Re: [Qemu-devel] [RFC PATCH 00/13] VT-d replay and misc cleanup

["Liu, Yi L" <yi.l.liu@linux.intel.com>]

On Tue, Dec 06, 2016 at 06:36:15PM +0800, Peter Xu wrote:
> This RFC series is a continue work for Aviv B.D.'s vfio enablement
> series with vt-d. Aviv has done a great job there, and what we still
> lack there are mostly the following:
> 
> (1) VFIO got duplicated IOTLB notifications due to splitted VT-d IOMMU
>     memory region.
> 
> (2) VT-d still haven't provide a correct replay() mechanism (e.g.,
>     when IOMMU domain switches, things will broke).
> 
> Here I'm trying to solve the above two issues.
> 
> (1) is solved by patch 7, (2) is solved by patch 11-12.
> 
> Basically it contains the following:
> 
> patch 1:    picked up from Jason's vhost DMAR series, which is a bugfix
> 
> patch 2-6:  Cleanups/Enhancements for existing vt-d codes (please see
>             specific commit message for details, there are patches
>             that I thought may be suitable for 2.8 as well, but looks
>             like it's too late)
> 
> patch 7:    Solve the issue that vfio is notified more than once for
>             IOTLB notifications with Aviv's patches
> 
> patch 8-10: Some trivial memory APIs added for further patches, and
>             add customize replay() support for MemoryRegion (I see
>             Aviv's latest v7 contains similar replay, I can rebase
>             onto that, merely the same thing)
> 
> patch 11:   Provide a valid vt-d replay() callback, using page walk
> 
Peter,
Does your patch set based on Aviv's patch？ I found the page cannot be
applied in my side.

BTW. it may be better if you can split the patches for mis cleanup
and the patches for replay/"fix duplicate notify".

Thanks,
Yi L
> patch 12:   Enable the domain switch support - we replay() when
>             context entry got invalidated
> 
> patch 13:   Enhancement for existing invalidation notification,
>             instead of using translate() for each page, we leverage
>             the new vtd_page_walk() interface, which should be faster.
> 
> I would glad to hear about any review comments for above patches
> (especially patch 8-13, which is the main part of this series),
> especially any issue I missed in the series.
> 
> =========
> Test Done
> =========
> 
> Build test passed for x86_64/arm/ppc64.
> 
> Simply tested with x86_64, assigning two PCI devices to a single VM,
> boot the VM using:
> 
> bin=x86_64-softmmu/qemu-system-x86_64
> $bin -M q35,accel=kvm,kernel-irqchip=split -m 1G \
>      -device intel-iommu,intremap=on,eim=off,cache-mode=on \
>      -netdev user,id=net0,hostfwd=tcp::5555-:22 \
>      -device virtio-net-pci,netdev=net0 \
>      -device vfio-pci,host=03:00.0 \
>      -device vfio-pci,host=02:00.0 \
>      -trace events=".trace.vfio" \
>      /var/lib/libvirt/images/vm1.qcow2
> 
> pxdev:bin [vtd-vfio-enablement]# cat .trace.vfio
> vtd_page_walk*
> vtd_replay*
> vtd_inv_desc*
> 
> Then, in the guest, run the following tool:
> 
>   https://github.com/xzpeter/clibs/blob/master/gpl/userspace/vfio-bind-group/vfio-bind-group.c
> 
> With parameter:
> 
>   ./vfio-bind-group 00:03.0 00:04.0
> 
> Check host side trace log, I can see pages are replayed and mapped in
> 00:04.0 device address space, like:
> 
> ...
> vtd_replay_ce_valid replay valid context device 00:04.00 hi 0x301 lo 0x3be77001
> vtd_page_walk Page walk for ce (0x301, 0x3be77001) iova range 0x0 - 0x8000000000
> vtd_page_walk_level Page walk (base=0x3be77000, level=3) iova range 0x0 - 0x8000000000
> vtd_page_walk_level Page walk (base=0x3c88a000, level=2) iova range 0x0 - 0x40000000
> vtd_page_walk_level Page walk (base=0x366cb000, level=1) iova range 0x0 - 0x200000
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x0 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x1000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x2000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x3000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x4000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x5000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x6000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x7000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x8000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0x9000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0xa000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0xb000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0xc000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0xd000 -> gpa 0x366cb000 mask 0xfff perm 3
> vtd_page_walk_one Page walk detected map level 0x1 iova 0xe000 -> gpa 0x366cb000 mask 0xfff perm 3
> ...
> 
> =========
> Todo List
> =========
> 
> - error reporting for the assigned devices (as Tianyu has mentioned)
> 
> - per-domain address-space: A better solution in the future may be -
>   we maintain one address space per IOMMU domain in the guest (so
>   multiple devices can share a same address space if they are sharing
>   the same IOMMU domains in the guest), rather than one address space
>   per device (which is current implementation of vt-d). However that's
>   a step further than this series, and let's see whether we can first
>   provide a workable version of device assignment with vt-d
>   protection.
> 
> - more to come...
> 
> Thanks,
> 
> Jason Wang (1):
>   intel_iommu: allocate new key when creating new address space
> 
> Peter Xu (12):
>   intel_iommu: simplify irq region translation
>   intel_iommu: renaming gpa to iova where proper
>   intel_iommu: fix trace for inv desc handling
>   intel_iommu: fix trace for addr translation
>   intel_iommu: vtd_slpt_level_shift check level
>   memory: add section range info for IOMMU notifier
>   memory: provide iommu_replay_all()
>   memory: introduce memory_region_notify_one()
>   memory: add MemoryRegionIOMMUOps.replay() callback
>   intel_iommu: provide its own replay() callback
>   intel_iommu: do replay when context invalidate
>   intel_iommu: use page_walk for iotlb inv notify
> 
>  hw/i386/intel_iommu.c | 521 ++++++++++++++++++++++++++++++++------------------
>  hw/i386/trace-events  |  27 +++
>  hw/vfio/common.c      |   7 +-
>  include/exec/memory.h |  30 +++
>  memory.c              |  42 +++-
>  5 files changed, 432 insertions(+), 195 deletions(-)
> 
> -- 
> 2.7.4
> 
>