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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 46B91C4338F for ; Tue, 27 Jul 2021 06:04:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AC1460FE4 for ; Tue, 27 Jul 2021 06:04:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235588AbhG0GE3 (ORCPT ); Tue, 27 Jul 2021 02:04:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46000 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235776AbhG0GEZ (ORCPT ); Tue, 27 Jul 2021 02:04:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627365865; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=M/b1lAkx30VoYdGCq4rZeKdpDBbSV2MTh3TK7cbWaIY=; b=D7C+SJC1dQTY2D7kRXW3lL2PMfp0Dt/xx6PmS5q0c6uSCYcclS8SM/gfqlw0d3naDaB2qk OP2+wMEN1V9QBVQ6hlSKv4UZMbyGKDeoUDTGRee6k6BCD8uvJtn2qtSZ09RcPI6JFNsvUl d4tBMUOE0sT3b7cJyB0pTn4t19fw7iA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-234-de9TROPlNBiBNCLvs915UQ-1; Tue, 27 Jul 2021 02:04:23 -0400 X-MC-Unique: de9TROPlNBiBNCLvs915UQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E7D5B801AE7; Tue, 27 Jul 2021 06:04:21 +0000 (UTC) Received: from localhost (unknown [10.39.192.46]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 91390687D5; Tue, 27 Jul 2021 06:04:17 +0000 (UTC) From: Cornelia Huck To: Alex Williamson , Jason Gunthorpe Cc: Christoph Hellwig , Kirti Wankhede , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] vfio/mdev: don't warn if ->request is not set In-Reply-To: <20210726172831.3a7978fd.alex.williamson@redhat.com> Organization: Red Hat GmbH References: <20210726143524.155779-1-hch@lst.de> <20210726143524.155779-3-hch@lst.de> <87zgu93sxz.fsf@redhat.com> <20210726230906.GD1721383@nvidia.com> <20210726172831.3a7978fd.alex.williamson@redhat.com> User-Agent: Notmuch/0.32.1 (https://notmuchmail.org) Date: Tue, 27 Jul 2021 08:04:16 +0200 Message-ID: <87wnpc47j3.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 26 2021, Alex Williamson wrote: > On Mon, 26 Jul 2021 20:09:06 -0300 > Jason Gunthorpe wrote: > >> On Mon, Jul 26, 2021 at 07:07:04PM +0200, Cornelia Huck wrote: >> >> > But I wonder why nobody else implements this? Lack of surprise removal? >> >> The only implementation triggers an eventfd that seems to be the same >> eventfd as the interrupt.. >> >> Do you know how this works in userspace? I'm surprised that the >> interrupt eventfd can trigger an observation that the kernel driver >> wants to be unplugged? > > I think we're talking about ccw, but I see QEMU registering separate > eventfds for each of the 3 IRQ indexes and the mdev driver specifically > triggering the req_trigger...? Thanks, > > Alex Exactly, ccw has a trigger for normal I/O interrupts, CRW (machine checks), and this one.