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[v2,0/4] selftests: arm64: vec-syscfg updates

Message ID 20210917120855.13858-1-broonie@kernel.org
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Series selftests: arm64: vec-syscfg updates | expand

Message

Mark Brown Sept. 17, 2021, 12:08 p.m. UTC
This series fixes up a few issues introduced into vec-syscfg during
refactoring in the review process, then adds a new test which ensures
that the behaviour when we attempt to set a vector length which is not
supported by the current system matches what is documented in the SVE
ABI documentation.

v2:
 - Fix handling of missing VLs when checking that vector length setting
   works as expected.

Mark Brown (4):
  selftests: arm64: Fix printf() format mismatch in vec-syscfg
  selftests: arm64: Remove bogus error check on writing to files
  selftests: arm64: Fix and enable test for setting current VL in
    vec-syscfg
  selftests: arm64: Verify that all possible vector lengths are handled

 tools/testing/selftests/arm64/fp/vec-syscfg.c | 89 ++++++++++++++++---
 1 file changed, 76 insertions(+), 13 deletions(-)


base-commit: 6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f
-- 
2.20.1

Comments

Will Deacon Sept. 29, 2021, 2:31 p.m. UTC | #1
On Fri, Sep 17, 2021 at 01:08:51PM +0100, Mark Brown wrote:
> This series fixes up a few issues introduced into vec-syscfg during

> refactoring in the review process, then adds a new test which ensures

> that the behaviour when we attempt to set a vector length which is not

> supported by the current system matches what is documented in the SVE

> ABI documentation.

> 

> v2:

>  - Fix handling of missing VLs when checking that vector length setting

>    works as expected.


With this series applied, I see a test failing under qemu with:

# selftests: arm64: vec-syscfg
# TAP version 13
# 1..10
# ok 1 SVE default vector length 64
# ok 2 # SKIP Need to be root to write to /proc
# ok 3 # SKIP Need to be root to write to /proc
# ok 4 SVE current VL is 64
# ok 5 SVE set VL 64 and have VL 64
# ok 6 # SKIP SVE only one VL supported
# ok 7 # SKIP SVE only one VL supported
# ok 8 # SKIP SVE only one VL supported
# ok 9 # SKIP SVE only one VL supported
# # SVE VL 272 returned 256 not maximum 0
# # SVE VL 288 returned 256 not maximum 0
# # SVE VL 304 returned 256 not maximum 0
# # SVE VL 320 returned 256 not maximum 0
# # SVE VL 336 returned 256 not maximum 0
# # SVE VL 352 returned 256 not maximum 0

[repeat similar messages for ages]

  # SVE VL 8160 returned 256 not maximum 0
# # SVE VL 8176 returned 256 not maximum 0
# # SVE VL 8192 returned 256 not maximum 0
# not ok 10 SVE prctl() set all VLs, 496 errors
# # Totals: pass:3 fail:1 xfail:0 xpass:0 skip:6 error:0

Will
Mark Brown Sept. 29, 2021, 2:43 p.m. UTC | #2
On Wed, Sep 29, 2021 at 03:31:14PM +0100, Will Deacon wrote:

> With this series applied, I see a test failing under qemu with:


> # selftests: arm64: vec-syscfg

> # TAP version 13

> # 1..10

> # ok 1 SVE default vector length 64

> # ok 2 # SKIP Need to be root to write to /proc

> # ok 3 # SKIP Need to be root to write to /proc


AFAICT this is due to running as a non-root user, the testsuite was
already having serious issues before then...

> # ok 4 SVE current VL is 64

> # ok 5 SVE set VL 64 and have VL 64

> # ok 6 # SKIP SVE only one VL supported

> # ok 7 # SKIP SVE only one VL supported

> # ok 8 # SKIP SVE only one VL supported

> # ok 9 # SKIP SVE only one VL supported

> # # SVE VL 272 returned 256 not maximum 0


...as it's starting off by testing an interface that's only writable by
root and then relying on that information, the existing tests were also
not working usefully.  qemu by default supports way more than one vector
length.  In any case it's just the test added by the last patch that's
causing the output here, the first four patches should be fine and fix
issues.

I'm not sure it's a particularly good idea to run kselftest as a
non-root user TBH, it's going to cause you to skip a lot of tests.
Will Deacon Sept. 29, 2021, 3:35 p.m. UTC | #3
On Wed, Sep 29, 2021 at 03:43:23PM +0100, Mark Brown wrote:
> On Wed, Sep 29, 2021 at 03:31:14PM +0100, Will Deacon wrote:

> 

> > With this series applied, I see a test failing under qemu with:

> 

> > # selftests: arm64: vec-syscfg

> > # TAP version 13

> > # 1..10

> > # ok 1 SVE default vector length 64

> > # ok 2 # SKIP Need to be root to write to /proc

> > # ok 3 # SKIP Need to be root to write to /proc

> 

> AFAICT this is due to running as a non-root user, the testsuite was

> already having serious issues before then...

> 

> > # ok 4 SVE current VL is 64

> > # ok 5 SVE set VL 64 and have VL 64

> > # ok 6 # SKIP SVE only one VL supported

> > # ok 7 # SKIP SVE only one VL supported

> > # ok 8 # SKIP SVE only one VL supported

> > # ok 9 # SKIP SVE only one VL supported

> > # # SVE VL 272 returned 256 not maximum 0

> 

> ...as it's starting off by testing an interface that's only writable by

> root and then relying on that information, the existing tests were also

> not working usefully.  qemu by default supports way more than one vector

> length.  In any case it's just the test added by the last patch that's

> causing the output here, the first four patches should be fine and fix

> issues.

