Re: [PATCH v3 3/3] vdpa: Check for iova range at mappings changes

[Jason Wang]

On Thu, Oct 14, 2021 at 1:57 PM Eugenio Perez Martin
<eperezma@redhat.com> wrote:
>
> On Thu, Oct 14, 2021 at 5:30 AM Jason Wang <jasowang@redhat.com> wrote:
> >
> > On Tue, Oct 12, 2021 at 10:07 PM Eugenio Pérez <eperezma@redhat.com> wrote:
> > >
> > > Check vdpa device range before updating memory regions so we don't add
> > > any outside of it, and report the invalid change if any.
> > >
> > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > > ---
> > >  include/hw/virtio/vhost-vdpa.h |  2 ++
> > >  hw/virtio/vhost-vdpa.c         | 62 +++++++++++++++++++++++++---------
> > >  hw/virtio/trace-events         |  1 +
> > >  3 files changed, 49 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/include/hw/virtio/vhost-vdpa.h 
> > > b/include/hw/virtio/vhost-vdpa.h
> > > index a8963da2d9..c288cf7ecb 100644
> > > --- a/include/hw/virtio/vhost-vdpa.h
> > > +++ b/include/hw/virtio/vhost-vdpa.h
> > > @@ -13,6 +13,7 @@
> > >  #define HW_VIRTIO_VHOST_VDPA_H
> > >
> > >  #include "hw/virtio/virtio.h"
> > > +#include "standard-headers/linux/vhost_types.h"
> > >
> > >  typedef struct VhostVDPAHostNotifier {
> > >      MemoryRegion mr;
> > > @@ -24,6 +25,7 @@ typedef struct vhost_vdpa {
> > >      uint32_t msg_type;
> > >      bool iotlb_batch_begin_sent;
> > >      MemoryListener listener;
> > > +    struct vhost_vdpa_iova_range iova_range;
> > >      struct vhost_dev *dev;
> > >      VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
> > >  } VhostVDPA;
> > > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > > index be7c63b4ba..dbf773d032 100644
> > > --- a/hw/virtio/vhost-vdpa.c
> > > +++ b/hw/virtio/vhost-vdpa.c
> > > @@ -37,20 +37,34 @@ static Int128 vhost_vdpa_section_end(const 
> > > MemoryRegionSection *section)
> > >      return llend;
> > >  }
> > >
> > > -static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection 
> > > *section)
> > > -{
> > > -    return (!memory_region_is_ram(section->mr) &&
> > > -            !memory_region_is_iommu(section->mr)) ||
> > > -            memory_region_is_protected(section->mr) ||
> > > -           /* vhost-vDPA doesn't allow MMIO to be mapped  */
> > > -            memory_region_is_ram_device(section->mr) ||
> > > -           /*
> > > -            * Sizing an enabled 64-bit BAR can cause spurious mappings to
> > > -            * addresses in the upper part of the 64-bit address space.  
> > > These
> > > -            * are never accessed by the CPU and beyond the address width 
> > > of
> > > -            * some IOMMU hardware.  TODO: VDPA should tell us the IOMMU 
> > > width.
> > > -            */
> > > -           section->offset_within_address_space & (1ULL << 63);
>
> [1]
>
> > > +static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection 
> > > *section,
> > > +                                                uint64_t iova_min,
> > > +                                                uint64_t iova_max)
> > > +{
> > > +    Int128 llend;
> > > +
> > > +    if ((!memory_region_is_ram(section->mr) &&
> > > +         !memory_region_is_iommu(section->mr)) ||
> > > +        memory_region_is_protected(section->mr) ||
> > > +        /* vhost-vDPA doesn't allow MMIO to be mapped  */
> > > +        memory_region_is_ram_device(section->mr)) {
> > > +        return true;
> > > +    }
> > > +
> > > +    if (section->offset_within_address_space < iova_min) {
> > > +        error_report("RAM section out of device range (min=%lu, 
> > > addr=%lu)",
> > > +                     iova_min, section->offset_within_address_space);
> > > +        return true;
> > > +    }
> > > +
> > > +    llend = vhost_vdpa_section_end(section);
> > > +    if (int128_gt(llend, int128_make64(iova_max))) {
> > > +        error_report("RAM section out of device range (max=%lu, end 
> > > addr=%lu)",
> > > +                     iova_max, int128_get64(llend));
> > > +        return true;
> > > +    }
> > > +
> > > +    return false;
> > >  }
> > >
> > >  static int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr 
> > > size,
> > > @@ -162,7 +176,8 @@ static void 
> > > vhost_vdpa_listener_region_add(MemoryListener *listener,
> > >      void *vaddr;
> > >      int ret;
> > >
> > > -    if (vhost_vdpa_listener_skipped_section(section)) {
> > > +    if (vhost_vdpa_listener_skipped_section(section, v->iova_range.first,
> > > +                                            v->iova_range.last)) {
> > >          return;
> > >      }
> > >
> > > @@ -220,7 +235,8 @@ static void 
> > > vhost_vdpa_listener_region_del(MemoryListener *listener,
> > >      Int128 llend, llsize;
> > >      int ret;
> > >
> > > -    if (vhost_vdpa_listener_skipped_section(section)) {
> > > +    if (vhost_vdpa_listener_skipped_section(section, v->iova_range.first,
> > > +                                            v->iova_range.last)) {
> > >          return;
> > >      }
> > >
> > > @@ -288,6 +304,19 @@ static void vhost_vdpa_add_status(struct vhost_dev 
> > > *dev, uint8_t status)
> > >      vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
> > >  }
> > >
> > > +static void vhost_vdpa_get_iova_range(struct vhost_vdpa *v)
> > > +{
> > > +    int ret = vhost_vdpa_call(v->dev, VHOST_VDPA_GET_IOVA_RANGE,
> > > +                              &v->iova_range);
> > > +    if (ret != 0) {
> > > +        v->iova_range.first = 0;
> > > +        v->iova_range.last = MAKE_64BIT_MASK(0, 63);
> >
> > Nit:
> >
> > ULLONG_MAX?
> >
>
> It should be ULLONG_MAX >> 1 to match the previous limit [1],

