From patchwork Wed Feb 14 15:16:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13556674 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 5C40BC48BC1 for ; Wed, 14 Feb 2024 15:19:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1raH16-0007rR-Mx; Wed, 14 Feb 2024 10:17:44 -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 1raH12-0007qz-Kf for qemu-devel@nongnu.org; Wed, 14 Feb 2024 10:17:40 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1raH10-0000PQ-SD for qemu-devel@nongnu.org; Wed, 14 Feb 2024 10:17:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707923858; 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=4XvHRrSZGz0C59Zu95hBu5n9kentS+2TwgEY3I45/xk=; b=AD5FKGKahUv1pmlXHSf08zkkLhL7DYZvhIIz3mr1QNjOvVNgDFx6cj/XRcpvFZV081z+fK ZL+zoWPTSesFuEaM5u5G8ts7U/q/2KemKUYHRlPs48SV6/sSzhuBsv0h3xyPjxJspljQm3 zXrPIrV3O8N2A1rf+gCthD/cXsnGe4U= 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-527-_3p6Hmf6OI-LMlamvCbY4g-1; Wed, 14 Feb 2024 10:17:34 -0500 X-MC-Unique: _3p6Hmf6OI-LMlamvCbY4g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (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 20724185A783; Wed, 14 Feb 2024 15:17:34 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.39.194.174]) by smtp.corp.redhat.com (Postfix) with ESMTP id 55A7E1C066AA; Wed, 14 Feb 2024 15:17:31 +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 , Raphael Norwitz Subject: [PATCH v2 09/14] libvhost-user: Factor out search for memory region by GPA and simplify Date: Wed, 14 Feb 2024 16:16:56 +0100 Message-ID: <20240214151701.29906-10-david@redhat.com> In-Reply-To: <20240214151701.29906-1-david@redhat.com> References: <20240214151701.29906-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.531, 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_H2=-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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.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. Reviewed-by: Raphael Norwitz Acked-by: Stefano Garzarella Signed-off-by: David Hildenbrand --- 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 7f29e01c30..d72f25396d 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;