> 

> I'm not sure it's a particularly good idea to run kselftest as a

> non-root user TBH, it's going to cause you to skip a lot of tests.


Ah, thanks for pointing that out. It would probably be better to skip the
tests rather than fail them if they're not running with sufficient
permissions, but I'll go ahead and queue your v3 for now.

Will
Mark Brown Sept. 29, 2021, 3:38 p.m. UTC | #4
On Wed, Sep 29, 2021 at 04:35:12PM +0100, Will Deacon wrote:
> On Wed, Sep 29, 2021 at 03:43:23PM +0100, Mark Brown wrote:


> > I'm not sure it's a particularly good idea to run kselftest as a

> > non-root user TBH, it's going to cause you to skip a lot of tests.


> Ah, thanks for pointing that out. It would probably be better to skip the

> tests rather than fail them if they're not running with sufficient

> permissions, but I'll go ahead and queue your v3 for now.


Yes, that's what my v3 does - it skips the new test if it failed to
enumerate minimum and maximum vector lengths, like the other tests do.
Shuah Khan Sept. 29, 2021, 4:26 p.m. UTC | #5
On 9/29/21 9:35 AM, Will Deacon wrote:
> On Wed, Sep 29, 2021 at 03:43:23PM +0100, Mark Brown wrote:

>> On Wed, Sep 29, 2021 at 03:31:14PM +0100, Will Deacon wrote:

>>

>>> With this series applied, I see a test failing under qemu with:

>>

>>> # selftests: arm64: vec-syscfg

>>> # TAP version 13

>>> # 1..10

>>> # ok 1 SVE default vector length 64

>>> # ok 2 # SKIP Need to be root to write to /proc

>>> # ok 3 # SKIP Need to be root to write to /proc

>>

>> AFAICT this is due to running as a non-root user, the testsuite was

>> already having serious issues before then...

>>

>>> # ok 4 SVE current VL is 64

>>> # ok 5 SVE set VL 64 and have VL 64

>>> # ok 6 # SKIP SVE only one VL supported

>>> # ok 7 # SKIP SVE only one VL supported

>>> # ok 8 # SKIP SVE only one VL supported

>>> # ok 9 # SKIP SVE only one VL supported

>>> # # SVE VL 272 returned 256 not maximum 0

>>

>> ...as it's starting off by testing an interface that's only writable by

>> root and then relying on that information, the existing tests were also

>> not working usefully.  qemu by default supports way more than one vector

>> length.  In any case it's just the test added by the last patch that's

>> causing the output here, the first four patches should be fine and fix

>> issues.

>>

>> I'm not sure it's a particularly good idea to run kselftest as a

>> non-root user TBH, it's going to cause you to skip a lot of tests.

> 


We don't want Kselftest default run to be as root. Users can choose to
run as root which would be an explicit choice so they expect and plan
for the impact. Example panic test.

> Ah, thanks for pointing that out. It would probably be better to skip the

> tests rather than fail them if they're not running with sufficient

> permissions, but I'll go ahead and queue your v3 for now.

> 


Correct. I would like to see tests skipped not failed if either config
or permissions are lacking to run the tests.

thanks,
-- Shuah
Mark Brown Sept. 29, 2021, 4:37 p.m. UTC | #6
On Wed, Sep 29, 2021 at 10:26:49AM -0600, Shuah Khan wrote:
> On 9/29/21 9:35 AM, Will Deacon wrote:

> > On Wed, Sep 29, 2021 at 03:43:23PM +0100, Mark Brown wrote:


> > > I'm not sure it's a particularly good idea to run kselftest as a

> > > non-root user TBH, it's going to cause you to skip a lot of tests.


> We don't want Kselftest default run to be as root. Users can choose to

> run as root which would be an explicit choice so they expect and plan

> for the impact. Example panic test.


OTOH if you're trying to verify that the tests aren't broken it's not
that great since it'll mean that you'll not be exercising a bunch of the
code.

> > Ah, thanks for pointing that out. It would probably be better to skip the

> > tests rather than fail them if they're not running with sufficient

> > permissions, but I'll go ahead and queue your v3 for now.


> Correct. I would like to see tests skipped not failed if either config

> or permissions are lacking to run the tests.


As I said previously that's what my v3 that Will referenced above does.
Shuah Khan Sept. 29, 2021, 6:23 p.m. UTC | #7
On 9/29/21 10:37 AM, Mark Brown wrote:
> On Wed, Sep 29, 2021 at 10:26:49AM -0600, Shuah Khan wrote:

>> On 9/29/21 9:35 AM, Will Deacon wrote:

>>> On Wed, Sep 29, 2021 at 03:43:23PM +0100, Mark Brown wrote:

> 

>>>> I'm not sure it's a particularly good idea to run kselftest as a

>>>> non-root user TBH, it's going to cause you to skip a lot of tests.

> 

>> We don't want Kselftest default run to be as root. Users can choose to

>> run as root which would be an explicit choice so they expect and plan

>> for the impact. Example panic test.

> 

> OTOH if you're trying to verify that the tests aren't broken it's not

> that great since it'll mean that you'll not be exercising a bunch of the

> code.

> 


Correct. Running Kselftest as root is the best approach for full coverage.

thanks,
-- Shuah