From edd31ce9c29d9ad2edda6d6e0ae9965261929b99 Mon Sep 17 00:00:00 2001
From: Red Bear OS <build@redbearos.org>
Date: Thu, 9 Jul 2026 12:45:05 +0300
Subject: [PATCH] virtio-gpud: enable VirGL 3D feature negotiation
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Uncommented VIRTIO_GPU_F_VIRGL (bit 0) and added feature
negotiation in probe_device(). When the host supports VirGL 3D,
the driver now acknowledges the feature, enabling Mesa's virgl
driver to use the 3D command path (CTX_CREATE, SUBMIT_3D,
RESOURCE_CREATE_3D, etc. already defined in CommandTy enum).

Cross-referenced with Linux 7.1 drivers/gpu/drm/virtio/virtgpu_drv.c
virtio_gpu_driver_open() and virtio spec v1.2 §5.7.6.

This is the enabling step for hardware-accelerated 3D rendering
in QEMU via virglrenderer.
---
 drivers/graphics/virtio-gpud/src/main.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/graphics/virtio-gpud/src/main.rs b/drivers/graphics/virtio-gpud/src/main.rs
index b27f4c56da..e73d8f45b6 100644
--- a/drivers/graphics/virtio-gpud/src/main.rs
+++ b/drivers/graphics/virtio-gpud/src/main.rs
@@ -32,7 +32,7 @@ use virtio_core::MSIX_PRIMARY_VECTOR;
 
 mod scheme;
 
-//const VIRTIO_GPU_F_VIRGL: u32 = 0;
+const VIRTIO_GPU_F_VIRGL: u32 = 0;
 const VIRTIO_GPU_F_EDID: u32 = 1;
 //const VIRTIO_GPU_F_RESOURCE_UUID: u32 = 2;
 //const VIRTIO_GPU_F_RESOURCE_BLOB: u32 = 3;
@@ -511,6 +511,11 @@ fn deamon(deamon: daemon::Daemon, mut pcid_handle: PciFunctionHandle) -> anyhow:
     if has_edid {
         device.transport.ack_driver_feature(VIRTIO_GPU_F_EDID);
     }
+    let has_virgl = device.transport.check_device_feature(VIRTIO_GPU_F_VIRGL);
+    if has_virgl {
+        device.transport.ack_driver_feature(VIRTIO_GPU_F_VIRGL);
+        log::info!("virtio-gpud: VirGL 3D acceleration enabled");
+    }
     device.transport.finalize_features();
 
     // Queue for sending control commands.