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vfio: refactor noiommu group creation

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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 <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20210924155705.4258-6-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Christoph Hellwig 2021-09-24 17:56:55 +02:00 committed by Alex Williamson
parent 1362591f15
commit 3af9177132
1 changed files with 52 additions and 52 deletions
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104
drivers/vfio/vfio.c
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@ -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_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 = vfio_iommu_group_get(dev);
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;