@Andrew, can you take this via the -mm tree? -- Let's add the basic infrastructure to exclude some physical memory regions marked as "IORESOURCE_SYSTEM_RAM" completely from /dev/mem access, even though they are not marked IORESOURCE_BUSY and even though "iomem=relaxed" is set. Resource IORESOURCE_EXCLUSIVE for that purpose instead of adding new flags to express something similar to "soft-busy" or "not busy yet, but already prepared by a driver and not to be mapped by user space". 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. Details can be found in patch #2 and #3. v4 -> v5: - "kernel/resource: disallow access to exclusive system RAM regions" -- Add CONFIG_EXCLUSIVE_SYSTEM_RAM - "virtio-mem: disallow mapping virtio-mem memory via /dev/mem" -- Use CONFIG_EXCLUSIVE_SYSTEM_RAM -- Add ACK from MST v3 -> v4: - Added Dans RBs (thanks!) - Actually send the patches to the CC list ... v2 -> v3: - "kernel/resource: clean up and optimize iomem_is_exclusive()" -- Reshuffled and moved for_each_resource() etc. into this patch - "kernel/resource: disallow access to exclusive system RAM regions" -- Leave CONFIG_STRICT_DEVMEM=n alone. Hoog into iomem_is_exclusive() instead. -- Improve comments - "virtio-mem: disallow mapping virtio-mem memory via /dev/mem" -- Don't allow building virtio_mem without CONFIG_STRICT_DEVMEM when we have CONFIG_DEVMEM, where we don't have any guarantees. - Rework all patch descriptions 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 <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 <andy.shevchenko@xxxxxxxxx> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx David Hildenbrand (3): kernel/resource: clean up and optimize iomem_is_exclusive() kernel/resource: disallow access to exclusive system RAM regions virtio-mem: disallow mapping virtio-mem memory via /dev/mem drivers/virtio/Kconfig | 1 + drivers/virtio/virtio_mem.c | 4 ++- kernel/resource.c | 54 ++++++++++++++++++++++++++----------- mm/Kconfig | 7 +++++ 4 files changed, 50 insertions(+), 16 deletions(-) base-commit: e4e737bb5c170df6135a127739a9e6148ee3da82 -- 2.31.1
