From 404cd6bffe17e25e0f94ed2775ffdd6cd10ac3fd Mon Sep 17 00:00:00 2001 From: Naman Jain Date: Mon, 6 Apr 2026 09:24:59 +0000 Subject: mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER 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: stable@vger.kernel.org Signed-off-by: Naman Jain Reviewed-by: Michael Kelley Signed-off-by: Wei Liu --- include/uapi/linux/mshv.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h index e0645a34b55b..32ff92b6342b 100644 --- a/include/uapi/linux/mshv.h +++ b/include/uapi/linux/mshv.h @@ -357,7 +357,7 @@ struct mshv_vtl_sint_post_msg { struct mshv_vtl_ram_disposition { __u64 start_pfn; - __u64 last_pfn; + __u64 last_pfn; /* last_pfn is excluded from the range [start_pfn, last_pfn) */ }; struct mshv_vtl_set_poll_file { -- cgit v1.2.3