From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=0.4 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 8F1C5C433EF for ; Wed, 13 Jun 2018 18:19:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DA2D208C3 for ; Wed, 13 Jun 2018 18:19:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4DA2D208C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=vmware.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935703AbeFMSTx (ORCPT ); Wed, 13 Jun 2018 14:19:53 -0400 Received: from ex13-edg-ou-002.vmware.com ([208.91.0.190]:19857 "EHLO EX13-EDG-OU-002.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935478AbeFMSS4 (ORCPT ); Wed, 13 Jun 2018 14:18:56 -0400 Received: from sc9-mailhost3.vmware.com (10.113.161.73) by EX13-EDG-OU-002.vmware.com (10.113.208.156) with Microsoft SMTP Server id 15.0.1156.6; Wed, 13 Jun 2018 11:18:50 -0700 Received: from sc2-haas01-esx0118.eng.vmware.com (sc2-haas01-esx0118.eng.vmware.com [10.172.44.118]) by sc9-mailhost3.vmware.com (Postfix) with ESMTP id 8F355409BF; Wed, 13 Jun 2018 11:18:54 -0700 (PDT) From: Nadav Amit To: Greg Kroah-Hartman CC: Xavier Deguillard , , Arnd Bergmann , Nadav Amit , Nadav Amit Subject: [PATCH 4/7] vmw_balloon: do not use 2MB without batching Date: Wed, 13 Jun 2018 04:03:56 -0700 Message-ID: <20180613110359.109033-5-namit@vmware.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180613110359.109033-1-namit@vmware.com> References: <20180613110359.109033-1-namit@vmware.com> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: None (EX13-EDG-OU-002.vmware.com: namit@vmware.com does not designate permitted sender hosts) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the hypervisor sets 2MB batching is on, while batching is cleared, the balloon code breaks. In this case the legacy mechanism is used with 2MB page. The VM would report a 2MB page is ballooned, and the hypervisor would only take the first 4KB. While the hypervisor should not report such settings, make the code more robust by not enabling 2MB support without batching. Reviewed-by: Xavier Deguillard Signed-off-by: Nadav Amit --- drivers/misc/vmw_balloon.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 496607a9046a..db3cf91a515d 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -339,7 +339,13 @@ static bool vmballoon_send_start(struct vmballoon *b, unsigned long req_caps) success = false; } - if (b->capabilities & VMW_BALLOON_BATCHED_2M_CMDS) + /* + * 2MB pages are only supported with batching. If batching is for some + * reason disabled, do not use 2MB pages, since otherwise the legacy + * mechanism is used with 2MB pages, causing a failure. + */ + if ((b->capabilities & VMW_BALLOON_BATCHED_2M_CMDS) && + (b->capabilities & VMW_BALLOON_BATCHED_CMDS)) b->supported_page_sizes = 2; else b->supported_page_sizes = 1; -- 2.17.0