From 3af917713230c8a6c3431e60601f0c7ad72eceb6 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 24 Sep 2021 17:56:55 +0200 Subject: vfio: refactor noiommu group creation Split the actual noiommu group creation from vfio_iommu_group_get into a new helper, and open code the rest of vfio_iommu_group_get in its only caller. This creates an entirely separate and clear code path for the noiommu group creation. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20210924155705.4258-6-hch@lst.de Signed-off-by: Alex Williamson --- drivers/vfio/vfio.c | 104 ++++++++++++++++++++++++++-------------------------- 1 file changed, 52 insertions(+), 52 deletions(-) (limited to 'drivers/vfio/vfio.c') diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 2b2679c7126f..b1ed156adccd 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -169,50 +169,6 @@ static void vfio_release_device_set(struct vfio_device *device) xa_unlock(&vfio_device_set_xa); } -static struct iommu_group *vfio_iommu_group_get(struct device *dev) -{ - struct iommu_group *group; - int __maybe_unused ret; - - group = iommu_group_get(dev); - -#ifdef CONFIG_VFIO_NOIOMMU - /* - * With noiommu enabled, an IOMMU group will be created for a device - * that doesn't already have one and doesn't have an iommu_ops on their - * bus. We set iommudata simply to be able to identify these groups - * as special use and for reclamation later. - */ - if (group || !noiommu || iommu_present(dev->bus)) - return group; - - group = iommu_group_alloc(); - if (IS_ERR(group)) - return NULL; - - iommu_group_set_name(group, "vfio-noiommu"); - iommu_group_set_iommudata(group, &noiommu, NULL); - ret = iommu_group_add_device(group, dev); - if (ret) { - iommu_group_put(group); - return NULL; - } - - /* - * Where to taint? At this point we've added an IOMMU group for a - * device that is not backed by iommu_ops, therefore any iommu_ - * callback using iommu_ops can legitimately Oops. So, while we may - * be about to give a DMA capable device to a user without IOMMU - * protection, which is clearly taint-worthy, let's go ahead and do - * it here. - */ - add_taint(TAINT_USER, LOCKDEP_STILL_OK); - dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n"); -#endif - - return group; -} - #ifdef CONFIG_VFIO_NOIOMMU static void *vfio_noiommu_open(unsigned long arg) { @@ -823,12 +779,61 @@ void vfio_uninit_group_dev(struct vfio_device *device) } EXPORT_SYMBOL_GPL(vfio_uninit_group_dev); -struct vfio_group *vfio_group_find_or_alloc(struct device *dev) +#ifdef CONFIG_VFIO_NOIOMMU +static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev) { struct iommu_group *iommu_group; struct vfio_group *group; + int ret; + + iommu_group = iommu_group_alloc(); + if (IS_ERR(iommu_group)) + return ERR_CAST(iommu_group); - iommu_group = vfio_iommu_group_get(dev); + iommu_group_set_name(iommu_group, "vfio-noiommu"); + iommu_group_set_iommudata(iommu_group, &noiommu, NULL); + ret = iommu_group_add_device(iommu_group, dev); + if (ret) + goto out_put_group; + + group = vfio_create_group(iommu_group); + if (IS_ERR(group)) { + ret = PTR_ERR(group); + goto out_remove_device; + } + + return group; + +out_remove_device: + iommu_group_remove_device(dev); +out_put_group: + iommu_group_put(iommu_group); + return ERR_PTR(ret); +} +#endif + +static struct vfio_group *vfio_group_find_or_alloc(struct device *dev) +{ + struct iommu_group *iommu_group; + struct vfio_group *group; + + iommu_group = iommu_group_get(dev); +#ifdef CONFIG_VFIO_NOIOMMU + if (!iommu_group && noiommu && !iommu_present(dev->bus)) { + /* + * With noiommu enabled, create an IOMMU group for devices that + * don't already have one and don't have an iommu_ops on their + * bus. Taint the kernel because we're about to give a DMA + * capable device to a user without IOMMU protection. + */ + group = vfio_noiommu_group_alloc(dev); + if (!IS_ERR(group)) { + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n"); + } + return group; + } +#endif if (!iommu_group) return ERR_PTR(-EINVAL); @@ -840,14 +845,9 @@ struct vfio_group *vfio_group_find_or_alloc(struct device *dev) /* a newly created vfio_group keeps the reference. */ group = vfio_create_group(iommu_group); if (IS_ERR(group)) - goto out_remove; + goto out_put; return group; -out_remove: -#ifdef CONFIG_VFIO_NOIOMMU - if (iommu_group_get_iommudata(iommu_group) == &noiommu) - iommu_group_remove_device(dev); -#endif out_put: iommu_group_put(iommu_group); return group; -- cgit v1.2.3-59-g8ed1b