| Message ID | 1459762426-18440-15-git-send-email-aik@ozlabs.ru |
|---|---|
| State | New |
| Headers | show |
On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: > The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - > a guest view of the table and a hardware TCE table. If there is no VFIO > presense in the address space, then just the guest view is used, if > this is the case, it is allocated in the KVM. However since there is no > support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, > we need to move the guest view from KVM to the userspace; and we need > to do this for every IOMMU on a bus with VFIO devices. > > This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to > notifiy IOMMU about changing environment so it can reallocate the table > to/from KVM or (when available) hook the IOMMU groups with the logical > bus (LIOBN) in the KVM. > > This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug > path as the new callbacks do this better - they notify IOMMU at > the exact moment when the configuration is changed, and this also > includes the case of PCI hot unplug. > > As there can be multiple containers attached to the same PHB/LIOBN, > this replaces the @need_vfio flag in sPAPRTCETable with the counter > of VFIO users. > > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> This looks correct, but there's one remaining ugly. > --- > Changes: > v15: > * s/need_vfio/vfio-Users/g > --- > hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- > hw/ppc/spapr_pci.c | 6 ------ > hw/vfio/common.c | 9 +++++++++ > include/exec/memory.h | 4 ++++ > include/hw/ppc/spapr.h | 2 +- > 5 files changed, 34 insertions(+), 17 deletions(-) > > diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c > index c945dba..ea09414 100644 > --- a/hw/ppc/spapr_iommu.c > +++ b/hw/ppc/spapr_iommu.c > @@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) > return 1ULL << tcet->page_shift; > } > > +static void spapr_tce_vfio_start(MemoryRegion *iommu) > +{ > + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); > +} > + > +static void spapr_tce_vfio_stop(MemoryRegion *iommu) > +{ > + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); > +} > + > static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); > static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); > > @@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { > static MemoryRegionIOMMUOps spapr_iommu_ops = { > .translate = spapr_tce_translate_iommu, > .get_page_sizes = spapr_tce_get_page_sizes, > + .vfio_start = spapr_tce_vfio_start, > + .vfio_stop = spapr_tce_vfio_stop, Ok, so AFAICT these callbacks are called whenever a VFIO context is added / removed from the gIOMMU's address space, and it's up to the gIOMMU code to ref count that to see if there are any current vfio users. That makes "vfio_start" and "vfio_stop" not great names. But.. better than changing the names would be to move the refcounting to the generic code if you can manage it, so the individual gIOMMU backends don't need to - they just told when they need to start / stop providing VFIO support. > }; > > static int spapr_tce_table_realize(DeviceState *dev) > @@ -248,7 +260,7 @@ static int spapr_tce_table_realize(DeviceState *dev) > char tmp[32]; > > tcet->fd = -1; > - tcet->need_vfio = false; > + tcet->vfio_users = 0; > snprintf(tmp, sizeof(tmp), "tce-root-%x", tcet->liobn); > memory_region_init(&tcet->root, tcetobj, tmp, UINT64_MAX); > > @@ -268,20 +280,18 @@ 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; > - } > + tcet->vfio_users += need_vfio ? 1 : -1; > + g_assert(tcet->vfio_users >= 0); > + g_assert(tcet->table); > > - if (!need_vfio) { > + if (!tcet->vfio_users) { > /* FIXME: We don't support transition back to KVM accelerated > * TCEs yet */ > return; > } > > - tcet->need_vfio = true; > - > - if (tcet->fd < 0) { > + if (tcet->vfio_users > 1) { > + g_assert(tcet->fd < 0); > /* Table is already in userspace, nothing to be do */ > return; > } > @@ -327,7 +337,7 @@ static void spapr_tce_table_do_enable(sPAPRTCETable *tcet) > tcet->page_shift, > tcet->nb_table, > &tcet->fd, > - tcet->need_vfio); > + tcet->vfio_users != 0); > > memory_region_set_size(&tcet->iommu, > (uint64_t)tcet->nb_table << tcet->page_shift); > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c > index 5497a18..f864fde 100644 > --- a/hw/ppc/spapr_pci.c > +++ b/hw/ppc/spapr_pci.c > @@ -1083,12 +1083,6 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc, > void *fdt = NULL; > int fdt_start_offset = 0, fdt_size; > > - if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) { > - sPAPRTCETable *tcet = spapr_tce_find_by_liobn(phb->dma_liobn); > - > - spapr_tce_set_need_vfio(tcet, true); > - } > - > if (dev->hotplugged) { > fdt = create_device_tree(&fdt_size); > fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0); > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index ea79311..5e5b77c 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -421,6 +421,9 @@ static void vfio_listener_region_add(MemoryListener *listener, > QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next); > > memory_region_register_iommu_notifier(giommu->iommu, &giommu->n); > + if (section->mr->iommu_ops && section->mr->iommu_ops->vfio_start) { > + section->mr->iommu_ops->vfio_start(section->mr); > + } > memory_region_iommu_replay(giommu->iommu, &giommu->n, > false); > > @@ -466,6 +469,7 @@ static void vfio_listener_region_del(MemoryListener *listener, > VFIOContainer *container = container_of(listener, VFIOContainer, listener); > hwaddr iova, end; > int ret; > + MemoryRegion *iommu = NULL; > > if (vfio_listener_skipped_section(section)) { > trace_vfio_listener_region_del_skip( > @@ -487,6 +491,7 @@ static void vfio_listener_region_del(MemoryListener *listener, > QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) { > if (giommu->iommu == section->mr) { > memory_region_unregister_iommu_notifier(&giommu->n); > + iommu = giommu->iommu; > QLIST_REMOVE(giommu, giommu_next); > g_free(giommu); > break; > @@ -519,6 +524,10 @@ static void vfio_listener_region_del(MemoryListener *listener, > "0x%"HWADDR_PRIx") = %d (%m)", > container, iova, end - iova, ret); > } > + > + if (iommu && iommu->iommu_ops && iommu->iommu_ops->vfio_stop) { > + iommu->iommu_ops->vfio_stop(section->mr); > + } > } > > static const MemoryListener vfio_memory_listener = { > diff --git a/include/exec/memory.h b/include/exec/memory.h > index eb5ce67..f1de133f 100644 > --- a/include/exec/memory.h > +++ b/include/exec/memory.h > @@ -152,6 +152,10 @@ struct MemoryRegionIOMMUOps { > IOMMUTLBEntry (*translate)(MemoryRegion *iommu, hwaddr addr, bool is_write); > /* Returns supported page sizes */ > uint64_t (*get_page_sizes)(MemoryRegion *iommu); > + /* Called when VFIO starts using this */ > + void (*vfio_start)(MemoryRegion *iommu); > + /* Called when VFIO stops using this */ > + void (*vfio_stop)(MemoryRegion *iommu); > }; > > typedef struct CoalescedMemoryRange CoalescedMemoryRange; > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h > index 471eb4a..5c00e38 100644 > --- a/include/hw/ppc/spapr.h > +++ b/include/hw/ppc/spapr.h > @@ -548,7 +548,7 @@ struct sPAPRTCETable { > uint32_t mig_nb_table; > uint64_t *mig_table; > bool bypass; > - bool need_vfio; > + int vfio_users; > int fd; > MemoryRegion root, iommu; > struct VIOsPAPRDevice *vdev; /* for @bypass migration compatibility only */
On 04/07/2016 10:40 AM, David Gibson wrote: > On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: >> The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - >> a guest view of the table and a hardware TCE table. If there is no VFIO >> presense in the address space, then just the guest view is used, if >> this is the case, it is allocated in the KVM. However since there is no >> support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, >> we need to move the guest view from KVM to the userspace; and we need >> to do this for every IOMMU on a bus with VFIO devices. >> >> This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to >> notifiy IOMMU about changing environment so it can reallocate the table >> to/from KVM or (when available) hook the IOMMU groups with the logical >> bus (LIOBN) in the KVM. >> >> This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug >> path as the new callbacks do this better - they notify IOMMU at >> the exact moment when the configuration is changed, and this also >> includes the case of PCI hot unplug. >> >> As there can be multiple containers attached to the same PHB/LIOBN, >> this replaces the @need_vfio flag in sPAPRTCETable with the counter >> of VFIO users. >> >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > > This looks correct, but there's one remaining ugly. > >> --- >> Changes: >> v15: >> * s/need_vfio/vfio-Users/g >> --- >> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- >> hw/ppc/spapr_pci.c | 6 ------ >> hw/vfio/common.c | 9 +++++++++ >> include/exec/memory.h | 4 ++++ >> include/hw/ppc/spapr.h | 2 +- >> 5 files changed, 34 insertions(+), 17 deletions(-) >> >> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c >> index c945dba..ea09414 100644 >> --- a/hw/ppc/spapr_iommu.c >> +++ b/hw/ppc/spapr_iommu.c >> @@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) >> return 1ULL << tcet->page_shift; >> } >> >> +static void spapr_tce_vfio_start(MemoryRegion *iommu) >> +{ >> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); >> +} >> + >> +static void spapr_tce_vfio_stop(MemoryRegion *iommu) >> +{ >> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); >> +} >> + >> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); >> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); >> >> @@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { >> static MemoryRegionIOMMUOps spapr_iommu_ops = { >> .translate = spapr_tce_translate_iommu, >> .get_page_sizes = spapr_tce_get_page_sizes, >> + .vfio_start = spapr_tce_vfio_start, >> + .vfio_stop = spapr_tce_vfio_stop, > > Ok, so AFAICT these callbacks are called whenever a VFIO context is > added / removed from the gIOMMU's address space, and it's up to the > gIOMMU code to ref count that to see if there are any current vfio > users. That makes "vfio_start" and "vfio_stop" not great names. > > But.. better than changing the names would be to move the refcounting > to the generic code if you can manage it, so the individual gIOMMU > backends don't need to - they just told when they need to start / stop > providing VFIO support. Everything is manageable... This referencing is needed for the case of >=2 containers so 2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per VFIOContainer so VFIOGuestIOMMU is not the right place for the reference counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from VFIOContainer to VFIOAddressSpace and then gIOMMU can handle refcounting? > >> }; >> >> static int spapr_tce_table_realize(DeviceState *dev) >> @@ -248,7 +260,7 @@ static int spapr_tce_table_realize(DeviceState *dev) >> char tmp[32]; >> >> tcet->fd = -1; >> - tcet->need_vfio = false; >> + tcet->vfio_users = 0; >> snprintf(tmp, sizeof(tmp), "tce-root-%x", tcet->liobn); >> memory_region_init(&tcet->root, tcetobj, tmp, UINT64_MAX); >> >> @@ -268,20 +280,18 @@ 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; >> - } >> + tcet->vfio_users += need_vfio ? 1 : -1; >> + g_assert(tcet->vfio_users >= 0); >> + g_assert(tcet->table); >> >> - if (!need_vfio) { >> + if (!tcet->vfio_users) { >> /* FIXME: We don't support transition back to KVM accelerated >> * TCEs yet */ >> return; >> } >> >> - tcet->need_vfio = true; >> - >> - if (tcet->fd < 0) { >> + if (tcet->vfio_users > 1) { >> + g_assert(tcet->fd < 0); >> /* Table is already in userspace, nothing to be do */ >> return; >> } >> @@ -327,7 +337,7 @@ static void spapr_tce_table_do_enable(sPAPRTCETable *tcet) >> tcet->page_shift, >> tcet->nb_table, >> &tcet->fd, >> - tcet->need_vfio); >> + tcet->vfio_users != 0); >> >> memory_region_set_size(&tcet->iommu, >> (uint64_t)tcet->nb_table << tcet->page_shift); >> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c >> index 5497a18..f864fde 100644 >> --- a/hw/ppc/spapr_pci.c >> +++ b/hw/ppc/spapr_pci.c >> @@ -1083,12 +1083,6 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc, >> void *fdt = NULL; >> int fdt_start_offset = 0, fdt_size; >> >> - if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) { >> - sPAPRTCETable *tcet = spapr_tce_find_by_liobn(phb->dma_liobn); >> - >> - spapr_tce_set_need_vfio(tcet, true); >> - } >> - >> if (dev->hotplugged) { >> fdt = create_device_tree(&fdt_size); >> fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0); >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index ea79311..5e5b77c 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -421,6 +421,9 @@ static void vfio_listener_region_add(MemoryListener *listener, >> QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next); >> >> memory_region_register_iommu_notifier(giommu->iommu, &giommu->n); >> + if (section->mr->iommu_ops && section->mr->iommu_ops->vfio_start) { >> + section->mr->iommu_ops->vfio_start(section->mr); >> + } >> memory_region_iommu_replay(giommu->iommu, &giommu->n, >> false); >> >> @@ -466,6 +469,7 @@ static void vfio_listener_region_del(MemoryListener *listener, >> VFIOContainer *container = container_of(listener, VFIOContainer, listener); >> hwaddr iova, end; >> int ret; >> + MemoryRegion *iommu = NULL; >> >> if (vfio_listener_skipped_section(section)) { >> trace_vfio_listener_region_del_skip( >> @@ -487,6 +491,7 @@ static void vfio_listener_region_del(MemoryListener *listener, >> QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) { >> if (giommu->iommu == section->mr) { >> memory_region_unregister_iommu_notifier(&giommu->n); >> + iommu = giommu->iommu; >> QLIST_REMOVE(giommu, giommu_next); >> g_free(giommu); >> break; >> @@ -519,6 +524,10 @@ static void vfio_listener_region_del(MemoryListener *listener, >> "0x%"HWADDR_PRIx") = %d (%m)", >> container, iova, end - iova, ret); >> } >> + >> + if (iommu && iommu->iommu_ops && iommu->iommu_ops->vfio_stop) { >> + iommu->iommu_ops->vfio_stop(section->mr); >> + } >> } >> >> static const MemoryListener vfio_memory_listener = { >> diff --git a/include/exec/memory.h b/include/exec/memory.h >> index eb5ce67..f1de133f 100644 >> --- a/include/exec/memory.h >> +++ b/include/exec/memory.h >> @@ -152,6 +152,10 @@ struct MemoryRegionIOMMUOps { >> IOMMUTLBEntry (*translate)(MemoryRegion *iommu, hwaddr addr, bool is_write); >> /* Returns supported page sizes */ >> uint64_t (*get_page_sizes)(MemoryRegion *iommu); >> + /* Called when VFIO starts using this */ >> + void (*vfio_start)(MemoryRegion *iommu); >> + /* Called when VFIO stops using this */ >> + void (*vfio_stop)(MemoryRegion *iommu); >> }; >> >> typedef struct CoalescedMemoryRange CoalescedMemoryRange; >> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h >> index 471eb4a..5c00e38 100644 >> --- a/include/hw/ppc/spapr.h >> +++ b/include/hw/ppc/spapr.h >> @@ -548,7 +548,7 @@ struct sPAPRTCETable { >> uint32_t mig_nb_table; >> uint64_t *mig_table; >> bool bypass; >> - bool need_vfio; >> + int vfio_users; >> int fd; >> MemoryRegion root, iommu; >> struct VIOsPAPRDevice *vdev; /* for @bypass migration compatibility only */ >
On Wed, Apr 20, 2016 at 07:15:15PM +1000, Alexey Kardashevskiy wrote: > On 04/07/2016 10:40 AM, David Gibson wrote: > >On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: > >>The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - > >>a guest view of the table and a hardware TCE table. If there is no VFIO > >>presense in the address space, then just the guest view is used, if > >>this is the case, it is allocated in the KVM. However since there is no > >>support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, > >>we need to move the guest view from KVM to the userspace; and we need > >>to do this for every IOMMU on a bus with VFIO devices. > >> > >>This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to > >>notifiy IOMMU about changing environment so it can reallocate the table > >>to/from KVM or (when available) hook the IOMMU groups with the logical > >>bus (LIOBN) in the KVM. > >> > >>This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug > >>path as the new callbacks do this better - they notify IOMMU at > >>the exact moment when the configuration is changed, and this also > >>includes the case of PCI hot unplug. > >> > >>As there can be multiple containers attached to the same PHB/LIOBN, > >>this replaces the @need_vfio flag in sPAPRTCETable with the counter > >>of VFIO users. > >> > >>Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > > > >This looks correct, but there's one remaining ugly. > > > >>--- > >>Changes: > >>v15: > >>* s/need_vfio/vfio-Users/g > >>--- > >> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- > >> hw/ppc/spapr_pci.c | 6 ------ > >> hw/vfio/common.c | 9 +++++++++ > >> include/exec/memory.h | 4 ++++ > >> include/hw/ppc/spapr.h | 2 +- > >> 5 files changed, 34 insertions(+), 17 deletions(-) > >> > >>diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c > >>index c945dba..ea09414 100644 > >>--- a/hw/ppc/spapr_iommu.c > >>+++ b/hw/ppc/spapr_iommu.c > >>@@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) > >> return 1ULL << tcet->page_shift; > >> } > >> > >>+static void spapr_tce_vfio_start(MemoryRegion *iommu) > >>+{ > >>+ spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); > >>+} > >>+ > >>+static void spapr_tce_vfio_stop(MemoryRegion *iommu) > >>+{ > >>+ spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); > >>+} > >>+ > >> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); > >> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); > >> > >>@@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { > >> static MemoryRegionIOMMUOps spapr_iommu_ops = { > >> .translate = spapr_tce_translate_iommu, > >> .get_page_sizes = spapr_tce_get_page_sizes, > >>+ .vfio_start = spapr_tce_vfio_start, > >>+ .vfio_stop = spapr_tce_vfio_stop, > > > >Ok, so AFAICT these callbacks are called whenever a VFIO context is > >added / removed from the gIOMMU's address space, and it's up to the > >gIOMMU code to ref count that to see if there are any current vfio > >users. That makes "vfio_start" and "vfio_stop" not great names. > > > >But.. better than changing the names would be to move the refcounting > >to the generic code if you can manage it, so the individual gIOMMU > >backends don't need to - they just told when they need to start / stop > >providing VFIO support. > > Everything is manageable... > > This referencing is needed for the case of >=2 containers so > 2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per > VFIOContainer so VFIOGuestIOMMU is not the right place for the reference > counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs > with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from > VFIOContainer to VFIOAddressSpace and then gIOMMU can handle > refcounting? I'm having a lot of trouble parsing that. I think the ref parsing has to be per-giommu (because individual giommus could, in theory, be mapped or unmapped from an address space). But I think that should be in the vfio core, rather than being necessary in every giommu implementation.
