[PATCH v3 08/15] crypto: iaa - Add IAA Compression Accelerator Documentation
From: Tom Zanussi
Date: Fri Apr 28 2023 - 16:56:33 EST
Because the IAA Compression Accelerator requires significant user
setup in order to be used properly, this adds documentation on the
iaa_crypto driver including setup, usage, and examples.
Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
---
.../driver-api/crypto/iaa/iaa-crypto.rst | 640 ++++++++++++++++++
Documentation/driver-api/crypto/iaa/index.rst | 20 +
Documentation/driver-api/crypto/index.rst | 20 +
Documentation/driver-api/index.rst | 1 +
4 files changed, 681 insertions(+)
create mode 100644 Documentation/driver-api/crypto/iaa/iaa-crypto.rst
create mode 100644 Documentation/driver-api/crypto/iaa/index.rst
create mode 100644 Documentation/driver-api/crypto/index.rst
diff --git a/Documentation/driver-api/crypto/iaa/iaa-crypto.rst b/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
new file mode 100644
index 000000000000..a6a716f8b906
--- /dev/null
+++ b/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
@@ -0,0 +1,640 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================================
+IAA Compression Accelerator Crypto Driver
+=========================================
+
+Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
+
+The IAA crypto driver supports compression/decompression compatible
+with the DEFLATE compression standard described in RFC 1951, which is
+the compression/decompression algorithm exported by this module.
+
+The IAA hardware spec can be found here:
+
+ https://cdrdv2.intel.com/v1/dl/getContent/721858
+
+The iaa_crypto driver is designed to work as a layer underneath
+higher-level compression devices such as zswap.
+
+Users can select IAA compress/decompress acceleration by specifying
+'iaa_crypto' as the compression algorithm to use by whatever facility
+allows compression algorithms to be selected.
+
+For example, a zswap device can select iaa_crypto via::
+
+ # echo iaa_crypto > /sys/module/zswap/parameters/compressor
+
+
+Config options and other setup
+==============================
+
+The IAA crypto driver is available via menuconfig using the following
+path::
+
+ Cryptographic API -> Hardware crypto devices -> Support for Intel(R) IAA Compression Accelerator
+
+In the configuration file the option called CONFIG_CRYPTO_DEV_IAA_CRYPTO.
+
+The IAA crypto driver also supports statistics, which are available
+via menuconfig using the following path::
+
+ Cryptographic API -> Hardware crypto devices -> Support for Intel(R) IAA Compression -> Enable Intel(R) IAA Compression Accelerator Statistics
+
+In the configuration file the option called CONFIG_CRYPTO_DEV_IAA_CRYPTO_STATS.
+
+The following config options should also be enabled::
+
+ CONFIG_IRQ_REMAP=y
+ CONFIG_INTEL_IOMMU=y
+ CONFIG_INTEL_IOMMU_SVM=y
+ CONFIG_PCI_ATS=y
+ CONFIG_PCI_PRI=y
+ CONFIG_PCI_PASID=y
+ CONFIG_INTEL_IDXD=m
+ CONFIG_INTEL_IDXD_SVM=y
+
+IAA is one of the first Intel accelerator IPs that can work in
+conjunction with the Intel IOMMU. There are multiple modes that exist
+for testing. Based on IOMMU configuration, there are 3 modes::
+
+ - Scalable
+ - Legacy
+ - No IOMMU
+
+
+Scalable mode
+-------------
+
+Scalable mode supports Shared Virtual Memory (SVM or SVA). It is
+entered when using the kernel boot commandline::
+
+ intel_iommu=on,sm_on
+
+with VT-d turned on in BIOS.
+
+With scalable mode, both shared and dedicated workqueues are available
+for use.
+
+For scalable mode, the following BIOS settings should be enabled::
+
+ Socket Configuration > IIO Configuration > Intel VT for Directed I/O (VT-d) > Intel VT for Directed I/O
+
+ Socket Configuration > IIO Configuration > PCIe ENQCMD > ENQCMDS
+
+
+Legacy mode
+-----------
+
+Legacy mode is entered when using the kernel boot commandline::
+
+ intel_iommu=off, intel_iommu=on
+
+or VT-d is not turned on in BIOS.
