On Fri, 22 Jul 2022 16:12:19 -0700 Nicolin Chen <nicolinc@xxxxxxxxxx> wrote: > On Fri, Jul 22, 2022 at 04:11:29PM -0600, Alex Williamson wrote: > > > GVT-g explodes for me with this series on my Broadwell test system, > > continuously spewing the following: > > Thank you for running additional tests. > > > [ 47.348778] WARNING: CPU: 3 PID: 501 at drivers/vfio/vfio_iommu_type1.c:978 vfio_iommu_type1_unpin_pages+0x7b/0x100 [vfio_iommu_type1] > > > Line 978 is the WARN_ON(i != npage) line. For the cases where we don't > > find a matching vfio_dma, I'm seeing addresses that look maybe like > > we're shifting a value that's already an iova by PAGE_SHIFT somewhere. > > Hmm..I don't understand the PAGE_SHIFT part. Do you mind clarifying? The iova was a very large address for a 4GB VM with a lot of zeros on the low order bits, ex. 0x162459000000. Thanks, Alex > And GVT code initiated an unpin request from gvt_unpin_guest_pag() > that is currently unpinning one page at a time on a contiguous IOVA > range, prior to this series. After this series, it leaves the per- > page routine to the internal loop of vfio_iommu_type1_unpin_pages(), > which is supposed to do the same. > > So, either resulted from the npage input being wrong or some other > factor weighed in that invoked a vfio_remove_dma on those iovas? > > Thanks > Nic >
