Re: [RFC v3 13/29] vhost: Add vhost_get_iova_range operation

[Eugenio Perez Martin]

On Thu, May 27, 2021 at 6:51 AM Jason Wang <jasowang@redhat.com> wrote:
>
>
> 在 2021/5/27 上午1:49, Eugenio Perez Martin 写道:
> > On Wed, May 26, 2021 at 3:14 AM Jason Wang <jasowang@redhat.com> wrote:
> >>
> >> 在 2021/5/20 上午12:28, Eugenio Pérez 写道:
> >>> For simplicity, If a device does not support this operation it means
> >>> that it can handle full (uint64_t)-1 iova address.
> >>
> >> Note that, we probably need a separated patch for this.
> >>
> > Actually the comment is not in the right commit, the next one is the
> > one that uses it. Is that what you mean?
>
>
> No, it's about the following suggestions.
>
>
> >
> >> And we need to this during vhost-vdpa initialization. If GPA is out of
> >> the range, we need to fail the start of vhost-vdpa.
>
>
> Note that this is for non-IOMMU case. For the case of vIOMMU we probably
> need to validate it against address width or other similar attributes.
>

Right.

What should qemu do if the memory of the guest gets expanded outside
of the range? I think there is not a clear way to fail the memory
addition, isn't it?

> Thanks
>
>
> >>
> > Right, that is still to-do.
> >
> > Maybe a series with just these two commits and failing the start if
> > GPA is not in the range, as you say, would help to split the amount of
> > changes.
> >
> > I will send it if no more comments arise about it.
> >
> > Thanks!
> >
> >> THanks
> >>
> >>
> >>> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> >>> ---
> >>>    include/hw/virtio/vhost-backend.h |  5 +++++
> >>>    hw/virtio/vhost-vdpa.c            | 18 ++++++++++++++++++
> >>>    hw/virtio/trace-events            |  1 +
> >>>    3 files changed, 24 insertions(+)
> >>>
> >>> diff --git a/include/hw/virtio/vhost-backend.h 
> >>> b/include/hw/virtio/vhost-backend.h
> >>> index 94d3323905..bcb112c166 100644
> >>> --- a/include/hw/virtio/vhost-backend.h
> >>> +++ b/include/hw/virtio/vhost-backend.h
> >>> @@ -36,6 +36,7 @@ struct vhost_vring_addr;
> >>>    struct vhost_scsi_target;
> >>>    struct vhost_iotlb_msg;
> >>>    struct vhost_virtqueue;
> >>> +struct vhost_vdpa_iova_range;
> >>>
> >>>    typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
> >>>    typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
> >>> @@ -127,6 +128,9 @@ typedef bool (*vhost_force_iommu_op)(struct vhost_dev 
> >>> *dev);
> >>>
> >>>    typedef int (*vhost_vring_pause_op)(struct vhost_dev *dev);
> >>>
> >>> +typedef int (*vhost_get_iova_range)(struct vhost_dev *dev,
> >>> +                                    hwaddr *first, hwaddr *last);
> >>> +
> >>>    typedef struct VhostOps {
> >>>        VhostBackendType backend_type;
> >>>        vhost_backend_init vhost_backend_init;
> >>> @@ -173,6 +177,7 @@ typedef struct VhostOps {
> >>>        vhost_get_device_id_op vhost_get_device_id;
> >>>        vhost_vring_pause_op vhost_vring_pause;
> >>>        vhost_force_iommu_op vhost_force_iommu;
> >>> +    vhost_get_iova_range vhost_get_iova_range;
> >>>    } VhostOps;
> >>>
> >>>    extern const VhostOps user_ops;
> >>> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> >>> index 01d2101d09..74fe92935e 100644
> >>> --- a/hw/virtio/vhost-vdpa.c
> >>> +++ b/hw/virtio/vhost-vdpa.c
> >>> @@ -579,6 +579,23 @@ static bool  vhost_vdpa_force_iommu(struct vhost_dev 
> >>> *dev)
> >>>        return true;
> >>>    }
> >>>
> >>> +static int vhost_vdpa_get_iova_range(struct vhost_dev *dev,
> >>> +                                     hwaddr *first, hwaddr *last)
> >>> +{
> >>> +    int ret;
> >>> +    struct vhost_vdpa_iova_range range;
> >>> +
> >>> +    ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_IOVA_RANGE, &range);
> >>> +    if (ret != 0) {
> >>> +        return ret;
> >>> +    }
> >>> +
> >>> +    *first = range.first;
> >>> +    *last = range.last;
> >>> +    trace_vhost_vdpa_get_iova_range(dev, *first, *last);
> >>> +    return ret;
> >>> +}
> >>> +
> >>>    const VhostOps vdpa_ops = {
> >>>            .backend_type = VHOST_BACKEND_TYPE_VDPA,
> >>>            .vhost_backend_init = vhost_vdpa_init,
> >>> @@ -611,4 +628,5 @@ const VhostOps vdpa_ops = {
> >>>            .vhost_get_device_id = vhost_vdpa_get_device_id,
> >>>            .vhost_vq_get_addr = vhost_vdpa_vq_get_addr,
> >>>            .vhost_force_iommu = vhost_vdpa_force_iommu,
> >>> +        .vhost_get_iova_range = vhost_vdpa_get_iova_range,
> >>>    };
> >>> diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> >>> index c62727f879..5debe3a681 100644
> >>> --- a/hw/virtio/trace-events
> >>> +++ b/hw/virtio/trace-events
> >>> @@ -52,6 +52,7 @@ vhost_vdpa_set_vring_call(void *dev, unsigned int 
> >>> index, int fd) "dev: %p index:
> >>>    vhost_vdpa_get_features(void *dev, uint64_t features) "dev: %p 
> >>> features: 0x%"PRIx64
> >>>    vhost_vdpa_set_owner(void *dev) "dev: %p"
> >>>    vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr, 
> >>> uint64_t avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p 
> >>> desc_user_addr: 0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr: 
> >>> 0x%"PRIx64
> >>> +vhost_vdpa_get_iova_range(void *dev, uint64_t first, uint64_t last) 
> >>> "dev: %p first: 0x%"PRIx64" last: 0x%"PRIx64
> >>>
> >>>    # virtio.c
> >>>    virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, 
> >>> unsigned out_num) "elem %p size %zd in_num %u out_num %u"
>