Let's add the basic infrastructure to exclude some physical memory regions completely from /dev/mem access, on any architecture and under any system configuration (independent of CONFIG_STRICT_DEVMEM and independent of "iomem="). Use it for virtio-mem, to disallow mapping any virtio-mem memory via /dev/mem to user space after the virtio-mem driver was loaded: there is no sane use case to access the device-managed memory region via /dev/mem once the driver is actively (un)plugging memory within that region and we want to make sure that nobody will accidentially access unplugged memory in a sane environment. Details can be found in patch #1. Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> Cc: Jason Wang <jasowang@xxxxxxxxxx> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Hanjun Guo <guohanjun@xxxxxxxxxx> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx David Hildenbrand (3): /dev/mem: disallow access to explicitly excluded system RAM regions virtio-mem: disallow mapping virtio-mem memory via /dev/mem kernel/resource: cleanup and optimize iomem_is_exclusive() drivers/char/mem.c | 22 ++++++------- drivers/virtio/virtio_mem.c | 4 ++- include/linux/ioport.h | 1 + kernel/resource.c | 61 ++++++++++++++++++++++++++++++++----- lib/Kconfig.debug | 4 ++- 5 files changed, 69 insertions(+), 23 deletions(-) -- 2.31.1