On 04/21/2016 01:59 PM, David Gibson wrote: > On Wed, Apr 20, 2016 at 07:15:15PM +1000, Alexey Kardashevskiy wrote: >> On 04/07/2016 10:40 AM, David Gibson wrote: >>> On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: >>>> The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - >>>> a guest view of the table and a hardware TCE table. If there is no VFIO >>>> presense in the address space, then just the guest view is used, if >>>> this is the case, it is allocated in the KVM. However since there is no >>>> support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, >>>> we need to move the guest view from KVM to the userspace; and we need >>>> to do this for every IOMMU on a bus with VFIO devices. >>>> >>>> This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to >>>> notifiy IOMMU about changing environment so it can reallocate the table >>>> to/from KVM or (when available) hook the IOMMU groups with the logical >>>> bus (LIOBN) in the KVM. >>>> >>>> This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug >>>> path as the new callbacks do this better - they notify IOMMU at >>>> the exact moment when the configuration is changed, and this also >>>> includes the case of PCI hot unplug. >>>> >>>> As there can be multiple containers attached to the same PHB/LIOBN, >>>> this replaces the @need_vfio flag in sPAPRTCETable with the counter >>>> of VFIO users. >>>> >>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> >>> >>> This looks correct, but there's one remaining ugly. >>> >>>> --- >>>> Changes: >>>> v15: >>>> * s/need_vfio/vfio-Users/g >>>> --- >>>> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- >>>> hw/ppc/spapr_pci.c | 6 ------ >>>> hw/vfio/common.c | 9 +++++++++ >>>> include/exec/memory.h | 4 ++++ >>>> include/hw/ppc/spapr.h | 2 +- >>>> 5 files changed, 34 insertions(+), 17 deletions(-) >>>> >>>> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c >>>> index c945dba..ea09414 100644 >>>> --- a/hw/ppc/spapr_iommu.c >>>> +++ b/hw/ppc/spapr_iommu.c >>>> @@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) >>>> return 1ULL << tcet->page_shift; >>>> } >>>> >>>> +static void spapr_tce_vfio_start(MemoryRegion *iommu) >>>> +{ >>>> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); >>>> +} >>>> + >>>> +static void spapr_tce_vfio_stop(MemoryRegion *iommu) >>>> +{ >>>> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); >>>> +} >>>> + >>>> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); >>>> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); >>>> >>>> @@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { >>>> static MemoryRegionIOMMUOps spapr_iommu_ops = { >>>> .translate = spapr_tce_translate_iommu, >>>> .get_page_sizes = spapr_tce_get_page_sizes, >>>> + .vfio_start = spapr_tce_vfio_start, >>>> + .vfio_stop = spapr_tce_vfio_stop, >>> >>> Ok, so AFAICT these callbacks are called whenever a VFIO context is >>> added / removed from the gIOMMU's address space, and it's up to the >>> gIOMMU code to ref count that to see if there are any current vfio >>> users. That makes "vfio_start" and "vfio_stop" not great names. >>> >>> But.. better than changing the names would be to move the refcounting >>> to the generic code if you can manage it, so the individual gIOMMU >>> backends don't need to - they just told when they need to start / stop >>> providing VFIO support. >> >> Everything is manageable... >> >> This referencing is needed for the case of >=2 containers so >> 2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per >> VFIOContainer so VFIOGuestIOMMU is not the right place for the reference >> counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs >> with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from >> VFIOContainer to VFIOAddressSpace and then gIOMMU can handle >> refcounting? > > I'm having a lot of trouble parsing that. I think the ref parsing has > to be per-giommu (because individual giommus could, in theory, be > mapped or unmapped from an address space). Example 1. POWER8, no DDW, one QEMU PHB, 2 IOMMU groups, table sharing so just 1 container, one TCE table (aka gIOMMU), one TCE table in KVM, no reference counting needed at all, simple. Example 2. POWER7, no DDW, one QEMU PHB, 2 IOMMU groups, no table sharing so there are 2 containers but still one IOMMU MR which is added to each container so there are 2 gIOMMU objects. And there is still one TCE table in KVM (which is a guest view). Where do I put the reference counter which will count that there are 2 gIOMMUs per KVM TCE table in this example? > But I think that should be > in the vfio core, rather than being necessary in every giommu > implementation. I agree, I am just asking where exactly to put this counter.
On 04/21/2016 02:22 PM, Alexey Kardashevskiy wrote: > On 04/21/2016 01:59 PM, David Gibson wrote: >> On Wed, Apr 20, 2016 at 07:15:15PM +1000, Alexey Kardashevskiy wrote: >>> On 04/07/2016 10:40 AM, David Gibson wrote: >>>> On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: >>>>> The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - >>>>> a guest view of the table and a hardware TCE table. If there is no VFIO >>>>> presense in the address space, then just the guest view is used, if >>>>> this is the case, it is allocated in the KVM. However since there is no >>>>> support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, >>>>> we need to move the guest view from KVM to the userspace; and we need >>>>> to do this for every IOMMU on a bus with VFIO devices. >>>>> >>>>> This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to >>>>> notifiy IOMMU about changing environment so it can reallocate the table >>>>> to/from KVM or (when available) hook the IOMMU groups with the logical >>>>> bus (LIOBN) in the KVM. >>>>> >>>>> This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug >>>>> path as the new callbacks do this better - they notify IOMMU at >>>>> the exact moment when the configuration is changed, and this also >>>>> includes the case of PCI hot unplug. >>>>> >>>>> As there can be multiple containers attached to the same PHB/LIOBN, >>>>> this replaces the @need_vfio flag in sPAPRTCETable with the counter >>>>> of VFIO users. >>>>> >>>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> >>>> >>>> This looks correct, but there's one remaining ugly. >>>> >>>>> --- >>>>> Changes: >>>>> v15: >>>>> * s/need_vfio/vfio-Users/g >>>>> --- >>>>> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- >>>>> hw/ppc/spapr_pci.c | 6 ------ >>>>> hw/vfio/common.c | 9 +++++++++ >>>>> include/exec/memory.h | 4 ++++ >>>>> include/hw/ppc/spapr.h | 2 +- >>>>> 5 files changed, 34 insertions(+), 17 deletions(-) >>>>> >>>>> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c >>>>> index c945dba..ea09414 100644 >>>>> --- a/hw/ppc/spapr_iommu.c >>>>> +++ b/hw/ppc/spapr_iommu.c >>>>> @@ -155,6 +155,16 @@ static uint64_t >>>>> spapr_tce_get_page_sizes(MemoryRegion *iommu) >>>>> return 1ULL << tcet->page_shift; >>>>> } >>>>> >>>>> +static void spapr_tce_vfio_start(MemoryRegion *iommu) >>>>> +{ >>>>> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, >>>>> iommu), true); >>>>> +} >>>>> + >>>>> +static void spapr_tce_vfio_stop(MemoryRegion *iommu) >>>>> +{ >>>>> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, >>>>> iommu), false); >>>>> +} >>>>> + >>>>> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); >>>>> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); >>>>> >>>>> @@ -239,6 +249,8 @@ static const VMStateDescription >>>>> vmstate_spapr_tce_table = { >>>>> static MemoryRegionIOMMUOps spapr_iommu_ops = { >>>>> .translate = spapr_tce_translate_iommu, >>>>> .get_page_sizes = spapr_tce_get_page_sizes, >>>>> + .vfio_start = spapr_tce_vfio_start, >>>>> + .vfio_stop = spapr_tce_vfio_stop, >>>> >>>> Ok, so AFAICT these callbacks are called whenever a VFIO context is >>>> added / removed from the gIOMMU's address space, and it's up to the >>>> gIOMMU code to ref count that to see if there are any current vfio >>>> users. That makes "vfio_start" and "vfio_stop" not great names. >>>> >>>> But.. better than changing the names would be to move the refcounting >>>> to the generic code if you can manage it, so the individual gIOMMU >>>> backends don't need to - they just told when they need to start / stop >>>> providing VFIO support. >>> >>> Everything is manageable... >>> >>> This referencing is needed for the case of >=2 containers so >>> 2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per >>> VFIOContainer so VFIOGuestIOMMU is not the right place for the reference >>> counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs >>> with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from >>> VFIOContainer to VFIOAddressSpace and then gIOMMU can handle >>> refcounting? >> >> I'm having a lot of trouble parsing that. I think the ref parsing has >> to be per-giommu (because individual giommus could, in theory, be >> mapped or unmapped from an address space). > > > Example 1. > POWER8, no DDW, one QEMU PHB, 2 IOMMU groups, table sharing so just 1 > container, one TCE table (aka gIOMMU), one TCE table in KVM, no reference > counting needed at all, simple. > > Example 2. > POWER7, no DDW, one QEMU PHB, 2 IOMMU groups, no table sharing so there are > 2 containers but still one IOMMU MR which is added to each container so > there are 2 gIOMMU objects. And there is still one TCE table in KVM (which > is a guest view). Where do I put the reference counter which will count > that there are 2 gIOMMUs per KVM TCE table in this example? Ping? > > >> But I think that should be >> in the vfio core, rather than being necessary in every giommu >> implementation. > > > I agree, I am just asking where exactly to put this counter. > >
On Thu, Apr 21, 2016 at 02:22:01PM +1000, Alexey Kardashevskiy wrote: > On 04/21/2016 01:59 PM, David Gibson wrote: > >On Wed, Apr 20, 2016 at 07:15:15PM +1000, Alexey Kardashevskiy wrote: > >>On 04/07/2016 10:40 AM, David Gibson wrote: > >>>On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: > >>>>The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - > >>>>a guest view of the table and a hardware TCE table. If there is no VFIO > >>>>presense in the address space, then just the guest view is used, if > >>>>this is the case, it is allocated in the KVM. However since there is no > >>>>support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, > >>>>we need to move the guest view from KVM to the userspace; and we need > >>>>to do this for every IOMMU on a bus with VFIO devices. > >>>> > >>>>This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to > >>>>notifiy IOMMU about changing environment so it can reallocate the table > >>>>to/from KVM or (when available) hook the IOMMU groups with the logical > >>>>bus (LIOBN) in the KVM. > >>>> > >>>>This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug > >>>>path as the new callbacks do this better - they notify IOMMU at > >>>>the exact moment when the configuration is changed, and this also > >>>>includes the case of PCI hot unplug. > >>>> > >>>>As there can be multiple containers attached to the same PHB/LIOBN, > >>>>this replaces the @need_vfio flag in sPAPRTCETable with the counter > >>>>of VFIO users. > >>>> > >>>>Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > >>> > >>>This looks correct, but there's one remaining ugly. > >>> > >>>>--- > >>>>Changes: > >>>>v15: > >>>>* s/need_vfio/vfio-Users/g > >>>>--- > >>>> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- > >>>> hw/ppc/spapr_pci.c | 6 ------ > >>>> hw/vfio/common.c | 9 +++++++++ > >>>> include/exec/memory.h | 4 ++++ > >>>> include/hw/ppc/spapr.h | 2 +- > >>>> 5 files changed, 34 insertions(+), 17 deletions(-) > >>>> > >>>>diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c > >>>>index c945dba..ea09414 100644 > >>>>--- a/hw/ppc/spapr_iommu.c > >>>>+++ b/hw/ppc/spapr_iommu.c > >>>>@@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) > >>>> return 1ULL << tcet->page_shift; > >>>> } > >>>> > >>>>+static void spapr_tce_vfio_start(MemoryRegion *iommu) > >>>>+{ > >>>>+ spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); > >>>>+} > >>>>+ > >>>>+static void spapr_tce_vfio_stop(MemoryRegion *iommu) > >>>>+{ > >>>>+ spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); > >>>>+} > >>>>+ > >>>> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); > >>>> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); > >>>> > >>>>@@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { > >>>> static MemoryRegionIOMMUOps spapr_iommu_ops = { > >>>> .translate = spapr_tce_translate_iommu, > >>>> .get_page_sizes = spapr_tce_get_page_sizes, > >>>>+ .vfio_start = spapr_tce_vfio_start, > >>>>+ .vfio_stop = spapr_tce_vfio_stop, > >>> > >>>Ok, so AFAICT these callbacks are called whenever a VFIO context is > >>>added / removed from the gIOMMU's address space, and it's up to the > >>>gIOMMU code to ref count that to see if there are any current vfio > >>>users. That makes "vfio_start" and "vfio_stop" not great names. > >>> > >>>But.. better than changing the names would be to move the refcounting > >>>to the generic code if you can manage it, so the individual gIOMMU > >>>backends don't need to - they just told when they need to start / stop > >>>providing VFIO support. > >> > >>Everything is manageable... > >> > >>This referencing is needed for the case of >=2 containers so > >>2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per > >>VFIOContainer so VFIOGuestIOMMU is not the right place for the reference > >>counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs > >>with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from > >>VFIOContainer to VFIOAddressSpace and then gIOMMU can handle > >>refcounting? > > > >I'm having a lot of trouble parsing that. I think the ref parsing has > >to be per-giommu (because individual giommus could, in theory, be > >mapped or unmapped from an address space). > > > Example 1. > POWER8, no DDW, one QEMU PHB, 2 IOMMU groups, table sharing so just 1 > container, one TCE table (aka gIOMMU), one TCE table in KVM, no reference > counting needed at all, simple. > > Example 2. > POWER7, no DDW, one QEMU PHB, 2 IOMMU groups, no table sharing so there are > 2 containers but still one IOMMU MR which is added to each container so > there are 2 gIOMMU objects. And there is still one TCE table in KVM (which > is a guest view). Where do I put the reference counter which will count that > there are 2 gIOMMUs per KVM TCE table in this example? Ah.. I'd forgotten that the gIOMMU object is per guest IOMMU window *and* per container, not just per guest IOMMU window. Ultimately it's the code implementing the guest side IOMMU which needs to know if it is supporting VFIO or not, so in generic terms that means per IOMMU-type MemoryRegion. Essentially you need to count the number of VFIOGuestIOMMU objects associated with each (gIOMMU) MemoryRegion, and notify the MemoryRegion if that changes from zero to non-zero or vice versa. I'd prefer if we can maintain that count from just the VFIO code and just notify the gIOMMU code on zero / non-zero changes. But I guess we'd need approval from Paolo to add that count to the MemoryRegion. The fallback would be similar to what you have - instead the MemoryRegion gets notified whenever a VFIOGuestIOMMU is attached or removed, and the MR (i.e. the guest side IOMMU code) has to maintain the count itself.
