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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4888DC56202 for ; Thu, 22 Oct 2020 07:42:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD9862245F for ; Thu, 22 Oct 2020 07:42:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="atQVgREl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2508775AbgJVHm1 (ORCPT ); Thu, 22 Oct 2020 03:42:27 -0400 Received: from mx2.suse.de ([195.135.220.15]:35524 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2507030AbgJVHm1 (ORCPT ); Thu, 22 Oct 2020 03:42:27 -0400 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=1603352546; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xSsu2Z5Xpwi6tRqum0tsNqNsbAp7L8TAp9ugr1gvsVI=; b=atQVgRElJPObBm4D7xYVyo/SuLwtBvhCQM9dSvPAK4KyHUJGtLTLR/ibBuL5cHA1w1q9BD TsaPzGWVrDRKrB/bssKNhDFnxlZJ5vs6T7Z0NsBy06HFiVay+eoJpwM7REhV/VPwOYQbl7 rhiGlLE8UurIByn89SWD+6pLMzqgBUk= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3E5C2B1A3; Thu, 22 Oct 2020 07:42:26 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Boris Ostrovsky , Stefano Stabellini , Jan Beulich Subject: [PATCH 4/5] xen/events: unmask a fifo event channel only if it was masked Date: Thu, 22 Oct 2020 09:42:13 +0200 Message-Id: <20201022074214.21693-5-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201022074214.21693-1-jgross@suse.com> References: <20201022074214.21693-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Unmasking an event channel with fifo events channels being used can require a hypercall to be made, so try to avoid that by checking whether the event channel was really masked. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross --- drivers/xen/events/events_fifo.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c index 243e7b6d7b96..f60c5a9ec833 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -236,6 +236,9 @@ static bool clear_masked_cond(volatile event_word_t *word) w = *word; + if (!(w & (1 << EVTCHN_FIFO_MASKED))) + return true; + do { if (w & (1 << EVTCHN_FIFO_PENDING)) return false; -- 2.26.2