Re: [PATCH v2] iommupt: Always add IOVA range to iotlb_gather in gather_range_pages()

[Joerg Roedel]

On Tue, Feb 03, 2026 at 04:29:34PM +0800, Yu Zhang wrote:
> Add current (iova, len) to the iotlb gather, regardless of the setting
> of PT_FEAT_FLUSH_RANGE or PT_FEAT_FLUSH_RANGE_NO_GAPS.
> 
> In gather_range_pages(), the current IOVA range is only added to
> iotlb_gather when PT_FEAT_FLUSH_RANGE is set. Yet a virtual IOMMU with
> NpCache uses only PT_FEAT_FLUSH_RANGE_NO_GAPS. In that case, iotlb_gather
> will stay empty (start=ULONG_MAX, end=0) after initialization, and the
> current (iova, len) will not be added to the iotlb_gather, causing
> subsequent iommu_iotlb_sync() to perform IOTLB invalidation with wrong
> parameters (e.g., amd_iommu_iotlb_sync() computes size from
> gather->end - gather->start + 1, leading to an invalid range).
> 
> The disjoint check and sync for PT_FEAT_FLUSH_RANGE_NO_GAPS remain
> unchanged: when the new range is disjoint from the existing gather,
> we still sync first and then add the new range, so semantics for
> NO_GAPS are preserved.
> 
> Fixes: 7c53f4238aa8 ("iommupt: Add unmap_pages op")
> Cc: stable@xxxxxxxxxxxxxxx
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Yu Zhang <zhangyu1@xxxxxxxxxxxxxxxxxxx>

Applied, thanks.