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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 5DBE8C433F5 for ; Tue, 15 Feb 2022 19:44:38 +0000 (UTC) Received: from localhost ([::1]:38214 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nK3kb-0000oW-Hh for qemu-devel@archiver.kernel.org; Tue, 15 Feb 2022 14:44:37 -0500 Received: from eggs.gnu.org ([209.51.188.92]:40846) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nK3bM-0007CY-Aj for qemu-devel@nongnu.org; Tue, 15 Feb 2022 14:35:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:51146) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nK3bI-0007Gc-Im for qemu-devel@nongnu.org; Tue, 15 Feb 2022 14:35:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644953699; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uNL5C3xYs7QhwLhYiFwuxBWTSXrY5lnND2f6/EFSt9c=; b=bZsE4ppBJIKBPOmyQN4VSLtPTGQZodCKi1oD0MWl0oHYqdfDeBBdJ96zyeWxEdb29KJ6z4 lf8TN7A5CiYZdd5q3vVjpfJ4dunF3A3iZK/neUyW2HQSBdXr/8FQ5AKXOYi5nnAyVZwUlZ EHPjtKkXt1xQTMtu8TdYNVv/bwUWdC0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-173-dxq1xSs9Mf663N8G9QuvQQ-1; Tue, 15 Feb 2022 14:34:58 -0500 X-MC-Unique: dxq1xSs9Mf663N8G9QuvQQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C92E32F25 for ; Tue, 15 Feb 2022 19:34:57 +0000 (UTC) Received: from eperezma.remote.csb (unknown [10.39.195.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4722160657; Tue, 15 Feb 2022 19:34:56 +0000 (UTC) From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: Jason Wang , Peter Xu Subject: [PATCH] util: Add iova_tree_alloc Date: Tue, 15 Feb 2022 20:34:23 +0100 Message-Id: <20220215193422.1777441-2-eperezma@redhat.com> In-Reply-To: <345cd684-0cc2-a685-0611-e2fcf0dfc52b@redhat.com> References: <345cd684-0cc2-a685-0611-e2fcf0dfc52b@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eperezma@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=eperezma@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.083, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This iova tree function allows it to look for a hole in allocated regions and return a totally new translation for a given translated address. It's usage is mainly to allow devices to access qemu address space, remapping guest's one into a new iova space where qemu can add chunks of addresses. Signed-off-by: Eugenio Pérez --- include/qemu/iova-tree.h | 17 +++++ util/iova-tree.c | 132 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 149 insertions(+) diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h index 8249edd764..eb6b6175a3 100644 --- a/include/qemu/iova-tree.h +++ b/include/qemu/iova-tree.h @@ -29,6 +29,7 @@ #define IOVA_OK (0) #define IOVA_ERR_INVALID (-1) /* Invalid parameters */ #define IOVA_ERR_OVERLAP (-2) /* IOVA range overlapped */ +#define IOVA_ERR_NOMEM (-3) /* Cannot allocate */ typedef struct IOVATree IOVATree; typedef struct DMAMap { @@ -119,6 +120,22 @@ const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova); */ void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator); +/** + * iova_tree_alloc: + * + * @tree: the iova tree to allocate from + * @map: the new map (as translated addr & size) to allocate in iova region + * @iova_begin: the minimum address of the allocation + * @iova_end: the maximum addressable direction of the allocation + * + * Allocates a new region of a given size, between iova_min and iova_max. + * + * Return: Same as iova_tree_insert, but cannot overlap and can be out of + * free contiguous range. Caller can get the assigned iova in map->iova. + */ +int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin, + hwaddr iova_end); + /** * iova_tree_destroy: * diff --git a/util/iova-tree.c b/util/iova-tree.c index 23ea35b7a4..1adefeb086 100644 --- a/util/iova-tree.c +++ b/util/iova-tree.c @@ -16,6 +16,39 @@ struct IOVATree { GTree *tree; }; +/* Args to pass