Re: [Qemu-devel] [RFC PATCH 8/8] iommu: introduce hw/core/iommu

["Liu, Yi L" <yi.l.liu@linux.intel.com>]

On Thu, Apr 27, 2017 at 05:34:20PM +0800, Peter Xu wrote:
> Time to consider a common stuff for IOMMU. Let's start from an common
> IOMMU object (which should be inlayed in custom IOMMU implementations)
> and a notifier mechanism.
> 
> Let VT-d IOMMU be the first user.
> 
> An example to use this per-iommu notifier:
> 
>   (when registering)
>   iommu = address_space_iommu_get(pci_device_iommu_address_space(dev));
>   notifier = iommu_notifier_register(iommu, IOMMU_EVENT_SVM_PASID, func);
>   ...
>   (when notify)
>   IOMMUEvent event = { .type = IOMMU_EVENT_SVM_PASID ... };
>   iommu_notify(iommu, &event);
>   ...
>   (when releasing)
>   iommu_notifier_unregister(notifier);
>   notifier = NULL;
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/core/Makefile.objs         |  1 +
>  hw/core/iommu.c               | 61 ++++++++++++++++++++++++++++++++++++
>  hw/i386/intel_iommu.c         |  2 +-
>  include/exec/memory.h         | 10 +-----
>  include/hw/core/iommu.h       | 72 +++++++++++++++++++++++++++++++++++++++++++
>  include/hw/i386/intel_iommu.h |  2 ++
>  6 files changed, 138 insertions(+), 10 deletions(-)
>  create mode 100644 hw/core/iommu.c
>  create mode 100644 include/hw/core/iommu.h
> 
> diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
> index 91450b2..85cca44 100644
> --- a/hw/core/Makefile.objs
> +++ b/hw/core/Makefile.objs
> @@ -5,6 +5,7 @@ common-obj-y += fw-path-provider.o
>  # irq.o needed for qdev GPIO handling:
>  common-obj-y += irq.o
>  common-obj-y += hotplug.o
> +common-obj-y += iommu.o
>  obj-y += nmi.o
>  
>  common-obj-$(CONFIG_EMPTY_SLOT) += empty_slot.o
> diff --git a/hw/core/iommu.c b/hw/core/iommu.c
> new file mode 100644
> index 0000000..e014e96
> --- /dev/null
> +++ b/hw/core/iommu.c
> @@ -0,0 +1,61 @@
> +/*
> + * QEMU emulation of IOMMU logic
> + *
> + * Copyright (C) 2017 Red Hat Inc.
> + *
> + * Authors: Peter Xu <peterx@redhat.com>,
> + *
> + * 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/core/iommu.h"
> +
> +IOMMUNotifier *iommu_notifier_register(IOMMUObject *iommu,
> +                                       IOMMUNotifyFn fn,
> +                                       uint64_t event_mask)
> +{
> +    IOMMUNotifier *notifier = g_new0(IOMMUNotifier, 1);
> +
> +    assert((event_mask & ~IOMMU_EVENT_MASK) == 0);
> +    notifier->event_mask = event_mask;
> +    notifier->iommu_notify = fn;
> +    QLIST_INSERT_HEAD(&iommu->iommu_notifiers, notifier, node);
> +
> +    return notifier;
> +}
> +
> +void iommu_notifier_unregister(IOMMUObject *iommu,
> +                               IOMMUNotifier *notifier)
> +{
> +    IOMMUNotifier *cur, *next;
> +
> +    QLIST_FOREACH_SAFE(cur, &iommu->iommu_notifiers, node, next) {
> +        if (cur == notifier) {
> +            QLIST_REMOVE(cur, node);
> +            break;
> +        }
> +    }
> +}
> +
> +void iommu_notify(IOMMUObject *iommu, IOMMUEvent *event)
> +{
> +    IOMMUNotifier *cur;
> +
> +    QLIST_FOREACH(cur, &iommu->iommu_notifiers, node) {
> +        if (cur->event_mask & event->type && cur->iommu_notify) {
> +            cur->iommu_notify(cur, event);
> +        }
> +    }
> +}
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 5131329..d6f6701 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -2635,7 +2635,7 @@ static const MemoryRegionOps vtd_mem_ir_ops = {
>  static IOMMUObject *vtd_as_iommu_get(AddressSpace *as)
>  {
>      VTDAddressSpace *vtd_dev_as = container_of(as, VTDAddressSpace, as);
> -    return (IOMMUObject *)vtd_dev_as->iommu_state;
> +    return &vtd_dev_as->iommu_state->iommu_common;
>  }
>  
>  VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 0b0b58b..5ca1dd0 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -27,6 +27,7 @@
>  #include "qemu/notify.h"
>  #include "qom/object.h"
>  #include "qemu/rcu.h"
> +#include "hw/core/iommu.h"
>  
>  #define RAM_ADDR_INVALID (~(ram_addr_t)0)
>  
> @@ -183,15 +184,6 @@ struct MemoryRegionOps {
>      const MemoryRegionMmio old_mmio;
>  };
>  
> -/*
> - * This stands for an IOMMU unit. Normally it should be exactly the
> - * IOMMU device, however this can also be actually anything which is
> - * related to that translation unit. What it is should be totally
> - * arch-dependent. Maybe one day we can have something better than a
> - * (void *) here.
> - */
> -typedef void *IOMMUObject;
> -
>  typedef struct MemoryRegionIOMMUOps MemoryRegionIOMMUOps;
>  
>  struct MemoryRegionIOMMUOps {
> diff --git a/include/hw/core/iommu.h b/include/hw/core/iommu.h
> new file mode 100644
> index 0000000..16e6adf
> --- /dev/null
> +++ b/include/hw/core/iommu.h
> @@ -0,0 +1,72 @@
> +/*
> + * QEMU emulation of IOMMU logic
> + *
> + * Copyright (C) 2017 Red Hat Inc.
> + *
> + * Authors: Peter Xu <peterx@redhat.com>,
> + *
> + * 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 __PCI_IOMMU_H__
> +#define __PCI_IOMMU_H__
> +
> +#include "qemu/queue.h"
> +
> +#define IOMMU_EVENT_SVM_PASID      (0)
> +#define IOMMU_EVENT_MASK           (IOMMU_EVENT_SVM_PASID)

