
         }
-        pci_std_vga_mmio_region_init(s, &d->mmio, d->mrs, qext);
+        pci_std_vga_mmio_region_init(s, &d->mmio, d->mrs);
 
         pci_register_bar(&d->dev, 2, PCI_BASE_ADDRESS_SPACE_MEMORY, &d->mmio);
     }
@@ -274,7 +286,6 @@ static void pci_secondary_vga_realize(PCIDevice *dev, Error **errp)
 {
     PCIVGAState *d = PCI_VGA(dev);
     VGACommonState *s = &d->vga;
-    bool qext = false;
 
     /* vga + console init */
     vga_common_init(s, OBJECT(dev), false);
@@ -284,10 +295,15 @@ static void pci_secondary_vga_realize(PCIDevice *dev, Error **errp)
     memory_region_init(&d->mmio, OBJECT(dev), "vga.mmio", 4096);
 
     if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT)) {
-        qext = true;
-        pci_set_byte(&d->dev.config[PCI_REVISION_ID], 2);
+        if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT_V2)) {
+            s->qext_size = PCI_VGA_QEXT_SIZE_V2;
+            pci_set_byte(&d->dev.config[PCI_REVISION_ID], 3);
+        } else {
+            s->qext_size = PCI_VGA_QEXT_SIZE_V1;
+            pci_set_byte(&d->dev.config[PCI_REVISION_ID], 2);
+        }
     }
-    pci_std_vga_mmio_region_init(s, &d->mmio, d->mrs, qext);
+    pci_std_vga_mmio_region_init(s, &d->mmio, d->mrs);
 
     pci_register_bar(&d->dev, 0, PCI_BASE_ADDRESS_MEM_PREFETCH, &s->vram);
     pci_register_bar(&d->dev, 2, PCI_BASE_ADDRESS_SPACE_MEMORY, &d->mmio);
@@ -311,6 +327,8 @@ static Property vga_pci_properties[] = {
     DEFINE_PROP_BIT("mmio", PCIVGAState, flags, PCI_VGA_FLAG_ENABLE_MMIO, true),
     DEFINE_PROP_BIT("qemu-extended-regs",
                     PCIVGAState, flags, PCI_VGA_FLAG_ENABLE_QEXT, true),
+    DEFINE_PROP_BIT("qemu-display-size",
+                    PCIVGAState, flags, PCI_VGA_FLAG_ENABLE_QEXT_V2, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -318,6 +336,8 @@ static Property secondary_pci_properties[] = {
     DEFINE_PROP_UINT32("vgamem_mb", PCIVGAState, vga.vram_size_mb, 16),
     DEFINE_PROP_BIT("qemu-extended-regs",
                     PCIVGAState, flags, PCI_VGA_FLAG_ENABLE_QEXT, true),
+    DEFINE_PROP_BIT("qemu-display-size",
+                    PCIVGAState, flags, PCI_VGA_FLAG_ENABLE_QEXT_V2, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/display/vga_int.h b/hw/display/vga_int.h
index dd6c958..51217cf 100644
--- a/hw/display/vga_int.h
+++ b/hw/display/vga_int.h
@@ -162,6 +162,7 @@ typedef struct VGACommonState {
     bool full_update_gfx;
     bool big_endian_fb;
     bool default_endian_fb;
+    uint32_t qext_size;
     /* hardware mouse cursor support */
     uint32_t invalidated_y_table[VGA_MAX_HEIGHT / 32];
     uint32_t hw_cursor_x;
@@ -223,7 +224,6 @@ extern const MemoryRegionOps vga_mem_ops;
 /* vga-pci.c */
 void pci_std_vga_mmio_region_init(VGACommonState *s,
                                   MemoryRegion *parent,
-                                  MemoryRegion *subs,
-                                  bool qext);
+                                  MemoryRegion *subs);
 
 #endif
diff --git a/hw/display/virtio-vga.c b/hw/display/virtio-vga.c
index f9b017d..8684dc0 100644
--- a/hw/display/virtio-vga.c
+++ b/hw/display/virtio-vga.c
@@ -153,8 +153,9 @@ static void virtio_vga_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     }
 
     /* add stdvga mmio regions */
+    vga->qext_size = 2 * 4; /* PCI_VGA_QEXT_SIZE_V1 */
     pci_std_vga_mmio_region_init(vga, &vpci_dev->modern_bar,
-                                 vvga->vga_mrs, true);
+                                 vvga->vga_mrs);
 
     vga->con = g->scanout[0].con;
     graphic_console_set_hwops(vga->con, &virtio_vga_ops, vvga);
-- 
1.8.3.1