Re: [PATCH 1/1] iommu/vt-d: Draining PRQ in sva unbind path when FPD bit set

[Baolu Lu <baolu.lu@linux.intel.com>]

On 12/17/24 10:42, Lu Baolu wrote:
> When a device uses a PASID for SVA (Shared Virtual Address), it's possible
> that the PASID entry is marked as non-present and FPD bit set before the
> device flushes all ongoing DMA requests and removes the SVA domain. This
> can occur when an exception happens and the process terminates before the
> device driver stops DMA and calls the iommu driver to unbind the PASID.
> 
> There's no need to drain the PRQ in the mm release path. Instead, the PRQ
> will be drained in the SVA unbind path. But in such case,
> intel_pasid_tear_down_entry() only checks the presence of the pasid entry
> and returns directly.
> 
> Add the code to clear the FPD bit and drain the PRQ.
> 
> Suggested-by: Kevin Tian<kevin.tian@intel.com>
> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com>
> ---
>   drivers/iommu/intel/pasid.c | 22 +++++++++++++++++++++-
>   drivers/iommu/intel/pasid.h |  6 ++++++
>   2 files changed, 27 insertions(+), 1 deletion(-)

Queued for v6.14.