Peter,

would it better to define it just like the IOTLB notifier flag?

> +struct IOMMUEvent {
> +    uint64_t type;
> +    union {
> +        struct {
> +            /* TODO: fill in correct stuff. */
> +            int value;
> +        } svm;
> +    } data;
> +};
> +typedef struct IOMMUEvent IOMMUEvent;
> +
> +typedef struct IOMMUNotifier IOMMUNotifier;
> +
> +typedef void (*IOMMUNotifyFn)(IOMMUNotifier *notifier, IOMMUEvent *event);

Regards to the IOMMUEvent definition, would it be helpful to use void*?
virt-SVM may have two notifiers. They will have different data to pass
in the notifier.

Thanks,
Yi L

> +struct IOMMUNotifier {
> +    IOMMUNotifyFn iommu_notify;
> +    /*
> +     * What events we are listening to. Let's allow multiple event
> +     * registrations from beginning.
> +     */
> +    uint64_t event_mask;
> +    QLIST_ENTRY(IOMMUNotifier) node;
> +};
> +
> +/*
> + * This stands for an IOMMU unit. Any translation device should have
> + * this struct inside its own structure to make sure it can leverage
> + * common IOMMU functionalities.
> + */
> +struct IOMMUObject {
> +    QLIST_HEAD(, IOMMUNotifier) iommu_notifiers;
> +};
> +typedef struct IOMMUObject IOMMUObject;
> +
> +IOMMUNotifier *iommu_notifier_register(IOMMUObject *iommu,
> +                                       IOMMUNotifyFn fn,
> +                                       uint64_t event_mask);
> +void iommu_notifier_unregister(IOMMUObject *iommu,
> +                               IOMMUNotifier *notifier);
> +void iommu_notify(IOMMUObject *iommu, IOMMUEvent *event);
> +
> +#endif
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index f9ac0ec..ec696f5 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -26,6 +26,7 @@
>  #include "hw/i386/x86-iommu.h"
>  #include "hw/i386/ioapic.h"
>  #include "hw/pci/msi.h"
> +#include "hw/core/iommu.h"
>  #include "hw/sysbus.h"
>  
>  #define TYPE_INTEL_IOMMU_DEVICE "intel-iommu"
> @@ -258,6 +259,7 @@ struct IntelIOMMUMRNotifierNode {
>  /* The iommu (DMAR) device state struct */
>  struct IntelIOMMUState {
>      X86IOMMUState x86_iommu;
> +    IOMMUObject iommu_common;
>      MemoryRegion csrmem;
>      uint8_t csr[DMAR_REG_SIZE];     /* register values */
>      uint8_t wmask[DMAR_REG_SIZE];   /* R/W bytes */
> -- 
> 2.7.4
> 
>