linux.git/drivers/virtio, branch v5.8-rc4

virtio-mem: add memory via add_memory_driver_managed()

2020-06-22T16:34:21+00:00

Virtio-mem managed memory is always detected and added by the virtio-mem
driver, never using something like the firmware-provided memory map.
This is the case after an ordinary system reboot, and has to be guaranteed
after kexec. Especially, virtio-mem added memory resources can contain
inaccessible parts ("unblocked memory blocks"), blindly forwarding them
to a kexec kernel is dangerous, as unplugged memory will get accessed
(esp. written).

Let's use the new way of adding special driver-managed memory introduced
in commit 7b7b27214bba ("mm/memory_hotplug: introduce
add_memory_driver_managed()").

This will result in no entries in /sys/firmware/memmap ("raw firmware-
provided memory map"), the memory resource will be flagged
IORESOURCE_MEM_DRIVER_MANAGED (esp., kexec_file_load() will not place
kexec images on this memory), and it is exposed as "System RAM
(virtio_mem)" in /proc/iomem, so esp. kexec-tools can properly handle it.

Example /proc/iomem before this change:
  [...]
  140000000-333ffffff : virtio0
    140000000-147ffffff : System RAM
  334000000-533ffffff : virtio1
    338000000-33fffffff : System RAM
    340000000-347ffffff : System RAM
    348000000-34fffffff : System RAM
  [...]

Example /proc/iomem after this change:
  [...]
  140000000-333ffffff : virtio0
    140000000-147ffffff : System RAM (virtio_mem)
  334000000-533ffffff : virtio1
    338000000-33fffffff : System RAM (virtio_mem)
    340000000-347ffffff : System RAM (virtio_mem)
    348000000-34fffffff : System RAM (virtio_mem)
  [...]

Cc: "Michael S. Tsirkin" 
Cc: Pankaj Gupta 
Cc: teawater 
Fixes: 5f1f79bbc9e26 ("virtio-mem: Paravirtualized memory hotplug")
Signed-off-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20200611093518.5737-1-david@redhat.com
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Pankaj Gupta

virtio-mem: silence a static checker warning

2020-06-22T16:34:21+00:00

Smatch complains that "rc" can be uninitialized if we hit the "break;"
statement on the first iteration through the loop.  I suspect that this
can't happen in real life, but returning a zero literal is cleaner and
silence the static checker warning.

Fixes: 5f1f79bbc9e2 ("virtio-mem: Paravirtualized memory hotplug")
Signed-off-by: Dan Carpenter 
Link: https://lore.kernel.org/r/20200610085911.GC5439@mwanda
Signed-off-by: Michael S. Tsirkin

treewide: replace '---help---' in Kconfig files with 'help'

2020-06-13T16:57:21+00:00

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada

virtio_mem: convert device block size into 64bit

2020-06-09T10:42:06+00:00

If subblock size is large (e.g. 1G) 32 bit math involving it
can overflow. Rather than try to catch all instances of that,
let's tweak block size to 64 bit.

It ripples through UAPI which is an ABI change, but it's not too late to
make it, and it will allow supporting >4Gbyte blocks while might
become necessary down the road.

Fixes: 5f1f79bbc9e26 ("virtio-mem: Paravirtualized memory hotplug")
Signed-off-by: Michael S. Tsirkin 
Acked-by: David Hildenbrand

virtio-mem: drop unnecessary initialization

2020-06-08T09:12:52+00:00

rc is initialized to -ENIVAL but that's never used. Drop it.

Fixes: 5f1f79bbc9e2 ("virtio-mem: Paravirtualized memory hotplug")
Reported-by: kernel test robot 
Signed-off-by: Michael S. Tsirkin 
Acked-by: David Hildenbrand

virtio-mem: Don't rely on implicit compiler padding for requests

2020-06-04T19:36:52+00:00

The compiler will add padding after the last member, make that explicit.
The size of a request is always 24 bytes. The size of a response always
10 bytes. Add compile-time checks.

Cc: "Michael S. Tsirkin" 
Cc: Pankaj Gupta 
Cc: teawater 
Signed-off-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20200515101402.16597-1-david@redhat.com
Signed-off-by: Michael S. Tsirkin

virtio-mem: Try to unplug the complete online memory block first

2020-06-04T19:36:52+00:00

Right now, we always try to unplug single subblocks when processing an
online memory block. Let's try to unplug the complete online memory block
first, in case it is fully plugged and the unplug request is large
enough. Fallback to single subblocks in case the memory block cannot get
unplugged as a whole.

Cc: "Michael S. Tsirkin" 
Cc: Pankaj Gupta 
Signed-off-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20200507140139.17083-16-david@redhat.com
Signed-off-by: Michael S. Tsirkin

virtio-mem: Use -ETXTBSY as error code if the device is busy

2020-06-04T19:36:52+00:00

Let's be able to distinguish if the device or if memory is busy.

Cc: "Michael S. Tsirkin" 
Cc: Pankaj Gupta 
Signed-off-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20200507140139.17083-15-david@redhat.com
Signed-off-by: Michael S. Tsirkin

virtio-mem: Unplug subblocks right-to-left

2020-06-04T19:36:52+00:00

We unplug blocks right-to-left, let's also unplug subblocks within a block
right-to-left.

Cc: "Michael S. Tsirkin" 
Cc: Pankaj Gupta 
Signed-off-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20200507140139.17083-14-david@redhat.com
Signed-off-by: Michael S. Tsirkin

virtio-mem: Drop manual check for already present memory

2020-06-04T19:36:52+00:00

Registering our parent resource will fail if any memory is still present
(e.g., because somebody unloaded the driver and tries to reload it). No
need for the manual check.

Move our "unplug all" handling to after registering the resource.

Cc: "Michael S. Tsirkin" 
Cc: Pankaj Gupta 
Signed-off-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20200507140139.17083-13-david@redhat.com
Signed-off-by: Michael S. Tsirkin