* Igor Mammedov (imamm...@redhat.com) wrote:
> On Wed, 13 Dec 2017 18:08:05 +0000
> "Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> wrote:
>
> > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
> >
> > As regions are reported by the listener to the _nop and _add
> > methods, add them to our new temporary list.
> > Regions that abut can be merged if the backend allows.
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > ---
> > hw/virtio/trace-events | 2 ++
> > hw/virtio/vhost.c | 70
> > ++++++++++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 72 insertions(+)
> >
> > diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
> > index 4a493bcd46..7de0663652 100644
> > --- a/hw/virtio/trace-events
> > +++ b/hw/virtio/trace-events
> > @@ -1,6 +1,8 @@
> > # See docs/devel/tracing.txt for syntax documentation.
> >
> > # hw/virtio/vhost.c
> > +vhost_region_add_tmp(const char *name, uint64_t gpa, uint64_t size,
> > uint64_t host) "%s: 0x%"PRIx64"+0x%"PRIx64" @ 0x%"PRIx64
> > +vhost_region_add_tmp_abut(const char *name, uint64_t new_size) "%s:
> > 0x%"PRIx64
> > vhost_section(const char *name, int r) "%s:%d"
> >
> > # hw/virtio/virtio.c
> > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> > index 4523f45587..2084888aa7 100644
> > --- a/hw/virtio/vhost.c
> > +++ b/hw/virtio/vhost.c
> > @@ -694,6 +694,67 @@ static void vhost_commit(MemoryListener *listener)
> > dev->memory_changed = false;
> > }
> >
> > +/* Adds the section data to the tmp_mem structure.
> > + * It relies on the listener calling us in memory address order
> > + * and for each region (via the _add and _nop methods).
> > + */
> > +static void vhost_region_add_tmp(struct vhost_dev *dev,
> > + MemoryRegionSection *section)
> > +{
> > + bool need_add = true;
> > + uint64_t mrs_size = int128_get64(section->size);
> > + uint64_t mrs_gpa = section->offset_within_address_space;
> > + uintptr_t mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr)
> > +
> > + section->offset_within_region;
> > +
> > + trace_vhost_region_add_tmp(section->mr->name, mrs_gpa, mrs_size,
> > mrs_host);
> > +
> > + if (dev->tmp_mem->nregions) {
> > + /* Since we already have at least one region, lets see if
> > + * this extends it; since we're scanning in order, we only
> > + * have to look at the last one, and the FlatView that calls
> > + * us shouldn't have overlaps.
> > + */
> > + struct vhost_memory_region *prev_vmr = dev->tmp_mem->regions +
> > + (dev->tmp_mem->nregions -
> > 1);
> > + uint64_t prev_gpa_start = prev_vmr->guest_phys_addr;
> > + uint64_t prev_gpa_end = range_get_last(prev_gpa_start,
> > + prev_vmr->memory_size);
> > + uint64_t prev_host_start = prev_vmr->userspace_addr;
> > + uint64_t prev_host_end = range_get_last(prev_host_start,
> > + prev_vmr->memory_size);
> > +
> > + if (prev_gpa_end + 1 == mrs_gpa &&
> > + prev_host_end + 1 == mrs_host &&
> > + (!dev->vhost_ops->vhost_backend_can_merge ||
> > + dev->vhost_ops->vhost_backend_can_merge(dev,
> > + mrs_host, mrs_size,
> > + prev_host_start, prev_vmr->memory_size))) {
> > + /* The two regions abut */
> > + need_add = false;
> > + mrs_size = mrs_size + prev_vmr->memory_size;
> > + prev_vmr->memory_size = mrs_size;
> > + trace_vhost_region_add_tmp_abut(section->mr->name, mrs_size);
> > + }
> > + }
> > +
> > + if (need_add) {
> > + uint32_t nregions = dev->tmp_mem->nregions;
> > + size_t s = offsetof(struct vhost_memory, regions) +
> > + (nregions + 1) * sizeof
> > dev->tmp_mem->regions[0];
> > + dev->tmp_mem = g_realloc(dev->tmp_mem, s);
> > + dev->tmp_mem->nregions++;
> > + struct vhost_memory_region *cur_vmr =
> > &dev->tmp_mem->regions[nregions];
> > +
> > + cur_vmr->guest_phys_addr = mrs_gpa;
> > + cur_vmr->memory_size = mrs_size;
> > + cur_vmr->userspace_addr = mrs_host;
> > + cur_vmr->flags_padding = 0;
> > + }
> > +
> > +
> > +}
> > +
> > static void vhost_region_add(MemoryListener *listener,
> > MemoryRegionSection *section)
> > {
> > @@ -703,6 +764,7 @@ static void vhost_region_add(MemoryListener *listener,
> > if (!vhost_section(section)) {
> > return;
> > }
> > + vhost_region_add_tmp(dev, section);
> >
> > ++dev->n_mem_sections;
> > dev->mem_sections = g_renew(MemoryRegionSection, dev->mem_sections,
> > @@ -800,9 +862,17 @@ static void vhost_iommu_region_del(MemoryListener
> > *listener,
> > }
> > }
> >
> > +/* Called on regions that have not changed */
> > static void vhost_region_nop(MemoryListener *listener,
> > MemoryRegionSection *section)
> > {
> move it close to add/del callbacks
>
> > + struct vhost_dev *dev = container_of(listener, struct vhost_dev,
> > + memory_listener);
> > + if (!vhost_section(section)) {
> > + return;
> > + }
> > +
> > + vhost_region_add_tmp(dev, section);
> if you'd operate on temporary mem_sections,
> I'd add memory_region_ref() and get rid of region_del callback
> with its section lookup, by unreffing old sections at commit time.
>
> Also it seems that we have a race in current code where
> region_del() unrefs memory region first and then by the
> commit time memory region could be gone since old flatview
> is unreffed before commit callback is called, but guest still
> uses old memory map until vhost_set_mem_table() is complete.
> We probably should unref deleted(old) sections after
> guest gets new memmap.
Will they really get cleaned up before the commit() returns?
There's no rcu like thing guarding it?
Dave
>
> > }
> >
> > static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
