On Wed, Sep 30, 2015 at 11:33:41AM +0200, Laurent Vivier wrote:
>
>
> On 30/09/2015 05:48, David Gibson wrote:
> > Because of the way non-VFIO guest IOMMU operations are KVM accelerated, not
> > all TCE tables (guest IOMMU contexts) can support VFIO devices. Currently,
> > this is decided at creation time.
> >
> > To support hotplug of VFIO devices, we need to allow a TCE table which
> > previously didn't allow VFIO devices to be switched so that it can. This
> > patch adds an spapr_tce_set_need_vfio() function to do this, by
> > reallocating the table in userspace if necessary.
> >
> > Currently this doesn't allow the KVM acceleration to be re-enabled if all
> > the VFIO devices are removed. That's an optimization for another time.
> >
> > Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> > ---
> > hw/ppc/spapr_iommu.c | 32 ++++++++++++++++++++++++++++++++
> > include/hw/ppc/spapr.h | 2 ++
> > 2 files changed, 34 insertions(+)
> >
> > diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
> > index 5166cde..8d60f8b 100644
> > --- a/hw/ppc/spapr_iommu.c
> > +++ b/hw/ppc/spapr_iommu.c
> > @@ -168,6 +168,38 @@ static int spapr_tce_table_realize(DeviceState *dev)
> > return 0;
> > }
> >
> > +void spapr_tce_set_need_vfio(sPAPRTCETable *tcet, bool need_vfio)
> > +{
> > + size_t table_size = tcet->nb_table * sizeof(uint64_t);
> > + void *newtable;
> > +
> > + if (need_vfio == tcet->need_vfio) {
> > + /* Nothing to do */
> > + return;
> > + }
> > +
> > + if (!need_vfio) {
> > + /* FIXME: We don't support transition back to KVM accelerated
> > + * TCEs yet */
>
> Report some warnings ?
I don't see much value in it. At present nothing calls this function
with need_vfio == false anyway. Switching back is harmless, just not
optimal.
>
> > + return;
> > + }
> > +
> > + tcet->need_vfio = true;
> > +
> > + if (tcet->fd < 0) {
> > + /* Table is already in userspace, nothing to be do */
> > + return;
> > + }
> > +
> > + newtable = g_malloc0(table_size);
> > + memcpy(newtable, tcet->table, table_size);
> > +
> > + kvmppc_remove_spapr_tce(tcet->table, tcet->fd, tcet->nb_table);
> > +
> > + tcet->fd = -1;
> > + tcet->table = newtable;
> > +}
> > +
> > sPAPRTCETable *spapr_tce_new_table(DeviceState *owner, uint32_t liobn,
> > uint64_t bus_offset,
> > uint32_t page_shift,
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 27d65d5..5baa906 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -589,6 +589,8 @@ sPAPRTCETable *spapr_tce_new_table(DeviceState *owner,
> > uint32_t liobn,
> > uint32_t page_shift,
> > uint32_t nb_table,
> > bool need_vfio);
> > +void spapr_tce_set_need_vfio(sPAPRTCETable *tcet, bool need_vfio);
> > +
> > MemoryRegion *spapr_tce_get_iommu(sPAPRTCETable *tcet);
> > int spapr_dma_dt(void *fdt, int node_off, const char *propname,
> > uint32_t liobn, uint64_t window, uint32_t size);
> >
>
> Reviewed-by: Laurent Vivier <lviv...@redhat.com>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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