This series contains three patches, 1) optimizes the code including walking DMA tables and rpcit handler 2) fixes the issue caused by IOTLB global refresh 3) uses the right pal and pba when registering ioat
The issue mentioned above was found when we tested SMC-r tools. This behavior has been introduced when linux guest started using a global refresh to purge the whole IOTLB of invalid entries in a lazy fashion instead of flushing each entry when invalidating table entries. The previous QEMU implementation didn't keep track of the mapping, didn't handle correctly the global flush demand from the guest and a major part of the IOTLB entries were not flushed. Consequently linux kernel on the host keeping the previous mapping reports, as it should, -EEXIST DMA mapping error on the next mapping with the same IOVA. The second patch fixes this issue. During the investigation, we noticed that the current code walking PCI IOMMU page tables didn't check important flags of table entries, including: 1) protection bit 2) table length 3) table offset 4) intermediate tables' invalid bit 5) format control bit We implement the checking in the first patch before handling the IOTLB global refresh issue. To keep track of the mapped IOTLB entries and be able to check if the host IOTLB entries need to be refreshed we implement a IOTLB cache in QEMU, and introduce some helper functions to check these bits. All S390IOTLBEntry instances are stored in a new hashtable which are indexed by IOVA. Each PCI device has its own IOMMU. Therefore each IOMMU also has its own hashtable caching corresponding PCI device's DMA entries. Finally, we split 1M contiguous DMA range into 4K pages to do DMA map, and the code about error notification is also optimized. Change log: v1->v2: 1) update commit messages 2) move some changes from the 2nd patch to the 1st patch 3) define macros for 'ett' in the 1st patch Yi Min Zhao (3): s390x/pci: fixup the code walking IOMMU tables s390x/pci: fixup global refresh s390x/pci: use the right pal and pba in reg_ioat() hw/s390x/s390-pci-bus.c | 233 ++++++++++++++++++++++++++++++++++++++--------- hw/s390x/s390-pci-bus.h | 17 ++++ hw/s390x/s390-pci-inst.c | 103 ++++++++++++++------- 3 files changed, 275 insertions(+), 78 deletions(-) -- 2.14.3 (Apple Git-98)