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

[Jason Wang <jasowang@xxxxxxxxxx>]

在 2021/6/1 下午3:17, Eugenio Perez Martin 写道:
> On Thu, May 27, 2021 at 6:51 AM Jason Wang <jasowang@xxxxxxxxxx> 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@xxxxxxxxxx> 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?


I'm not sure, but I guess there should be a way to fail the memory hot-add.

(otherwise we can introduce the error reporting for them)

Thanks


> > 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@xxxxxxxxxx>
> > > > > ---
> > > > >     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"

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