linux-kernel - Re: [PATCH v3 08/10] x86/mtrr: let cache_aps_delayed_init replace mtrr_aps_delayed

lists.openwall.net		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 linux-hardening linux-cve-announce 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]

Message-ID: <6d37c273-423c-fdce-c140-e5b90d723b9e@suse.com>
Date:   Wed, 28 Sep 2022 18:32:20 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     xen-devel@...ts.xenproject.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v3 08/10] x86/mtrr: let cache_aps_delayed_init replace
 mtrr_aps_delayed_init

On 28.09.22 18:12, Borislav Petkov wrote:
> On Wed, Sep 28, 2022 at 03:43:56PM +0200, Juergen Gross wrote:
>> Would you feel better with adding a new enum member CPUHP_AP_CACHECTRL_ONLINE?
>>
>> This would avoid a possible source of failure during resume in case no slot
>> for CPUHP_AP_ONLINE_DYN is found (quite improbable, but in theory possible).
> 
> Let's keep that in the bag for the time when we get to cross that bridge.
> 
>> You wouldn't want to do that there, as there are multiple places where
>> pm_sleep_enable_secondary_cpus() is being called.
> 
> We want all of them, I'd say. They're all some sort of suspend AFAICT.
> But yes, if we get to do it, that would need a proper audit.
> 
>> Additionally not all cases are coming in via
>> pm_sleep_enable_secondary_cpus(), as there is e.g. a call of
>> suspend_enable_secondary_cpus() from kernel_kexec(), which wants to
>> have the same handling.
> 
> Which means, more hairy.
> 
>> arch_thaw_secondary_cpus_begin() and arch_thaw_secondary_cpus_end() are
>> the functions to mark start and end of the special region where the
>> delayed MTRR setup should happen.
> 
> Yap, it seems like the best solution at the moment. Want me to do a
> proper patch and test it on real hw?

I can do that.


Juergen


Download attachment "OpenPGP_0xB0DE9DD628BF132F.asc" of type "application/pgp-keys" (3099 bytes)

Download attachment "OpenPGP_signature" of type "application/pgp-signature" (496 bytes)