kernel: Present physical TU104 to guest + emulate GSP boot (FWSEC/Booter) + VBIOS serving

Guest driver probe fixes (unmodified 570.144 open driver on physical path):

- kernel/main.c: add show_description to the mdev driver. Userspace mdev
  management tools parse 'framebuffer=<n>M' from every mdev type's
  description sysfs file before creating an mdev; the missing file made
  such tools fail to create the vGPU. Also fix create_mdev.sh for the real
  type dir name pci-nvidia-vgpu-* (mdev core names dirs
  dev_driver_string(parent)-<sysfs_name>; the parent registers before
  nvidia.ko binds so dev_driver_string == 'pci').

- kernel/bar_emulation.c: seed BAR0 shadow so guest sees a REAL, PHYSICAL,
  non-virtual TU104 (user directive: no PV/VF vGPU paths, unmodified driver):
  * PMC_BOOT_0/1/42 = physical TU104 values captured from host hardware
    (0x164000a1 / 0x0 / 0x164a1000). Without these, halmgrGetHalForGpu()
    fails and probe aborts with 'does not include the required GSP'.
  * Serve a valid VBIOS at the PROM window (BAR0+0x300000) loaded from
    /lib/firmware/tu104_vbios.bin (dump of host TU104 ROM). Guest's
    kgspExtractVbiosFromRom_TU102 needs it for the mandatory FWSEC ucode
    (kgspGetFrtsSize is hardwired to 1MB on Turing).
  * Pre-set GSP secure-boot (GFW) completion state: PGC6 PLM (0x118128)=1,
    GFW_BOOT progress (0x118234)=0xFF, GSP falcon CPUCTL HALTED (0x110100).
    The driver's post-FLR GFW wait only *waits* (never kicks), so the
    pre-set state satisfies it immediately.

- kernel/gsp_emulation.c/h: physical GSP boot emulation.
  * Falcon boot-watch: poll GSP falcon/PGC6/WPR2/scratch registers and log
    changes (guest BAR0 is mmap-based, otherwise invisible to host).
  * gsp_emu_poll_boot: STARTCPU auto-complete state machine. Guest kicks
    FWSEC then Booter Load via GSP falcon CPUCTL; detect each kick and
    complete the stage (HALTED + FRTS err NONE + WPR2 + mailbox +
    RISCV-active) so the guest believes its ucodes ran.

Diagnosis that led here (documented in Handoff-vGPU-IO.md):
- Open nvidia.ko can never be an SR-IOV VF vGPU guest: os_is_grid_supported()
  is a stub returning FALSE in the open build (disassembled). PV path also
  rejected per user directive. Only the physical path with a fully emulated
  local GSP boot remains.

1 files changed, 2 insertions, 2 deletions

diff --git a/scripts/create_mdev.sh b/scripts/create_mdev.sh
index 7bafaae..a6ea91e 100755
--- a/scripts/create_mdev.sh
+++ b/scripts/create_mdev.sh
@@ -5,10 +5,10 @@
 set -euo pipefail
 
 PCI_ADDR="${1:-}"
-VGPU_TYPE="${2:-nvidia-nvidia-vgpu-turing}"
+VGPU_TYPE="${2:-pci-nvidia-vgpu-turing}"
 
 # Supported vGPU types (matching the mdev type names)
-VALID_TYPES=("nvidia-nvidia-vgpu-ampere" "nvidia-nvidia-vgpu-hopper" "nvidia-nvidia-vgpu-turing" "nvidia-nvidia-vgpu-pascal")
+VALID_TYPES=("pci-nvidia-vgpu-ampere" "pci-nvidia-vgpu-hopper" "pci-nvidia-vgpu-turing" "pci-nvidia-vgpu-pascal")
 
 # Find NVIDIA GPU if not specified
 if [[ -z "$PCI_ADDR" ]]; then