On 2023/11/21 13:19, Nicolin Chen wrote:
On Tue, Nov 21, 2023 at 01:02:49PM +0800, Baolu Lu wrote:
On 11/17/23 9:07 PM, Yi Liu wrote:
In nested translation, the stage-1 page table is user-managed but cached
by the IOMMU hardware, so an update on present page table entries in the
stage-1 page table should be followed with a cache invalidation.
Add an IOMMU_HWPT_INVALIDATE ioctl to support such a cache invalidation.
It takes hwpt_id to specify the iommu_domain, and a multi-entry array to
support multiple invalidation requests in one ioctl.
Check cache_invalidate_user op in the iommufd_hw_pagetable_alloc_nested,
since all nested domains need that.
Co-developed-by: Nicolin Chen<nicolinc@xxxxxxxxxx>
Signed-off-by: Nicolin Chen<nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu<yi.l.liu@xxxxxxxxx>
---
drivers/iommu/iommufd/hw_pagetable.c | 35 +++++++++++++++++++++++++
drivers/iommu/iommufd/iommufd_private.h | 9 +++++++
drivers/iommu/iommufd/main.c | 3 +++
include/uapi/linux/iommufd.h | 35 +++++++++++++++++++++++++
4 files changed, 82 insertions(+)
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 2abbeafdbd22..367459d92f69 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -238,6 +238,11 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
rc = -EINVAL;
goto out_abort;
}
+ /* Driver is buggy by missing cache_invalidate_user in domain_ops */
+ if (WARN_ON_ONCE(!hwpt->domain->ops->cache_invalidate_user)) {
+ rc = -EINVAL;
+ goto out_abort;
+ }
return hwpt_nested;
The WARN message here may cause kernel regression when users bisect
issues. Till this patch, there are no drivers support the
cache_invalidation_user callback yet.
Ah, this is an unintended consequence from our uAPI bisect to
merge the nesting alloc first...
Would removing the WARN_ON_ONCE be okay? Although having this
WARN is actually the point here...
seems like we may need to remove it. how about your opinion, @Jason?
Thanks
Nic
--
Regards,
Yi Liu
