From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Farman Subject: Re: [PATCH v3 0/6] vfio-ccw: support hsch/csch (kernel part) Date: Fri, 8 Feb 2019 16:19:58 -0500 Message-ID: <1981d9bc-e950-62ef-d2d2-66a17771c8f4@linux.ibm.com> References: <20190130132212.7376-1-cohuck@redhat.com> <20190206150016.6fdfaf8f.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190206150016.6fdfaf8f.cohuck@redhat.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel2=m.gmane.org@nongnu.org Sender: "Qemu-devel" List-Archive: List-Post: To: Cornelia Huck , Halil Pasic , Farhan Ali , Pierre Morel Cc: linux-s390@vger.kernel.org, qemu-s390x@nongnu.org, Alex Williamson , qemu-devel@nongnu.org, kvm@vger.kernel.org List-ID: On 02/06/2019 09:00 AM, Cornelia Huck wrote: > On Wed, 30 Jan 2019 14:22:06 +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 > > I've pushed out the changes I've made so far (patch 1) to > vfio-ccw-eagain-caps-v3.5. I'll wait a bit for more comments before > sending a new version. > Thanks for that branch... For patch 1 in v3.5: Reviewed-by: Eric Farman >> >> The companion QEMU patches are available at >> https://github.com/cohuck/qemu vfio-ccw-caps >> This is the previously posted v2 version, which should continue to work.] > > I would not mind if somebody looked at those as well :) Not precluding anyone else from doing so :) ... I'd planned on looking at them as I get into the meat of patches 4-6 on the kernel side, where the overlap occurs. I'm getting close. :) FWIW, I've been running with both series for the last week or two, along with some host kernel traces to prove things got executed the way I thought, and it's seemed to be working well. So that makes me optimistic for the later patches. - Eric > >> >> 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 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 | 20 ++- >> 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 | 210 +++++++++++++++++++++++----- >> drivers/s390/cio/vfio_ccw_private.h | 48 ++++++- >> include/uapi/linux/vfio.h | 4 + >> include/uapi/linux/vfio_ccw.h | 12 ++ >> 11 files changed, 531 insertions(+), 57 deletions(-) >> create mode 100644 drivers/s390/cio/vfio_ccw_async.c >> >