From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C3EB5D3A699 for ; Tue, 29 Oct 2024 19:40:06 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7F29410E6F3; Tue, 29 Oct 2024 19:40:06 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="ZrTkSy4k"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) by gabe.freedesktop.org (Postfix) with ESMTPS id 75A7910E6F0 for ; Tue, 29 Oct 2024 19:40:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1730230802; x=1761766802; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=V4hBJ7LjtcdIvbJsmLvL/EUIjMiirepKVSqwYoVCQkE=; b=ZrTkSy4kefUtnWijypu5ZpWe9q8wRMn9Z/qBMlKJay5DeCXcLFiskqu1 9q9CEDSnZ7rzuIXPBrEe1sowGChWXIYOWBlk+cEBqPZsrKSPM797QJ8pO faqr8q/VnBlyZOERqzWDPmu2U9UzLHt9kfShwSLfRHsPQdAGmPyvvCUgT nz2BMPwpMzQQxU9X5PhfE6L5igTMiwRBY61g6KU0+GY3bKDXhdAc6yGue p+os8sPKVczHcH2ELJtjO/kKmY+OELRSXDdLpYge5hyB2BSsifR7WdiYf 9E+3ZLah4SnczuC8F17us9lJYVakdYuglQBn9IXm5gGQAahECb+BhE6Mv g==; X-CSE-ConnectionGUID: 3TXRfVn5TzCAVEBUVtGDqw== X-CSE-MsgGUID: wF11J87hQLOLD3Ml7cxLFA== X-IronPort-AV: E=McAfee;i="6700,10204,11240"; a="17537324" X-IronPort-AV: E=Sophos;i="6.11,241,1725346800"; d="scan'208";a="17537324" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Oct 2024 12:40:02 -0700 X-CSE-ConnectionGUID: EjHd8eB0T0uTxODWdMdonQ== X-CSE-MsgGUID: nC3i7nVTRsuhhSPQhmI91Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,241,1725346800"; d="scan'208";a="81996518" Received: from gkczarna.igk.intel.com ([10.102.139.130]) by orviesa009.jf.intel.com with ESMTP; 29 Oct 2024 12:40:02 -0700 From: Tomasz Lis To: intel-xe@lists.freedesktop.org Cc: =?UTF-8?q?Micha=C5=82=20Winiarski?= , =?UTF-8?q?Micha=C5=82=20Wajdeczko?= Subject: [PATCH v5 2/5] drm/xe/vf: Document SRIOV VF restore flow Date: Tue, 29 Oct 2024 20:39:53 +0100 Message-Id: <20241029193956.1043614-3-tomasz.lis@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20241029193956.1043614-1-tomasz.lis@intel.com> References: <20241029193956.1043614-1-tomasz.lis@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" This adds a documentation chapter, containing high level flow of VF restore procedure. Signed-off-by: Tomasz Lis --- drivers/gpu/drm/xe/xe_sriov_vf.h | 93 ++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.h b/drivers/gpu/drm/xe/xe_sriov_vf.h index 7b8622cff2b7..22683dd643f8 100644 --- a/drivers/gpu/drm/xe/xe_sriov_vf.h +++ b/drivers/gpu/drm/xe/xe_sriov_vf.h @@ -8,6 +8,99 @@ struct xe_device; +/** + * DOC: VF restore procedure in PF KMD and VF KMD + * + * Restoring previously saved state of a VF is one of core features of + * SR-IOV. All major VM Management applications allow saving and restoring + * the VM state, and doing that to a VM which uses SRIOV VF as one of + * the accessible devices requires support from KMD on both PF and VF side. + * VMM initiates all required operations through VFIO module, which then + * translates them into PF KMD calls. This description will focus on these + * calls, leaving out the module which initiates these steps (VFIO). + * + * In order to start the restore procedure, GuC needs to keep the VF in + * proper state. The PF driver can ensure VF entered this state by + * performing Function Level Reset on said VF. The FLR procedure ends with + * GuC sending message `GUC_PF_NOTIFY_VF_FLR_DONE`, and then the actual + * restore can begin. + * + * During VF Restore, state of several resources is restored. These may + * include local memory content (system memory is restored by VMM itself), + * values of MMIO registers, stateless compression metadata and others. + * The final resource which also needs restoring is state of the VF + * submission maintained within GuC. For that, `GUC_PF_OPCODE_VF_RESTORE` + * message is used, with reference to the state blob to be consumed by + * GuC. + * + * Next, when VFIO is asked to set the VM into running state, the PF driver + * sends `GUC_PF_TRIGGER_VF_RESUME` to GuC. When sent after restore, this + * changes VF state within GuC to `VF_RESFIX_BLOCKED` rather than the + * usual `VF_RUNNING`. At this point GuC triggers an interrupt to inform + * the VF KMD within the VM that it was migrated. + * + * As soon as Virtual GPU of the VM starts, the VF driver within receives + * the MIGRATED interrupt and schedules post-migration recovery worker. + * That worker queries GuC for new provisioning (using MMIO communication), + * and applies fixups to any non-virtualized resources used by the VF. + * + * When the VF driver is ready to continue operation on the newly connected + * hardware, it sends `VF2GUC_NOTIFY_RESFIX_DONE` which causes it to + * enter the long awaited `VF_RUNNING` state, and therefore start handling + * CTB messages and scheduling workloads from the VF:: + * + * PF GuC VF + * [ ] [ ] | + * [ ] GUC_PF_NOTIFY_VF_FLR_DONE [ ] | + * [ ] <---------------------------[ ] | + * [ ] | | + * [ ] PF loads resources from the | | + * [ ]------- saved image supplied | | + * [ ] | | | + * [ ] <----- | | + * [ ] | | + * [ ] GUC_PF_OPCODE_VF_RESTORE | | + * [ ]---------------------------> [ ] | + * [ ] [ ] GuC loads contexts and CTB | + * [ ] [ ]------- state from image | + * [ ] [ ] | | + * [ ] success [ ] <----- | + * [ ] <---------------------------[ ] | + * [ ] | | + * [ ] GUC_PF_TRIGGER_VF_RESUME | | + * [ ]---------------------------> [ ] | + * [ ] [ ] GuC sets new VF state to | + * [ ] [ ]------- VF_RESFIX_BLOCKED | + * [ ] [ ] | | + * [ ] [ ] <----- | + * [ ] [ ] | + * [ ] [ ] GUC_INTR_SW_INT_0 | + * [ ] success [ ]---------------------------> [ ] + * [ ] <---------------------------[ ] [ ] + * | | VF2GUC_QUERY_SINGLE_KLV [ ] + * | [ ] <---------------------------[ ] + * | [ ] [ ] + * | [ ] new VF provisioning [ ] + * | [ ]---------------------------> [ ] + * | | [ ] + * | | VF driver applies post [ ] + * | | migration fixups -------[ ] + * | | | [ ] + * | | -----> [ ] + * | | [ ] + * | | VF2GUC_NOTIFY_RESFIX_DONE [ ] + * | [ ] <---------------------------[ ] + * | [ ] [ ] + * | [ ] GuC sets new VF state to [ ] + * | [ ]------- VF_READY [ ] + * | [ ] | [ ] + * | [ ] <----- [ ] + * | [ ] success [ ] + * | [ ]---------------------------> [ ] + * | | | + * | | | + */ + void xe_sriov_vf_init_early(struct xe_device *xe); void xe_sriov_vf_start_migration_recovery(struct xe_device *xe); -- 2.25.1