From 7aef82a5112ee72ee2fc5a430db072085933e927 Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Wed, 23 Sep 2026 00:41:46 -0400 Subject: kernel: serve GMMU static info + per-VF fault/access-counter sizes for UVM Three fixes that clear all driver-visible errors in UVM's device create (cuInit still fails later in UVM_REGISTER_GPU): 1. GSP_RM_CONTROL 0x20800a59 INTERNAL_GMMU_GET_STATIC_INFO (new handler): kgmmu.pStaticInfo->replayableFaultBufferSize feeds kgmmuFaultBufferReplayableAllocate (called by faultbufConstruct when UVM opens the device). The generic zero reply made it a 0-page allocation: "faultbufConstruct_IMPL: Failed to setup Replayable Fault buffer (status=0x51)". Report 64KB replayable / 4KB legacy, mirroring kgmmuSetAndGetDefaultFaultBufferSize_TU102 defaults. 2. VF-window NV_VIRTUAL_FUNCTION_PRIV_MMU_FAULT_BUFFER_SIZE(0/1) (BAR0+0xB83010/0xB83030, plus plain aliases) pre-filled with _VAL in NVC369_BUF_SIZE units (0x800=64KB, 0x80=4KB) so the local (non-RPC) path reads the same values the control handler reports. 3. VF-window NV_VIRTUAL_FUNCTION_PRIV_ACCESS_COUNTER_NOTIFY_BUFFER_SIZE (BAR0+0xB83110, plus plain alias) = 0x1000 (the value the host's physical TU104 reports; x32B = 128KB). uvmGetAccessCounterBufferSize_ TU102 multiplied our zero and uvmInitializeAccessCntrBuffer failed with NV_ERR_NO_MEMORY at mem_desc.c:1353. Also note (companion finding, no code change): the guest must be placed behind a pcie-root-port; on the Q35 root bus QEMU rewrites the PCIe cap to Root Complex Integrated Endpoint and zeroes LNKCAP/LNKCTL/DeviceCaps (vfio_setup_pcie_cap: "On a Root Complex bus Endpoints become Root Complex Integrated Endpoints, which changes the type and clears the LNK & LNK2 fields"), which is what made getPCIELinkRateMBps read speed 0. --- kernel/gsp_rm_emulation.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'kernel/gsp_rm_emulation.c') diff --git a/kernel/gsp_rm_emulation.c b/kernel/gsp_rm_emulation.c index 1f029b1..c2b306a 100644 --- a/kernel/gsp_rm_emulation.c +++ b/kernel/gsp_rm_emulation.c @@ -1064,6 +1064,40 @@ static void gsp_rm_handle_ce_get_fault_method_buffer_size( nv_vgpu_info(ctx->vgpu, "GSPRM: CE_GET_FAULT_METHOD_BUFFER_SIZE -> %u", val32); } +/* + * INTERNAL_GMMU_GET_STATIC_INFO (0x20800a59) + * + * The guest asks GSP-RM (us) for the GMMU static info; kgmmu. pStaticInfo-> + * replayableFaultBufferSize feeds kgmmuFaultBufferReplayableAllocate (called + * from faultbufConstruct when UVM opens the device). Zero -> 0-page alloc -> + * NV_ERR_NO_MEMORY -> faultbufConstruct fails and cuInit aborts. + * params: replayableFaultBufferSize(4) + replayableShadowFaultBufferMetadata + * Size(4) + nonReplayableFaultBufferSize(4) + nonReplayableShadowFaultBuffer + * MetadataSize(4). Shadow metadata is only used with confidential computing, + * so it stays 0. + */ +static void gsp_rm_handle_gmmu_get_static_info(struct gsp_emu_context *ctx, + u32 sequence, + u32 *out_status, + u8 *out_params, + u32 *out_params_size) +{ + u32 replay = TU104_GMMU_REPLAYABLE_FAULT_BUFFER_SIZE; + u32 nonreplay = TU104_GMMU_NONREPLAYABLE_FAULT_BUFFER_SIZE; + u32 zero = 0; + + memcpy(out_params + 0, &replay, 4); + memcpy(out_params + 4, &zero, 4); + memcpy(out_params + 8, &nonreplay, 4); + memcpy(out_params + 12, &zero, 4); + + *out_params_size = 16; + *out_status = 0; + + nv_vgpu_info(ctx->vgpu, "GSPRM: GMMU_GET_STATIC_INFO -> replayFaultBuf=0x%x nonReplayFaultBuf=0x%x", + replay, nonreplay); +} + /* * STATIC_KGR_GET_GLOBAL_SM_ORDER (0x20800a22) * @@ -1548,6 +1582,12 @@ static void gsp_rm_handle_rm_control(struct gsp_emu_context *ctx, reply + GSP_RM_CTRL_HDR_SIZE, &out_params_size); break; + case TU104_CTRL_INTERNAL_GMMU_GET_STATIC_INFO: + gsp_rm_handle_gmmu_get_static_info(ctx, sequence, + &out_status, + reply + GSP_RM_CTRL_HDR_SIZE, &out_params_size); + break; + case TU104_CTRL_STATIC_KGR_GET_GLOBAL_SM_ORDER: gsp_rm_handle_kgr_get_global_sm_order(ctx, sequence, &out_status, -- cgit v1.2.3