From nobody Tue Nov 11 08:31:26 2025 Delivered-To: importer@patchew.org Received-SPF: none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; spf=none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=none dis=none) header.from=intel.com ARC-Seal: i=1; a=rsa-sha256; t=1569426675; cv=none; d=zoho.com; s=zohoarc; b=N95ZjBOXODzNPEvyV0hOiuhH6JL4Zl1WTMc/luE6LBLRh0s+n7fmptaWUv7yhllhIY8wixQbR6nts8s8T5Hxve2LEsO6ifTyzpx5N4fg02pqWjzlyn8XIEHti+ylNgU/vN5EEGJVXr5npNe+voOvLzCMAuFX/1/QAxAxtUSQ8ag= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1569426675; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=40PP2YBwar68atnLs1eA00map5oQ/Ns04Fo1nVmQ+3c=; b=Z0UyhR2yBgDZ3xOXDU5GlGX60zlZUJjD8mwKr98DcwFFq7JGxF2psuNvfYT3rFyBgXbbH9XWV7FmBjxgaDzRGWTH4qD5yBzwkmCDB9JWh/PsJc9nugWwizi53kVvSqVH1c8r+wdTx6lPdTHHEXjspHJig8v1OoWQ5li5P9BCTa8= ARC-Authentication-Results: i=1; mx.zoho.com; spf=none (zoho.com: 192.237.175.120 is neither permitted nor denied by domain of lists.xenproject.org) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 156942667515543.41335157438243; Wed, 25 Sep 2019 08:51:15 -0700 (PDT) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iD9Yn-0002DT-0L; Wed, 25 Sep 2019 15:50:33 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iD9Yl-0002CM-Of for xen-devel@lists.xenproject.org; Wed, 25 Sep 2019 15:50:31 +0000 Received: from mga12.intel.com (unknown [192.55.52.136]) by localhost (Halon) with ESMTPS id 14936df0-dfac-11e9-8628-bc764e2007e4; Wed, 25 Sep 2019 15:49:38 +0000 (UTC) Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Sep 2019 08:49:38 -0700 Received: from tlengyel-mobl2.amr.corp.intel.com (HELO localhost.localdomain) ([10.252.129.153]) by orsmga006.jf.intel.com with ESMTP; 25 Sep 2019 08:49:37 -0700 X-Inumbo-ID: 14936df0-dfac-11e9-8628-bc764e2007e4 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,548,1559545200"; d="scan'208";a="193812709" From: Tamas K Lengyel To: xen-devel@lists.xenproject.org Date: Wed, 25 Sep 2019 08:48:54 -0700 Message-Id: X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Subject: [Xen-devel] [RFC PATCH for-next 16/18] x86/mem_sharing: check page type count earlier X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Tamas K Lengyel , Tamas K Lengyel , Wei Liu , George Dunlap , Andrew Cooper , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" --- xen/arch/x86/mm/mem_sharing.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c index d35b7eb138..f54969bcad 100644 --- a/xen/arch/x86/mm/mem_sharing.c +++ b/xen/arch/x86/mm/mem_sharing.c @@ -649,19 +649,18 @@ static int page_make_sharable(struct domain *d, return -EBUSY; } =20 - /* Change page type and count atomically */ - if ( !get_page_and_type(page, d, PGT_shared_page) ) + /* Check if page is already typed and bail early if it is */ + if ( (page->u.inuse.type_info & PGT_count_mask) !=3D 1 ) { spin_unlock(&d->page_alloc_lock); - return -EINVAL; + return -EEXIST; } =20 - /* Check it wasn't already sharable and undo if it was */ - if ( (page->u.inuse.type_info & PGT_count_mask) !=3D 1 ) + /* Change page type and count atomically */ + if ( !get_page_and_type(page, d, PGT_shared_page) ) { spin_unlock(&d->page_alloc_lock); - put_page_and_type(page); - return -EEXIST; + return -EINVAL; } =20 /* --=20 2.20.1 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel