On 05.04.19 01:16, Halil Pasic wrote: > Enhanced virtualization protection technology may require the use of > bounce buffers for I/O. While support for this was built into the virtio > core, virtio-ccw wasn't changed accordingly. Can you elaborate some more about the general approach (Enhanced virtualization protection technology, ultravisor, concept, issues, how to squeeze it into QEMU/KVM/kernel) etc = For my taste, this cover letter misses some important context :) > > Thus what needs to be done to bring virtio-ccw up to speed with respect > to this is: > * use some 'new' common virtio stuff > * make sure that virtio-ccw specific stuff uses shared memory when > talking to the hypervisor (except communication blocks like ORB, these > are handled by the hypervisor) > * make sure the DMA API does what is necessary to talk through shared > memory if we are a protected virtualization guest. > * make sure the common IO layer plays along as well (airqs, sense). > > The series is structured in incremental fashion: some of the changes are > overridden by following patches. The main reason why is that this is how I > developed. But I think it ain't bad for the didactic and we are a bit more > flexible with regards to throwing out some of the stuff in the end. > > Important notes: > > * This is an early (WIP) RFC that does not add any function to the > kernel at his stage, as the ultravisor interactions are left out. > The purpose is getting some early feedback ASAP. > > * In future these patches will depend on some code interacting with the > ultravisor (WIP by Vasily and Janosch). > > * The s390 names are by no means final, and are not properly explained. Should > not hamper understanding too much. If it does please ask. > > * The existing naming in the common infrastructure (kernel internal > interfaces) is pretty much based on the AMD SEV terminology. Thus the > names aren't always perfect. There might be merit to changing these > names to more abstract ones. I did not put much thought into that at > the current stage. > > > Testing: > > Please use iommu_platform=on for any virtio devices you are going > to test this code with (so virtio actually uses the DMA API). > > Looking forward to your review or any other type of input. > > Halil Pasic (12): > virtio/s390: use vring_create_virtqueue > virtio/s390: DMA support for virtio-ccw > s390/mm: force swiotlb for protected virtualization > s390/cio: introduce cio DMA pool > s390/cio: add protected virtualization support to cio > s390/airq: use DMA memory for adapter interrupts > virtio/s390: use DMA memory for ccw I/O > virtio/s390: add indirection to indicators access > virtio/s390: use DMA memory for notifiers > virtio/s390: consolidate DMA allocations > virtio/s390: use the cio DMA pool > virtio/s390: make airq summary indicators DMA > > arch/s390/Kconfig | 5 + > arch/s390/include/asm/Kbuild | 1 - > arch/s390/include/asm/airq.h | 2 + > arch/s390/include/asm/cio.h | 4 + > arch/s390/include/asm/dma-mapping.h | 13 ++ > arch/s390/include/asm/mem_encrypt.h | 18 +++ > arch/s390/mm/init.c | 44 +++++ > drivers/s390/cio/airq.c | 18 ++- > drivers/s390/cio/ccwreq.c | 8 +- > drivers/s390/cio/css.c | 63 ++++++++ > drivers/s390/cio/device.c | 46 ++++-- > drivers/s390/cio/device_fsm.c | 40 ++--- > drivers/s390/cio/device_id.c | 18 +-- > drivers/s390/cio/device_ops.c | 4 +- > drivers/s390/cio/device_pgid.c | 20 +-- > drivers/s390/cio/device_status.c | 24 +-- > drivers/s390/cio/io_sch.h | 19 ++- > drivers/s390/virtio/virtio_ccw.c | 310 ++++++++++++++++++++---------------- > 18 files changed, 444 insertions(+), 213 deletions(-) > create mode 100644 arch/s390/include/asm/dma-mapping.h > create mode 100644 arch/s390/include/asm/mem_encrypt.h > -- Thanks, David / dhildenb