+
+If you have booted into Linux and not sure if VT-d is on, do a "dmesg
+| grep -i dmar". If you don't see a number of DMAR devices enumerated,
+most likely VT-d is not on.
+
+With legacy mode, only dedicated workqueues are available for use.
+
+
+No IOMMU mode
+-------------
+
+No IOMMU mode is entered when using the kernel boot commandline::
+
+ iommu=off.
+
+With no IOMMU mode, only dedicated workqueues are available for use.
+
+
+Usage
+=====
+
+accel-config
+------------
+
+Unlike typical drivers, the iaa_crypto driver does not enable the
+device on driver load. Due to complexity and configurability of the
+accelerator devices, it was a design decision to have the user
+configure the device and manually enable the desired devices and
+workqueues.
+
+The userspace tool to help doing that is called accel-config. Using
+accel-config to configure device or loading a previously saved config
+is highly recommended. The device can be controlled via sysfs
+directly but comes with the warning that do this ONLY if you know
+exactly what you are doing. This document will not cover the sysfs
+interface but assumes you will be using accel-config.
+
+The accel-config tool along with instructions for building it can be
+found here:
+
+ https://github.com/intel/idxd-config/#readme
+
+
+Typical usage
+-------------
+
+In order for the iaa_crypto module to actually do any
+compression/decompression work on behalf of a facility, one or more
+IAA workqueues need to be bound to the iaa_crypto driver.
+
+For instance, here's an example of configuring an IAA workqueue and
+binding it to the iaa_crypto driver (note that device names are
+specified as 'iax' rather than 'iaa' - this is because upstream still
+has the old 'iax' device naming in place) ::
+
+ # configure wq1.0
+
+ accel-config config-wq --group-id=0 --mode=dedicated --type=kernel --name="iaa_crypto" --device_name="crypto" iax1/wq1.0
+
+ # enable IAA device iax1
+
+ accel-config enable-device iax1
+
+ # enable wq1.0 on IAX device iax1
+
+ accel-config enable-wq iax1/wq1.0
+
+Whenever a new workqueue is bound to or unbound from the iaa_crypto
+driver, the available workqueues are 'rebalanced' such that work
+submitted from a particular CPU is given to the most appropriate
+workqueue available. Current best practice is to configure and bind
+at least one workqueue for each IAA device, but as long as there is at
+least one workqueue configured and bound to any IAA device in the
+system, the iaa_crypto driver will work, albeit most likely not as
+efficiently.
+
+The IAA crypto algorigthms is operational and compression and
+decompression operations are fully enabled following the successful
+binding of the first IAA workqueue to the iaa_crypto driver.
+
+Similarly, the IAA crypto algorithm is not operational and compression
+and decompression operations are disabled following the unbinding of
+the last IAA worqueue to the iaa_crypto driver.
+
+As a result, the iaa_crypto crypto algorithm and thus the IAA hardware
+are only available when one or more workques are bound to the
+iaa_crypto driver.
+
+When there are no IAA workqueues bound to the driver, the IAA crypto
+algorithm can be unregistered by removing the module.
+
+
+Driver attributes
+-----------------
+
+There are a few user-configurable driver attributes that can be used
+to configure various modes of operation. They're listed below, along
+with their default values. To set any of these attributes, echo the
+appropriate values to the attribute file located under
+/sys/bus/dsa/drivers/crypto/
+
+ - verify_compress
+
+ Toggle compression verification. If set, each compress will be
+ internally decompressed and the contents verified, returning error
+ codes if unsuccessful. This can be toggled with 0/1:
+
+ echo 0 > /sys/bus/dsa/drivers/crypto/verify_compress
+
+ The default setting is '1' - verify all compresses.
