Merge tag 'kvmarm-fixes-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.12, take #1

- Fix pKVM error path on init, making sure we do not change critical
  system registers as we're about to fail

- Make sure that the host's vector length is at capped by a value
  common to all CPUs

- Fix kvm_has_feat*() handling of "negative" features, as the current
  code is pretty broken

- Promote Joey to the status of official reviewer, while James steps
  down -- hopefully only temporarly

1 files changed, 47 insertions, 19 deletions

diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index 091e8bb38887..678d70d6e1c3 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -102,17 +102,41 @@ Examples::
 	#select lzo compression algorithm
 	echo lzo > /sys/block/zram0/comp_algorithm
 
-For the time being, the `comp_algorithm` content does not necessarily
-show every compression algorithm supported by the kernel. We keep this
-list primarily to simplify device configuration and one can configure
-a new device with a compression algorithm that is not listed in
-`comp_algorithm`. The thing is that, internally, ZRAM uses Crypto API
-and, if some of the algorithms were built as modules, it's impossible
-to list all of them using, for instance, /proc/crypto or any other
-method. This, however, has an advantage of permitting the usage of
-custom crypto compression modules (implementing S/W or H/W compression).
-
-4) Set Disksize
+For the time being, the `comp_algorithm` content shows only compression
+algorithms that are supported by zram.
+
+4) Set compression algorithm parameters: Optional
+=================================================
+
+Compression algorithms may support specific parameters which can be
+tweaked for particular dataset. ZRAM has an `algorithm_params` device
+attribute which provides a per-algorithm params configuration.
+
+For example, several compression algorithms support `level` parameter.
+In addition, certain compression algorithms support pre-trained dictionaries,
+which significantly change algorithms' characteristics. In order to configure
+compression algorithm to use external pre-trained dictionary, pass full
+path to the `dict` along with other parameters::
+
+	#pass path to pre-trained zstd dictionary
+	echo "algo=zstd dict=/etc/dictioary" > /sys/block/zram0/algorithm_params
+
+	#same, but using algorithm priority
+	echo "priority=1 dict=/etc/dictioary" > \
+		/sys/block/zram0/algorithm_params
+
+	#pass path to pre-trained zstd dictionary and compression level
+	echo "algo=zstd level=8 dict=/etc/dictioary" > \
+		/sys/block/zram0/algorithm_params
+
+Parameters are algorithm specific: not all algorithms support pre-trained
+dictionaries, not all algorithms support `level`. Furthermore, for certain
+algorithms `level` controls the compression level (the higher the value the
+better the compression ratio, it even can take negatives values for some
+algorithms), for other algorithms `level` is acceleration level (the higher
+the value the lower the compression ratio).
+
+5) Set Disksize
 ===============
 
 Set disk size by writing the value to sysfs node 'disksize'.
@@ -132,7 +156,7 @@ There is little point creating a zram of greater than twice the size of memory
 since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the
 size of the disk when not in use so a huge zram is wasteful.
 
-5) Set memory limit: Optional
+6) Set memory limit: Optional
 =============================
 
 Set memory limit by writing the value to sysfs node 'mem_limit'.
@@ -151,7 +175,7 @@ Examples::
 	# To disable memory limit
 	echo 0 > /sys/block/zram0/mem_limit
 
-6) Activate
+7) Activate
 ===========
 
 ::
@@ -162,7 +186,7 @@ Examples::
 	mkfs.ext4 /dev/zram1
 	mount /dev/zram1 /tmp
 
-7) Add/remove zram devices
+8) Add/remove zram devices
 ==========================
 
 zram provides a control interface, which enables dynamic (on-demand) device
@@ -182,7 +206,7 @@ execute::
 
 	echo X > /sys/class/zram-control/hot_remove
 
-8) Stats
+9) Stats
 ========
 
 Per-device statistics are exported as various nodes under /sys/block/zram<id>/
@@ -205,6 +229,7 @@ writeback_limit_enable  RW	show and set writeback_limit feature
 max_comp_streams  	RW	the number of possible concurrent compress
 				operations
 comp_algorithm    	RW	show and change the compression algorithm
+algorithm_params	WO	setup compression algorithm parameters
 compact           	WO	trigger memory compaction
 debug_stat        	RO	this file is used for zram debugging purposes
 backing_dev	  	RW	set up backend storage for zram to write out
@@ -283,15 +308,15 @@ a single line of text and contains the following stats separated by whitespace:
 		Unit: 4K bytes
  ============== =============================================================
 
-9) Deactivate
-=============
+10) Deactivate
+==============
 
 ::
 
 	swapoff /dev/zram0
 	umount /dev/zram1
 
-10) Reset
+11) Reset
 =========
 
 	Write any positive value to 'reset' sysfs node::
@@ -487,11 +512,14 @@ registered compression algorithms, increases our chances of finding the
 algorithm that successfully compresses a particular page. Sometimes, however,
 it is convenient (and sometimes even necessary) to limit recompression to
 only one particular algorithm so that it will not try any other algorithms.
-This can be achieved by providing a algo=NAME parameter:::
+This can be achieved by providing a `algo` or `priority` parameter:::
 
 	#use zstd algorithm only (if registered)
 	echo "type=huge algo=zstd" > /sys/block/zramX/recompress
 
+	#use zstd algorithm only (if zstd was registered under priority 1)
+	echo "type=huge priority=1" > /sys/block/zramX/recompress
+
 memory tracking
 ===============