[PATCH v3 2/3] vfio/display: add xres + yres properties

[Gerd Hoffmann]

This allows configure the display resolution which the vgpu should use.
The information will be passed to the guest using EDID, so the mdev
driver must support the vfio edid region for this to work.

Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 hw/vfio/pci.h     |  2 ++
 hw/vfio/display.c | 12 ++++++++++--
 hw/vfio/pci.c     | 12 ++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index b1ae4c07549a..c11c3f167070 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -149,6 +149,8 @@ typedef struct VFIOPCIDevice {
 #define VFIO_FEATURE_ENABLE_IGD_OPREGION \
                                 (1 << VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT)
     OnOffAuto display;
+    uint32_t display_xres;
+    uint32_t display_yres;
     int32_t bootindex;
     uint32_t igd_gms;
     OffAutoPCIBAR msix_relo;
diff --git a/hw/vfio/display.c b/hw/vfio/display.c
index f59fcc487128..8bf7c890be96 100644
--- a/hw/vfio/display.c
+++ b/hw/vfio/display.c
@@ -46,8 +46,8 @@ static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
     qemu_edid_info edid = {
         .maxx  = dpy->edid_regs->max_xres,
         .maxy  = dpy->edid_regs->max_yres,
-        .prefx = prefx,
-        .prefy = prefy,
+        .prefx = prefx ?: vdev->display_xres,
+        .prefy = prefy ?: vdev->display_yres,
     };
 
     dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_DOWN;
@@ -128,6 +128,14 @@ static void vfio_display_edid_init(VFIOPCIDevice *vdev)
     pread_field(fd, dpy->edid_info, dpy->edid_regs, max_yres);
     dpy->edid_blob = g_malloc0(dpy->edid_regs->edid_max_size);
 
+    /* if xres + yres properties are unset use the maximum resolution */
+    if (!vdev->display_xres) {
+        vdev->display_xres = dpy->edid_regs->max_xres;
+    }
+    if (!vdev->display_yres) {
+        vdev->display_yres = dpy->edid_regs->max_yres;
+    }
+
     vfio_display_edid_update(vdev, true, 0, 0);
     return;
 
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index dd12f363915d..504019c4582b 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3068,6 +3068,16 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         error_setg(errp, "ramfb=on requires display=on");
         goto out_teardown;
     }
+    if (vdev->display_xres || vdev->display_yres) {
+        if (vdev->dpy == NULL) {
+            error_setg(errp, "xres and yres properties require display=on");
+            goto out_teardown;
+        }
+        if (vdev->dpy->edid_regs == NULL) {
+            error_setg(errp, "xres and yres properties need edid support");
+            goto out_teardown;
+        }
+    }
 
     vfio_register_err_notifier(vdev);
     vfio_register_req_notifier(vdev);
@@ -3182,6 +3192,8 @@ static Property vfio_pci_dev_properties[] = {
     DEFINE_PROP_STRING("sysfsdev", VFIOPCIDevice, vbasedev.sysfsdev),
     DEFINE_PROP_ON_OFF_AUTO("display", VFIOPCIDevice,
                             display, ON_OFF_AUTO_OFF),
+    DEFINE_PROP_UINT32("xres", VFIOPCIDevice, display_xres, 0),
+    DEFINE_PROP_UINT32("yres", VFIOPCIDevice, display_yres, 0),
     DEFINE_PROP_UINT32("x-intx-mmap-timeout-ms", VFIOPCIDevice,
                        intx.mmap_timeout, 1100),
     DEFINE_PROP_BIT("x-vga", VFIOPCIDevice, features,
-- 
2.9.3