From patchwork Thu Apr 18 17:49:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 13635205 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 D4DAFC4345F for ; Thu, 18 Apr 2024 17:54:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rxVvW-0003zX-O9; Thu, 18 Apr 2024 13:52:02 -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 1rxVvF-0003Ab-H4; Thu, 18 Apr 2024 13:51:46 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rxVvD-0007hR-IF; Thu, 18 Apr 2024 13:51:45 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 72C5B5FD78; Thu, 18 Apr 2024 20:50:05 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id C3E54B9352; Thu, 18 Apr 2024 20:50:02 +0300 (MSK) Received: (nullmailer pid 947875 invoked by uid 1000); Thu, 18 Apr 2024 17:49:55 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Richard Henderson , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Michael Tokarev Subject: [Stable-8.2.3 111/116] linux-user/x86_64: Handle the vsyscall page in open_self_maps_{2, 4} Date: Thu, 18 Apr 2024 20:49:41 +0300 Message-Id: <20240418174955.947730-24-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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 From: Richard Henderson This is the only case in which we expect to have no host memory backing for a guest memory page, because in general linux user processes cannot map any pages in the top half of the 64-bit address space. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2170 Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson (cherry picked from commit 4ef1f559f270c66b3ffc23f6c845ff3d008c6356) Signed-off-by: Michael Tokarev diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 834a254895..11c75e3b4e 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -7994,6 +7994,10 @@ static void open_self_maps_4(const struct open_self_maps_data *d, path = "[heap]"; } else if (start == info->vdso) { path = "[vdso]"; +#ifdef TARGET_X86_64 + } else if (start == TARGET_VSYSCALL_PAGE) { + path = "[vsyscall]"; +#endif } /* Except null device (MAP_ANON), adjust offset for this fragment. */ @@ -8082,6 +8086,18 @@ static int open_self_maps_2(void *opaque, target_ulong guest_start, uintptr_t host_start = (uintptr_t)g2h_untagged(guest_start); uintptr_t host_last = (uintptr_t)g2h_untagged(guest_end - 1); +#ifdef TARGET_X86_64 + /* + * Because of the extremely high position of the page within the guest + * virtual address space, this is not backed by host memory at all. + * Therefore the loop below would fail. This is the only instance + * of not having host backing memory. + */ + if (guest_start == TARGET_VSYSCALL_PAGE) { + return open_self_maps_3(opaque, guest_start, guest_end, flags); + } +#endif + while (1) { IntervalTreeNode *n = interval_tree_iter_first(d->host_maps, host_start, host_start);