On 04/27/2016 04:39 PM, David Gibson wrote: > On Thu, Apr 21, 2016 at 02:22:01PM +1000, Alexey Kardashevskiy wrote: >> On 04/21/2016 01:59 PM, David Gibson wrote: >>> On Wed, Apr 20, 2016 at 07:15:15PM +1000, Alexey Kardashevskiy wrote: >>>> On 04/07/2016 10:40 AM, David Gibson wrote: >>>>> On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: >>>>>> The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - >>>>>> a guest view of the table and a hardware TCE table. If there is no VFIO >>>>>> presense in the address space, then just the guest view is used, if >>>>>> this is the case, it is allocated in the KVM. However since there is no >>>>>> support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, >>>>>> we need to move the guest view from KVM to the userspace; and we need >>>>>> to do this for every IOMMU on a bus with VFIO devices. >>>>>> >>>>>> This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to >>>>>> notifiy IOMMU about changing environment so it can reallocate the table >>>>>> to/from KVM or (when available) hook the IOMMU groups with the logical >>>>>> bus (LIOBN) in the KVM. >>>>>> >>>>>> This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug >>>>>> path as the new callbacks do this better - they notify IOMMU at >>>>>> the exact moment when the configuration is changed, and this also >>>>>> includes the case of PCI hot unplug. >>>>>> >>>>>> As there can be multiple containers attached to the same PHB/LIOBN, >>>>>> this replaces the @need_vfio flag in sPAPRTCETable with the counter >>>>>> of VFIO users. >>>>>> >>>>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> >>>>> >>>>> This looks correct, but there's one remaining ugly. >>>>> >>>>>> --- >>>>>> Changes: >>>>>> v15: >>>>>> * s/need_vfio/vfio-Users/g >>>>>> --- >>>>>> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- >>>>>> hw/ppc/spapr_pci.c | 6 ------ >>>>>> hw/vfio/common.c | 9 +++++++++ >>>>>> include/exec/memory.h | 4 ++++ >>>>>> include/hw/ppc/spapr.h | 2 +- >>>>>> 5 files changed, 34 insertions(+), 17 deletions(-) >>>>>> >>>>>> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c >>>>>> index c945dba..ea09414 100644 >>>>>> --- a/hw/ppc/spapr_iommu.c >>>>>> +++ b/hw/ppc/spapr_iommu.c >>>>>> @@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) >>>>>> return 1ULL << tcet->page_shift; >>>>>> } >>>>>> >>>>>> +static void spapr_tce_vfio_start(MemoryRegion *iommu) >>>>>> +{ >>>>>> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); >>>>>> +} >>>>>> + >>>>>> +static void spapr_tce_vfio_stop(MemoryRegion *iommu) >>>>>> +{ >>>>>> + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); >>>>>> +} >>>>>> + >>>>>> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); >>>>>> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); >>>>>> >>>>>> @@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { >>>>>> static MemoryRegionIOMMUOps spapr_iommu_ops = { >>>>>> .translate = spapr_tce_translate_iommu, >>>>>> .get_page_sizes = spapr_tce_get_page_sizes, >>>>>> + .vfio_start = spapr_tce_vfio_start, >>>>>> + .vfio_stop = spapr_tce_vfio_stop, >>>>> >>>>> Ok, so AFAICT these callbacks are called whenever a VFIO context is >>>>> added / removed from the gIOMMU's address space, and it's up to the >>>>> gIOMMU code to ref count that to see if there are any current vfio >>>>> users. That makes "vfio_start" and "vfio_stop" not great names. >>>>> >>>>> But.. better than changing the names would be to move the refcounting >>>>> to the generic code if you can manage it, so the individual gIOMMU >>>>> backends don't need to - they just told when they need to start / stop >>>>> providing VFIO support. >>>> >>>> Everything is manageable... >>>> >>>> This referencing is needed for the case of >=2 containers so >>>> 2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per >>>> VFIOContainer so VFIOGuestIOMMU is not the right place for the reference >>>> counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs >>>> with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from >>>> VFIOContainer to VFIOAddressSpace and then gIOMMU can handle >>>> refcounting? >>> >>> I'm having a lot of trouble parsing that. I think the ref parsing has >>> to be per-giommu (because individual giommus could, in theory, be >>> mapped or unmapped from an address space). >> >> >> Example 1. >> POWER8, no DDW, one QEMU PHB, 2 IOMMU groups, table sharing so just 1 >> container, one TCE table (aka gIOMMU), one TCE table in KVM, no reference >> counting needed at all, simple. >> >> Example 2. >> POWER7, no DDW, one QEMU PHB, 2 IOMMU groups, no table sharing so there are >> 2 containers but still one IOMMU MR which is added to each container so >> there are 2 gIOMMU objects. And there is still one TCE table in KVM (which >> is a guest view). Where do I put the reference counter which will count that >> there are 2 gIOMMUs per KVM TCE table in this example? > > Ah.. I'd forgotten that the gIOMMU object is per guest IOMMU window > *and* per container, not just per guest IOMMU window. > > Ultimately it's the code implementing the guest side IOMMU which needs > to know if it is supporting VFIO or not, so in generic terms that > means per IOMMU-type MemoryRegion. > > Essentially you need to count the number of VFIOGuestIOMMU objects > associated with each (gIOMMU) MemoryRegion, and notify the > MemoryRegion if that changes from zero to non-zero or vice versa. > > I'd prefer if we can maintain that count from just the VFIO code and > just notify the gIOMMU code on zero / non-zero changes. But I guess > we'd need approval from Paolo to add that count to the MemoryRegion. Why MR? I could wrap MR to "VFIOIOMMUMR", add a counter and keep a list of these VFIOIOMMUMRs in VFIOAddressSpace. I am adding Paolo, just for the case :) > The fallback would be similar to what you have - instead the > MemoryRegion gets notified whenever a VFIOGuestIOMMU is attached or > removed, and the MR (i.e. the guest side IOMMU code) has to maintain > the count itself.
