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=-10.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 7607CC433DB for ; Mon, 8 Feb 2021 10:34:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2FC0564E8C for ; Mon, 8 Feb 2021 10:34:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232037AbhBHKds (ORCPT ); Mon, 8 Feb 2021 05:33:48 -0500 Received: from esa2.hc3370-68.iphmx.com ([216.71.145.153]:48512 "EHLO esa2.hc3370-68.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232181AbhBHKWU (ORCPT ); Mon, 8 Feb 2021 05:22:20 -0500 X-Greylist: delayed 334 seconds by postgrey-1.27 at vger.kernel.org; Mon, 08 Feb 2021 05:22:17 EST DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1612779740; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=qqXwtjOco8fjJeHnQYr5Tm8x0nM5NCab4a40inMqm1A=; b=fcTVzDBYpf2tKDB3IzCcNvCAf9qMNg9nBqGfbOGLQeRme9horfeefQk1 9EFGru3c9LRPAg4KiqqrnxGqOtx9gDk59fgAn2tiJ0o8r/bKWmTT05mfK l9qOvtlgnRsuMkAE5+3cOLJNdvwZ+PdopqZj2uT4frUDZeNuKZq6zb7dF A=; Authentication-Results: esa2.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: rjLiNJ3vCQ9cpicm4ICWdmqbU0Vr/mR7YGxVzAVJ52hyZBx42ePUyqcKVcg6h7iZihXAwtKnvk /u2ugcsHkCr2tjlPPtTnxOG0gr7hIogThvz1V16ht6iY6ej2VQBERCF/JonZUOAMxcv1kmMigu t848MnWL4C9XA83gbWwfXTwIC+UvubXumL2q3pImtIFTIMF3nv5XVgU+Y3eWieoOYu+wqvg7aw 5/aeHo7oBKNfyDvBwrXzr6XxnepobkJpK0X8OPTp9b8GRTuQ0FaGUL8wvw83yykXckovqWbTs8 NP0= X-SBRS: 5.1 X-MesageID: 36787092 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.81,161,1610427600"; d="scan'208";a="36787092" Subject: Re: [PATCH 2/7] xen/events: don't unmask an event channel when an eoi is pending To: Juergen Gross , , CC: Boris Ostrovsky , Stefano Stabellini , , Julien Grall References: <20210206104932.29064-1-jgross@suse.com> <20210206104932.29064-3-jgross@suse.com> From: Ross Lagerwall Message-ID: Date: Mon, 8 Feb 2021 10:15:31 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.2 MIME-Version: 1.0 In-Reply-To: <20210206104932.29064-3-jgross@suse.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-02-06 10:49, Juergen Gross wrote: > An event channel should be kept masked when an eoi is pending for it. > When being migrated to another cpu it might be unmasked, though. > > In order to avoid this keep two different flags for each event channel > to be able to distinguish "normal" masking/unmasking from eoi related > masking/unmasking. The event channel should only be able to generate > an interrupt if both flags are cleared. > > Cc: stable@vger.kernel.org > Fixes: 54c9de89895e0a36047 ("xen/events: add a new late EOI evtchn framework") > Reported-by: Julien Grall > Signed-off-by: Juergen Gross ...> +static void lateeoi_ack_dynirq(struct irq_data *data) > +{ > + struct irq_info *info = info_for_irq(data->irq); > + evtchn_port_t evtchn = info ? info->evtchn : 0; > + > + if (VALID_EVTCHN(evtchn)) { > + info->eoi_pending = true; > + mask_evtchn(evtchn); > + } > +} Doesn't this (and the one below) need a call to clear_evtchn() to actually ack the pending event? Otherwise I can't see what clears the pending bit. I tested out this patch but processes using the userspace evtchn device did not work very well without the clear_evtchn() call. Ross > + > +static void lateeoi_mask_ack_dynirq(struct irq_data *data) > +{ > + struct irq_info *info = info_for_irq(data->irq); > + evtchn_port_t evtchn = info ? info->evtchn : 0; > + > + if (VALID_EVTCHN(evtchn)) { > + info->masked = true; > + info->eoi_pending = true; > + mask_evtchn(evtchn); > + } > +} > +