On Mon, Mar 25, 2024 at 12:02:28PM -0700, nifan....@gmail.com wrote: > From: Fan Ni <fan...@samsung.com> > > All dpa ranges in the DC regions are invalid to access until an extent > covering the range has been added. Add a bitmap for each region to > record whether a DC block in the region has been backed by DC extent. > For the bitmap, a bit in the bitmap represents a DC block. When a DC > extent is added, all the bits of the blocks in the extent will be set, > which will be cleared when the extent is released. > > Reviewed-by: Jonathan Cameron <jonathan.came...@huawei.com> > Signed-off-by: Fan Ni <fan...@samsung.com> > --- > hw/cxl/cxl-mailbox-utils.c | 6 +++ > hw/mem/cxl_type3.c | 76 +++++++++++++++++++++++++++++++++++++ > include/hw/cxl/cxl_device.h | 7 ++++ > 3 files changed, 89 insertions(+) > > diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c > index 7094e007b9..a0d2239176 100644 > --- a/hw/cxl/cxl-mailbox-utils.c > +++ b/hw/cxl/cxl-mailbox-utils.c > @@ -1620,6 +1620,7 @@ static CXLRetCode cmd_dcd_add_dyn_cap_rsp(const struct > cxl_cmd *cmd, > > cxl_insert_extent_to_extent_list(extent_list, dpa, len, NULL, 0); > ct3d->dc.total_extent_count += 1; > + ct3_set_region_block_backed(ct3d, dpa, len); > > ent = QTAILQ_FIRST(&ct3d->dc.extents_pending); > cxl_remove_extent_from_extent_list(&ct3d->dc.extents_pending, ent);
while looking at the MHD code, we had decided to "reserve" the blocks in the bitmap in the call to `qmp_cxl_process_dynamic_capacity` in order to prevent a potential double-allocation (basically we need to sanity check that two hosts aren't reserving the region PRIOR to the host being notified). I did not see any checks in the `qmp_cxl_process_dynamic_capacity` path to prevent pending extents from being double-allocated. Is this an explicit choice? I can see, for example, why you may want to allow the following in the pending list: [Add X, Remove X, Add X]. I just want to know if this is intentional or not. If not, you may consider adding a pending check during the sanity check phase of `qmp_cxl_process_dynamic_capacity` ~Gregory
