On Tue, Dec 02, 2025 at 06:39:51PM +0000, Michael Kelley wrote: > From: Stanislav Kinsburskii <[email protected]> Sent: Tuesday, > November 25, 2025 6:09 PM > > > > Refactor region overlap check in mshv_partition_create_region to use > > mshv_partition_region_by_gfn for both start and end guest PFNs, replacing > > manual iteration. > > > > This is a cleaner approach that leverages existing functionality to > > accurately detect overlapping memory regions. > > Unfortunately, the cleaner approach doesn't work. :-( It doesn't detect a > new region request that completely overlaps an existing region. > > See > https://lore.kernel.org/linux-hyperv/[email protected]/T/#ma91254da1900de61da520acb96c0de38c43562f6. > I couldn't see anything that prevents the scenario. Nuno created this > patch less than a month ago: > https://lore.kernel.org/linux-hyperv/1762467211-8213-2-git-send-email-nunodasne...@linux.microsoft.com/. > > Michael >
I see. I'll drop it then. Thanks, Stanislav > > > > Signed-off-by: Stanislav Kinsburskii <[email protected]> > > --- > > drivers/hv/mshv_root_main.c | 8 ++------ > > 1 file changed, 2 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c > > index 5dfb933da981..ae600b927f49 100644 > > --- a/drivers/hv/mshv_root_main.c > > +++ b/drivers/hv/mshv_root_main.c > > @@ -1086,13 +1086,9 @@ static int mshv_partition_create_region(struct > > mshv_partition *partition, > > u64 nr_pages = HVPFN_DOWN(mem->size); > > > > /* Reject overlapping regions */ > > - hlist_for_each_entry(rg, &partition->pt_mem_regions, hnode) { > > - if (mem->guest_pfn + nr_pages <= rg->start_gfn || > > - rg->start_gfn + rg->nr_pages <= mem->guest_pfn) > > - continue; > > - > > + if (mshv_partition_region_by_gfn(partition, mem->guest_pfn) || > > + mshv_partition_region_by_gfn(partition, mem->guest_pfn + nr_pages - > > 1)) > > return -EEXIST; > > - } > > > > rg = mshv_region_create(mem->guest_pfn, nr_pages, > > mem->userspace_addr, mem->flags, > > > > >
