From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423520AbcFMNUo (ORCPT ); Mon, 13 Jun 2016 09:20:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50488 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423115AbcFMNUm (ORCPT ); Mon, 13 Jun 2016 09:20:42 -0400 Subject: Re: [PATCH V3] vfio: platform: support No-IOMMU mode To: Peng Fan , eric.auger@linaro.org, b.reynal@virtualopensystems.com, alex.williamson@redhat.com References: <1463996850-12559-1-git-send-email-van.freenix@gmail.com> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org From: Auger Eric Message-ID: Date: Mon, 13 Jun 2016 15:20:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <1463996850-12559-1-git-send-email-van.freenix@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 13 Jun 2016 13:20:42 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peng Le 23/05/2016 à 11:47, Peng Fan a écrit : > The vfio No-IOMMU mode was supported by this > 'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")', > but it only support vfio-pci. > > Using vfio_iommu_group_get/put, but not iommu_group_get/put, > the platform devices can be exposed to userspace with > CONFIG_VFIO_NOIOMMU and the "enable_unsafe_noiommu_mode" > option enabled. > > From 'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")', > "This should make it very clear that this mode is not safe. > Additionally, CAP_SYS_RAWIO privileges are necessary to work > with groups and containers using this mode. Groups making > use of this support are named /dev/vfio/noiommu-$GROUP and > can only make use of the special VFIO_NOIOMMU_IOMMU for the > container. Use of this mode, specifically binding a device > without a native IOMMU group to a VFIO bus driver will taint > the kernel and should therefore not be considered supported." > > Signed-off-by: Peng Fan > Cc: Eric Auger > Cc: Baptiste Reynal > Cc: Alex Williamson Looks good to me. Reviewed-by: Eric Auger as a reminder may conflict with HiDma ACPI reset series. Best Regards Eric > --- > > V3: > The platform device can be programmed to do DMA without > caring out mmap + VFIO_IOMMU_MAP_DMA which are not > support by noiommu. So drop the last sentence of commit log > in V2, which is misleading. > > V2: > Rename subject to support No-IOMMU > Add more commit log. > I wrote a simple program following this > https://github.com/virtualopensystems/vfio-host-test/blob/master/src_test/vfio_device_test.c > ,no dma support. The device's register can be > accessed in userspace using command './vfio_dev_test 30b60000.usdhc 0 1 platform' > > drivers/vfio/platform/vfio_platform_common.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c > index e65b142..993b2f9 100644 > --- a/drivers/vfio/platform/vfio_platform_common.c > +++ b/drivers/vfio/platform/vfio_platform_common.c > @@ -561,7 +561,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, > > vdev->device = dev; > > - group = iommu_group_get(dev); > + group = vfio_iommu_group_get(dev); > if (!group) { > pr_err("VFIO: No IOMMU group for device %s\n", vdev->name); > return -EINVAL; > @@ -569,7 +569,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, > > ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev); > if (ret) { > - iommu_group_put(group); > + vfio_iommu_group_put(group, dev); > return ret; > } > > @@ -589,7 +589,7 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev) > > if (vdev) { > vfio_platform_put_reset(vdev); > - iommu_group_put(dev->iommu_group); > + vfio_iommu_group_put(dev->iommu_group, dev); > } > > return vdev; >