+
+ - compression_mode
+
+ Select compression mode to be used by all compresses and
+ decompresses. There are a number ofcompression modes available,
+ each identified by a unique string. These can be selected by
+ echoing the string to the 'compression_mode' driver attribute.
+ Currently, there are only two compression modes available,
+ 'canned' and 'fixed' modes.
+
+ The 'fixed' compression mode implements the compression scheme
+ specified by RFC 1951.
+
+ The 'canned' compression mode implements a good general-purpose
+ compression scheme whose tables were generated from statistics
+ derived from a wide variety of SPEC17 workloads. It provides much
+ better overall characteristics than the existing deflate-1951
+ tables implemented by 'fixed'.
+
+ Either 'fixed' or 'canned' modes can be chosen as the mode to be used
+ for compression/decompression via the iaa_crypto compression_mode
+ iaa_crypto driver attribute:
+
+ echo "canned" > /sys/bus/dsa/drivers/crypto/compression_mode
+
+ The default setting is 'fixed'.
+
+ - sync_mode
+
+ Select mode to be used to wait for completion of each compresses
+ and decompress operation.
+
+ The crypto async interface support implemented by iaa_crypto
+ provides an implementation that satisfies the interface but does
+ so in a synchronous manner - it fills and submits the IDXD
+ descriptor and then loops around waiting for it to complete before
+ returning. This isn't a problem at the moment, since all existing
+ callers (e.g. zswap) wrap any asynchronous callees in a
+ synchronous wrapper anyway.
+
+ The iaa_crypto driver does however provide true asynchronous
+ support for callers that can make use of it. In this mode, it
+ fills and submits the IDXD descriptor, then returns immediately
+ with -EINPROGRESS. The caller can then either poll for completion
+ itself, which requires specific code in the caller which currently
+ nothing in the upstream kernel implements, or go to sleep and wait
+ for an interrupt signaling completion. This latter mode is
+ supported by current users in the kernel such as zswap via
+ synchronous wrappers. Although it is supported this mode is
+ significantly slower than the synchronous mode that does the
+ polling in the iaa_crypto driver previously mentioned.
+
+ This mode can be enabled by writing 'async_irq' to the sync_mode
+ iaa_crypto driver attribute:
+
+ echo async_irq > /sys/bus/dsa/drivers/crypto/sync_mode
+
+ Async mode without interrupts (caller must poll) can be enabled by
+ writing 'async' to it:
+
+ echo async > /sys/bus/dsa/drivers/crypto/sync_mode
+
+ The mode that does the polling in the iaa_crypto driver can be
+ enabled by writing 'sync' to it:
+
+ echo sync > /sys/bus/dsa/drivers/crypto/sync_mode
+
+ The default mode is 'sync'.
+
+
+Statistics
+==========
+
+If the optional debugfs statistics support is enabled, the IAA crypto
+driver will generate statistics which can be accessed in debugfs at::
+
+ # ls -al /sys/kernel/debug/iaa-crypto/
+ total 0
+ drwxr-xr-x 2 root root 0 Mar 3 09:35 .
+ drwx------ 47 root root 0 Mar 3 09:35 ..
