On Wed, Jan 29, 2020 at 04:16:34AM -0800, Liu, Yi L wrote: > From: Peter Xu <peterx@xxxxxxxxxx> > > Currently, many platform vendors provide the capability of dual stage > DMA address translation in hardware. For example, nested translation > on Intel VT-d scalable mode, nested stage translation on ARM SMMUv3, > and etc. Also there are efforts to make QEMU vIOMMU be backed by dual > stage DMA address translation capability provided by hardware to have > better address translation support for passthru devices. > > As so, making vIOMMU be backed by dual stage translation capability > requires QEMU vIOMMU to have a way to get aware of such hardware > capability and also require a way to receive DMA address translation > faults (e.g. I/O page request) from host as guest owns stage-1 translation > structures in dual stage DAM address translation. > > This patch adds IOMMUContext as an abstract of vIOMMU related operations. > Like provide a way for passthru modules (e.g. VFIO) to register > DualStageIOMMUObject instances. And in future, it is expected to offer > support for receiving host DMA translation faults happened on stage-1 > translation. > > For more backgrounds, may refer to the discussion below, while there > is also difference between the current implementation and original > proposal. This patch introduces the IOMMUContext as an abstract layer > for passthru module (e.g. VFIO) calls into vIOMMU. The first introduced > interface is to make QEMU vIOMMU be aware of dual stage translation > capability. > > https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg05022.html Again, is there a reason for not making this a QOM class or interface? I'm not very clear on the relationship betwen an IOMMUContext and a DualStageIOMMUObject. Can there be many IOMMUContexts to a DualStageIOMMUOBject? The other way around? Or is it just zero-or-one DualStageIOMMUObjects to an IOMMUContext? > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Cc: Peter Xu <peterx@xxxxxxxxxx> > Cc: Eric Auger <eric.auger@xxxxxxxxxx> > Cc: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx> > Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx> > --- > hw/iommu/Makefile.objs | 1 + > hw/iommu/iommu_context.c | 54 +++++++++++++++++++++++++++++++++++ > include/hw/iommu/iommu_context.h | 61 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 116 insertions(+) > create mode 100644 hw/iommu/iommu_context.c > create mode 100644 include/hw/iommu/iommu_context.h > > diff --git a/hw/iommu/Makefile.objs b/hw/iommu/Makefile.objs > index d4f3b39..1e45072 100644 > --- a/hw/iommu/Makefile.objs > +++ b/hw/iommu/Makefile.objs > @@ -1 +1,2 @@ > obj-y += dual_stage_iommu.o > +obj-y += iommu_context.o > diff --git a/hw/iommu/iommu_context.c b/hw/iommu/iommu_context.c > new file mode 100644 > index 0000000..6340ca3 > --- /dev/null > +++ b/hw/iommu/iommu_context.c > @@ -0,0 +1,54 @@ > +/* > + * QEMU abstract of vIOMMU context > + * > + * Copyright (C) 2020 Red Hat Inc. > + * > + * Authors: Peter Xu <peterx@xxxxxxxxxx>, > + * Liu Yi L <yi.l.liu@xxxxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + > + * You should have received a copy of the GNU General Public License along > + * with this program; if not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include "qemu/osdep.h" > +#include "hw/iommu/iommu_context.h" > + > +int iommu_context_register_ds_iommu(IOMMUContext *iommu_ctx, > + DualStageIOMMUObject *dsi_obj) > +{ > + if (!iommu_ctx || !dsi_obj) { Would this ever happen apart from a bug in the caller? If not it should be an assert(). > + return -ENOENT; > + } > + > + if (iommu_ctx->ops && iommu_ctx->ops->register_ds_iommu) { > + return iommu_ctx->ops->register_ds_iommu(iommu_ctx, dsi_obj); > + } > + return -ENOENT; > +} > + > +void iommu_context_unregister_ds_iommu(IOMMUContext *iommu_ctx, > + DualStageIOMMUObject *dsi_obj) > +{ > + if (!iommu_ctx || !dsi_obj) { > + return; > + } > + > + if (iommu_ctx->ops && iommu_ctx->ops->unregister_ds_iommu) { > + iommu_ctx->ops->unregister_ds_iommu(iommu_ctx, dsi_obj); > + } > +} > + > +void iommu_context_init(IOMMUContext *iommu_ctx, IOMMUContextOps *ops) > +{ > + iommu_ctx->ops = ops; > +} > diff --git a/include/hw/iommu/iommu_context.h b/include/hw/iommu/iommu_context.h > new file mode 100644 > index 0000000..6f2ccb5 > --- /dev/null > +++ b/include/hw/iommu/iommu_context.h > @@ -0,0 +1,61 @@ > +/* > + * QEMU abstraction of IOMMU Context > + * > + * Copyright (C) 2020 Red Hat Inc. > + * > + * Authors: Peter Xu <peterx@xxxxxxxxxx>, > + * Liu, Yi L <yi.l.liu@xxxxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + > + * You should have received a copy of the GNU General Public License along > + * with this program; if not, see <http://www.gnu.org/licenses/>. > + */ > + > +#ifndef HW_IOMMU_CONTEXT_H > +#define HW_IOMMU_CONTEXT_H > + > +#include "qemu/queue.h" > +#ifndef CONFIG_USER_ONLY > +#include "exec/hwaddr.h" > +#endif > +#include "hw/iommu/dual_stage_iommu.h" > + > +typedef struct IOMMUContext IOMMUContext; > +typedef struct IOMMUContextOps IOMMUContextOps; > + > +struct IOMMUContextOps { > + /* > + * Register DualStageIOMMUObject to vIOMMU thus vIOMMU > + * is aware of dual stage translation capability, and > + * also be able to setup dual stage translation via > + * interfaces exposed by DualStageIOMMUObject. > + */ > + int (*register_ds_iommu)(IOMMUContext *iommu_ctx, > + DualStageIOMMUObject *dsi_obj); > + void (*unregister_ds_iommu)(IOMMUContext *iommu_ctx, > + DualStageIOMMUObject *dsi_obj); > +}; > + > +/* > + * This is an abstraction of IOMMU context. > + */ > +struct IOMMUContext { > + IOMMUContextOps *ops; > +}; > + > +int iommu_context_register_ds_iommu(IOMMUContext *iommu_ctx, > + DualStageIOMMUObject *dsi_obj); > +void iommu_context_unregister_ds_iommu(IOMMUContext *iommu_ctx, > + DualStageIOMMUObject *dsi_obj); > +void iommu_context_init(IOMMUContext *iommu_ctx, IOMMUContextOps *ops); > + > +#endif -- 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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