From nobody Fri May 3 19:49:26 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=quarantine dis=none) header.from=suse.com ARC-Seal: i=1; a=rsa-sha256; t=1618479710; cv=none; d=zohomail.com; s=zohoarc; b=RtltRZ794BdhfVzcln47WwFCVPErPXhnZ4vq5YvJ6GCB/O+mOBavHQMZRYZRdscLJ5f4r1wfMy9cCKZI0k4p7zEyOOImANe2uRSzckGjCOOmtDqbjXzRFFoepoZ0lN/A79iXfMol3c/xIfEnFwKkI3ISa189WsUgoFM0A072jxM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1618479710; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=DJ55pGTV1Ycmrz3jU7NCoDWaPsEth8XN2XbbDgtsXps=; b=Nx1747riEq+uYVMQKaUOMJ7o710tAft8cCq7a6vVWt05ZxMTNju92nUXqHBaWrhj52tS/JuzYVfn0mxsdwA+l73kDlRRgB/ze73guzUkl1eSzUeIaROoWcyt+Va3SrcEelwW1HBrZrm6iAai6QxdiMUa3LruE7wKUnJIOZVa89M= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=quarantine 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 1618479710991798.8489371858293; Thu, 15 Apr 2021 02:41:50 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.110976.212070 (Exim 4.92) (envelope-from ) id 1lWyV9-0001Wq-UG; Thu, 15 Apr 2021 09:41:31 +0000 Received: by outflank-mailman (output) from mailman id 110976.212070; Thu, 15 Apr 2021 09:41:31 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWyV9-0001Wj-RS; Thu, 15 Apr 2021 09:41:31 +0000 Received: by outflank-mailman (input) for mailman id 110976; Thu, 15 Apr 2021 09:41:31 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lWyV9-0001We-6G for xen-devel@lists.xenproject.org; Thu, 15 Apr 2021 09:41:31 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 87f9c48e-6b83-45f4-b161-bd061daff44d; Thu, 15 Apr 2021 09:41:30 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 38852AC87; Thu, 15 Apr 2021 09:41:29 +0000 (UTC) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 87f9c48e-6b83-45f4-b161-bd061daff44d X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1618479689; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=DJ55pGTV1Ycmrz3jU7NCoDWaPsEth8XN2XbbDgtsXps=; b=VMdxY6pVbLmlOd8UNH5jMmtZrZlbg6cpeJARtuShvfJ64cctg7gEptccF9PlI13E7QaDjo jBTocpRsma0J43aTzw7uptnEY0wqlfflfaqy1YX2XQIwfnrc9hMCjen4r4ieeNbzs6+KDZ MQl7WfFmVT2ovdTRtRoeKxqZPc8X+Ho= From: Jan Beulich Subject: [PATCH v3] gnttab: defer allocation of status frame tracking array To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Wei Liu Message-ID: Date: Thu, 15 Apr 2021 11:41:29 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) Content-Type: text/plain; charset="utf-8" This array can be large when many grant frames are permitted; avoid allocating it when it's not going to be used anyway, by doing this only in gnttab_populate_status_frames(). Signed-off-by: Jan Beulich --- v3: Drop smp_wmb(). Re-base. v2: Defer allocation to when a domain actually switches to the v2 grant API. --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -1747,6 +1747,17 @@ gnttab_populate_status_frames(struct dom /* Make sure, prior version checks are architectural visible */ block_speculation(); =20 + if ( gt->status =3D=3D ZERO_BLOCK_PTR ) + { + gt->status =3D xzalloc_array(grant_status_t *, + grant_to_status_frames(gt->max_grant_fr= ames)); + if ( !gt->status ) + { + gt->status =3D ZERO_BLOCK_PTR; + return -ENOMEM; + } + } + for ( i =3D nr_status_frames(gt); i < req_status_frames; i++ ) { if ( (gt->status[i] =3D alloc_xenheap_page()) =3D=3D NULL ) @@ -1767,18 +1778,23 @@ status_alloc_failed: free_xenheap_page(gt->status[i]); gt->status[i] =3D NULL; } + if ( !nr_status_frames(gt) ) + { + xfree(gt->status); + gt->status =3D ZERO_BLOCK_PTR; + } return -ENOMEM; } =20 static int gnttab_unpopulate_status_frames(struct domain *d, struct grant_table *gt) { - unsigned int i; + unsigned int i, n =3D nr_status_frames(gt); =20 /* Make sure, prior version checks are architectural visible */ block_speculation(); =20 - for ( i =3D 0; i < nr_status_frames(gt); i++ ) + for ( i =3D 0; i < n; i++ ) { struct page_info *pg =3D virt_to_page(gt->status[i]); gfn_t gfn =3D gnttab_get_frame_gfn(gt, true, i); @@ -1833,12 +1849,11 @@ gnttab_unpopulate_status_frames(struct d page_set_owner(pg, NULL); } =20 - for ( i =3D 0; i < nr_status_frames(gt); i++ ) - { - free_xenheap_page(gt->status[i]); - gt->status[i] =3D NULL; - } gt->nr_status_frames =3D 0; + for ( i =3D 0; i < n; i++ ) + free_xenheap_page(gt->status[i]); + xfree(gt->status); + gt->status =3D ZERO_BLOCK_PTR; =20 return 0; } @@ -1969,11 +1984,11 @@ int grant_table_init(struct domain *d, i if ( gt->shared_raw =3D=3D NULL ) goto out; =20 - /* Status pages for grant table - for version 2 */ - gt->status =3D xzalloc_array(grant_status_t *, - grant_to_status_frames(gt->max_grant_frames= )); - if ( gt->status =3D=3D NULL ) - goto out; + /* + * Status page tracking array for v2 gets allocated on demand. But don= 't + * leave a NULL pointer there. + */ + gt->status =3D ZERO_BLOCK_PTR; =20 grant_write_lock(gt); =20 @@ -4047,11 +4062,12 @@ int gnttab_acquire_resource( if ( gt->gt_version !=3D 2 ) break; =20 + rc =3D gnttab_get_status_frame_mfn(d, final_frame, &tmp); + /* Check that void ** is a suitable representation for gt->status.= */ BUILD_BUG_ON(!__builtin_types_compatible_p( typeof(gt->status), grant_status_t **)); vaddrs =3D (void **)gt->status; - rc =3D gnttab_get_status_frame_mfn(d, final_frame, &tmp); break; } =20