On Mon, Apr 06, 2026 at 02:08:07PM +0000, Michael Kelley wrote: > From: Naman Jain <[email protected]> Sent: Monday, April 6, 2026 > 2:25 AM > > > > When registering VTL0 memory via MSHV_ADD_VTL0_MEMORY, the kernel > > computes pgmap->vmemmap_shift as the number of trailing zeros in the > > OR of start_pfn and last_pfn, intending to use the largest compound > > page order both endpoints are aligned to. > > > > However, this value is not clamped to MAX_FOLIO_ORDER, so a > > sufficiently aligned range (e.g. physical range > > [0x800000000000, 0x800080000000), corresponding to start_pfn=0x800000000 > > with 35 trailing zeros) can produce a shift larger than what > > memremap_pages() accepts, triggering a WARN and returning -EINVAL: > > > > WARNING: ... memremap_pages+0x512/0x650 > > requested folio size unsupported > > > > The MAX_FOLIO_ORDER check was added by > > commit 646b67d57589 ("mm/memremap: reject unreasonable folio/compound > > page sizes in memremap_pages()"). > > > > Fix this by clamping vmemmap_shift to MAX_FOLIO_ORDER so we always > > request the largest order the kernel supports, in those cases, rather > > than an out-of-range value. > > > > Also fix the error path to propagate the actual error code from > > devm_memremap_pages() instead of hard-coding -EFAULT, which was > > masking the real -EINVAL return. > > > > Fixes: 7bfe3b8ea6e3 ("Drivers: hv: Introduce mshv_vtl driver") > > Cc: [email protected] > > Signed-off-by: Naman Jain <[email protected]>
Applied. Thanks.
