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 19575C4828F for ; Fri, 2 Feb 2024 21:55:16 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rW1UE-0008G4-7q; Fri, 02 Feb 2024 16:54:14 -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 1rW1UC-0008Fe-Na for qemu-devel@nongnu.org; Fri, 02 Feb 2024 16:54:12 -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 1rW1UB-0004uY-4B for qemu-devel@nongnu.org; Fri, 02 Feb 2024 16:54:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706910850; 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=czNYp4U5+ggmqgLkvs4/GbnY/M6qHCdVm83DexN7PvQ=; b=KqVPBG9UpYNL2ypWYfatc4AxFkUfeNUus88w23zo4Usuzz7tCO6Jzt15waxy7ce5rdx0iW trVNWcZ3kiGsGrWXweAGv79awsjZ55mzzNJ0wQYbWyUC18gs1pZRqzIEo0HpNf+xnN5hoD VSWPBS8AKnv+9JI87BYZ4lnWmrXVTWo= 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-300-7azcj647P_SgeriKma39zA-1; Fri, 02 Feb 2024 16:54:06 -0500 X-MC-Unique: 7azcj647P_SgeriKma39zA-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 1922086C141; Fri, 2 Feb 2024 21:54:06 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id E38E32166B31; Fri, 2 Feb 2024 21:54:03 +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 11/15] libvhost-user: Speedup gpa_to_mem_region() and vu_gpa_to_va() Date: Fri, 2 Feb 2024 22:53:28 +0100 Message-ID: <20240202215332.118728-12-david@redhat.com> In-Reply-To: <20240202215332.118728-1-david@redhat.com> References: <20240202215332.118728-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Let's speed up GPA to memory region / virtual address lookup. Store the memory regions ordered by guest physical addresses, and use binary search for address translation, as well as when adding/removing memory regions. Most importantly, this will speed up GPA->VA address translation when we have many memslots. Signed-off-by: David Hildenbrand --- subprojects/libvhost-user/libvhost-user.c | 49 +++++++++++++++++++++-- 1 file changed, 45 insertions(+), 4 deletions(-) diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c index d036b54ed0..75e47b7bb3 100644 --- a/subprojects/libvhost-user/libvhost-user.c +++ b/subprojects/libvhost-user/libvhost-user.c @@ -199,19 +199,30 @@ vu_panic(VuDev *dev, const char *msg, ...) static VuDevRegion * vu_gpa_to_mem_region(VuDev *dev, uint64_t guest_addr) { - unsigned int i; + int low = 0; + int high = dev->nregions - 1; /* * Memory regions cannot overlap in guest physical address space. Each * GPA belongs to exactly one memory region, so there can only be one * match. + * + * We store our memory regions ordered by GPA and can simply perform a + * binary search. */ - for (i = 0; i < dev->nregions; i++) { - VuDevRegion *cur = &dev->regions[i]; + while (low <= high) { + unsigned int mid = low + (high - low) / 2; + VuDevRegion *cur = &dev->regions[mid]; if (guest_addr >= cur->gpa && guest_addr < cur->gpa + cur->size) { return cur; } + if (guest_addr >= cur->gpa + cur->size) { + low = mid + 1; + } + if (guest_addr < cur->gpa) { + high = mid - 1; + } } return NULL; } @@ -273,9 +284,14 @@ vu_remove_all_mem_regs(VuDev *dev) static void _vu_add_mem_reg(VuDev *dev, VhostUserMemoryRegion *msg_region, int fd) { + const uint64_t start_gpa = msg_region->guest_phys_addr; + const uint64_t end_gpa = start_gpa + msg_region->memory_size; int prot = PROT_READ | PROT_WRITE; VuDevRegion *r; void *mmap_addr; + int low = 0; + int high = dev->nregions - 1; + unsigned int idx; DPRINT("Adding region %d\n", dev->nregions); DPRINT(" guest_phys_addr: 0x%016"PRIx64"\n", @@ -295,6 +311,29 @@ _vu_add_mem_reg(VuDev *dev, VhostUserMemoryRegion *msg_region, int fd) prot = PROT_NONE; } + /* + * We will add memory regions into the array sorted by GPA. Perform a + * binary search to locate the insertion point: it will be at the low + * index. + */ + while (low <= high) { + unsigned int mid = low + (high - low) / 2; + VuDevRegion *cur = &dev->regions[mid]; + + /* Overlap of GPA addresses. */ + if (start_gpa < cur->gpa + cur->size && cur->gpa < end_gpa) { + vu_panic(dev, "regions with overlapping guest physical addresses"); + return; + } + if (start_gpa >= cur->gpa + cur->size) { + low = mid + 1; + } + if (start_gpa < cur->gpa) { + high = mid - 1; + } + } + idx = low; + /* * We don't use offset argument of mmap() since the mapped address has * to be page aligned, and we use huge pages. @@ -308,7 +347,9 @@ _vu_add_mem_reg(VuDev *dev, VhostUserMemoryRegion *msg_region, int fd) DPRINT(" mmap_addr: 0x%016"PRIx64"\n", (uint64_t)(uintptr_t)mmap_addr); - r = &dev->regions[dev->nregions]; + /* Shift all affected entries by 1 to open a hole at idx. */ + r = &dev->regions[idx]; + memmove(r + 1, r, sizeof(VuDevRegion) * (dev->nregions - idx)); r->gpa = msg_region->guest_phys_addr; r->size = msg_region->memory_size; r->qva = msg_region->userspace_addr; -- 2.43.0