On Fri, Mar 20, 2026 at 02:08:12PM -0700, Nathan Chancellor wrote: > Hi Lorenzo, > > On Thu, Mar 19, 2026 at 06:23:39PM +0000, Lorenzo Stoakes (Oracle) wrote: > > A user can invoke mmap_action_map_kernel_pages() to specify that the > > mapping should map kernel pages starting from desc->start of a specified > > number of pages specified in an array. > > > > In order to implement this, adjust mmap_action_prepare() to be able to > > return an error code, as it makes sense to assert that the specified > > parameters are valid as quickly as possible as well as updating the VMA > > flags to include VMA_MIXEDMAP_BIT as necessary. > > > > This provides an mmap_prepare equivalent of vm_insert_pages(). We > > additionally update the existing vm_insert_pages() code to use > > range_in_vma() and add a new range_in_vma_desc() helper function for the > > mmap_prepare case, sharing the code between the two in range_is_subset(). > > > > We add both mmap_action_map_kernel_pages() and > > mmap_action_map_kernel_pages_full() to allow for both partial and full VMA > > mappings. > > > > We update the documentation to reflect the new features. > > > > Finally, we update the VMA tests accordingly to reflect the changes. > > > > Reviewed-by: Suren Baghdasaryan <[email protected]> > > Signed-off-by: Lorenzo Stoakes (Oracle) <[email protected]> > ... > > diff --git a/mm/util.c b/mm/util.c > > index 8cf59267a9ac..682d0d24e1c6 100644 > > --- a/mm/util.c > > +++ b/mm/util.c > > @@ -1446,6 +1446,8 @@ int mmap_action_prepare(struct vm_area_desc *desc) > > return io_remap_pfn_range_prepare(desc); > > case MMAP_SIMPLE_IO_REMAP: > > return simple_ioremap_prepare(desc); > > + case MMAP_MAP_KERNEL_PAGES: > > + return map_kernel_pages_prepare(desc); > > } > > > > WARN_ON_ONCE(1); > > @@ -1476,6 +1478,9 @@ int mmap_action_complete(struct vm_area_struct *vma, > > case MMAP_REMAP_PFN: > > err = remap_pfn_range_complete(vma, action); > > break; > > + case MMAP_MAP_KERNEL_PAGES: > > + err = map_kernel_pages_complete(vma, action); > > + break; > > case MMAP_IO_REMAP_PFN: > > case MMAP_SIMPLE_IO_REMAP: > > /* Should have been delegated. */ > > @@ -1497,6 +1502,7 @@ int mmap_action_prepare(struct vm_area_desc *desc) > > case MMAP_REMAP_PFN: > > case MMAP_IO_REMAP_PFN: > > case MMAP_SIMPLE_IO_REMAP: > > + case MMAP_MAP_KERNEL_PAGES: > > WARN_ON_ONCE(1); /* nommu cannot handle these. */ > > break; > > } > > Not sure if it has been reported/addressed yet but it looks like > mmap_action_complete() was missed here, as pointed out by clang: > > $ make -skj"$(nproc)" ARCH=arm LLVM=1 mrproper allnoconfig mm/util.o > mm/util.c:1520:10: warning: enumeration value 'MMAP_MAP_KERNEL_PAGES' not > handled in switch [-Wswitch] > 1520 | switch (action->type) { > | ^~~~~~~~~~~~ > > I assume > > diff --git a/mm/util.c b/mm/util.c > index 682d0d24e1c6..c41c119a5a74 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -1523,6 +1523,7 @@ int mmap_action_complete(struct vm_area_struct *vma, > case MMAP_REMAP_PFN: > case MMAP_IO_REMAP_PFN: > case MMAP_SIMPLE_IO_REMAP: > + case MMAP_MAP_KERNEL_PAGES: > WARN_ON_ONCE(1); /* nommu cannot handle this. */ > > err = -EINVAL; > -- > > should be the fix? > > Cheers, > Nathan
Thanks, will fix, working on a respin now anyway :) Cheers, Lorenzo
