linux-kernel - Re: [PATCH v2 00/19] mm: Support huge pfnmaps

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACw3F53QfJ4anR0Fk=MHJv8ad_vcG-575DX=bp7mfPpzLgUxbQ@mail.gmail.com>
Date: Wed, 28 Aug 2024 09:10:34 -0700
From: Jiaqi Yan <jiaqiyan@...gle.com>
To: Jason Gunthorpe <jgg@...dia.com>
Cc: Peter Xu <peterx@...hat.com>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	Gavin Shan <gshan@...hat.com>, Catalin Marinas <catalin.marinas@....com>, x86@...nel.org, 
	Ingo Molnar <mingo@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	Paolo Bonzini <pbonzini@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>, 
	Thomas Gleixner <tglx@...utronix.de>, Alistair Popple <apopple@...dia.com>, kvm@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, Sean Christopherson <seanjc@...gle.com>, 
	Oscar Salvador <osalvador@...e.de>, Borislav Petkov <bp@...en8.de>, Zi Yan <ziy@...dia.com>, 
	Axel Rasmussen <axelrasmussen@...gle.com>, David Hildenbrand <david@...hat.com>, 
	Yan Zhao <yan.y.zhao@...el.com>, Will Deacon <will@...nel.org>, 
	Kefeng Wang <wangkefeng.wang@...wei.com>, Alex Williamson <alex.williamson@...hat.com>
Subject: Re: [PATCH v2 00/19] mm: Support huge pfnmaps

On Wed, Aug 28, 2024 at 7:24 AM Jason Gunthorpe <jgg@...dia.com> wrote:
>
> On Tue, Aug 27, 2024 at 05:42:21PM -0700, Jiaqi Yan wrote:
>
> > Instead of removing the whole pud, can driver or memory_failure do
> > something similar to non-struct-page-version of split_huge_page? So
> > driver doesn't need to re-fault good pages back?
>
> It would be far nicer if we didn't have to poke a hole in a 1G mapping
> just for memory failure reporting.

If I follow this, which of the following sounds better? 1. remove pud
and rely on the driver to re-fault PFNs that it knows are not poisoned
(what Peter suggested), or 2. keep the pud and allow access to both
good and bad PFNs.

Or provide some knob (configured by ?) so that kernel + driver can
switch between the two?

>
> Jason