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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS 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 8C174C10F0E for ; Mon, 15 Apr 2019 16:44:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F8DF21904 for ; Mon, 15 Apr 2019 16:44:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727456AbfDOQoL (ORCPT ); Mon, 15 Apr 2019 12:44:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59826 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727164AbfDOQoL (ORCPT ); Mon, 15 Apr 2019 12:44:11 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DF651C0842AF; Mon, 15 Apr 2019 16:44:10 +0000 (UTC) Received: from gondolin (unknown [10.40.205.58]) by smtp.corp.redhat.com (Postfix) with ESMTP id A5C725B680; Mon, 15 Apr 2019 16:44:03 +0000 (UTC) Date: Mon, 15 Apr 2019 18:43:59 +0200 From: Cornelia Huck To: Halil Pasic , Eric Farman , Farhan Ali , Pierre Morel Cc: linux-s390@vger.kernel.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, qemu-s390x@nongnu.org, Alex Williamson Subject: Re: [PATCH v4 0/6] vfio-ccw: support hsch/csch (kernel part) Message-ID: <20190415184359.452613ae.cohuck@redhat.com> In-Reply-To: <20190301093902.27799-1-cohuck@redhat.com> References: <20190301093902.27799-1-cohuck@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 15 Apr 2019 16:44:11 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 1 Mar 2019 10:38:56 +0100 Cornelia Huck wrote: > [This is the Linux kernel part, git tree is available at > https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw.git vfio-ccw-eagain-caps-v3 > > The companion QEMU patches are available at > https://github.com/cohuck/qemu vfio-ccw-caps] > > Currently, vfio-ccw only relays START SUBCHANNEL requests to the real > device. This tends to work well for the most common 'good path' scenarios; > however, as we emulate {HALT,CLEAR} SUBCHANNEL in QEMU, things like > clearing pending requests at the device is currently not supported. > This may be a problem for e.g. error recovery. > > This patch series introduces capabilities (similar to what vfio-pci uses) > and exposes a new async region for handling hsch/csch. > > Lightly tested (I can interact with a dasd as before, and reserve/release > seems to work well.) Not sure if there is a better way to test this, ideas > welcome. > > Changes v3->v4: > - shrunk the capability offset, we don't need to accommodate as much as pci > - make checks in patch 1 more consistent and less buggy > - rebased on top of my current vfio-ccw branch > > Changes v2->v3: > - Unb0rked patch 1, improved scope > - Split out the new mutex from patch 2 into new patch 3; added missing > locking and hopefully improved description > - Patch 2 now reworks the state handling by splitting the BUSY state > into CP_PROCESSING and CP_PENDING > - Patches 3 and 5 adapted on top of the reworked patches; hsch/csch > are allowed in CP_PENDING, but not in CP_PROCESSING (did not add > any R-b due to that) > - Added missing free in patch 5 > - Probably some small changes I forgot to note down > > Changes v1->v2: > - New patch 1: make it safe to use the cp accessors at any time; this > should avoid problems with unsolicited interrupt handling > - New patch 2: handle concurrent accesses to the io region; the idea is > to return -EAGAIN to userspace more often (so it can simply retry) > - also handle concurrent accesses to the async io region > - change VFIO_REGION_TYPE_CCW > - merge events for halt and clear to a single async event; this turned out > to make the code quite a bit simpler > - probably some small changes I forgot to note down > > Cornelia Huck (6): > vfio-ccw: make it safe to access channel programs > vfio-ccw: rework ssch state handling > vfio-ccw: protect the I/O region > vfio-ccw: add capabilities chain > s390/cio: export hsch to modules > vfio-ccw: add handling for async channel instructions > > drivers/s390/cio/Makefile | 3 +- > drivers/s390/cio/ioasm.c | 1 + > drivers/s390/cio/vfio_ccw_async.c | 88 ++++++++++++ > drivers/s390/cio/vfio_ccw_cp.c | 21 ++- > drivers/s390/cio/vfio_ccw_cp.h | 2 + > drivers/s390/cio/vfio_ccw_drv.c | 57 ++++++-- > drivers/s390/cio/vfio_ccw_fsm.c | 143 +++++++++++++++++- > drivers/s390/cio/vfio_ccw_ops.c | 215 +++++++++++++++++++++++----- > drivers/s390/cio/vfio_ccw_private.h | 48 ++++++- > include/uapi/linux/vfio.h | 4 + > include/uapi/linux/vfio_ccw.h | 12 ++ > 11 files changed, 537 insertions(+), 57 deletions(-) > create mode 100644 drivers/s390/cio/vfio_ccw_async.c > Queued (with the touchups discussed in the thread) to the vfio-ccw branch on kernel.org.