From patchwork Sat Jul 15 13:53:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 1808170 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org 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=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=PK6NCBQ1; dkim-atps=neutral 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 4R39050pKcz20c3 for ; Sat, 15 Jul 2023 23:57:41 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qKfjm-000738-5e; Sat, 15 Jul 2023 09:55:06 -0400 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 1qKfid-000497-Su for qemu-devel@nongnu.org; Sat, 15 Jul 2023 09:53:59 -0400 Received: from mail-wr1-x42c.google.com ([2a00:1450:4864:20::42c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qKfiZ-0001Kh-OQ for qemu-devel@nongnu.org; Sat, 15 Jul 2023 09:53:54 -0400 Received: by mail-wr1-x42c.google.com with SMTP id ffacd0b85a97d-307d20548adso2876698f8f.0 for ; Sat, 15 Jul 2023 06:53:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1689429228; x=1692021228; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=LwsEQEgJb6LbDaZv4vgO4Dp17xTKrnyDcX9Cf57n7+Y=; b=PK6NCBQ11EP0lR00GNVRNRVEUJBe5UKTgcyP6kURdm3MgvaUhca6ycc8EhwpbZDq7v KGeu0WpGDi/3/9XMmdVS6ljII9JqQUHtZBBCsVAoT8HurlsX26Y+MDjxCVlyQIsWwWez ayIr6bF22eZaRW6vnCJMla6TQePATSgLW78WntuU00w+qoWqZkNPEDRXwGNGBQMlwSeS knkz4xq3/+RRvI+juKG/pGTXrV2n9wXjY8QJsrst2abcC7hrOfLZg1uJUnDeMqMjix1c LrbrFly5WQm384Ngq80AoIruqea93BGwkvizffz2aa6i82E2DJpaQaQEqiFXLBpNPlkC PcLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689429228; x=1692021228; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LwsEQEgJb6LbDaZv4vgO4Dp17xTKrnyDcX9Cf57n7+Y=; b=VxmFLdZEPyf9Dlx5cPbLG5hol5eKoE9AMw0C37ys+3MOlFuYlH4DO/F0uZvtlY/m/H RPz++NSLGk6l84QOruNIXU9jFpa5wpdlENO9ZwBI302I6ACVw+5hKYlizE8a9Fl2QAwv czCKAxzy/hPcmrxd6yZzGx6I4rC+DDLx9pb9nQE5hUnzKRv9N0Agsd16YZdVOxZoEnjb HRgq0EwdsCbydKG3Rn94uQ/P7/PxTIP1xc3x+22hmAW56WdbvkRQ8jXH+1Lhd+55BsDD DpfbhzGq8sFxEJiusew66Gxg9YynTyFfeyIqUgz3T/hh20bPJZi5LND9vsxmpCrA2yLg kDvA== X-Gm-Message-State: ABy/qLb94hOFwQMvIMzDbR9lpmqpmcPC6QbCddEFth+COAm+QmObQ7Gb OE5tpy+v8vwE2G1anMQOSWEz+PxnORNKoIrML3ywzA== X-Google-Smtp-Source: APBJJlEbdwWb+lpGM3JTsDErOePndQgWtFQcJXuZEZ/MP5bOn29kKPDPAXbwQ/dGbASrvwlfYjZVpA== X-Received: by 2002:adf:de8e:0:b0:30f:c56c:b5b3 with SMTP id w14-20020adfde8e000000b0030fc56cb5b3mr6760789wrl.4.1689429228141; Sat, 15 Jul 2023 06:53:48 -0700 (PDT) Received: from stoup.lan ([51.219.12.49]) by smtp.gmail.com with ESMTPSA id k10-20020a5d66ca000000b00313f9085119sm13838014wrw.113.2023.07.15.06.53.47 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 15 Jul 2023 06:53:47 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PULL 37/47] linux-user: Rewrite mmap_reserve Date: Sat, 15 Jul 2023 14:53:07 +0100 Message-Id: <20230715135317.7219-38-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230715135317.7219-1-richard.henderson@linaro.org> References: <20230715135317.7219-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::42c; envelope-from=richard.henderson@linaro.org; helo=mail-wr1-x42c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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 Use 'last' variables instead of 'end' variables; be careful about avoiding overflow. Assert that the mmap succeeded. Signed-off-by: Richard Henderson Message-Id: <20230707204054.8792-21-richard.henderson@linaro.org> --- linux-user/mmap.c | 68 +++++++++++++++++++++++++++++------------------ 1 file changed, 42 insertions(+), 26 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index bb9cbe52cd..6308787942 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -722,47 +722,63 @@ fail: return -1; } -static void mmap_reserve(abi_ulong start, abi_ulong size) +static void mmap_reserve(abi_ulong start, abi_ulong len) { abi_ulong real_start; - abi_ulong real_end; - abi_ulong addr; - abi_ulong end; + abi_ulong real_last; + abi_ulong real_len; + abi_ulong last; + abi_ulong a; + void *host_start, *ptr; int prot; + last = start + len - 1; real_start = start & qemu_host_page_mask; - real_end = HOST_PAGE_ALIGN(start + size); - end = start + size; - if (start > real_start) { - /* handle host page containing start */ + real_last = HOST_PAGE_ALIGN(last) - 1; + + /* + * If guest pages remain on the first or last host pages, + * adjust the deallocation to retain those guest pages. + * The single page special case is required for the last page, + * lest real_start overflow to zero. + */ + if (real_last - real_start < qemu_host_page_size) { prot = 0; - for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { - prot |= page_get_flags(addr); + for (a = real_start; a < start; a += TARGET_PAGE_SIZE) { + prot |= page_get_flags(a); } - if (real_end == real_start + qemu_host_page_size) { - for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { - prot |= page_get_flags(addr); - } - end = real_end; + for (a = last; a < real_last; a += TARGET_PAGE_SIZE) { + prot |= page_get_flags(a + 1); + } + if (prot != 0) { + return; + } + } else { + for (prot = 0, a = real_start; a < start; a += TARGET_PAGE_SIZE) { + prot |= page_get_flags(a); } if (prot != 0) { real_start += qemu_host_page_size; } - } - if (end < real_end) { - prot = 0; - for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { - prot |= page_get_flags(addr); + + for (prot = 0, a = last; a < real_last; a += TARGET_PAGE_SIZE) { + prot |= page_get_flags(a + 1); } if (prot != 0) { - real_end -= qemu_host_page_size; + real_last -= qemu_host_page_size; + } + + if (real_last < real_start) { + return; } } - if (real_start != real_end) { - mmap(g2h_untagged(real_start), real_end - real_start, PROT_NONE, - MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, - -1, 0); - } + + real_len = real_last - real_start + 1; + host_start = g2h_untagged(real_start); + + ptr = mmap(host_start, real_len, PROT_NONE, + MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0); + assert(ptr == host_start); } int target_munmap(abi_ulong start, abi_ulong len)