From patchwork Fri Feb 2 21:53:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 1894777 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=KkUVZqKV; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TRV1Z2KGkz1yhq for ; Sat, 3 Feb 2024 08:54:58 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rW1UB-0008FG-6R; Fri, 02 Feb 2024 16:54:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rW1U9-0008F0-Kk for qemu-devel@nongnu.org; Fri, 02 Feb 2024 16:54:09 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rW1U7-0004uH-Vl for qemu-devel@nongnu.org; Fri, 02 Feb 2024 16:54:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706910847; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QGmenbdCAUIMi0LDoLYDRKXhVIbagKvxeclGQjh1d48=; b=KkUVZqKV9uIxTNN9gjCn5MnqWFRDYrmAE5KqrZY1z1zBDzMXf6DRHXFY7LY/7msJuXR9qu +dpeJRcpDFiMvDIlhbgzOFPV3NmqzYd2rRG+1TaaAxZ0nUxwD3DKlHaIp/czhHh5BpLOJG sT8SIrH5H7f35jORupIi+VwfXhuHqP0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-86-GzfXMkQDPqipNrByfOagQg-1; Fri, 02 Feb 2024 16:54:03 -0500 X-MC-Unique: GzfXMkQDPqipNrByfOagQg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 85DA6185A786; Fri, 2 Feb 2024 21:54:03 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id A6A4E2166B31; Fri, 2 Feb 2024 21:54:01 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , "Michael S . Tsirkin" , Jason Wang , Stefan Hajnoczi , Stefano Garzarella , Germano Veit Michel , Raphael Norwitz Subject: [PATCH v1 10/15] libvhost-user: Factor out search for memory region by GPA and simplify Date: Fri, 2 Feb 2024 22:53:27 +0100 Message-ID: <20240202215332.118728-11-david@redhat.com> In-Reply-To: <20240202215332.118728-1-david@redhat.com> References: <20240202215332.118728-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.276, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Memory regions cannot overlap, and if we ever hit that case something would be really flawed. For example, when vhost code in QEMU decides to increase the size of memory regions to cover full huge pages, it makes sure to never create overlaps, and if there would be overlaps, it would bail out. QEMU commits 48d7c9757749 ("vhost: Merge sections added to temporary list"), c1ece84e7c93 ("vhost: Huge page align and merge") and e7b94a84b6cb ("vhost: Allow adjoining regions") added and clarified that handling and how overlaps are impossible. Consequently, each GPA can belong to at most one memory region, and everything else doesn't make sense. Let's factor out our search to prepare for further changes. Signed-off-by: David Hildenbrand Reviewed-by: Raphael Norwitz --- subprojects/libvhost-user/libvhost-user.c | 79 +++++++++++++---------- 1 file changed, 45 insertions(+), 34 deletions(-) diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c index 22154b217f..d036b54ed0 100644 --- a/subprojects/libvhost-user/libvhost-user.c +++ b/subprojects/libvhost-user/libvhost-user.c @@ -195,30 +195,47 @@ vu_panic(VuDev *dev, const char *msg, ...) */ } +/* Search for a memory region that covers this guest physical address. */ +static VuDevRegion * +vu_gpa_to_mem_region(VuDev *dev, uint64_t guest_addr) +{ + unsigned int i; + + /* + * Memory regions cannot overlap in guest physical address space. Each + * GPA belongs to exactly one memory region, so there can only be one + * match. + */ + for (i = 0; i < dev->nregions; i++) { + VuDevRegion *cur = &dev->regions[i]; + + if (guest_addr >= cur->gpa && guest_addr < cur->gpa + cur->size) { + return cur; + } + } + return NULL; +} + /* Translate guest physical address to our virtual address. */ void * vu_gpa_to_va(VuDev *dev, uint64_t *plen, uint64_t guest_addr) { - unsigned int i; + VuDevRegion *r; if (*plen == 0) { return NULL; } - /* Find matching memory region. */ - for (i = 0; i < dev->nregions; i++) { - VuDevRegion *r = &dev->regions[i]; - - if ((guest_addr >= r->gpa) && (guest_addr < (r->gpa + r->size))) { - if ((guest_addr + *plen) > (r->gpa + r->size)) { - *plen = r->gpa + r->size - guest_addr; - } - return (void *)(uintptr_t) - guest_addr - r->gpa + r->mmap_addr + r->mmap_offset; - } + r = vu_gpa_to_mem_region(dev, guest_addr); + if (!r) { + return NULL; } - return NULL; + if ((guest_addr + *plen) > (r->gpa + r->size)) { + *plen = r->gpa + r->size - guest_addr; + } + return (void *)(uintptr_t)guest_addr - r->gpa + r->mmap_addr + + r->mmap_offset; } /* Translate qemu virtual address to our virtual address. */ @@ -854,8 +871,8 @@ static inline bool reg_equal(VuDevRegion *vudev_reg, static bool vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m; - unsigned int i; - bool found = false; + unsigned int idx; + VuDevRegion *r; if (vmsg->fd_num > 1) { vmsg_close_fds(vmsg); @@ -882,28 +899,22 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { DPRINT(" mmap_offset 0x%016"PRIx64"\n", msg_region->mmap_offset); - for (i = 0; i < dev->nregions; i++) { - if (reg_equal(&dev->regions[i], msg_region)) { - VuDevRegion *r = &dev->regions[i]; - - munmap((void *)(uintptr_t)r->mmap_addr, r->size + r->mmap_offset); - - /* Shift all affected entries by 1 to close the hole at index. */ - memmove(dev->regions + i, dev->regions + i + 1, - sizeof(VuDevRegion) * (dev->nregions - i - 1)); - DPRINT("Successfully removed a region\n"); - dev->nregions--; - i--; - - found = true; - break; - } - } - - if (!found) { + r = vu_gpa_to_mem_region(dev, msg_region->guest_phys_addr); + if (!r || !reg_equal(r, msg_region)) { + vmsg_close_fds(vmsg); vu_panic(dev, "Specified region not found\n"); + return false; } + munmap((void *)(uintptr_t)r->mmap_addr, r->size + r->mmap_offset); + + idx = r - dev->regions; + assert(idx < dev->nregions); + /* Shift all affected entries by 1 to close the hole. */ + memmove(r, r + 1, sizeof(VuDevRegion) * (dev->nregions - idx - 1)); + DPRINT("Successfully removed a region\n"); + dev->nregions--; + vmsg_close_fds(vmsg); return false;