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. v1 -> v2: - "/dev/mem: disallow access to explicitly excluded system RAM regions" -- Introduce and use for_each_resource() and next_resource_skip_children() -- s/iomem_range_contains_excluded/iomem_range_contains_excluded_devmem/ - "kernel/resource: cleanup and optimize iomem_is_exclusive()" -- Use for_each_resource() Cc: Arnd Bergmann <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: "Michael S. Tsirkin" <[email protected]> Cc: Jason Wang <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Dan Williams <[email protected]> Cc: Hanjun Guo <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: [email protected] Cc: [email protected] 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 | 60 +++++++++++++++++++++++++++++++++---- lib/Kconfig.debug | 4 ++- 5 files changed, 71 insertions(+), 20 deletions(-) base-commit: 7c60610d476766e128cc4284bb6349732cbd6606 -- 2.31.1 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
