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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42792 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kdWp4-0006Af-0L for qemu-devel@archiver.kernel.org; Fri, 13 Nov 2020 06:00:54 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:42508) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kdWo4-0005iu-7K for qemu-devel@nongnu.org; Fri, 13 Nov 2020 05:59:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:56716) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kdWo0-0002fe-W7 for qemu-devel@nongnu.org; Fri, 13 Nov 2020 05:59:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605265187; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mjOwi1gtfFaDSecHid7U/ROl8B6Gg/EZ0CZoJWOTc4Y=; b=CJwEcMaT01bDx6ZsQTquVHedQ3d0qHmK4Hd+lSeRf7WuRSTISn0BJ8r1dNHN1j6AhyJi9J 0UfIl7coVmnr0WYU/hkJJNJMrg44GjAW7NiXfQfJwH2sPUmmViKtxXe0fzTNyBNB4O0L2d 4ZlCaebd8oxIMOxz/fpklmCaZClmhXU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-30--Rm5cthqPG-wc9lTX9q9Gw-1; Fri, 13 Nov 2020 05:59:45 -0500 X-MC-Unique: -Rm5cthqPG-wc9lTX9q9Gw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 842FA188C13E for ; Fri, 13 Nov 2020 10:59:44 +0000 (UTC) Received: from work-vm (ovpn-114-160.ams2.redhat.com [10.36.114.160]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 608D75D9E8; Fri, 13 Nov 2020 10:59:43 +0000 (UTC) Date: Fri, 13 Nov 2020 10:59:40 +0000 From: "Dr. David Alan Gilbert" To: Markus Armbruster Subject: Re: [PATCH 4/6] migration: Check xbzrle-cache-size more carefully Message-ID: <20201113105940.GC3251@work-vm> References: <20201113065236.2644169-1-armbru@redhat.com> <20201113065236.2644169-5-armbru@redhat.com> MIME-Version: 1.0 In-Reply-To: <20201113065236.2644169-5-armbru@redhat.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/12 16:09:27 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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, DKIMWL_WL_HIGH=-0.001, 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 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Markus Armbruster (armbru@redhat.com) wrote: > migrate-set-parameters passes the size to xbzrle_cache_resize(). > xbzrle_cache_resize() checks it fits into size_t before it passes it > on to cache_init(). cache_init() checks it is a power of two no > smaller than @page_size. > > cache_init() is also called from xbzrle_init(), bypassing > xbzrle_cache_resize()'s check. > > Drop xbzrle_cache_resize()'s check, and check more carefully in > cache_init(). > > Signed-off-by: Markus Armbruster > --- > migration/page_cache.c | 15 ++++----------- > migration/ram.c | 7 ------- > 2 files changed, 4 insertions(+), 18 deletions(-) > > diff --git a/migration/page_cache.c b/migration/page_cache.c > index b384f265fb..e07f4ad1dc 100644 > --- a/migration/page_cache.c > +++ b/migration/page_cache.c > @@ -41,17 +41,10 @@ struct PageCache { > PageCache *cache_init(uint64_t new_size, size_t page_size, Error **errp) > { > int64_t i; > - size_t num_pages = new_size / page_size; > + uint64_t num_pages = new_size / page_size; > PageCache *cache; > > - if (new_size < page_size) { > - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", > - "is smaller than one target page size"); > - return NULL; > - } > - > - /* round down to the nearest power of 2 */ > - if (!is_power_of_2(num_pages)) { > + if (num_pages != (size_t)num_pages || !is_power_of_2(num_pages)) { > error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", > "is not a power of two number of pages"); That error message is now wrong since it includes a whole bunch of reasons. Also, the comparison is now on the divided num_pages, it's not that obvious to me that checking the num_pages makes sense in acomparison to checking the actual cache size. (Arguably the check should also happen in migrate_params_test_apply) Dave > return NULL; > @@ -71,8 +64,8 @@ PageCache *cache_init(uint64_t new_size, size_t page_size, Error **errp) > trace_migration_pagecache_init(cache->max_num_items); > > /* We prefer not to abort if there is no memory */ > - cache->page_cache = g_try_malloc((cache->max_num_items) * > - sizeof(*cache->page_cache)); > + cache->page_cache = g_try_malloc_n(cache->max_num_items, > + sizeof(*cache->page_cache)); > if (!cache->page_cache) { > error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", > "Failed to allocate page cache"); > diff --git a/migration/ram.c b/migration/ram.c > index a84425d04f..d632ae694c 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -131,13 +131,6 @@ int xbzrle_cache_resize(uint64_t new_size, Error **errp) > PageCache *new_cache; > int64_t ret = 0; > > - /* Check for truncation */ > - if (new_size != (size_t)new_size) { > - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", > - "exceeding address space"); > - return -1; > - } > - > if (new_size == migrate_xbzrle_cache_size()) { > /* nothing to do */ > return 0; > -- > 2.26.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK