Re: [PATCH 08/18] vfio/common: Record DMA mapped IOVA ranges

[Avihai Horon]

On 27/01/2023 23:42, Alex Williamson wrote:
> External email: Use caution opening links or attachments
>
>
> On Thu, 26 Jan 2023 20:49:38 +0200
> Avihai Horon <avihaih@nvidia.com> wrote:
>
> > From: Joao Martins <joao.m.martins@oracle.com>
> >
> > According to the device DMA logging uAPI, IOVA ranges to be logged by
> > the device must be provided all at once upon DMA logging start.
> >
> > As preparation for the following patches which will add device dirty
> > page tracking, keep a record of all DMA mapped IOVA ranges so later they
> > can be used for DMA logging start.
> >
> > Note that when vIOMMU is enabled DMA mapped IOVA ranges are not tracked.
> > This is due to the dynamic nature of vIOMMU DMA mapping/unmapping.
> > Following patches will address the vIOMMU case specifically.
> >
> > Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> > Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> > ---
> >   include/hw/vfio/vfio-common.h |  3 ++
> >   hw/vfio/common.c              | 86 +++++++++++++++++++++++++++++++++--
> >   2 files changed, 86 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> > index 88c2194fb9..d54000d7ae 100644
> > --- a/include/hw/vfio/vfio-common.h
> > +++ b/include/hw/vfio/vfio-common.h
> > @@ -23,6 +23,7 @@
> >
> >   #include "exec/memory.h"
> >   #include "qemu/queue.h"
> > +#include "qemu/iova-tree.h"
> >   #include "qemu/notify.h"
> >   #include "ui/console.h"
> >   #include "hw/display/ramfb.h"
> > @@ -94,6 +95,8 @@ typedef struct VFIOContainer {
> >       uint64_t max_dirty_bitmap_size;
> >       unsigned long pgsizes;
> >       unsigned int dma_max_mappings;
> > +    IOVATree *mappings;
> > +    QemuMutex mappings_mutex;
> >       QLIST_HEAD(, VFIOGuestIOMMU) giommu_list;
> >       QLIST_HEAD(, VFIOHostDMAWindow) hostwin_list;
> >       QLIST_HEAD(, VFIOGroup) group_list;
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > index e554573eb5..fafc361cea 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -43,6 +43,7 @@
> >   #include "migration/misc.h"
> >   #include "migration/qemu-file.h"
> >   #include "sysemu/tpm.h"
> > +#include "qemu/iova-tree.h"
> >
> >   VFIOGroupList vfio_group_list =
> >       QLIST_HEAD_INITIALIZER(vfio_group_list);
> > @@ -373,6 +374,11 @@ bool vfio_mig_active(void)
> >       return true;
> >   }
> >
> > +static bool vfio_have_giommu(VFIOContainer *container)
> > +{
> > +    return !QLIST_EMPTY(&container->giommu_list);
> > +}
> > +
> >   static void vfio_set_migration_error(int err)
> >   {
> >       MigrationState *ms = migrate_get_current();
> > @@ -450,6 +456,51 @@ static bool 
> > vfio_devices_all_running_and_mig_active(VFIOContainer *container)
> >       return true;
> >   }
> >
> > +static int vfio_record_mapping(VFIOContainer *container, hwaddr iova,
> > +                               hwaddr size, bool readonly)
> > +{
> > +    DMAMap map = {
> > +        .iova = iova,
> > +        .size = size - 1, /* IOVATree is inclusive, so subtract 1 from size */
> <facepalm>

I am not sure what's the error you are referring here.
Is it because DMAMap.size is not actually the size?
Something else?

Thanks.