From c3a295efd1b1132bbaa5d422cd05b3fa8e89a8bf Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Mon, 21 Sep 2026 13:06:51 -0400 Subject: kernel: Fix GSP emulation shadow binding, eventfd wiring, RPC livelocks + docs suite + repo reorg CRITICAL FIXES (guest driver bring-up): - gsp_emulation.c: emulation engine bound to the WRONG BAR0 - it polled the host physical BAR0 (bars[0].vaddr ioremap) for the doorbell and read RPCs from a local dma_alloc_wc buffer, while the guest writes land in the vzalloc'd bar0_shadow. The RPC path could never work; PBA writes even corrupted the host GPU's physical BAR0+0x3000. gsp_emu_init now binds exclusively to bar0_shadow (doorbell/mailbox/PBA aliases; shared_mem_dma==0 marks the alias so cleanup never dma_free's it). - main.c SET_IRQS: DATA_EVENTFD eventfds were DISCARDED ('TODO' + kfree) - the guest never received MSI-X completions. Full wiring now: eventfd_ctx_fdget per vector, fd -1 clears, dev_close releases refs. gsp_emu_inject_completion_interrupt looks up vgpu->irqs[0].trigger LIVE (init-time copy was permanently NULL since QEMU wires after gsp_emu_init). - gsp_rpc_client.c: BAR_TRAP/MIGRATE in emulation mode called gsp_rpc_submit_raw which rings the SAME doorbell the thread polls - self-triggered RPC livelock + multi-second stalls. Now fail fast with -ENOTSUPP + pr_warn_ratelimited (guest BAR access is direct MMIO). MORE FIXES: - main.c: nv_vgpu_config_write returned SIZE_MAX (while(count--) wrap) and was dead code while the VFIO write handler did unfiltered byte copies (guest could rewrite vendor ID/BARs). Return fixed; VFIO write handler now routes through the per-register filter. - kernel/Makefile: M=$(PWD) used the env var which is stale when invoked via the top-level make (pointed at repo root -> kbuild silently built NOTHING; explains every 'stale .ko' incident). Now M=$(CURDIR). - Warnings sweep: header prototypes for mdev/type functions, format casts in gsp_comm.c DRY-RUN logs, unused variable. ROBUSTNESS (harness/tooling): - vgpu_vm.py: run had no timeout (start could block forever); guest_shell recv could block forever on a wedged guest. Both now bounded; guest_shell pre-flights guest-ping and reports wedge diagnostics. - stack_manager.sh: qemu/qemu-debug now launch via the vgpu_vm.py harness (workflow rule: never raw QEMU). REPO REORGANIZATION: - driver/ (legacy guest-side gsp-vgpu.ko) moved to legacy-driver-guest/ (reference only, not built; README explains). 3 legacy un-buildable test files moved to legacy-driver-guest/kernel-tests/. Top-level Makefile cleaned of the dead DRIVER_DIR reference. DOCUMENTATION SUITE (new): - docs/GSP_EMULATION_ARCHITECTURE.md - emulator deep-dive: shadow BAR0 model, doorbell protocol, dispatch table, MSI-X path, lifecycle, memory- model caveats - docs/DEBUGGING.md - QEMU GDB stub workflow, serial console, QMP NMI, failure taxonomy, full bring-up validation checklist, EPT-livelock case study, version-matrix discipline - docs/ONBOARDING.md - repo tour, coding standards (incl. virt_to_phys / dma_addr_t / get-put rules), first build & test - docs/VERSION_UPGRADE.md - end-to-end new-driver-version procedure (firmware fetch, Ghidra analysis, configs, signatures, validation) - docs/PERFORMANCE.md - bare-metal A/B methodology + targets - README.md doc index; STATE.md refreshed; DEVELOPMENT_WORKFLOW.md corrected (load order: open-iov-vfio BEFORE nvidia; stock-driver blacklist note) --- kernel/gsp_comm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel/gsp_comm.c') diff --git a/kernel/gsp_comm.c b/kernel/gsp_comm.c index a8d0664..094fcfb 100644 --- a/kernel/gsp_comm.c +++ b/kernel/gsp_comm.c @@ -37,7 +37,6 @@ static void nv_vgpu_gsp_rpc_work(struct work_struct *work) static void nv_vgpu_gsp_poll_work(struct work_struct *work) { struct nv_vgpu_gsp_comm_ctx *ctx = container_of(work, struct nv_vgpu_gsp_comm_ctx, poll_work.work); - struct nv_vgpu_device *vgpu = ctx->vgpu; u32 status; if (!ctx || !ctx->irq_enabled || !ctx->gsp_doorbell) @@ -221,7 +220,7 @@ int nv_vgpu_gsp_boot(struct nv_vgpu_device *vgpu) nv_vgpu_info(vgpu, "DRY-RUN: Would write GSP binary (%zu bytes) to offset 0x200000", ctx->firmware.gsp_size); nv_vgpu_info(vgpu, "DRY-RUN: Would kick GSP doorbell at offset 0x%llx", - NV_VGPU_GSP_DOORBELL_OFFSET); + (u64)NV_VGPU_GSP_DOORBELL_OFFSET); return 0; } @@ -267,7 +266,7 @@ int nv_vgpu_gsp_init(struct nv_vgpu_device *vgpu) return -ENODEV; } nv_vgpu_info(vgpu, "DRY-RUN: BAR0 mapped at %p, GSP doorbell offset 0x%llx, shared mem offset 0x%llx", - bar->vaddr, NV_VGPU_GSP_DOORBELL_OFFSET, NV_VGPU_GSP_SHARED_MEM_OFFSET); + bar->vaddr, (u64)NV_VGPU_GSP_DOORBELL_OFFSET, (u64)NV_VGPU_GSP_SHARED_MEM_OFFSET); /* Validate firmware files exist */ ret = request_firmware(NULL, NV_VGPU_GSP_BOOTLOADER_FILE, &vgpu->pdev->dev); if (ret) { -- cgit v1.2.3