On Wed, Apr 27, 2016 at 07:14:15PM +1000, Alexey Kardashevskiy wrote: > On 04/27/2016 04:39 PM, David Gibson wrote: > >On Thu, Apr 21, 2016 at 02:22:01PM +1000, Alexey Kardashevskiy wrote: > >>On 04/21/2016 01:59 PM, David Gibson wrote: > >>>On Wed, Apr 20, 2016 at 07:15:15PM +1000, Alexey Kardashevskiy wrote: > >>>>On 04/07/2016 10:40 AM, David Gibson wrote: > >>>>>On Mon, Apr 04, 2016 at 07:33:43PM +1000, Alexey Kardashevskiy wrote: > >>>>>>The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - > >>>>>>a guest view of the table and a hardware TCE table. If there is no VFIO > >>>>>>presense in the address space, then just the guest view is used, if > >>>>>>this is the case, it is allocated in the KVM. However since there is no > >>>>>>support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, > >>>>>>we need to move the guest view from KVM to the userspace; and we need > >>>>>>to do this for every IOMMU on a bus with VFIO devices. > >>>>>> > >>>>>>This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to > >>>>>>notifiy IOMMU about changing environment so it can reallocate the table > >>>>>>to/from KVM or (when available) hook the IOMMU groups with the logical > >>>>>>bus (LIOBN) in the KVM. > >>>>>> > >>>>>>This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug > >>>>>>path as the new callbacks do this better - they notify IOMMU at > >>>>>>the exact moment when the configuration is changed, and this also > >>>>>>includes the case of PCI hot unplug. > >>>>>> > >>>>>>As there can be multiple containers attached to the same PHB/LIOBN, > >>>>>>this replaces the @need_vfio flag in sPAPRTCETable with the counter > >>>>>>of VFIO users. > >>>>>> > >>>>>>Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > >>>>> > >>>>>This looks correct, but there's one remaining ugly. > >>>>> > >>>>>>--- > >>>>>>Changes: > >>>>>>v15: > >>>>>>* s/need_vfio/vfio-Users/g > >>>>>>--- > >>>>>> hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- > >>>>>> hw/ppc/spapr_pci.c | 6 ------ > >>>>>> hw/vfio/common.c | 9 +++++++++ > >>>>>> include/exec/memory.h | 4 ++++ > >>>>>> include/hw/ppc/spapr.h | 2 +- > >>>>>> 5 files changed, 34 insertions(+), 17 deletions(-) > >>>>>> > >>>>>>diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c > >>>>>>index c945dba..ea09414 100644 > >>>>>>--- a/hw/ppc/spapr_iommu.c > >>>>>>+++ b/hw/ppc/spapr_iommu.c > >>>>>>@@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) > >>>>>> return 1ULL << tcet->page_shift; > >>>>>> } > >>>>>> > >>>>>>+static void spapr_tce_vfio_start(MemoryRegion *iommu) > >>>>>>+{ > >>>>>>+ spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); > >>>>>>+} > >>>>>>+ > >>>>>>+static void spapr_tce_vfio_stop(MemoryRegion *iommu) > >>>>>>+{ > >>>>>>+ spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); > >>>>>>+} > >>>>>>+ > >>>>>> static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); > >>>>>> static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); > >>>>>> > >>>>>>@@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { > >>>>>> static MemoryRegionIOMMUOps spapr_iommu_ops = { > >>>>>> .translate = spapr_tce_translate_iommu, > >>>>>> .get_page_sizes = spapr_tce_get_page_sizes, > >>>>>>+ .vfio_start = spapr_tce_vfio_start, > >>>>>>+ .vfio_stop = spapr_tce_vfio_stop, > >>>>> > >>>>>Ok, so AFAICT these callbacks are called whenever a VFIO context is > >>>>>added / removed from the gIOMMU's address space, and it's up to the > >>>>>gIOMMU code to ref count that to see if there are any current vfio > >>>>>users. That makes "vfio_start" and "vfio_stop" not great names. > >>>>> > >>>>>But.. better than changing the names would be to move the refcounting > >>>>>to the generic code if you can manage it, so the individual gIOMMU > >>>>>backends don't need to - they just told when they need to start / stop > >>>>>providing VFIO support. > >>>> > >>>>Everything is manageable... > >>>> > >>>>This referencing is needed for the case of >=2 containers so > >>>>2xvfio_listener_region_add will create 2xVFIOGuestIOMMU as they are per > >>>>VFIOContainer so VFIOGuestIOMMU is not the right place for the reference > >>>>counting, VFIOAddressSpace seems to be that place (=> add list of IOMMU MRs > >>>>with refcounter). Or even IOMMU MR. Or move VFIOGuestIOMMU list from > >>>>VFIOContainer to VFIOAddressSpace and then gIOMMU can handle > >>>>refcounting? > >>> > >>>I'm having a lot of trouble parsing that. I think the ref parsing has > >>>to be per-giommu (because individual giommus could, in theory, be > >>>mapped or unmapped from an address space). > >> > >> > >>Example 1. > >>POWER8, no DDW, one QEMU PHB, 2 IOMMU groups, table sharing so just 1 > >>container, one TCE table (aka gIOMMU), one TCE table in KVM, no reference > >>counting needed at all, simple. > >> > >>Example 2. > >>POWER7, no DDW, one QEMU PHB, 2 IOMMU groups, no table sharing so there are > >>2 containers but still one IOMMU MR which is added to each container so > >>there are 2 gIOMMU objects. And there is still one TCE table in KVM (which > >>is a guest view). Where do I put the reference counter which will count that > >>there are 2 gIOMMUs per KVM TCE table in this example? > > > >Ah.. I'd forgotten that the gIOMMU object is per guest IOMMU window > >*and* per container, not just per guest IOMMU window. > > > >Ultimately it's the code implementing the guest side IOMMU which needs > >to know if it is supporting VFIO or not, so in generic terms that > >means per IOMMU-type MemoryRegion. > > > >Essentially you need to count the number of VFIOGuestIOMMU objects > >associated with each (gIOMMU) MemoryRegion, and notify the > >MemoryRegion if that changes from zero to non-zero or vice versa. > > > >I'd prefer if we can maintain that count from just the VFIO code and > >just notify the gIOMMU code on zero / non-zero changes. But I guess > >we'd need approval from Paolo to add that count to the MemoryRegion. > > > Why MR? I could wrap MR to "VFIOIOMMUMR", add a counter and keep a list of > these VFIOIOMMUMRs in VFIOAddressSpace. Ah, yes I guess we could. It's just kinda ugly to have to keep another object with the same lifetime around for one extra counter. > I am adding Paolo, just for the case :) > > > >The fallback would be similar to what you have - instead the > >MemoryRegion gets notified whenever a VFIOGuestIOMMU is attached or > >removed, and the MR (i.e. the guest side IOMMU code) has to maintain > >the count itself. > > > > > >
diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c index c945dba..ea09414 100644 --- a/hw/ppc/spapr_iommu.c +++ b/hw/ppc/spapr_iommu.c @@ -155,6 +155,16 @@ static uint64_t spapr_tce_get_page_sizes(MemoryRegion *iommu) return 1ULL << tcet->page_shift; } +static void spapr_tce_vfio_start(MemoryRegion *iommu) +{ + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), true); +} + +static void spapr_tce_vfio_stop(MemoryRegion *iommu) +{ + spapr_tce_set_need_vfio(container_of(iommu, sPAPRTCETable, iommu), false); +} + static void spapr_tce_table_do_enable(sPAPRTCETable *tcet); static void spapr_tce_table_do_disable(sPAPRTCETable *tcet); @@ -239,6 +249,8 @@ static const VMStateDescription vmstate_spapr_tce_table = { static MemoryRegionIOMMUOps spapr_iommu_ops = { .translate = spapr_tce_translate_iommu, .get_page_sizes = spapr_tce_get_page_sizes, + .vfio_start = spapr_tce_vfio_start, + .vfio_stop = spapr_tce_vfio_stop, }; static int spapr_tce_table_realize(DeviceState *dev) @@ -248,7 +260,7 @@ static int spapr_tce_table_realize(DeviceState *dev) char tmp[32]; tcet->fd = -1; - tcet->need_vfio = false; + tcet->vfio_users = 0; snprintf(tmp, sizeof(tmp), "tce-root-%x", tcet->liobn); memory_region_init(&tcet->root, tcetobj, tmp, UINT64_MAX); @@ -268,20 +280,18 @@ 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; - } + tcet->vfio_users += need_vfio ? 1 : -1; + g_assert(tcet->vfio_users >= 0); + g_assert(tcet->table); - if (!need_vfio) { + if (!tcet->vfio_users) { /* FIXME: We don't support transition back to KVM accelerated * TCEs yet */ return; } - tcet->need_vfio = true; - - if (tcet->fd < 0) { + if (tcet->vfio_users > 1) { + g_assert(tcet->fd < 0); /* Table is already in userspace, nothing to be do */ return; } @@ -327,7 +337,7 @@ static void spapr_tce_table_do_enable(sPAPRTCETable *tcet) tcet->page_shift, tcet->nb_table, &tcet->fd, - tcet->need_vfio); + tcet->vfio_users != 0); memory_region_set_size(&tcet->iommu, (uint64_t)tcet->nb_table << tcet->page_shift); diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c index 5497a18..f864fde 100644 --- a/hw/ppc/spapr_pci.c +++ b/hw/ppc/spapr_pci.c @@ -1083,12 +1083,6 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc, void *fdt = NULL; int fdt_start_offset = 0, fdt_size; - if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) { - sPAPRTCETable *tcet = spapr_tce_find_by_liobn(phb->dma_liobn); - - spapr_tce_set_need_vfio(tcet, true); - } - if (dev->hotplugged) { fdt = create_device_tree(&fdt_size); fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0); diff --git a/hw/vfio/common.c b/hw/vfio/common.c index ea79311..5e5b77c 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -421,6 +421,9 @@ static void vfio_listener_region_add(MemoryListener *listener, QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next); memory_region_register_iommu_notifier(giommu->iommu, &giommu->n); + if (section->mr->iommu_ops && section->mr->iommu_ops->vfio_start) { + section->mr->iommu_ops->vfio_start(section->mr); + } memory_region_iommu_replay(giommu->iommu, &giommu->n, false); @@ -466,6 +469,7 @@ static void vfio_listener_region_del(MemoryListener *listener, VFIOContainer *container = container_of(listener, VFIOContainer, listener); hwaddr iova, end; int ret; + MemoryRegion *iommu = NULL; if (vfio_listener_skipped_section(section)) { trace_vfio_listener_region_del_skip( @@ -487,6 +491,7 @@ static void vfio_listener_region_del(MemoryListener *listener, QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) { if (giommu->iommu == section->mr) { memory_region_unregister_iommu_notifier(&giommu->n); + iommu = giommu->iommu; QLIST_REMOVE(giommu, giommu_next); g_free(giommu); break; @@ -519,6 +524,10 @@ static void vfio_listener_region_del(MemoryListener *listener, "0x%"HWADDR_PRIx") = %d (%m)", container, iova, end - iova, ret); } + + if (iommu && iommu->iommu_ops && iommu->iommu_ops->vfio_stop) { + iommu->iommu_ops->vfio_stop(section->mr); + } } static const MemoryListener vfio_memory_listener = { diff --git a/include/exec/memory.h b/include/exec/memory.h index eb5ce67..f1de133f 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -152,6 +152,10 @@ struct MemoryRegionIOMMUOps { IOMMUTLBEntry (*translate)(MemoryRegion *iommu, hwaddr addr, bool is_write); /* Returns supported page sizes */ uint64_t (*get_page_sizes)(MemoryRegion *iommu); + /* Called when VFIO starts using this */ + void (*vfio_start)(MemoryRegion *iommu); + /* Called when VFIO stops using this */ + void (*vfio_stop)(MemoryRegion *iommu); }; typedef struct CoalescedMemoryRange CoalescedMemoryRange; diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index 471eb4a..5c00e38 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -548,7 +548,7 @@ struct sPAPRTCETable { uint32_t mig_nb_table; uint64_t *mig_table; bool bypass; - bool need_vfio; + int vfio_users; int fd; MemoryRegion root, iommu; struct VIOsPAPRDevice *vdev; /* for @bypass migration compatibility only */
The sPAPR TCE tables manage 2 copies when VFIO is using an IOMMU - a guest view of the table and a hardware TCE table. If there is no VFIO presense in the address space, then just the guest view is used, if this is the case, it is allocated in the KVM. However since there is no support yet for VFIO in KVM TCE hypercalls, when we start using VFIO, we need to move the guest view from KVM to the userspace; and we need to do this for every IOMMU on a bus with VFIO devices. This adds vfio_start/vfio_stop callbacks in MemoryRegionIOMMUOps to notifiy IOMMU about changing environment so it can reallocate the table to/from KVM or (when available) hook the IOMMU groups with the logical bus (LIOBN) in the KVM. This removes explicit spapr_tce_set_need_vfio() call from PCI hotplug path as the new callbacks do this better - they notify IOMMU at the exact moment when the configuration is changed, and this also includes the case of PCI hot unplug. As there can be multiple containers attached to the same PHB/LIOBN, this replaces the @need_vfio flag in sPAPRTCETable with the counter of VFIO users. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- Changes: v15: * s/need_vfio/vfio-Users/g --- hw/ppc/spapr_iommu.c | 30 ++++++++++++++++++++---------- hw/ppc/spapr_pci.c | 6 ------ hw/vfio/common.c | 9 +++++++++ include/exec/memory.h | 4 ++++ include/hw/ppc/spapr.h | 2 +- 5 files changed, 34 insertions(+), 17 deletions(-)