From c62a0c7ce34ed99a7c45199b9fddeafaba73f3bf Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Mon, 11 Mar 2019 11:14:40 -0600
Subject: [PATCH] vfio/display: add xres + yres properties

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@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/display.c | 12 ++++++++++--
 hw/vfio/pci.c     | 12 ++++++++++++
 hw/vfio/pci.h     |  2 ++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/display.c b/hw/vfio/display.c
index 276fba090d..212ad1674e 100644
--- a/hw/vfio/display.c
+++ b/hw/vfio/display.c
@@ -45,8 +45,8 @@ 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;
@@ -142,6 +142,14 @@ static void vfio_display_edid_init(VFIOPCIDevice *vdev)
 
     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 dd12f36391..504019c458 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,
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index b1ae4c0754..c11c3f1670 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;