On Tue, May 24, 2016 at 05:36:22PM +0800, Jason Wang wrote: > This patch tries to implement an device IOTLB for vhost. This could be > used with for co-operation with userspace IOMMU implementation (qemu) > for a secure DMA environment (DMAR) in guest. > > The idea is simple. When vhost meets an IOTLB miss, it will request > the assistance of userspace to do the translation, this is done > through: > > - when there's a IOTLB miss, it will notify userspace through > vhost_net fd and then userspace read the fault address, size and > access from vhost fd. > - userspace write the translation result back to vhost fd, vhost can > then update its IOTLB. > > The codes were optimized for fixed mapping users e.g dpdk in guest. It > will be slow if dynamic mappings were used in guest. We could do > optimizations on top. > > The codes were designed to be architecture independent. It should be > easily ported to any architecture. > > Stress tested with l2fwd/vfio in guest with 4K/2M/1G page size. On 1G > hugepage case, 100% TLB hit rate were noticed. > > Changes from V2: > - introduce memory accessors for vhost > - switch from ioctls to oridinary file read/write for iotlb miss and > updating > - do not assume virtqueue were virtually mapped contiguously, all > virtqueue access were done throug IOTLB > - verify memory access during IOTLB update and fail early > - introduce a module parameter for the size of IOTLB > > Changes from V1: > - support any size/range of updating and invalidation through > introducing the interval tree. > - convert from per device iotlb request to per virtqueue iotlb > request, this solves the possible deadlock in V1. > - read/write permission check support. > > Please review. Nice, this looks good to me. Can you post a non-rfc please? > Jason Wang (3): > vhost: introduce vhost memory accessors > vhost: convert pre sorted vhost memory array to interval tree > vhost: device IOTLB API > > drivers/vhost/net.c | 63 +++- > drivers/vhost/vhost.c | 760 ++++++++++++++++++++++++++++++++++++++------- > drivers/vhost/vhost.h | 60 +++- > include/uapi/linux/vhost.h | 28 ++ > 4 files changed, 790 insertions(+), 121 deletions(-) > > -- > 2.7.4 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