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 max_acomp_delay_ns
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 max_adecomp_delay_ns
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 max_comp_delay_ns
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 max_decomp_delay_ns
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 stats_reset
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 total_comp_bytes_out
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 total_comp_calls
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 total_decomp_bytes_in
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 total_decomp_calls
+ -rw-r--r-- 1 root root 0 Mar 3 09:35 wq_stats
+
+Most of the above statisticss are self-explanatory. The wq_stats file
+shows per-wq stats, a set for each iaa device and wq in addition to
+some global stats::
+
+ # cat wq_stats
+ global stats:
+ total_comp_calls: 100
+ total_decomp_calls: 100
+ total_comp_bytes_out: 22800
+ total_decomp_bytes_in: 22800
+ total_completion_einval_errors: 0
+ total_completion_timeout_errors: 0
+ total_completion_comp_buf_overflow_errors: 0
+
+ iaa device:
+ id: 1
+ n_wqs: 1
+ comp_calls: 0
+ comp_bytes: 0
+ decomp_calls: 0
+ decomp_bytes: 0
+ wqs:
+ name: iaa_crypto
+ comp_calls: 0
+ comp_bytes: 0
+ decomp_calls: 0
+ decomp_bytes: 0
+
+ iaa device:
+ id: 3
+ n_wqs: 1
+ comp_calls: 0
+ comp_bytes: 0
+ decomp_calls: 0
+ decomp_bytes: 0
+ wqs:
+ name: iaa_crypto
+ comp_calls: 0
+ comp_bytes: 0
+ decomp_calls: 0
+ decomp_bytes: 0
+
+ iaa device:
+ id: 5
+ n_wqs: 1
+ comp_calls: 100
+ comp_bytes: 22800
+ decomp_calls: 100
+ decomp_bytes: 22800
+ wqs:
+ name: iaa_crypto
+ comp_calls: 100
+ comp_bytes: 22800
+ decomp_calls: 100
+ decomp_bytes: 22800
+
+Writing 0 to 'stats_reset' resets all the stats, including the
+per-device and per-wq stats::
+
+ # echo 0 > stats_reset
+ # cat wq_stats
+ global stats:
+ total_comp_calls: 0
+ total_decomp_calls: 0
+ total_comp_bytes_out: 0
+ total_decomp_bytes_in: 0
+ total_completion_einval_errors: 0
+ total_completion_timeout_errors: 0
+ total_completion_comp_buf_overflow_errors: 0
+ ...
+
+
+Use cases
+=========
+
+Simple zswap test
+-----------------
+
+For this example, the kernel should be configured according to the
+dedicated mode options described above, and zswap should be enabled as
+well::
+
+ CONFIG_ZSWAP=y
+
+This is a simple test that uses iaa_compress as the compressor for a
+swap (zswap) device. It sets up the zswap device and then uses the
+memory_memadvise program listed below to forcibly swap out and in a
+specified number of pages, demonstrating both compress and decompress.
+
+The zswap test expects the work queues for each IAA device on the
+system to be configured properly as a kernel workqueue with a
+workqueue driver_name of "crypto".
+
+The first step is to make sure the iaa_crypto module is loaded::
+
+ modprobe iaa_crypto
+
+Following that the IAA device(s) should be configured and enabled.
+
+The zswap test expects the work queues for each IAA device on the
+system to be configured properly as a kernel workqueue with a
+workqueue driver_name of "crypto".
+
+The below script automatically does that::
+
+ #!/bin/bash
+
+ echo "IAA devices:"
