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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B337FC433EF for ; Mon, 18 Apr 2022 12:32:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238930AbiDRMfY (ORCPT ); Mon, 18 Apr 2022 08:35:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239921AbiDRM3I (ORCPT ); Mon, 18 Apr 2022 08:29:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2E4622BE5; Mon, 18 Apr 2022 05:22:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8B443B80EDC; Mon, 18 Apr 2022 12:22:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0633C385A7; Mon, 18 Apr 2022 12:22:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650284571; bh=9WpKRmzPIMz90Vitck4aKghxMNPz4j5Xq4Pusf3jXaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mQflNXoYbWjM0WVmtL5zk0U3GzgYDXe1ltxdvMiDPtOALYF86WAa6qJU4RWW/91u9 0t5xuil+KlWA91/iUfgFlvghY4ipbtYltjKzFzdookuliJORgQTuP0QBVNJB3Ef1XS uwfJ7/fvy5Jj2AegJ7MKH4DU9Opxe3s9574BCv60= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Boqun Feng , Michael Kelley , Wei Liu , Sasha Levin Subject: [PATCH 5.17 158/219] Drivers: hv: balloon: Disable balloon and hot-add accordingly Date: Mon, 18 Apr 2022 14:12:07 +0200 Message-Id: <20220418121211.307137631@linuxfoundation.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220418121203.462784814@linuxfoundation.org> References: <20220418121203.462784814@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Boqun Feng [ Upstream commit be5802795cf8d0b881745fa9ba7790293b382280 ] Currently there are known potential issues for balloon and hot-add on ARM64: * Unballoon requests from Hyper-V should only unballoon ranges that are guest page size aligned, otherwise guests cannot handle because it's impossible to partially free a page. This is a problem when guest page size > 4096 bytes. * Memory hot-add requests from Hyper-V should provide the NUMA node id of the added ranges or ARM64 should have a functional memory_add_physaddr_to_nid(), otherwise the node id is missing for add_memory(). These issues require discussions on design and implementation. In the meanwhile, post_status() is working and essential to guest monitoring. Therefore instead of disabling the entire hv_balloon driver, the ballooning (when page size > 4096 bytes) and hot-add are disabled accordingly for now. Once the issues are fixed, they can be re-enable in these cases. Signed-off-by: Boqun Feng Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220325023212.1570049-3-boqun.feng@gmail.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- drivers/hv/hv_balloon.c | 36 ++++++++++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index 439f99b8b5de..3cf334c46c31 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1653,6 +1653,38 @@ static void disable_page_reporting(void) } } +static int ballooning_enabled(void) +{ + /* + * Disable ballooning if the page size is not 4k (HV_HYP_PAGE_SIZE), + * since currently it's unclear to us whether an unballoon request can + * make sure all page ranges are guest page size aligned. + */ + if (PAGE_SIZE != HV_HYP_PAGE_SIZE) { + pr_info("Ballooning disabled because page size is not 4096 bytes\n"); + return 0; + } + + return 1; +} + +static int hot_add_enabled(void) +{ + /* + * Disable hot add on ARM64, because we currently rely on + * memory_add_physaddr_to_nid() to get a node id of a hot add range, + * however ARM64's memory_add_physaddr_to_nid() always return 0 and + * DM_MEM_HOT_ADD_REQUEST doesn't have the NUMA node information for + * add_memory(). + */ + if (IS_ENABLED(CONFIG_ARM64)) { + pr_info("Memory hot add disabled on ARM64\n"); + return 0; + } + + return 1; +} + static int balloon_connect_vsp(struct hv_device *dev) { struct dm_version_request version_req; @@ -1724,8 +1756,8 @@ static int balloon_connect_vsp(struct hv_device *dev) * currently still requires the bits to be set, so we have to add code * to fail the host's hot-add and balloon up/down requests, if any. */ - cap_msg.caps.cap_bits.balloon = 1; - cap_msg.caps.cap_bits.hot_add = 1; + cap_msg.caps.cap_bits.balloon = ballooning_enabled(); + cap_msg.caps.cap_bits.hot_add = hot_add_enabled(); /* * Specify our alignment requirements as it relates -- 2.35.1