From: Erdem Aktas <erdemaktas@google.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Joerg Roedel <jroedel@suse.de>, Andi Kleen <ak@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Jon Grimm <jon.grimm@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
"Kaplan, David" <David.Kaplan@amd.com>,
Varad Gautam <varad.gautam@suse.com>,
Dario Faggioli <dfaggioli@suse.com>, x86 <x86@kernel.org>,
linux-mm@kvack.org, linux-coco@lists.linux.dev
Subject: Re: Runtime Memory Validation in Intel-TDX and AMD-SNP
Date: Mon, 26 Jul 2021 18:35:59 -0700 [thread overview]
Message-ID: <CAAYXXYyRKt88xJFFAqiN0xr3DHiBzxtSxDf7bLB9=FkZWwT95A@mail.gmail.com> (raw)
In-Reply-To: <20210726235417.fuxa5s32jta76lcv@box.shutemov.name>
On Mon, Jul 26, 2021 at 4:54 PM Kirill A. Shutemov <kirill@shutemov.name> wrote:
> >
> > Is not the above code will accept the pages that are already accepted?
>
> No. This code will get called for all UNACCEPTED ranges in EFI table.
> If such memory is accepted it is a bug.
>
> > It is accepting the pages in the same 2MB region that is before start
> > and after end. We do not know what code/data is stored on those pages,
> > right? This might cause security issues depending on what is stored on
> > those pages.
>
> As I told above, it only get called for unaccepted memory and nothing can
> be stored there before the point.
Thanks Kirill! You are right, it looks like I messed up with
round_up/down in my mind. Thanks for the clarification.
> Yes, because we constructed the bitmap this way. Non-2M-aligned chunks get
> accepted when we accept upfront when we populate the bitmap.
>
> See mark_unaccepted().
>
> (mark_unaccepted() has few bugs that will be fixed in the next version)
>
> Have you looked at what __accept_pages() does? It only accept unaccepted
> pages, according to the bitmap.
Ahh, makes sense!
Thanks for the explanation and sorry for my confusion, Kirill!
-Erdem
next prev parent reply other threads:[~2021-07-27 1:36 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 12:58 Runtime Memory Validation in Intel-TDX and AMD-SNP Joerg Roedel
2021-07-19 13:07 ` Matthew Wilcox
2021-07-19 15:02 ` Joerg Roedel
2021-07-19 20:39 ` Andi Kleen
2021-07-20 8:55 ` Joerg Roedel
2021-07-20 9:34 ` Dr. David Alan Gilbert
2021-07-20 11:50 ` Joerg Roedel
2021-07-20 0:26 ` Andy Lutomirski
2021-07-20 1:51 ` Erdem Aktas
2021-07-20 2:00 ` Erdem Aktas
2021-07-20 3:30 ` Andy Lutomirski
2021-07-20 19:54 ` Erdem Aktas
2021-07-20 22:01 ` Andi Kleen
2021-07-20 23:55 ` Erdem Aktas
2021-07-21 0:35 ` Andi Kleen
2021-07-21 8:51 ` Joerg Roedel
2021-07-20 5:17 ` Andi Kleen
2021-07-20 9:11 ` Joerg Roedel
2021-07-20 17:32 ` Andi Kleen
2021-07-20 23:09 ` Erdem Aktas
2021-07-21 0:38 ` Andi Kleen
2021-07-22 17:31 ` Marc Orr
2021-07-26 18:55 ` Joerg Roedel
2021-07-20 8:44 ` Joerg Roedel
2021-07-20 14:14 ` Dave Hansen
2021-07-20 17:30 ` Kirill A. Shutemov
2021-07-21 9:20 ` Mike Rapoport
2021-07-21 10:02 ` Kirill A. Shutemov
2021-07-21 10:22 ` Mike Rapoport
2021-07-21 10:53 ` Joerg Roedel
2021-07-21 9:25 ` Joerg Roedel
2021-07-21 10:25 ` Kirill A. Shutemov
2021-07-21 10:48 ` Joerg Roedel
2021-07-22 15:46 ` David Hildenbrand
2021-07-26 19:02 ` Joerg Roedel
2021-07-27 9:34 ` David Hildenbrand
2021-08-02 10:19 ` Joerg Roedel
2021-08-02 18:47 ` David Hildenbrand
2021-07-22 15:57 ` David Hildenbrand
2021-07-22 19:51 ` Kirill A. Shutemov
2021-07-23 15:23 ` Mike Rapoport
2021-07-23 16:29 ` Kirill A. Shutemov
2021-07-25 9:16 ` Mike Rapoport
2021-07-25 18:28 ` Kirill A. Shutemov
2021-07-26 10:00 ` Mike Rapoport
2021-07-26 11:53 ` Kirill A. Shutemov
2021-07-26 19:13 ` Joerg Roedel
2021-07-26 23:02 ` Erdem Aktas
2021-07-26 23:54 ` Kirill A. Shutemov
2021-07-27 1:35 ` Erdem Aktas [this message]
2021-07-23 11:04 ` Varad Gautam
2021-07-23 14:34 ` Kaplan, David
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