Kernel commit 492855939bdb added a limit to the number of outstanding DMA requests for a type1 vfio container. However, lazy unmapping in s390 can in fact cause quite a large number of outstanding DMA requests to build up prior to being purged, potentially the entire guest DMA space. This results in unexpected 'VFIO_MAP_DMA failed: No space left on device' conditions seen in QEMU. This patchset adds support to qemu to retrieve the number of allowable DMA requests via the VFIO_IOMMU_GET_INFO ioctl. The patches are separated into vfio hits which add support for reading in VFIO_IOMMU_GET_INFO capability chains and getting the per-container dma_avail value, and s390 hits to track DMA usage on a per-container basis. Associated kernel patch: https://marc.info/?l=kvm&m=160019703922812&w=2 Changes from v2: - Patch 1 (new): Added a placeholder linux-headers sync - Patch 2: Re-arranged so that this patch that adds a shared routine for finding info capabilities is first - Patch 3: Adjusted vfio_get_info_dma_avail() logic to be able to return true when the capability exists but the caller did not provide a buffer on input. - Patch 4 (new): Introduce hw/s390x/s390-pci-vfio.* to better-separate PCI emulation code from code that interfaces with vfio - Patch 4: s/s390_sync_dma_avail/s390_pci_update_dma_avail/ - Since it's now moved into a different file it can't be static so I added '_pci'. - Patch 4: Use g_autofree as suggested - drop the goto/out as a result - Patch 4+5: Added asserts() in a few locations per suggestion - Patch 5: lowercase inline function names - Patch 5: fix dma_avail initialization in rpcit_service_call() and ensure we still allow unmaps to call s390_pci_update_iotlb when dma_avail == 0 Matthew Rosato (5): linux-headers: update against 5.9-rc5 vfio: Create shared routine for scanning info capabilities vfio: Find DMA available capability s390x/pci: Add routine to get the vfio dma available count s390x/pci: Honor DMA limits set by vfio hw/s390x/meson.build | 1 + hw/s390x/s390-pci-bus.c | 56 ++++++++- hw/s390x/s390-pci-bus.h | 9 ++ hw/s390x/s390-pci-inst.c | 34 ++++- hw/s390x/s390-pci-inst.h | 3 + hw/s390x/s390-pci-vfio.c | 54 ++++++++ hw/s390x/s390-pci-vfio.h | 17 +++ hw/vfio/common.c | 52 ++++++-- include/hw/vfio/vfio-common.h | 2 + include/standard-headers/drm/drm_fourcc.h | 140 +++++++++++++++++++++ include/standard-headers/linux/ethtool.h | 87 +++++++++++++ include/standard-headers/linux/input-event-codes.h | 3 +- include/standard-headers/linux/vhost_types.h | 11 ++ include/standard-headers/linux/virtio_9p.h | 4 +- include/standard-headers/linux/virtio_blk.h | 26 ++-- include/standard-headers/linux/virtio_config.h | 8 +- include/standard-headers/linux/virtio_console.h | 8 +- include/standard-headers/linux/virtio_net.h | 6 +- include/standard-headers/linux/virtio_scsi.h | 20 +-- linux-headers/asm-generic/unistd.h | 6 +- linux-headers/asm-mips/unistd_n32.h | 1 + linux-headers/asm-mips/unistd_n64.h | 1 + linux-headers/asm-mips/unistd_o32.h | 1 + linux-headers/asm-powerpc/kvm.h | 5 + linux-headers/asm-powerpc/unistd_32.h | 1 + linux-headers/asm-powerpc/unistd_64.h | 1 + linux-headers/asm-s390/kvm.h | 7 +- linux-headers/asm-s390/unistd_32.h | 1 + linux-headers/asm-s390/unistd_64.h | 1 + linux-headers/asm-x86/unistd_32.h | 1 + linux-headers/asm-x86/unistd_64.h | 1 + linux-headers/asm-x86/unistd_x32.h | 1 + linux-headers/linux/kvm.h | 10 +- linux-headers/linux/vfio.h | 18 ++- linux-headers/linux/vhost.h | 2 + 35 files changed, 537 insertions(+), 62 deletions(-) create mode 100644 hw/s390x/s390-pci-vfio.c create mode 100644 hw/s390x/s390-pci-vfio.h -- 1.8.3.1
