Fix detection of IBM Power8 machines (ISA 2.07)

[mcmilk]

An IBM POWER7 system with Power ISA 2.06 tried to execute zfs_sha256_power8() - which should only be run on ISA 2.07 machines.

The detection is implemented via the zfs_isa207_available() call, but this check was not used.

This pull request will fix this.

Motivation and Context

#13741 (comment)

Description

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[Low-power]

Please add the followings to fix #13741 (comment):

diff --git a/module/icp/algs/sha2/sha512_impl.c b/module/icp/algs/sha2/sha512_impl.c
index b6341f6..8e1dfab 100644
--- a/module/icp/algs/sha2/sha512_impl.c
+++ b/module/icp/algs/sha2/sha512_impl.c
@@ -131,14 +131,14 @@ const sha512_ops_t sha512_ppc_impl = {
 	.name = "ppc"
 };
 
-static boolean_t sha512_have_vsx(void)
+static boolean_t sha512_have_isa207(void)
 {
-	return (kfpu_allowed() && zfs_vsx_available());
+	return (kfpu_allowed() && zfs_isa207_available());
 }
 
 TF(zfs_sha512_power8, tf_sha512_power8);
 const sha512_ops_t sha512_power8_impl = {
-	.is_supported = sha512_have_vsx,
+	.is_supported = sha512_have_isa207,
 	.transform = tf_sha512_power8,
 	.name = "power8"
 };

[Low-power]

Confirmed to work on both POWER7 and POWER8 machines in my environment.

[mcmilk]

Confirmed to work on both POWER7 and POWER8 machines in my environment.

Could you post the output of cat /proc/spl/kstat/zfs/chksum_bench ?

[Low-power]

POWER7 machine:

root@debian:~# modinfo zfs | grep ^version:
version:        2.1.99-1780_g620a977
root@debian:~# lscpu
Architecture:            ppc64
  CPU op-mode(s):        32-bit, 64-bit
  Byte Order:            Big Endian
CPU(s):                  4
  On-line CPU(s) list:   0-3
Model name:              POWER7 (architected), altivec supported
  Model:                 2.3 (pvr 003f 0203)
  Thread(s) per core:    4
  Core(s) per socket:    1
  Socket(s):             1
Virtualization features: 
  Hypervisor vendor:     pHyp
  Virtualization type:   para
Caches (sum of all):     
  L1d:                   32 KiB (1 instance)
  L1i:                   32 KiB (1 instance)
  L2:                    256 KiB (1 instance)
  L3:                    4 MiB (1 instance)
NUMA:                    
  NUMA node(s):          1
  NUMA node0 CPU(s):     0-3
root@debian:~# cat /proc/spl/kstat/zfs/chksum_bench
15 0 0x01 -1 0 302165441347 9745603564008
implementation               1k      4k     16k     64k    256k      1m      4m     16m
edonr-generic               336     439     475     472     480     486     782     786
skein-generic               194     213     223     222     222     222     102     212
sha256-generic               87      92      94      95      61      98      99      86
sha256-ppc                  177     192     189     195     196     197     196     179
sha512-generic              121     134     141     143     143     146     232     235
sha512-ppc                  287     325     333     339     343     344     345     347
blake3-generic              275     287     281     286     287     286     332     334

POWER8 machine:

root@debiansid-be:~# modinfo zfs | grep ^version:
version:        2.1.99-1780_g620a977f2
root@debiansid-be:~# lscpu
Architecture:          ppc64
  CPU op-mode(s):      32-bit, 64-bit
  Byte Order:          Big Endian
CPU(s):                176
  On-line CPU(s) list: 0-175
Model name:            POWER8 (raw), altivec supported
  Model:               2.0 (pvr 004d 0200)
  Thread(s) per core:  8
  Core(s) per socket:  11
  Socket(s):           2
  CPU(s) scaling MHz:  100%
  CPU max MHz:         3225.0000
  CPU min MHz:         2061.0000
Caches (sum of all):   
  L1d:                 1.4 MiB (22 instances)
  L1i:                 704 KiB (22 instances)
  L2:                  11 MiB (22 instances)
  L3:                  176 MiB (22 instances)
NUMA:                  
  NUMA node(s):        2
  NUMA node0 CPU(s):   0-87
  NUMA node8 CPU(s):   88-175
Vulnerabilities:       
  Itlb multihit:       Not affected
  L1tf:                Mitigation; RFI Flush
  Mds:                 Not affected
  Meltdown:            Mitigation; RFI Flush
  Mmio stale data:     Not affected
  Retbleed:            Not affected
  Spec store bypass:   Mitigation; Kernel entry/exit barrier (hwsync)
  Spectre v1:          Mitigation; __user pointer sanitization
  Spectre v2:          Vulnerable
  Srbds:               Not affected
  Tsx async abort:     Not affected
root@debiansid-be:~# cat /proc/spl/kstat/zfs/chksum_bench 
15 0 0x01 -1 0 21176320767 5428882179462
implementation               1k      4k     16k     64k    256k      1m      4m     16m
edonr-generic               871    1074    1138    1160    1168    1166    1169    1170
skein-generic               263     288     295     297     298     298     298     298
sha256-generic              121     129     131     132     132     132     132     132
sha256-ppc                  178     192     196     197     198     197     197     197
sha256-power8               284     310     317     319     319     319     319     319
sha512-generic              175     197     203     204     205     205     205     205
sha512-ppc                  261     296     308     311     312     312     312     312
sha512-power8               417     484     504     509     510     511     510     511
blake3-generic              183     181     182     182     182     182     182     182