+ lspci -d:0cfe
+ echo "# IAA devices:"
+ lspci -d:0cfe | wc -l
+
+ #
+ # count iaa instances
+ #
+ iaa_dev_id="0cfe"
+ num_iaa=$(lspci -d:${iaa_dev_id} | wc -l)
+ echo "Found ${num_iaa} IAA instances"
+
+ #
+ # disable iaa wqs and devices
+ #
+ echo "Disable IAA"
+
+ for ((i = 1; i < ${num_iaa} * 2; i += 2)); do
+ echo disable wq iax${i}/wq${i}.0
+ accel-config disable-wq iax${i}/wq${i}.0
+ echo disable iaa iax${i}
+ accel-config disable-device iax${i}
+ done
+
+ echo "End Disable IAA"
+
+ #
+ # configure iaa wqs and devices
+ #
+ echo "Configure IAA"
+ for ((i = 1; i < ${num_iaa} * 2; i += 2)); do
+ accel-config config-wq --group-id=0 --mode=dedicated --size=128 --priority=10 --type=kernel --name="iaa_crypto" --driver_name="crypto" iax${i}/wq${i}
+ done
+
+ echo "End Configure IAA"
+
+ #
+ # enable iaa wqs and devices
+ #
+ echo "Enable IAA"
+
+ for ((i = 1; i < ${num_iaa} * 2; i += 2)); do
+ echo enable iaa iaa${i}
+ accel-config enable-device iaa${i}
+ echo enable wq iaa${i}/wq${i}.0
+ accel-config enable-wq iaa${i}/wq${i}.0
+ done
+
+ echo "End Enable IAA"
+
+When the workqueues are bound to the iaa_crypto driver, you should
+see something similar to the following in dmesg output if you've
+enabled debug output (echo -n 'module iaa_crypto +p' >
+/sys/kernel/debug/dynamic_debug/control)::
+
+ [ 60.752344] idxd 0000:f6:02.0: add_iaa_wq: added wq 000000004068d14d to iaa 00000000c9585ba2, n_wq 1
+ [ 60.752346] iaa_crypto: rebalance_wq_table: nr_nodes=2, nr_cpus 160, nr_iaa 8, cpus_per_iaa 20
+ [ 60.752347] iaa_crypto: rebalance_wq_table: iaa=0
+ [ 60.752349] idxd 0000:6a:02.0: request_iaa_wq: getting wq from iaa_device 0000000042d7bc52 (0)
+ [ 60.752350] idxd 0000:6a:02.0: request_iaa_wq: returning unused wq 00000000c8bb4452 (0) from iaa device 0000000042d7bc52 (0)
+ [ 60.752352] iaa_crypto: rebalance_wq_table: assigned wq for cpu=0, node=0 = wq 00000000c8bb4452
+ [ 60.752354] iaa_crypto: rebalance_wq_table: iaa=0
+ [ 60.752355] idxd 0000:6a:02.0: request_iaa_wq: getting wq from iaa_device 0000000042d7bc52 (0)
+ [ 60.752356] idxd 0000:6a:02.0: request_iaa_wq: returning unused wq 00000000c8bb4452 (0) from iaa device 0000000042d7bc52 (0)
+ [ 60.752358] iaa_crypto: rebalance_wq_table: assigned wq for cpu=1, node=0 = wq 00000000c8bb4452
+ [ 60.752359] iaa_crypto: rebalance_wq_table: iaa=0
+ [ 60.752360] idxd 0000:6a:02.0: request_iaa_wq: getting wq from iaa_device 0000000042d7bc52 (0)
+ [ 60.752361] idxd 0000:6a:02.0: request_iaa_wq: returning unused wq 00000000c8bb4452 (0) from iaa device 0000000042d7bc52 (0)
+ [ 60.752362] iaa_crypto: rebalance_wq_table: assigned wq for cpu=2, node=0 = wq 00000000c8bb4452
+ [ 60.752364] iaa_crypto: rebalance_wq_table: iaa=0
+ .
+ .
+ .
+
+Once the workqueues and devices have been enabled, the iaa_crypto
+algorithm is enabled and available. When the iaa_crypto algorithm has
+been successfully enabled, you should see the following dmesg output::
+
+ [ 64.893759] iaa_crypto: iaa_crypto_enable: iaa_crypto now ENABLED
+
+Now run the following zswap-specific setup commands::
+
+ echo 0 > /sys/module/zswap/parameters/enabled
+ echo 50 > /sys/module/zswap/parameters/max_pool_percent
+ echo iaa_crypto > /sys/module/zswap/parameters/compressor
