diff options
| author | Jason Gunthorpe <jgg@nvidia.com> | 2024-02-22 10:07:41 -0400 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2024-02-23 16:45:05 +0100 |
| commit | 65d4418c5002ec5b0e529455bf4152fd43459079 (patch) | |
| tree | 5e9cdeb9b970da41c8901b8f4bd1320f10e7f0e9 /include | |
| parent | 16b1b39126e5d5d49eedb2245f9e781b22bde926 (diff) | |
iommu/sva: Restore SVA handle sharing
Prior to commit 092edaddb660 ("iommu: Support mm PASID 1:n with sva
domains") the code allowed a SVA handle to be bound multiple times to the
same (mm, device) pair. This was alluded to in the kdoc comment, but we
had understood this to be more a remark about allowing multiple devices,
not a literal same-driver re-opening the same SVA.
It turns out uacce and idxd were both relying on the core code to handle
reference counting for same-device same-mm scenarios. As this looks hard
to resolve in the drivers bring it back to the core code.
The new design has changed the meaning of the domain->users refcount to
refer to the number of devices that are sharing that domain for the same
mm. This is part of the design to lift the SVA domain de-duplication out
of the drivers.
Return the old behavior by explicitly de-duplicating the struct iommu_sva
handle. The same (mm, device) will return the same handle pointer and the
core code will handle tracking this. The last unbind of the handle will
destroy it.
Fixes: 092edaddb660 ("iommu: Support mm PASID 1:n with sva domains")
Reported-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Closes: https://lore.kernel.org/all/20240221110658.529-1-zhangfei.gao@linaro.org/
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/0-v1-9455fc497a6f+3b4-iommu_sva_sharing_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/iommu.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 1ea2a820e1eb..5e27cb3a3be9 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -892,11 +892,14 @@ struct iommu_fwspec { struct iommu_sva { struct device *dev; struct iommu_domain *domain; + struct list_head handle_item; + refcount_t users; }; struct iommu_mm_data { u32 pasid; struct list_head sva_domains; + struct list_head sva_handles; }; int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode, |