[PATCH qemu-server v4 1/3] fix #6277: virtio-vga-gl: add OpenGL 4.6 and Vulkan (Venus) support

[Markus Frank <m.frank@proxmox.com>]

Adding the 'blob=on,hostmem=<size>' parameters to the 'virtio-gpu-gl'
device allows the VM to use OpenGL 4.6. By default virtio-gpu-gl only
supports up to OpenGL 4.3.

If Vulkan support is needed, the 'venus=on' parameter is added to the
'virtio-gpu-gl' device, in addition to the two parameters required for
OpenGL 4.6.

The Venus protocol facilitates the translation of Vulkan API calls via
the virglrenderer. To use it, the virgl-server package must be installed
on the host.

Set the default VirGL memory window to 2048 MiB, as having less could
lead to instability inside the VM.

Signed-off-by: Markus Frank <m.frank@proxmox.com>
---
v4:
* made the description of virgl-features more general
* added bugzilla number to commit message

 src/PVE/QemuServer.pm | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 63d8c135..65c4a804 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -171,6 +171,20 @@ my $vga_fmt = {
             qw(cirrus qxl qxl2 qxl3 qxl4 none serial0 serial1 serial2 serial3 std virtio virtio-gl vmware)
         ],
     },
+    'virgl-features' => {
+        description => 'Enable additional features on VirGL GPU.',
+        type => 'string',
+        optional => 1,
+        enum => ['opengl4.6', 'opengl4.6+vulkan'],
+    },
+    'virgl-memory-window' => {
+        description => 'Set the VirGL host memory window. This option allocates'
+            . ' host memory to act as VRAM in the VM.',
+        type => 'string',
+        default => '2048',
+        optional => 1,
+        enum => ['512', '1024', '2048', '4096', '8192'],
+    },
     memory => {
         description => "Sets the VGA memory (in MiB). Has no effect with serial display.",
         type => 'integer',
@@ -1549,6 +1563,23 @@ sub print_vga_device {
         $pciaddr = print_pci_addr($vgaid, $bridges, $arch);
     }
 
+    my $virgl_param = "";
+    my $virgl_mode = $vga->{'virgl-features'};
+    if ($virgl_mode) {
+        my $virgl_memory_window = $vga->{'virgl-memory-window'}
+            // $vga_fmt->{'virgl-memory-window'}->{'default'};
+        $virgl_param = ",hostmem=${virgl_memory_window}M,blob=on";
+
+        if ($virgl_mode eq 'opengl4.6+vulkan') {
+            $virgl_param .= ",venus=on";
+            log_warn(
+                "missing virgl render server for Vulkan (Venus) support! Please install 'virgl-server'.\n"
+            ) if !-e "/usr/libexec/virgl_render_server";
+        }
+    } elsif ($vga->{'virgl-memory-window'}) {
+        die "To use a VirGL host memory window, please select a compatible VirGL feature set.\n";
+    }
+
     if ($vga->{type} eq 'virtio-gl') {
         # VirGL renders on the host, so the guest arch is irrelevant for the library lookup
         my $host_arch = get_host_arch();
@@ -1560,9 +1591,12 @@ sub print_vga_device {
         die
             "no DRM render node detected (/dev/dri/renderD*), no GPU? - needed for '$vga->{type}' display\n"
             if !PVE::Tools::dir_glob_regex('/dev/dri/', "renderD.*");
+
+    } elsif ($virgl_mode) {
+        die "You need to use virtio-gl to enable OpenGL 4.6 or Vulkan support!\n";
     }
 
-    return "$type,id=${vgaid}${memory}${max_outputs}${pciaddr}${edidoff}";
+    return "$type,id=${vgaid}${memory}${max_outputs}${pciaddr}${edidoff}${virgl_param}";
 }
 
 sub vm_is_volid_owner {
-- 
2.47.3