> From: David Gibson [mailto:david@xxxxxxxxxxxxxxxxxxxxx] > Sent: Monday, October 28, 2019 1:39 AM > To: Liu, Yi L <yi.l.liu@xxxxxxxxx> > Subject: Re: [RFC v2 04/22] hw/iommu: introduce IOMMUContext > > On Thu, Oct 24, 2019 at 08:34:25AM -0400, Liu Yi L wrote: > > From: Peter Xu <peterx@xxxxxxxxxx> > > > > This patch adds IOMMUContext as an abstract layer of IOMMU related > > operations. The current usage of this abstract layer is setup dual- > > stage IOMMU translation (vSVA) for vIOMMU. > > > > To setup dual-stage IOMMU translation, vIOMMU needs to propagate > > guest changes to host via passthru channels (e.g. VFIO). To have > > a better abstraction, it is better to avoid direct calling between > > vIOMMU and VFIO. So we have this new structure to act as abstract > > layer between VFIO and vIOMMU. So far, it is proposed to provide a > > notifier mechanism, which registered by VFIO and fired by vIOMMU. > > > > For more background, may refer to the discussion below: > > > > https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg05022.html > > > > 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/Makefile.objs | 1 + > > hw/iommu/Makefile.objs | 1 + > > hw/iommu/iommu.c | 66 ++++++++++++++++++++++++++++++++++++++++ > > include/hw/iommu/iommu.h | 79 > ++++++++++++++++++++++++++++++++++++++++++++++++ > > 4 files changed, 147 insertions(+) > > create mode 100644 hw/iommu/Makefile.objs > > create mode 100644 hw/iommu/iommu.c > > create mode 100644 include/hw/iommu/iommu.h > > > > diff --git a/hw/Makefile.objs b/hw/Makefile.objs > > index ece6cc3..ac19f9c 100644 > > --- a/hw/Makefile.objs > > +++ b/hw/Makefile.objs > > @@ -39,6 +39,7 @@ devices-dirs-y += xen/ > > devices-dirs-$(CONFIG_MEM_DEVICE) += mem/ > > devices-dirs-y += semihosting/ > > devices-dirs-y += smbios/ > > +devices-dirs-y += iommu/ > > endif > > > > common-obj-y += $(devices-dirs-y) > > diff --git a/hw/iommu/Makefile.objs b/hw/iommu/Makefile.objs > > new file mode 100644 > > index 0000000..0484b79 > > --- /dev/null > > +++ b/hw/iommu/Makefile.objs > > @@ -0,0 +1 @@ > > +obj-y += iommu.o > > diff --git a/hw/iommu/iommu.c b/hw/iommu/iommu.c > > new file mode 100644 > > index 0000000..2391b0d > > --- /dev/null > > +++ b/hw/iommu/iommu.c > > @@ -0,0 +1,66 @@ > > +/* > > + * QEMU abstract of IOMMU context > > + * > > + * Copyright (C) 2019 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.h" > > + > > +void iommu_ctx_notifier_register(IOMMUContext *iommu_ctx, > > + IOMMUCTXNotifier *n, > > + IOMMUCTXNotifyFn fn, > > + IOMMUCTXEvent event) > > +{ > > + n->event = event; > > + n->iommu_ctx_event_notify = fn; > > + QLIST_INSERT_HEAD(&iommu_ctx->iommu_ctx_notifiers, n, node); > > Having this both modify the IOMMUCTXNotifier structure and insert it > in the list seems confusing to me - and gratuitously different from > the interface for both IOMMUNotifier and Notifier. > > Separating out a iommu_ctx_notifier_init() as a helper and having > register take a fully initialized structure seems better to me. Thanks, will do it in next version. > > + return; > > Using an explicit return at the end of a function returning void is an > odd style. got it, will fix it in next version. > > > +} > > + > > +void iommu_ctx_notifier_unregister(IOMMUContext *iommu_ctx, > > + IOMMUCTXNotifier *notifier) > > +{ > > + IOMMUCTXNotifier *cur, *next; > > + > > + QLIST_FOREACH_SAFE(cur, &iommu_ctx->iommu_ctx_notifiers, node, next) { > > + if (cur == notifier) { > > + QLIST_REMOVE(cur, node); > > + break; > > + } > > + } > > +} > > + > > +void iommu_ctx_event_notify(IOMMUContext *iommu_ctx, > > + IOMMUCTXEventData *event_data) > > +{ > > + IOMMUCTXNotifier *cur; > > + > > + QLIST_FOREACH(cur, &iommu_ctx->iommu_ctx_notifiers, node) { > > + if ((cur->event == event_data->event) && > > + cur->iommu_ctx_event_notify) { > > Do you actually need the test on iommu_ctx_event_notify? I can't see > any reason to register a notifier with a NULL function pointer. sure, let me remove the check. I may have been too careful here. :-) > > + cur->iommu_ctx_event_notify(cur, event_data); > > + } > > + } > > +} > > + > > +void iommu_context_init(IOMMUContext *iommu_ctx) > > +{ > > + QLIST_INIT(&iommu_ctx->iommu_ctx_notifiers); > > +} > > diff --git a/include/hw/iommu/iommu.h b/include/hw/iommu/iommu.h > > new file mode 100644 > > index 0000000..c22c442 > > --- /dev/null > > +++ b/include/hw/iommu/iommu.h > > @@ -0,0 +1,79 @@ > > +/* > > + * QEMU abstraction of IOMMU Context > > + * > > + * Copyright (C) 2019 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_PCI_PASID_H > > +#define HW_PCI_PASID_H > > These guards need to be updated for the new header name. Oops, thanks for spotting it out. > > + > > +#include "qemu/queue.h" > > +#ifndef CONFIG_USER_ONLY > > +#include "exec/hwaddr.h" > > +#endif > > + > > +typedef struct IOMMUContext IOMMUContext; > > + > > +enum IOMMUCTXEvent { > > + IOMMU_CTX_EVENT_NUM, > > +}; > > +typedef enum IOMMUCTXEvent IOMMUCTXEvent; > > + > > +struct IOMMUCTXEventData { > > + IOMMUCTXEvent event; > > + uint64_t length; > > + void *data; > > +}; > > +typedef struct IOMMUCTXEventData IOMMUCTXEventData; > > + > > +typedef struct IOMMUCTXNotifier IOMMUCTXNotifier; > > + > > +typedef void (*IOMMUCTXNotifyFn)(IOMMUCTXNotifier *notifier, > > + IOMMUCTXEventData *event_data); > > + > > +struct IOMMUCTXNotifier { > > + IOMMUCTXNotifyFn iommu_ctx_event_notify; > > + /* > > + * What events we are listening to. Let's allow multiple event > > + * registrations from beginning. > > + */ > > + IOMMUCTXEvent event; > > + QLIST_ENTRY(IOMMUCTXNotifier) node; > > +}; > > + > > +/* > > + * This is an abstraction of IOMMU context. > > + */ > > +struct IOMMUContext { > > + uint32_t pasid; > > This confuses me a bit. I thought the idea was that IOMMUContext with > SVM would represent all the PASIDs in use, but here we have a specific > pasid stored in the structure. It's added by mistake. Should not be included. No patch will use this field. Will remove it. Thanks for the careful review. Thanks, Yi Liu
