Michael, > storvsc_queuecommand() maps the scatter/gather list using scsi_dma_map(), > which in a confidential VM allocates swiotlb bounce buffers. If the > I/O submission fails in storvsc_do_io(), the I/O is typically retried > by higher level code, but the bounce buffer memory is never freed. > The mostly like cause of I/O submission failure is a full VMBus > channel ring buffer, which is not uncommon under high I/O loads. > Eventually enough bounce buffer memory leaks that the confidential > VM can't do any I/O. The same problem can arise in a non-confidential > VM with kernel boot parameter swiotlb=force. Applied to 6.2/scsi-staging, thanks! -- Martin K. Petersen Oracle Linux Engineering
