From 247a82da6f563dcfd9074a68f99a0c0997d0679c Mon Sep 17 00:00:00 2001 From: Ilia Levi Date: Tue, 8 Sep 2026 17:50:48 +0100 Subject: [PATCH] drm/xe/mmio_gem: forbid VMA split The fault handler assumes it always operates on a VMA spanning the entire GEM object. This does not hold when the VMA has been split, e.g. by a partial munmap or mprotect. In that case the handler may map wrong physical pages or cause SIGBUS. Handle this by forbidding VMA split, as partial unmaps are not deemed useful for MMIO GEMs. Suggested-by: Matthew Auld Signed-off-by: Ilia Levi Fixes: 1ffcf8b8ae8a ("drm/xe: Support for mmap-ing mmio regions") Reviewed-by: Matthew Auld Signed-off-by: Matthew Auld Link: https://patch.msgid.link/20260908165046.1393557-11-matthew.auld@intel.com (cherry picked from commit f3391a0b12d7bf826a0b21600d2f294f3dce4c14) Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_mmio_gem.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_mmio_gem.c b/drivers/gpu/drm/xe/xe_mmio_gem.c index 3741ae60f532..d54477b93b6e 100644 --- a/drivers/gpu/drm/xe/xe_mmio_gem.c +++ b/drivers/gpu/drm/xe/xe_mmio_gem.c @@ -39,10 +39,20 @@ struct xe_mmio_gem { phys_addr_t phys_addr; }; +static int xe_mmio_gem_vm_may_split(struct vm_area_struct *area, unsigned long addr) +{ + /* + * Forbid splitting. Together with VM_DONTEXPAND, this keeps the VMA + * matching the GEM object exactly. + */ + return -EINVAL; +} + static const struct vm_operations_struct vm_ops = { .open = drm_gem_vm_open, .close = drm_gem_vm_close, .fault = xe_mmio_gem_vm_fault, + .may_split = xe_mmio_gem_vm_may_split, }; static const struct drm_gem_object_funcs xe_mmio_gem_funcs = {