On Wed, Dec 16, 2020 at 02:47:57PM +0800, Jason Wang wrote: > Hi All: > > This series tries to add the support for control virtqueue in vDPA. > > Control virtqueue is used by networking device for accepting various > commands from the driver. It's a must to support multiqueue and other > configurations. > > When used by vhost-vDPA bus driver for VM, the control virtqueue > should be shadowed via userspace VMM (Qemu) instead of being assigned > directly to Guest. This is because Qemu needs to know the device state > in order to start and stop device correctly (e.g for Live Migration). > > This requies to isolate the memory mapping for control virtqueue > presented by vhost-vDPA to prevent guest from accesing it directly. > To achieve this, vDPA introduce two new abstractions: > > - address space: identified through address space id (ASID) and a set > of memory mapping in maintained > - virtqueue group: the minimal set of virtqueues that must share an > address space How will this support the pretty common case where control vq is programmed by the kernel through the PF, and others by the VFs? I actually thought the way to support it is by exposing something like an "inject buffers" API which sends data to a given VQ. Maybe an ioctl, and maybe down the road uio ring can support batching these .... > > Device needs to advertise the following attributes to vDPA: > > - the number of address spaces supported in the device > - the number of virtqueue groups supported in the device > - the mappings from a specific virtqueue to its virtqueue groups > > The mappings from virtqueue to virtqueue groups is fixed and defined > by vDPA device driver. E.g: > > - For the device that has hardware ASID support, it can simply > advertise a per virtqueue virtqueue group. > - For the device that does not have hardware ASID support, it can > simply advertise a single virtqueue group that contains all > virtqueues. Or if it wants a software emulated control virtqueue, it > can advertise two virtqueue groups, one is for cvq, another is for > the rest virtqueues. > > vDPA also allow to change the association between virtqueue group and > address space. So in the case of control virtqueue, userspace > VMM(Qemu) may use a dedicated address space for the control virtqueue > group to isolate the memory mapping. > > The vhost/vhost-vDPA is also extend for the userspace to: > > - query the number of virtqueue groups and address spaces supported by > the device > - query the virtqueue group for a specific virtqueue > - assocaite a virtqueue group with an address space > - send ASID based IOTLB commands > > This will help userspace VMM(Qemu) to detect whether the control vq > could be supported and isolate memory mappings of control virtqueue > from the others. > > To demonstrate the usage, vDPA simulator is extended to support > setting MAC address via a emulated control virtqueue. > > Please review. > > Changes since RFC: > > - tweak vhost uAPI documentation > - switch to use device specific IOTLB really in patch 4 > - tweak the commit log > - fix that ASID in vhost is claimed to be 32 actually but 16bit > actually > - fix use after free when using ASID with IOTLB batching requests > - switch to use Stefano's patch for having separated iov > - remove unused "used_as" variable > - fix the iotlb/asid checking in vhost_vdpa_unmap() > > Thanks > > Jason Wang (20): > vhost: move the backend feature bits to vhost_types.h > virtio-vdpa: don't set callback if virtio doesn't need it > vhost-vdpa: passing iotlb to IOMMU mapping helpers > vhost-vdpa: switch to use vhost-vdpa specific IOTLB > vdpa: add the missing comment for nvqs in struct vdpa_device > vdpa: introduce virtqueue groups > vdpa: multiple address spaces support > vdpa: introduce config operations for associating ASID to a virtqueue > group > vhost_iotlb: split out IOTLB initialization > vhost: support ASID in IOTLB API > vhost-vdpa: introduce asid based IOTLB > vhost-vdpa: introduce uAPI to get the number of virtqueue groups > vhost-vdpa: introduce uAPI to get the number of address spaces > vhost-vdpa: uAPI to get virtqueue group id > vhost-vdpa: introduce uAPI to set group ASID > vhost-vdpa: support ASID based IOTLB API > vdpa_sim: advertise VIRTIO_NET_F_MTU > vdpa_sim: factor out buffer completion logic > vdpa_sim: filter destination mac address > vdpasim: control virtqueue support > > Stefano Garzarella (1): > vdpa_sim: split vdpasim_virtqueue's iov field in out_iov and in_iov > > drivers/vdpa/ifcvf/ifcvf_main.c | 9 +- > drivers/vdpa/mlx5/net/mlx5_vnet.c | 11 +- > drivers/vdpa/vdpa.c | 8 +- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 292 ++++++++++++++++++++++++------ > drivers/vhost/iotlb.c | 23 ++- > drivers/vhost/vdpa.c | 246 ++++++++++++++++++++----- > drivers/vhost/vhost.c | 23 ++- > drivers/vhost/vhost.h | 4 +- > drivers/virtio/virtio_vdpa.c | 2 +- > include/linux/vdpa.h | 42 ++++- > include/linux/vhost_iotlb.h | 2 + > include/uapi/linux/vhost.h | 25 ++- > include/uapi/linux/vhost_types.h | 10 +- > 13 files changed, 561 insertions(+), 136 deletions(-) > > -- > 2.25.1
