Documentation: fixups for L1D flushing

[PATCH 0/2] Documentation: fixups for L1D flushing

Posted by Brendan Jackman 2 months ago

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
Brendan Jackman (2):
      Documentation: clarify PR_SPEC_L1D_FLUSH
      Documentation: fix reference to PR_SPEC_L1D_FLUSH

 Documentation/admin-guide/hw-vuln/l1d_flush.rst | 2 +-
 Documentation/userspace-api/spec_ctrl.rst       | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)
---
base-commit: 0292ef418ce08aad597fc0bba65b6dbb841808ba
change-id: 20251015-l1d-flush-doc-029f64d2b0d3

Best regards,
-- 
Brendan Jackman <jackmanb@google.com>

Re: [PATCH 0/2] Documentation: fixups for L1D flushing

Posted by Jonathan Corbet 1 month, 3 weeks ago

Brendan Jackman <jackmanb@google.com> writes:

> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
> Brendan Jackman (2):
>       Documentation: clarify PR_SPEC_L1D_FLUSH
>       Documentation: fix reference to PR_SPEC_L1D_FLUSH
>
>  Documentation/admin-guide/hw-vuln/l1d_flush.rst | 2 +-
>  Documentation/userspace-api/spec_ctrl.rst       | 6 +++++-
>  2 files changed, 6 insertions(+), 2 deletions(-)

I've gone ahead and applied these two, thanks.

jon

Re: [PATCH 0/2] Documentation: fixups for L1D flushing

Posted by Brendan Jackman 2 months ago

On Wed Oct 15, 2025 at 5:02 PM UTC, Brendan Jackman wrote:
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
> Brendan Jackman (2):
>       Documentation: clarify PR_SPEC_L1D_FLUSH
>       Documentation: fix reference to PR_SPEC_L1D_FLUSH
>
>  Documentation/admin-guide/hw-vuln/l1d_flush.rst | 2 +-
>  Documentation/userspace-api/spec_ctrl.rst       | 6 +++++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
> ---
> base-commit: 0292ef418ce08aad597fc0bba65b6dbb841808ba
> change-id: 20251015-l1d-flush-doc-029f64d2b0d3
>
> Best regards,

I just noticed another issue - the docs say you get -ENXIO if control
isn't possible, but for L1D_FLUSH and INDIR_BRANCH you get -EPERM.

TBH I think this is a bug but it seems like it's still better to just
document it than change the behaviour.

Re: [PATCH 0/2] Documentation: fixups for L1D flushing

Posted by Brendan Jackman 1 month, 2 weeks ago

On Thu Oct 16, 2025 at 2:54 PM UTC, Brendan Jackman wrote:
> On Wed Oct 15, 2025 at 5:02 PM UTC, Brendan Jackman wrote:
>> Signed-off-by: Brendan Jackman <jackmanb@google.com>
>> ---
>> Brendan Jackman (2):
>>       Documentation: clarify PR_SPEC_L1D_FLUSH
>>       Documentation: fix reference to PR_SPEC_L1D_FLUSH
>>
>>  Documentation/admin-guide/hw-vuln/l1d_flush.rst | 2 +-
>>  Documentation/userspace-api/spec_ctrl.rst       | 6 +++++-
>>  2 files changed, 6 insertions(+), 2 deletions(-)
>> ---
>> base-commit: 0292ef418ce08aad597fc0bba65b6dbb841808ba
>> change-id: 20251015-l1d-flush-doc-029f64d2b0d3
>>
>> Best regards,
>
> I just noticed another issue - the docs say you get -ENXIO if control
> isn't possible, but for L1D_FLUSH and INDIR_BRANCH you get -EPERM.
>
> TBH I think this is a bug but it seems like it's still better to just
> document it than change the behaviour.

Since I didn't have to respin this series I sent a separate one for this
issue:

https://lore.kernel.org/all/DDJU0415JEBQ.H2SD942NMDWX@google.com/T/#t