lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Mon, 25 Feb 2019 09:51:18 -0700
From:   Keith Busch <>
To:     "Rafael J. Wysocki" <>
Cc:     Linux Kernel Mailing List <>,
        ACPI Devel Maling List <>,
        Linux Memory Management List <>,
        Linux API <>,
        Greg Kroah-Hartman <>,
        Dave Hansen <>,
        Dan Williams <>
Subject: Re: [PATCHv6 07/10] acpi/hmat: Register processor domain to its

On Sun, Feb 24, 2019 at 08:59:45PM +0100, Rafael J. Wysocki wrote:
> On Fri, Feb 22, 2019 at 7:48 PM Keith Busch <> wrote:
> > If I do it the other way around, that's going to make HMEM_REPORTING
> > complicated if a non-ACPI implementation wants to report HMEM
> > properties.
> But the mitigations that Dave was talking about get in the way, don't they?
> Say there is another Kconfig option,CACHE_MITIGATIONS, to enable them.
> Then you want ACPI_HMAT to be set when that it set and you also want
> ACPI_HMAT to be set when HMEM_REPORTING and ACPI_NUMA are both set.
> OTOH, you may not want HMEM_REPORTING to be set when CACHE_MITIGATIONS
> is set, but that causes ACPI_HMAT to be set and which means that
> ACPI_HMAT alone will not be sufficient to determine the

I can't think of when we'd want to suppress reporting these attributes
to user space, but I can split HMAT enabling so it doesn't depend on
HMEM_REPORTING just in case there really is an in-kernel user that
definitely does not want the same attributes exported.

> Now, if you prompt for HMEM_REPORTING and make it depend on ACPI_NUMA,
> then ACPI_HMAT can be selected by that (regardless of the
> And if someone wants to use HMEM_REPORTING without ACPI_NUMA, it can
> be made depend on whatever new option is there for that non-ACPI
> mechanism.
> There might be a problem if someone wanted to enable the alternative
> way of HMEM_REPORTING if ACPI_NUMA was set (in which case HMAT would
> have to be ignored even if it was present), but in that case there
> would need to be an explicit way to choose between HMAT and non-HMAT
> anyway.
> In any case, I prefer providers to be selected by consumers and not
> the other way around, in case there are multiple consumers for one
> provider.

Well, the HMEM_REPORTING fundamentally has no dependency on any of these
things and I've put some effort into making this part provider agnostic.
I will change it if this concern is gating acceptance, but I don't
think it's as intuitive for generic interfaces to be the selector for
implementation specific providers.

Powered by blists - more mailing lists