+ echo zsmalloc > /sys/module/zswap/parameters/zpool
+ echo 1 > /sys/module/zswap/parameters/enabled
+ echo 0 > /sys/module/zswap/parameters/same_filled_pages_enabled
+
+ echo 100 > /proc/sys/vm/swappiness
+ echo never > /sys/kernel/mm/transparent_hugepage/enabled
+ echo 1 > /proc/sys/vm/overcommit_memory
+
+Finally, you can now run the zswap workload you want to measure. For
+example, using the code below, the following command will swap in and
+out 100 pages::
+
+ ./memory_madvise 100
+
+ Allocating 100 pages to swap in/out
+ Swapping out 100 pages
+ Swapping in 100 pages
+ Swapped out and in 100 pages
+
+You should see something like the following in the dmesg output if
+you've enabled debug output (echo -n 'module iaa_crypto +p' >
+/sys/kernel/debug/dynamic_debug/control)::
+
+ [ 404.202972] idxd 0000:e7:02.0: iaa_comp_acompress: dma_map_sg, src_addr 223925c000, nr_sgs 1, req->src 00000000ee7cb5e6, req->slen 4096, sg_dma_len(sg) 4096
+ [ 404.202973] idxd 0000:e7:02.0: iaa_comp_acompress: dma_map_sg, dst_addr 21dadf8000, nr_sgs 1, req->dst 000000008d6acea8, req->dlen 4096, sg_dma_len(sg) 8192
+ [ 404.202975] idxd 0000:e7:02.0: iaa_compress: desc->src1_addr 223925c000, desc->src1_size 4096, desc->dst_addr 21dadf8000, desc->max_dst_size 4096, desc->src2_addr 2203543000, desc->src2_size 1568
+ [ 404.202981] idxd 0000:e7:02.0: iaa_compress_verify: (verify) desc->src1_addr 21dadf8000, desc->src1_size 228, desc->dst_addr 223925c000, desc->max_dst_size 4096, desc->src2_addr 0, desc->src2_size 0
+ [ 409.203227] idxd 0000:e7:02.0: iaa_comp_adecompress: dma_map_sg, src_addr 21ddd8b100, nr_sgs 1, req->src 0000000084adab64, req->slen 228, sg_dma_len(sg) 228
+ [ 409.203235] idxd 0000:e7:02.0: iaa_comp_adecompress: dma_map_sg, dst_addr 21ee3dc000, nr_sgs 1, req->dst 000000004e2990d0, req->dlen 4096, sg_dma_len(sg) 4096
+ [ 409.203239] idxd 0000:e7:02.0: iaa_decompress: desc->src1_addr 21ddd8b100, desc->src1_size 228, desc->dst_addr 21ee3dc000, desc->max_dst_size 4096, desc->src2_addr 0, desc->src2_size 0
+ [ 409.203254] idxd 0000:e7:02.0: iaa_comp_adecompress: dma_map_sg, src_addr 21ddd8b100, nr_sgs 1, req->src 0000000084adab64, req->slen 228, sg_dma_len(sg) 228
+ [ 409.203256] idxd 0000:e7:02.0: iaa_comp_adecompress: dma_map_sg, dst_addr 21f1551000, nr_sgs 1, req->dst 000000004e2990d0, req->dlen 4096, sg_dma_len(sg) 4096
+ [ 409.203257] idxd 0000:e7:02.0: iaa_decompress: desc->src1_addr 21ddd8b100, desc->src1_size 228, desc->dst_addr 21f1551000, desc->max_dst_size 4096, desc->src2_addr 0, desc->src2_size 0
+
+In order to unregister the iaa_crypto algorithm, and register a new
+one using different parameters, any users of the current algorithm
+should be stopped and the IAA workqueues and devices disabled.
+
+In the case of zswap, remove the iaa_crypto algorithm as the
+compressor and turn off swap (to remove all references to
+iaa_crypto)::
+
+ echo lzo > /sys/module/zswap/parameters/compressor
+ swapoff -a
+
+ echo 0 > /sys/module/zswap/parameters/accept_threshold_percent
+ echo 0 > /sys/module/zswap/parameters/max_pool_percent
+ echo 0 > /sys/module/zswap/parameters/enabled
+
+Once zswap is disabled and no longer using iaa_crypto, the IAA wqs and
+devices can be disabled.
