Re: [RFC PATCH 2/3] vfio: Add vfio_prereg_listener_log_sync in nested stage

[Kunkun Jiang]

Hi Eric,

On 2021/4/8 21:56, Auger Eric wrote:
> Hi Kunkun,
>
> On 2/19/21 10:42 AM, Kunkun Jiang wrote:
> > On Intel, the DMA mapped through the host single stage. Instead
> > we set up the stage 2 and stage 1 separately in nested mode as there
> > is no "Caching Mode".
> You need to rewrite the above sentences, Missing ARM and also the 1st
> sentences misses a verb.
Thanks for your review! I will fix it in the next version.
> > Legacy vfio_listener_log_sync cannot be used in nested stage as we
> > don't need to pay close attention to stage 1 mapping. This patch adds
> > vfio_prereg_listener_log_sync to mark dirty pages in nested mode.
> >
> > Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
> > ---
> >   hw/vfio/common.c | 25 +++++++++++++++++++++++++
> >   1 file changed, 25 insertions(+)
> >
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > index 7c50905856..af333e0dee 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -1216,6 +1216,22 @@ static int 
> > vfio_dma_sync_ram_section_dirty_bitmap(VFIOContainer *container,
> >                          int128_get64(section->size), ram_addr);
> >   }
> >   
> > +static void vfio_prereg_listener_log_sync(MemoryListener *listener,
> > +                                          MemoryRegionSection *section)
> > +{
> > +    VFIOContainer *container =
> > +        container_of(listener, VFIOContainer, prereg_listener);
> > +
> > +    if (!memory_region_is_ram(section->mr) ||
> > +        !container->dirty_pages_supported) {
> > +        return;
> > +    }
> > +
> > +    if (vfio_devices_all_saving(container)) {
> I fail to see where is this defined?
Keqian modified vfio_devices_all_saving to vfio_devices_all_dirty_tracking
in 758b96b61d5.

When I posted this series patches, it was vfio_devices_all_saving. In 
v2[1], I
have updated it based on the lasted qemu.

[1] 
https://lore.kernel.org/qemu-devel/20210331101259.2153-3-jiangkunkun@huawei.com/

Thanks,
Kunkun Jiang
> > +        vfio_dma_sync_ram_section_dirty_bitmap(container, section);
> > +    }
> > +}
> > +
> >   typedef struct {
> >       IOMMUNotifier n;
> >       VFIOGuestIOMMU *giommu;
> > @@ -1260,6 +1276,14 @@ static int vfio_sync_dirty_bitmap(VFIOContainer 
> > *container,
> >       if (memory_region_is_iommu(section->mr)) {
> >           VFIOGuestIOMMU *giommu;
> >   
> > +        /*
> > +         * In nested mode, stage 2 and stage 1 are set up separately. We
> > +         * only need to focus on stage 2 mapping when marking dirty pages.
> > +         */
> > +        if (container->iommu_type == VFIO_TYPE1_NESTING_IOMMU) {
> > +            return 0;
> > +        }
> > +
> >           QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
> >               if (MEMORY_REGION(giommu->iommu) == section->mr &&
> >                   giommu->n.start == section->offset_within_region) {
> > @@ -1312,6 +1336,7 @@ static const MemoryListener vfio_memory_listener = {
> >   static MemoryListener vfio_memory_prereg_listener = {
> >       .region_add = vfio_prereg_listener_region_add,
> >       .region_del = vfio_prereg_listener_region_del,
> > +    .log_sync = vfio_prereg_listener_log_sync,
> >   };
> >   
> >   static void vfio_listener_release(VFIOContainer *container)
> Thanks
>
> Eric
>
> .