Ran "make generate".

builder/virtualbox/iso/builder.hcl2spec.go

@@ -119,10 +119,15 @@ type FlatConfig struct {
 	GuestAdditionsURL         *string           `mapstructure:"guest_additions_url" required:"false" cty:"guest_additions_url" hcl:"guest_additions_url"`
 	Chipset                   *string           `mapstructure:"chipset" required:"false" cty:"chipset" hcl:"chipset"`
 	Firmware                  *string           `mapstructure:"firmware" required:"false" cty:"firmware" hcl:"firmware"`
+	NestedVirt                *bool             `mapstructure:"nested_virt" required:"false" cty:"nested_virt" hcl:"nested_virt"`
+	RTCTimeBase               *string           `mapstructure:"rtc_time_base" required:"false" cty:"rtc_time_base" hcl:"rtc_time_base"`
 	DiskSize                  *uint             `mapstructure:"disk_size" required:"false" cty:"disk_size" hcl:"disk_size"`
 	NICType                   *string           `mapstructure:"nic_type" required:"false" cty:"nic_type" hcl:"nic_type"`
 	AudioController           *string           `mapstructure:"audio_controller" required:"false" cty:"audio_controller" hcl:"audio_controller"`
 	GfxController             *string           `mapstructure:"gfx_controller" required:"false" cty:"gfx_controller" hcl:"gfx_controller"`
+	GfxVramSize               *uint             `mapstructure:"gfx_vram_size" required:"false" cty:"gfx_vram_size" hcl:"gfx_vram_size"`
+	GfxAccelerate3D           *bool             `mapstructure:"gfx_accelerate_3d" required:"false" cty:"gfx_accelerate_3d" hcl:"gfx_accelerate_3d"`
+	GfxEFIResolution          *string           `mapstructure:"gfx_efi_resolution" required:"false" cty:"gfx_efi_resolution" hcl:"gfx_efi_resolution"`
 	GuestOSType               *string           `mapstructure:"guest_os_type" required:"false" cty:"guest_os_type" hcl:"guest_os_type"`
 	HardDriveDiscard          *bool             `mapstructure:"hard_drive_discard" required:"false" cty:"hard_drive_discard" hcl:"hard_drive_discard"`
 	HardDriveInterface        *string           `mapstructure:"hard_drive_interface" required:"false" cty:"hard_drive_interface" hcl:"hard_drive_interface"`
@@ -256,10 +261,15 @@ func (*FlatConfig) HCL2Spec() map[string]hcldec.Spec {
 		"guest_additions_url":          &hcldec.AttrSpec{Name: "guest_additions_url", Type: cty.String, Required: false},
 		"chipset":                      &hcldec.AttrSpec{Name: "chipset", Type: cty.String, Required: false},
 		"firmware":                     &hcldec.AttrSpec{Name: "firmware", Type: cty.String, Required: false},
+		"nested_virt":                  &hcldec.AttrSpec{Name: "nested_virt", Type: cty.Bool, Required: false},
+		"rtc_time_base":                &hcldec.AttrSpec{Name: "rtc_time_base", Type: cty.String, Required: false},
 		"disk_size":                    &hcldec.AttrSpec{Name: "disk_size", Type: cty.Number, Required: false},
 		"nic_type":                     &hcldec.AttrSpec{Name: "nic_type", Type: cty.String, Required: false},
 		"audio_controller":             &hcldec.AttrSpec{Name: "audio_controller", Type: cty.String, Required: false},
 		"gfx_controller":               &hcldec.AttrSpec{Name: "gfx_controller", Type: cty.String, Required: false},
+		"gfx_vram_size":                &hcldec.AttrSpec{Name: "gfx_vram_size", Type: cty.Number, Required: false},
+		"gfx_accelerate_3d":            &hcldec.AttrSpec{Name: "gfx_accelerate_3d", Type: cty.Bool, Required: false},
+		"gfx_efi_resolution":           &hcldec.AttrSpec{Name: "gfx_efi_resolution", Type: cty.String, Required: false},
 		"guest_os_type":                &hcldec.AttrSpec{Name: "guest_os_type", Type: cty.String, Required: false},
 		"hard_drive_discard":           &hcldec.AttrSpec{Name: "hard_drive_discard", Type: cty.Bool, Required: false},
 		"hard_drive_interface":         &hcldec.AttrSpec{Name: "hard_drive_interface", Type: cty.String, Required: false},

website/content/partials/builder/virtualbox/iso/Config-not-required.mdx

@@ -8,6 +8,14 @@
   When set to bios, the firmare is BIOS. This is the default.
   When set to efi, the firmare is EFI.
 
+- `nested_virt` (bool) - Nested virtualization: false or true.
+  When set to true, nested virtualisation (VT-x/AMD-V) is enabled.
+  When set to false, nested virtualisation is disabled. This is the default.
+
+- `rtc_time_base` (string) - RTC time base: UTC or local.
+  When set to true, the RTC is set as UTC time.
+  When set to false, the RTC is set as local time. This is the default.
+
 - `disk_size` (uint) - The size, in megabytes, of the hard disk to create for the VM. By
   default, this is 40000 (about 40 GB).
 
@@ -31,6 +39,17 @@
   When set to vmsvga, the graphics controller is VMware SVGA.
   When set to none, the graphics controller is disabled.
 
+- `gfx_vram_size` (uint) - The VRAM size to be used. By default, this is 4 MiB.
+
+- `gfx_accelerate_3d` (bool) - 3D acceleration: true or false.
+  When set to true, 3D acceleration is enabled.
+  When set to false, 3D acceleration is disabled. This is the default.
+
+- `gfx_efi_resolution` (string) - Screen resolution in EFI mode: WIDTHxHEIGHT.
+  When set to WIDTHxHEIGHT, it provides the given width and height as screen resolution
+  to EFI, for example 1920x1080 for Full-HD resolution. By default, no screen resolution
+  is set. Note, that this option only affects EFI boot, not the (default) BIOS boot.
+
 - `guest_os_type` (string) - The guest OS type being installed. By default this is other, but you can
   get dramatic performance improvements by setting this to the proper
   value. To view all available values for this run VBoxManage list