Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755952AbbFRPX5 (ORCPT ); Thu, 18 Jun 2015 11:23:57 -0400 Received: from mail-qc0-f169.google.com ([209.85.216.169]:34392 "EHLO mail-qc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755882AbbFRPXt (ORCPT ); Thu, 18 Jun 2015 11:23:49 -0400 MIME-Version: 1.0 X-Originating-IP: [80.15.154.113] In-Reply-To: <1434580294.5628.135.camel@redhat.com> References: <1434359385-19916-1-git-send-email-eric.auger@linaro.org> <1434580294.5628.135.camel@redhat.com> Date: Thu, 18 Jun 2015 17:23:48 +0200 Message-ID: Subject: Re: [PATCH v4 0/4] VFIO platform reset From: Baptiste Reynal To: Alex Williamson Cc: Eric Auger , eric.auger@st.com, "moderated list:ARM SMMU DRIVER" , open list , patches@linaro.org, Christoffer Dall , Christian Pinto , Daniel Raho Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4956 Lines: 127 Hello everyone, I tested and reviewed the patches, everything's fine for me. I agree to be maintainer of vfio platform drivers, though I don't think the volume of patches about VFIO will justify a new mailing list. Regards, Baptiste On Thu, Jun 18, 2015 at 12:31 AM, Alex Williamson wrote: > On Mon, 2015-06-15 at 11:09 +0200, Eric Auger wrote: >> In situations where the userspace driver is stopped abnormally and the >> VFIO platform device is released, the assigned HW device currently is >> left running. As a consequence the HW device might continue issuing IRQs >> and performing DMA accesses. >> >> On release, no physical IRQ handler is setup anymore. Also the DMA buffers >> are unmapped leading to IOMMU aborts. So there is no serious consequence. >> >> However when assigning that HW device again to another userspace driver, >> this latter might face some unexpected IRQs and DMA accesses, which are >> the result of the previous assignment. >> >> In virtualization use-case, a VM newly granted with that HW device may be >> impacted by the assignment of that device to a previous VM: >> - IRQs may be injected very early when booting the new guest, even before >> the guest driver has initialized leading to possible driver state >> inconsistency. >> - DMA accesses may hit the newly mapped VM address space at addresses that >> may jeopardize the integrity of the newly installed VM. >> >> Obviously the criticity depends on the assigned HW device. >> >> As opposed to PCI, there is no standard mechanism to reset the platform >> device. >> >> This series proposes to implement device specific reset functions in >> separate in-kernel vfio reset modules. The vfio-platform driver holds >> a whitelist of implemented triplets (compat string, module name, >> reset function name). When the vfio-platform driver is probed it identifies >> the fellow reset module/function matching the compat string of the >> device, if any, and forces the load of this reset module. >> >> A first reset module is provided: the vfio-platform-calxedaxgmac >> module which implements a basic reset for the Calxeda xgmac. >> >> The series can be found at >> https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.1-rc8-reset-v4 >> >> History: >> v3 -> v4: >> - fix the commit message of "VFIO: platform: add reset struct and lookup table" > > Baptiste, > > Any comments? Should we also add something like this to MAINTAINERS > before we go much further? > > diff --git a/MAINTAINERS b/MAINTAINERS > index d8afd29..c6bf7f6 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -10545,6 +10545,12 @@ F: drivers/vfio/ > F: include/linux/vfio.h > F: include/uapi/linux/vfio.h > > +VFIO PLATFORM DRIVER > +M: Baptiste Reynal > +L: kvm@vger.kernel.org > +S: Maintained > +F: drivers/vfio/platform/ > + > VIDEOBUF2 FRAMEWORK > M: Pawel Osciak > M: Marek Szyprowski > > I'm not sure what you want to be the primary list, maybe it's time to > ask for a vfio list. Thanks, > Alex > >> >> v2 -> v3: >> - remove void module_init/exit functions in calxeda reset module >> - remove enum vfio_platform_reset_type >> - for reset lookup, use ARRAY_SIZE >> - in reset put use symbol_put_addr >> >> v1 -> v2: >> - much simplified compared to v1 although principle of external modules is >> kept: removed mechanism of dynamic registration of reset functions >> - list is replaced by whitelist lookup table >> - name of the reset function also stored in the lookup table >> - autoload of reset modules >> >> RFC -> PATCH v1: >> - solution now based on a lookup list instead of specialized driver >> >> >> Eric Auger (4): >> VFIO: platform: add reset struct and lookup table >> VFIO: platform: add reset callback >> VFIO: platform: populate the reset function on probe >> VFIO: platform: Calxeda xgmac reset module >> >> drivers/vfio/platform/Kconfig | 2 + >> drivers/vfio/platform/Makefile | 2 + >> drivers/vfio/platform/reset/Kconfig | 7 ++ >> drivers/vfio/platform/reset/Makefile | 5 ++ >> .../platform/reset/vfio_platform_calxedaxgmac.c | 86 ++++++++++++++++++++++ >> drivers/vfio/platform/vfio_platform_common.c | 60 ++++++++++++++- >> drivers/vfio/platform/vfio_platform_private.h | 7 ++ >> 7 files changed, 166 insertions(+), 3 deletions(-) >> create mode 100644 drivers/vfio/platform/reset/Kconfig >> create mode 100644 drivers/vfio/platform/reset/Makefile >> create mode 100644 drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c >> > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/