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 F0EC7C4363A for ; Thu, 22 Oct 2020 09:49:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E62D24196 for ; Thu, 22 Oct 2020 09:49:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="XdZFpfUX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2896150AbgJVJtM (ORCPT ); Thu, 22 Oct 2020 05:49:12 -0400 Received: from mx2.suse.de ([195.135.220.15]:48974 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2896143AbgJVJtM (ORCPT ); Thu, 22 Oct 2020 05:49:12 -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=1603360151; 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=YVuxwJ3hyt25tYMDo7KA9FGUbENDEaFuW9/mMP2hjWY=; b=XdZFpfUX5Q4edukPRqbno2sAVNX/9lStsFCY0SbUMIZdMDeuyPiBXOXTtEtl5tfur0ohB+ v75te7c9mliV8OqxcIfKDJgE5Igkrfgo8YRH5iJ8yl5l20L8mN4rIR4CY6qW1Sv+fYvd/3 q+PdCKHsYamkNp0VFS8CEvO750kZgLQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 000A5AE2B; Thu, 22 Oct 2020 09:49:10 +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 v2 4/5] xen/events: unmask a fifo event channel only if it was masked Date: Thu, 22 Oct 2020 11:49:06 +0200 Message-Id: <20201022094907.28560-5-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201022094907.28560-1-jgross@suse.com> References: <20201022094907.28560-1-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 Reviewed-by: Jan Beulich --- V2: - move test for already unmasked into loop (Jan Beulich) --- 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..b234f1766810 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -237,6 +237,9 @@ static bool clear_masked_cond(volatile event_word_t *word) w = *word; do { + if (!(w & (1 << EVTCHN_FIFO_MASKED))) + return true; + if (w & (1 << EVTCHN_FIFO_PENDING)) return false; -- 2.26.2