Hi, Ani,
On Tue, Sep 10, 2024 at 05:31:00PM +0530, Ani Sinha wrote:
> When a new listener for an address space is registered, the hypervisor must be
> informed of all existing eventfds for that address space by calling
> eventfd_add() for that listener. Similarly, when a listener is de-registered
> from an address space, the hypervisor must be informed of all existing
> eventfds
> for that address space with a call to eventfd_del().
>
> Same is also true for coalesced io. Send coalesced io add/del listener
> notifications if any flatrage for the address space registered with the
> listener intersects with any coalesced io range.
>
> Suggested-by: Paolo Bonzini <pbonz...@redhat.com>
> Signed-off-by: Ani Sinha <anisi...@redhat.com>
This is only to make the API clean, as I see that only kvm uses either of
the features (while kvm never registers during VM running). Am I right?
I'd like to double check whether we need to copy stable, or whether there's
a real bug.
> ---
> system/memory.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 77 insertions(+)
>
> changelog:
> v2: tags added, indentation fixed, commit log fixed, code cleanup.
>
> diff --git a/system/memory.c b/system/memory.c
> index 5e6eb459d5..8379e086fb 100644
> --- a/system/memory.c
> +++ b/system/memory.c
> @@ -941,6 +941,38 @@ static void flat_range_coalesced_io_add(FlatRange *fr,
> AddressSpace *as)
> }
> }
>
> +static void
> +flat_range_coalesced_io_notify_listener_add_del(FlatRange *fr,
> + MemoryRegionSection *mrs,
> + MemoryListener *listener,
> + AddressSpace *as, bool add)
> +{
> + CoalescedMemoryRange *cmr;
> + MemoryRegion *mr = fr->mr;
> + AddrRange tmp;
> +
> + QTAILQ_FOREACH(cmr, &mr->coalesced, link) {
> + tmp = addrrange_shift(cmr->addr,
> + int128_sub(fr->addr.start,
> +
> int128_make64(fr->offset_in_region)));
> +
> + if (!addrrange_intersects(tmp, fr->addr)) {
> + return;
> + }
> + tmp = addrrange_intersection(tmp, fr->addr);
> +
> + if (add) {
Do we need to check ->coalesced_io_add != NULL here? I wonder whether this
could crash if some dynamic listener got inserted (with coalesced list
non-empty).
> + listener->coalesced_io_add(listener, mrs,
> + int128_get64(tmp.start),
> + int128_get64(tmp.size));
> + } else {
> + listener->coalesced_io_del(listener, mrs,
Same.
> + int128_get64(tmp.start),
> + int128_get64(tmp.size));
> + }
> + }
> +}
> +
> static void address_space_update_topology_pass(AddressSpace *as,
> const FlatView *old_view,
> const FlatView *new_view,
> @@ -3015,8 +3047,10 @@ void memory_global_dirty_log_stop(unsigned int flags)
> static void listener_add_address_space(MemoryListener *listener,
> AddressSpace *as)
> {
> + unsigned i;
> FlatView *view;
> FlatRange *fr;
> + MemoryRegionIoeventfd *fd;
>
> if (listener->begin) {
> listener->begin(listener);
> @@ -3041,10 +3075,31 @@ static void listener_add_address_space(MemoryListener
> *listener,
> if (listener->region_add) {
> listener->region_add(listener, §ion);
> }
> +
> + /* send coalesced io add notifications */
> + flat_range_coalesced_io_notify_listener_add_del(fr, §ion,
> + listener, as, true);
> +
> if (fr->dirty_log_mask && listener->log_start) {
> listener->log_start(listener, §ion, 0, fr->dirty_log_mask);
> }
> }
> +
> + /*
> + * register all eventfds for this address space for the newly registered
> + * listener.
> + */
> + for (i = 0; i < as->ioeventfd_nb; i++) {
> + fd = &as->ioeventfds[i];
> + MemoryRegionSection section = (MemoryRegionSection) {
> + .fv = address_space_to_flatview(as),
Nitpick: I don't think it'll be anything different if we hold BQL anyway,
but.. might be good to use "view" directly here, as we're holding a
refcount there via address_space_get_flatview().
While it's not crystal clear otherwise (when without knowing BQL held) that
address_space_to_flatview() will return the same flatview.
> + .offset_within_address_space = int128_get64(fd->addr.start),
> + .size = fd->addr.size,
> + };
> + listener->eventfd_add(listener, §ion,
> + fd->match_data, fd->data, fd->e);
Check ->eventfd_add != NULL?
> + }
> +
> if (listener->commit) {
> listener->commit(listener);
> }
> @@ -3054,8 +3109,10 @@ static void listener_add_address_space(MemoryListener
> *listener,
> static void listener_del_address_space(MemoryListener *listener,
> AddressSpace *as)
> {
> + unsigned i;
> FlatView *view;
> FlatRange *fr;
> + MemoryRegionIoeventfd *fd;
>
> if (listener->begin) {
> listener->begin(listener);
> @@ -3067,10 +3124,30 @@ static void listener_del_address_space(MemoryListener
> *listener,
> if (fr->dirty_log_mask && listener->log_stop) {
> listener->log_stop(listener, §ion, fr->dirty_log_mask, 0);
> }
> +
> + /* send coalesced io del notifications */
> + flat_range_coalesced_io_notify_listener_add_del(fr, §ion,
> + listener, as, false);
> if (listener->region_del) {
> listener->region_del(listener, §ion);
> }
> }
> +
> + /*
> + * de-register all eventfds for this address space for the current
> + * listener.
> + */
> + for (i = 0; i < as->ioeventfd_nb; i++) {
> + fd = &as->ioeventfds[i];
> + MemoryRegionSection section = (MemoryRegionSection) {
> + .fv = address_space_to_flatview(as),
Same.
> + .offset_within_address_space = int128_get64(fd->addr.start),
> + .size = fd->addr.size,
> + };
> + listener->eventfd_del(listener, §ion,
> + fd->match_data, fd->data, fd->e);
Check eventfd_del != NULL?
Thanks,
> + }
> +
> if (listener->commit) {
> listener->commit(listener);
> }
> --
> 2.42.0
>
--
Peter Xu