+
+The below script automatically does that::
+
+ #!/bin/bash
+
+ echo "IAA devices:"
+ lspci -d:0cfe
+ echo "# IAA devices:"
+ lspci -d:0cfe | wc -l
+
+ #
+ # count iaa instances
+ #
+ iaa_dev_id="0cfe"
+ num_iaa=$(lspci -d:${iaa_dev_id} | wc -l)
+ echo "Found ${num_iaa} IAA instances"
+
+ #
+ # disable iaa wqs and devices
+ #
+ echo "Disable IAA"
+
+ for ((i = 1; i < ${num_iaa} * 2; i += 2)); do
+ echo disable wq iax${i}/wq${i}.0
+ accel-config disable-wq iax${i}/wq${i}.0
+ echo disable iaa iax${i}
+ accel-config disable-device iax${i}
+ done
+
+ echo "End Disable IAA"
+
+Finally, at this point the iaa_crypto module can be removed, which
+will unregister the current iaa_crypto algorithm::
+
+ rmmod iaa_crypto
+
+
+memory_madvise.c (gcc -o memory_memadvise memory_madvise.c)::
+
+ #include <stdio.h>
+ #include <stdlib.h>
+ #include <string.h>
+ #include <unistd.h>
+ #include <sys/mman.h>
+ #include <linux/mman.h>
+
+ #ifndef MADV_PAGEOUT
+ #define MADV_PAGEOUT 21 /* force pages out immediately */
+ #endif
+
+ #define PG_SZ 4096
+
+ int main(int argc, char **argv)
+ {
+ int i, nr_pages = 1;
+ int64_t *dump_ptr;
+ char *addr, *a;
+ int loop = 1;
+
+ if (argc > 1)
+ nr_pages = atoi(argv[1]);
+
+ printf("Allocating %d pages to swap in/out\n", nr_pages);
+
+ /* allocate pages */
+ addr = mmap(NULL, nr_pages * PG_SZ, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+ *addr = 1;
+
+ /* initialize data in page to all '*' chars */
+ memset(addr, '*', nr_pages * PG_SZ);
+
+ printf("Swapping out %d pages\n", nr_pages);
+
+ /* Tell kernel to swap it out */
+ madvise(addr, nr_pages * PG_SZ, MADV_PAGEOUT);
+
+ while (loop > 0) {
+ /* Wait for swap out to finish */
+ sleep(5);
+
+ a = addr;
+
+ printf("Swapping in %d pages\n", nr_pages);
+
+ /* Access the page ... this will swap it back in again */
+ for (i = 0; i < nr_pages; i++) {
+ if (a[0] != '*') {
+ printf("Bad data from decompress!!!!!\n");
+
+ dump_ptr = (int64_t *)a;
+ for (int j = 0; j < 100; j++) {
+ printf(" page %d data: %#llx\n", i, *dump_ptr);
+ dump_ptr++;
+ }
+ }
+
+ a += PG_SZ;
+ }
+
+ loop --;
+ }
+
+ printf("Swapped out and in %d pages\n", nr_pages);
diff --git a/Documentation/driver-api/crypto/iaa/index.rst b/Documentation/driver-api/crypto/iaa/index.rst
new file mode 100644
index 000000000000..aa6837e27264
--- /dev/null
+++ b/Documentation/driver-api/crypto/iaa/index.rst
@@ -0,0 +1,20 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================================
+IAA (Intel Analytics Accelerator)
+=================================
+
+IAA provides hardware compression and decompression via the crypto
+API.
+
+.. toctree::
+ :maxdepth: 1
+
+ iaa-crypto
+
+.. only:: subproject and html
+
+ Indices
+ =======
+
+ * :ref:`genindex`
diff --git a/Documentation/driver-api/crypto/index.rst b/Documentation/driver-api/crypto/index.rst
new file mode 100644
index 000000000000..fb9709b98bea
--- /dev/null
+++ b/Documentation/driver-api/crypto/index.rst
@@ -0,0 +1,20 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==============
+Crypto Drivers
+==============
+
+Documentation for crypto drivers that may need more involved setup and
+configuration.
+
+.. toctree::
+ :maxdepth: 1
+
+ iaa/index
+
+.. only:: subproject and html
+
+ Indices
+ =======
+
+ * :ref:`genindex`
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index ff9aa1afdc62..2ad1237d5d5f 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -113,6 +113,7 @@ available subsections can be seen below.
xillybus
zorro
hte/index
+ crypto/index
.. only:: subproject and html
--
2.34.1