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Groups > linux.kernel > #1428646
| From | Jason Wang <jasowang@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH V3 0/3] basic device IOTLB support |
| Date | 2016-06-22 12:10 +0200 |
| Message-ID | <rMNgC-221-41@gated-at.bofh.it> (permalink) |
| References | <rCgYF-1um-3@gated-at.bofh.it> <rMx29-8iu-25@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 2016年06月22日 00:44, Michael S. Tsirkin wrote: > 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? > > Posted, thanks. >> 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 > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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Re: [RFC PATCH V3 0/3] basic device IOTLB support "Michael S. Tsirkin" <mst@redhat.com> - 2016-06-21 18:50 +0200 Re: [RFC PATCH V3 0/3] basic device IOTLB support Jason Wang <jasowang@redhat.com> - 2016-06-22 12:10 +0200
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