Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754096AbbH0NFy (ORCPT ); Thu, 27 Aug 2015 09:05:54 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:38294 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752753AbbH0NFx (ORCPT ); Thu, 27 Aug 2015 09:05:53 -0400 Message-ID: <55DF0AFD.7020806@linaro.org> Date: Thu, 27 Aug 2015 15:05:01 +0200 From: Eric Auger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: eric.auger@st.com, linux-arm-kernel@lists.infradead.org, b.reynal@virtualopensystems.com, alex.williamson@redhat.com CC: linux-kernel@vger.kernel.org, patches@linaro.org, christoffer.dall@linaro.org Subject: Re: [PATCH v4 0/4] VFIO platform reset References: <1434359385-19916-1-git-send-email-eric.auger@linaro.org> <55DEFAFE.3000909@linaro.org> In-Reply-To: <55DEFAFE.3000909@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4358 Lines: 109 Dear all, Please ignore this email. It is a reply to a wrong thread (was targeting [PATCH v4 0/4] irqchip: GICv2/v3: Add support for irq_vcpu_affinity). My apologies Best Regards Eric On 08/27/2015 01:56 PM, Eric Auger wrote: > Hi Marc, > > I tested the series on Calxeda Midway with VFIO use case. Also reviewed > it again without finding anything new. > > Tested-by: Eric Auger > Reviewed-by: Eric Auger > > Best Regards > > Eric > > On 06/15/2015 11:09 AM, 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" >> >> 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/