linux-kernel - Re: [PATCH 05/12] x86/mm: add INVLPGB support code

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: <c9c7c983235a5aaaee111f8ad258a99c8e4b04ba.camel@surriel.com>
Date: Mon, 06 Jan 2025 12:32:38 -0500
From: Rik van Riel <riel@...riel.com>
To: Dave Hansen <dave.hansen@...el.com>, Borislav Petkov <bp@...en8.de>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, kernel-team@...a.com, 
	dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org, 
	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
 akpm@...ux-foundation.org, 	nadav.amit@...il.com,
 zhengqi.arch@...edance.com, linux-mm@...ck.org
Subject: Re: [PATCH 05/12] x86/mm: add INVLPGB support code

On Mon, 2025-01-06 at 08:50 -0800, Dave Hansen wrote:
> On 1/2/25 04:42, Borislav Petkov wrote:
> > > +#define INVLPGB_VA			BIT(0)
> > > +#define INVLPGB_PCID			BIT(1)
> > > +#define INVLPGB_ASID			BIT(2)
> > > +#define INVLPGB_INCLUDE_GLOBAL		BIT(3)
> > > +#define INVLPGB_FINAL_ONLY		BIT(4)
> > > +#define INVLPGB_INCLUDE_NESTED		BIT(5)
> > Please add only the defines which are actually being used. Ditto
> > for the
> > functions.
> 
> There's some precedent for defining them all up front, like we did
> for
> invpcid_flush_*().
> 
> For INVPCID, there are four variants and two of them got used up
> front.
> But I get that it's a balancing act between having untested code that
> might bitrot and introducing helpers at a time when someone (Rik) is
> very likely to get all the variants coded up correctly.
> 
> Rik, how many of these end up being used by the end of the series?
> 

Only invlpgb_flush_single_asid is unused at the
end of the series.

I'll remove that one.

As for the bit flags, those are a hardware
interface. I can remove the unused ones, but
would like to know why :)

-- 
All Rights Reversed.