to iova_tree_alloc foreach function. */ +struct IOVATreeAllocArgs { + /* Size of the desired allocation */ + size_t new_size; + + /* The minimum address allowed in the allocation */ + hwaddr iova_begin; + + /* Map at the left of the hole, can be NULL if "this" is first one */ + const DMAMap *prev; + + /* Map at the right of the hole, can be NULL if "prev" is the last one */ + const DMAMap *this; + + /* If found, we fill in the IOVA here */ + hwaddr iova_result; + + /* Whether have we found a valid IOVA */ + bool iova_found; +}; + +/** + * Iterate args to tne next hole + * + * @args The alloc arguments + * @next The next mapping in the tree. Can be NULL to signal the last one + */ +static void iova_tree_alloc_args_iterate(struct IOVATreeAllocArgs *args, + const DMAMap *next) { + args->prev = args->this; + args->this = next; +} + static int iova_tree_compare(gconstpointer a, gconstpointer b, gpointer data) { const DMAMap *m1 = a, *m2 = b; @@ -107,6 +140,105 @@ int iova_tree_remove(IOVATree *tree, const DMAMap *map) return IOVA_OK; } +/** + * Try to find an unallocated IOVA range between prev and this elements. + * + * @args Arguments to allocation + * + * Cases: + * + * (1) !prev, !this: No entries allocated, always succeed + * + * (2) !prev, this: We're iterating at the 1st element. + * + * (3) prev, !this: We're iterating at last element. + * + * (4) prev, this: this is the most common case, we'll try to find a hole + * between "prev" and "this" mapping. + * + * Note that this function assumes last valid iova is HWADDR_MAX, but it + * searches linearly so it's easy to discard result if it's not the case. + */ +static void iova_tree_alloc_map_in_hole(struct IOVATreeAllocArgs *args) +{ + const DMAMap *prev = args->prev, *this = args->this; + uint64_t hole_start, hole_last; + + if (this && this->iova + this->size < args->iova_begin) { + return; + } + + hole_start = MAX(prev ? prev->iova + prev->size + 1 : 0, args->iova_begin); + hole_last = this ? this->iova : HWADDR_MAX; + + if (hole_last - hole_start > args->new_size) { + args->iova_result = hole_start; + args->iova_found = true; + } +} + +/** + * Foreach dma node in the tree, compare if there is a hole wit its previous + * node (or minimum iova address allowed) and the node. + * + * @key Node iterating + * @value Node iterating + * @pargs Struct to communicate with the outside world + * + * Return: false to keep iterating, true if needs break. + */ +static gboolean iova_tree_alloc_traverse(gpointer key, gpointer value, + gpointer pargs) +{ + struct IOVATreeAllocArgs *args = pargs; + DMAMap *node = value; + + assert(key == value); + + iova_tree_alloc_args_iterate(args, node); + iova_tree_alloc_map_in_hole(args); + return args->iova_found; +} + +int iova_tree_alloc_map(IOVATree *tree, DMAMap *map, hwaddr iova_begin, + hwaddr iova_last) +{ + struct IOVATreeAllocArgs args = { + .new_size = map->size, + .iova_begin = iova_begin, + }; + + assert(iova_begin < iova_last); + + /* + * Find a valid hole for the mapping + * + * Assuming low iova_begin, so no need to do a binary search to + * locate the first node. + * + * TODO: Replace all this with g_tree_node_first/next/last when available + * (from glib since 2.68). To do it with g_tree_foreach complicates the + * code a lot. + * + */ + g_tree_foreach(tree->tree, iova_tree_alloc_traverse, &args); + if (!args.iova_found) { + /* + * Tree can be empty or last hole is still not checked because the + * g_tree_foreach does not compare (last, iova_end] range. + */ + iova_tree_alloc_args_iterate(&args, NULL); + iova_tree_alloc_map_in_hole(&args); + } + + if (!args.iova_found || args.iova_result + map->size > iova_last) { + return IOVA_ERR_NOMEM; + } + + map->iova = args.iova_result; + return iova_tree_insert(tree, map); +} + void iova_tree_destroy(IOVATree *tree) { g_tree_destroy(tree->tree); -- 2.27.0