I think they don't conflict. We just want to preserve the default iova
range as what the kernel did. Kernel will give ULLONG_MAX if
get_iova_range() is not implemented by the device?


> and
> trusting that uint64_t is effectively unsigned long long. I see a 63
> bits mask immediately with MAKE_64BIT_MASK (once I remember the
> parameter order), but I find it harder to see it with (ULLONG_MAX >>
> 1).
>
> If you prefer the _MAX options, I would say it is better to stick with
> (UINT64_MAX >> 1) or (HWADDR_MAX >> 1), because of this in
> CODING_STYLE.rst:
>
> "If you're using "int" or "long", odds are good that there's a better
> type. ...", "In the event that you require a specific width, use a
> standard type like int32_t, uint32_t, uint64_t, etc", "Use hwaddr for
> guest physical addresses".
>
> Does it make sense to you?

If I was not wrong, we can use UINT64_MAX.

Thanks

>
> Thanks!
>
> > Others look good.
> >
> > Thanks
> >
> > > +    }
> > > +
> > > +    trace_vhost_vdpa_get_iova_range(v->dev, v->iova_range.first,
> > > +                                    v->iova_range.last);
> > > +}
> > > +
> > >  static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error 
> > > **errp)
> > >  {
> > >      struct vhost_vdpa *v;
> > > @@ -300,6 +329,7 @@ static int vhost_vdpa_init(struct vhost_dev *dev, 
> > > void *opaque, Error **errp)
> > >      v->listener = vhost_vdpa_memory_listener;
> > >      v->msg_type = VHOST_IOTLB_MSG_V2;
> > >
> > > +    vhost_vdpa_get_iova_range(v);
> > >      vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
> > >                                 VIRTIO_CONFIG_S_DRIVER);
> > >
> > > diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> > > index 8ed19e9d0c..650e521e35 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"
> > > --
> > > 2.27.0
> > >
> >
>